phylo_roadking

I'm putting this here, although it's as mch about artillery as it is about tanks!

I'm chasing down information on the Close Support tanks in the british Army in WW2 - the couple of howitzer-armed tanks attached to squadron HQs to provide smoke and an occasional HE round for self-protection...

Up until certain later marks of the Churchill, and the Cromwell - various British tank types were occasionaly fitted with a low-velocity QF 3in howitzer in place of their 2-pdr tank guns.

Up until the middle of the war, these were primarily (supposed to be!) used for throwing smoke for the squadron they were attached to to manouver in...and their "ammo" load-outs reflected this, several dozen smoke rounds vs. a couple of H.E. rounds for self-protection if an antitank gun came a'knocking!

Now - in 1939-1940 a low velocity 3in howitzer replaced the old Vickers 3.7in howitzer that had been used in some Vickers' designed tank types until then, specifically the just-prewar Cruiser A9s and A10s...and the Matilda MkII C.S., Tetrarch C.S., Churchill MkI and II C.S. Crusader C.S. and Covenanter C.S. all mounted the new 3in weapon.

The Churchill MKI "gun" tank ALSO mounted it in their hull front glacis for infantry support...

And in THIS application mounted the No.30 tank gun Sighting Telescope....the same crosshair telescope sight as the 2-pdr high velocity gun!

In fact - its muzzle velocity was four times higher than the 3in howitzer!

I also have learned that the standard "gun tank" Matildas, Covenanters, Tetrarchs and Crusaders all used the No.30 Sight for their 2-pdrs...what I'm trying to find out is did they use the SAME No.30 sight for their C.S. howitzer-armed versions???

The 3in howitzer in the C.S. tanks has a pathetic anecdotal reputation for accuracy; apart from the low muzzle velocity and short range...just over 2,000 yards...I've recently begun to wonder if that reputation was "helped" by trying to use the same sight for a low-velocity "lobbing" arcing-trajectory howitzer as a direct-fire, high-velocity, flatter trajectory tank gun??? :shocked:

Can anyone help fill in the blanks???

Hi Richard - THIS is particularly intersting...

Firstly from the Workshop Manual for the K5, and to quote " piston skirt fitting has been increased from .0025"-.0028" to .004"-.0045" to make engines with new pistons immediately suitable for wading through water without fear of siezure. Pistons with the original smaller clearance can be used for engines which it is known will not be called on for wading".

 

OK, I first interpreted that as only those vehicles with waterproof servos having the increased clearance as they might have been the one specially set aside for wading. There is a contract of K5's which just have the word "Water" after the vehicle type, I am certain these were not water tankers and can only think that these were the ones prepared as above. There appears to be 500 lorries in that contract. Reading the manual again and it is dated 1946, so after the event, and after final production so it might indicate if vehicles were being prepared for water, then this is the data.

Does that mean there was a contract of 500 with the increased-clearance pistons in them straight of the production line...in addition to the 1,400 that were modified for wading with the new pistons in May '44?

Just to confuse things further, I have a document, Inspection Standards (Provisional) for the Austin K6 6x4, issued by REME Central Inspectorate. Handwritten on the cover are the words "Comments by 26 Feb 1955". In there is some interesting wordings and bear in mind this is 10 years later;

"Pistons must be selectively fitted to obtain clearance. Feeler gauge applied to thrust side of the piston skirt, tight .0045" and loose .004" will suffice for practical purposes. When assembled and on test, piston slap will be apparent and is permissible"

 

The clearances mention are the increased ones stated for wading, so maybe they set all the 4 litres up this way, in case of the eventuality. Further on in the engine testing data there is a another mention;

"NOTE: Due to increased piston to bore clearance piston slap will be apparent and is permissible."

Looks like the new pistons in Wellworthy's proprietary cast iron alloy grades provided a longterm cure then! Piston slap, yes...but no accelerated wear

I think you are confusing yourself here, and I should point out that referring to engine spec changes in 2 ton ambulances or trucks only muddies the water. They had the 3.5 litre engine, bore sizes different, no link, never heard of them being built for wading.

Richard, here's what I mean; Tom has since been back to the "big" D.M.E. file and found THIS regarding the pre D-Day issue...

....13th Meeting of DME W/P Committee for 5 May 1944 which I found in WO229/76/0/1:

 

3. Austin 3 ton 4 x 4 and 3 ton 6 x 4

DME made a statement with reference to the re-working of the engines of these vehicles which had failed owing to engine trouble due to inadequate piston clearance, on large-scale trials at No.1 M.T.C. WEYMOUTH.

Austin Motor Company is re-working all engines required for vehicles for Assault Force, and the vehicles should be completed by 17 May 1944...

Reserve vehicles of these types are not having their engines re-worked as the defect is only experienced when wading.

Now - that WOULD indeed make it look as of only one set of vehicles, those for the assault companies, were intended to be waterproofed for wading...to wade...and need the increased-clearance pistons, as you say...

...but some time AFTER that something at Austins seem to have changed...

A representative of D.M.E. attended a meeting between T.T.2, C.I.E.M.E. and the Manufacturers on 8.11.44. The manufacturers offered new and completely interchangeable piston rings, both for new production and re-working of "frozen" stocks of new vehicles. Tapered Compression rings (2 off) in D.T.D. 485. Scraper rings (1 off) in D.T.D.233. Tests on three vehicles fitted with these rings show satisfactory oil consumption and a steadily rising m.p.g. at 2,500 miles. It was agreed that in view of the satisfactory preliminary results and complete interchangability of rings, the new rings could be introduced into production as soon as supplies are available. It was also agreed that if the test results continued to be satisfactory after 5,000 miles re-working of the "frozen" bank of vehicles with the new rings might commence.

According to the War Office D.M.E. progress report for period ending 3.12.44, "new and interchangeable piston rings of improved material and design should be incorporated into production now, and fitted to the 3,000 vehicles at present frozen in V.R.Ds".

...the engines of 4x2 vehicles first fitted with the modified compression and scraper rings, part numbers 1K1420 and 1K1421 respectively, are as follows:-

 

2-Ton W.D. Ambulances, engine no. 75090, during Contract S.3165

2-Ton (4x2) R.A.F. vehicles, engine no. 71804, during Contract S.6566

...and the NEW Wellworthy rings in DTD 485 and DTD 233 were going to be out into NEW 6-clyinder engines on Austin vehicles on the production line.

So do we read that as Austins fitting the new-spec rings (or the War Office WANTING them to!) to vehicles that weren't intended for wading and didn't have the New "May" spec increased-clearance piston...and didn't need them..."are not having their engines re-workedas the defect is only experienced when wading"...and had been running happily on HD30 for some two years...

OR...

In the interim....SINCE May and the resolution of that earlier problem... had Austins at some point settled on a single piston specification - the increased-clearance one...for ALL their K5/K6 engines?

I hope that explains better what I'm trying to find out

Hi Richard...

and no where can I see that some of these K5 were partly prepared for wading on production.

No, what I meant is that from the comment from December...

According to the War Office D.M.E. progress report for period ending 3.12.44, "new and interchangeable piston rings of improved material and design should be incorporated into production now, and fitted to the 3,000 vehicles at present frozen in V.R.Ds".

....and...

Further to the article appearing on page 98, Volume 8, of this Journal, the engines of 4x2 vehicles first fitted with the modified compression and scraper rings, part numbers 1K1420 and 1K1421 respectively, are as follows:-

 

2-Ton W.D. Ambulances, engine no. 75090, during Contract S.3165

2-Ton (4x2) R.A.F. vehicles, engine no. 71804, during Contract S.6566

...do those mean that from May on Austins were using the increased-clearance pistons for ALL K5 production??? Even vehicles that would never see any wading? If they didn't have the increased-clearance piston, they wouldn't need the new rings - the OLD spec K5 engines had been fine for several years! :-) Until the seizure-on-wading problem had materialised...

EDIT: Just had a minor Eureka! moment :-D

Surely we should be able to tell this from the manuals??? There should be one single part number for pistons for both GS K5s....and all K5 variants...from May 1944 on??? And this should be different from the piston part number from BEFORE May 1944 :-)

Hi Richard - that certainly makes sense!

Are you aware of anywhere where this particular aspect of the problem was recorded? Or possibly - when K5s were first waterproofed for training prior to D-Day?

All - between myself, Tom O'Brien and a number of members at HMVF, we've managed to produce a VERY good timeline for the legendary problems the Austin K5 "Screamer" 4x4 suffered in 21st Army Group hands beginning in September 1944...until its resolution with new-specification piston rings in December.

The BRIEF version is that the famous problems the K5 came to suffer....very accelerated piston ring wear, leading to burnt and contaminated oil; very worn valve guides and bent/damaged valves, and heavy carbon/burnt oil desposits in the combustion chamber...ALL arose from a combination of the following;

1/ a new piston fitted to the K5s prepared for "wading" in May '44; these had increased clearance for the piston skirt because (possibly) of an earlier overheating issue - which led to the pistons "rocking" and the rings wearing far too fast - in turn because...

2/ Austins used old-spec rectangular-edged piston rings on these new pistons, and they gave marginal sealing; certainly not enough to prevent accelerated wear and oil contamination, or cope with the pistons rocking;

3/ There was very fast valve guide wear, leading to BOTH oil in the combustion chamber and badly damaged valves - both because of the contaminted, heavily graphited oil AND because of local overheating - the latter possibly because of...

4/ The changeover to 80 octane "MT 80 Pool" iin service just before D-Day....which was KNOWN to cause local overheating and hotspots in some older engines, particularly ones designed to run on a lower octane rating fuel - and finally...

5/ that new, increased-clearance piston fitted in May? It very possibly led to problems with the new, low viscosity "HD30" high-detergent oil grade that had come into common use , along with other HD grades, in late 1942; this oil had prviously given no problems - but the new pistons and fast wearing rings meant that the oil film wasn't being scraped off the cylinder walls properly - leading to oil drag, increased wear in turn AND burnt oil due ti blow-by on the worn rings.

The whole problem - after various attempts to find other cures - was put right at the start of December by the fitment of a new specification of piston ring that would fit in the existing, increased-clearance pistons; these rings, in a much harder grade of cast iron alloy that was a patented product of Wellworthy's, the piston ring specialists....had a tapered edge for better support of the "rocking" piston and of course wouldn't wear anything like as fast. Both the compression rings AND the oil scraper ring was revised - and because of the taper they were "one-sided" they could only be fitted one way up - and THAT side was marked...."HD30"!!!

And thus the famous problem was resolved - or at least the Director of Mechanical Engineering at the War Office thought so! Obviously...any overheating due to the MT 80 could be coped with once all the piston ring wear and dirty/burnt oil issues were removed from the equation.

BUT HERE'S THE PROBLEM...

In May, 1,400 K5s were "recalled" and fitted with those new pistons at Austins; these lorries had ALREADY been waterproofed and issued to assault companies....and REME had to waterproof them AGAIN! So this particular activity - the fitting of the new pistons LESS THAN A MONTH BEFORE OVERLORD - must have been a rapid reaction to some OTHER problem!!!

And given that it was "solved" by increasing the piston skirt clearance to allow for more thermal expansion - this problem must ALSO have been something to do with overheating...

So my question is very simple - is anyone aware of, or ever heard of, problems with the Austin K5 4x4 BEFORE D-Day?

....THIS;

This vehicle had been fitted with new standard pistons and rings. It was also fitted with two re-built exhaust valves, one modified Bedford exhaust valve and three re-faced standard Austin exhaust valves.

 

The vehicle was driven over normal roads, including two fairly steep gradients. For the first 300 miles the performance was good. The first sign of roughness occurred at 350 miles and this grew steadily worse until, at 480 miles, two cylinders began to miss badly. At the conclusion of the run, reasonable compression could be felt on all six cylinders.

 

Engine oil pressure was 48 lbs per sq. in. at 30 m.p.h. with an engine temperature of 160° F at the commencement of the test. This dropped to 40 lbs per sq. in. at the same temperature and speed after 150 miles and then remained consistently at this figure throughout the remainder of the test.

 

On completion of the test the cylinder head was removed for examination. It was at once apparent that heavy oil burning had been taking place. The combustion chambers of Nos 3 and 4 cylinders had a heavy deposit of carbonised oil and the sparking plugs were heavily oiled. There was an appreciable hard carbon deposit on all other cylinders.

 

All inlet valves were in good condition but the exhaust valve heads were distorted in all cases, and there were signs of pitting. One of the built-up valves was showing definite signs of leakage. There was excessive oil present on the guides of Nos. 3 and 4 valves.

...this reads to be a test of a number of possible workrounds that REME in Normandy came up with to deal with the valve/top end aspects of the issue.

But it was a failure :-( It looks as if none of the kludges held up to the rigours of the test...and they had tested them in the face of the worst deeds of the culprit -"this vehicle had been fitted with new standard pistons and rings". And the piston/ring problem beat the best efforts of REME with what they had at their disposal in Normandy.

So...the affected vehicles REMAINED "at present frozen in V.R.Ds" until the end of the testing period on "..3.12.44..." - when "new and interchangeable piston rings of improved material and design should be incorporated into production now, and fitted to the 3,000 vehicles at present frozen in V.R.Ds".

The "test period" itself had lasted from some time before the 8th of November 1944...

A representative of D.M.E. attended a meeting between T.T.2, C.I.E.M.E. and the Manufacturers

on 8.11.44

. The manufacturers offered new and completely intercahngeable piston rings, both for new production and re-working of "frozen" stocks of new vehicles. Tapered Compression rings (2 off) in D.T.D. 485. Scraper rings (1 off) in D.T.D.233. Tests

on three vehicles fitted with these rings show satisfactory oil consumption and a steadily rising m.p.g. at 2,500 miles.

It was agreed that in view of the satisfactory preliminary results and complete interchangability of rings, the new rings could be introduced into production as soon as supplies are available.

It was also agreed that if the test results continued to be satisfactory after 5,000 miles re-working of the "frozen" bank of vehicles with the new rings might commence

.

....to the 3rd of December 1944.

And THAT was the official end of the Austin K5 problem in Normandy, as far as the Director of Mechanical Engineering at the War Office was concerned. Having found a cure that involved "new and interchangeable piston rings of improved material and design".

Less blowby to contaminate the HD30 oil...which could therefore carry on being used; as could the "standard" (standard that is for the "assault" K5s) increased clearance "wading" pistons. No contaminated, heavily-graphited "dirty" oil circulating around the engine creating high wear rates in the top end. No coking up of the valves or the combustion chamber, no oiled-up plugs.

And just to square the circle on the above - I doubt there is much coincidence to the fact that there were 1,400 Austin K5s in "wading" kit provided for issue before the start of June '44 to assault GT companies for D-Day according to other details that Tom found....and 1,400 Austin K5s in Normandy affected by problems of faulty parts and accelerated wear three months later; some with as little as 2,000 miles on "new" engines.

It's also worth noting that Tom had also discovered and recorded on the lorry thread on ww2talk that 1,400 K5s were pulled and prepared for issue to the assault companies in May '44...by Austins themselves...I wonder if THIS was when the increased-clearance "wading" pistons were fitted???

Finally - the issue of the change to MT 80. We know from various locations and histories that this change on the eve of OVERLORD did cause problems for many british vehicle manufacturers...and that litany of valve problems on the REME "test" K5 does mention two symptoms of overheating/poor cooling of the valves - the pitting of the valve faces and the "definite signs of leakage" I.E. the valves not sealing on their seats. It's a bit "chicken and egg" whether the SECOND of these would be down to the valves burning OR the valves rocking around due to the guide wear ....but pitting on the valve faces would be a sign of overheating/poor cooling all right...

One of the British Army veterans on ww2talk confirmed that the Austin manual for these engines (in 1946 at least!) DID contain instructions for advancing for retarding the ignition timing to match the fuel used...so as a problem this one was easily dealt with. But it IS interesting that Austins (and I presume the War Office!) thought it essential to fit "wading" pistons with increased piston skirt clearance to deal with extra thermal expansion A MONTH before D-Day! THAT is definitely "last minute" stuff!!!

So - one set of problems brought on/complemented the other??? Need for increased piston skirt clearance due to overheating in waterproofed engines -> fast bore/ring wear 'cos the new pistons used the old design/grade of rings -> high oil consumption AND carbon blowback contaminating engine oil -> worn valve guides...which are ALSO going to be hit by overheating issues anyway because of the MT 80...

It's worth noting that from everything I've read, and comments from several members on ww2talk - that while altering the timing on internal combustion engines to prevent pre-detonation etc. with higher-octane fuels is one action that's necessary...it doesn't ACTUALLY make the engine run any cooler! THAT is a problem that an engine still has to cope with....or in the case of the K5, exhibit overheating valve issues as well as worn valve guide issues.

However, looking at that final closure of the book on the K5 problem as of 3/12/44 by the War Office - I think we have to assume that the overheating issues brought on by MT80 were "officially" thought to be by far the lesser issue involved compared to the damage done by the fast-wearing piston/rings issue. Once THAT was addressed, the K5s could handle a little overheating...???

Courtesy of Richard Farrant on HMVF

Piston skirt clearance was increased from .0025" - .0028" to .004" - .0045" to make engines with new pistons immediately suitable for wading through water without fear of seizure. Pistons with original smaller clearance can be used for engines of vehicles which it is known will not be called upon for wading.

It's not the oil scraper/oil control ring that REMOVES oil from the cylinder walls as a piston goes up and down; it's the edge of the piston skirt. The "oil control ring" makes sure a certain metered amount REMAINS on the bore!

The clearance between the piston skirt and the cylinder wall was increased I.E. it was a sloppier fit from the factory - to allow for overheating and a greater expansion of working parts due to the "wading" regime on the K5's engines making them run hotter than normal

In layman's terms - they arrived NEW from the factory with a what we would interpret/regard as a degree of wear already present! Within a short time, the increased "sealing" load put upon the "standard" rings would result in premature wear...and increasing carbon "blow-by"...contaminating/absorbed by the high-detergent oil, leading to the high wear rate on the valve guides...in turn leading to oil in the combustion mixture and in turn the combustion chamber I.E. "the heavy deposit of carbonised oil and the sparking plugs were heavily oiled".

Richard Farrant had one more thing to note up this thread that applies to this scenario... the -

...modified compression and scraper rings which exerted greater pressure on the cylinder walls, these were actually marked HD30 and had to be fitted the correct way up.

Well, first of all -

Engine oil consumed 12 pints= 335 m.p.g.

...forgive me for wondering if the K5's 3,990 cc motor was actually a two-stroke!

It was also fitted with two re-built exhaust valves, one modified Bedford exhaust valve and three re-faced standard Austin exhaust valves.

On completion of the test the cylinder head was removed for examination. It was at once apparent that heavy oil burning had been taking place. The combustion chambers of Nos 3 and 4 cylinders had a heavy deposit of carbonised oil and the sparking plugs were heavily oiled. There was an appreciable hard carbon deposit on all other cylinders.

 

All inlet valves were in good condition but the exhaust valve heads were distorted in all cases, and there were signs of pitting. One of the built-up valves was showing definite signs of leakage.

It was at once apparent that heavy oil burning had been taking place. The combustion chambers of Nos 3 and 4 cylinders had a heavy deposit of carbonised oil and the sparking plugs were heavily oiled. There was an appreciable hard carbon deposit on all other cylinders.

All inlet valves were in good condition but the exhaust valve heads were distorted in all cases, and there were signs of pitting. One of the built-up valves was showing definite signs of leakage. There was excessive oil present on the guides of Nos. 3 and 4 valves.

This vehicle had been fitted with new standard pistons and rings

"RINGS. Two compression, one oil control, all above gudgeon pin. Ring gap ·008/·012-in. Groove widths: Compression ·1265/·1270-in. Oil Control ·1577/·1582-ins. Groove clearance, ·002-in. to ·0025-in."

Lorry, 3-ton, 4x4, and 6x4, Austin - Excessive oil consumption.

A representative of D.M.E. attended a meeting between T.T.2, C.I.E.M.E. and the Manufacturers on 8.11.44. The manufacturers offered new and completely interchangeable piston rings, both for new production and re-working of "frozen" stocks of new vehicles. Tapered Compression rings (2 off) in D.T.D. 485. Scraper rings (1 off) in D.T.D.233. Tests on three vehicles fitted with these rings show satisfactory oil consumption and a steadily rising m.p.g. at 2,500 miles. It was agreed that in view of the satisfactory preliminary results and complete interchangability of rings, the new rings could be introduced into production as soon as supplies are available. It was also agreed that if the test results continued to be satisfactory after 5,000 miles re-working of the "frozen" bank of vehicles with the new rings might commence. The tests will thereafter continue up to 8,000 - 10,000 miles."

AND...

According to the War Office D.M.E. progress report for period ending 3.12.44, "new and interchangeable

piston rings of

improved material a

nd design

should be incorporated into production now, and fitted to the 3,000 vehicles at present frozen in V.R.Ds".

Further to the article appearing on page 98, Volume 8, of this Journal, the engines of 4x2 vehicles first

fitted with the modified compression and scraper rings

, part numbers 1K1420 and 1K1421 respectively, are as follows:-

 

2-Ton W.D. Ambulances, engine no. 75090, during Contract S.3165

2-Ton (4x2) R.A.F. vehicles, engine no. 71804, during Contract S.6566

Guys - I might just have come up with the answer! And it turns out ot be courtesy of Some of Tom O'Brien's earlier hunting trips to Kew...

Early in the history of the AHF thread where he and I did the bulk of our digging, he noted that he had come across a REME workshop report from September 1944 detailing some tentative mods done to a K5, and that lorry being tested....and failing. At the time i didn't think to query that....but two nights ago I got him to post up the DETAILS of the test and what REME found after the test concluded...and when put together with some OTHER stuff Tom has found over the years, and some of the stuff contributed to this thread by various members here - put together in the right time order! - I believe I've got an answer, and very possibly THE answer!

First of all - here's the core of the REME test report -

APPENDIX ‘A’

 

PERFORMANCE REPORT ON AUSTIN 3-TON 4 X 4 W.D. No. L/5192471

 

Odometer reading at commencement of test 6082

Odometer reading at completion of test 6585

 

Mileage covered 503

Petrol consumed 68 gallons

= 7.3 m.p.g

 

Engine oil consumed 12 pints

= 335 m.p.g.

 

Oil consumed in other assemblies Negligible

 

Load during test 3 tons.

 

This vehicle had been fitted with new standard pistons and rings. It was also fitted with two re-built exhaust valves, one modified Bedford exhaust valve and three re-faced standard Austin exhaust valves.

 

The vehicle was driven over normal roads, including two fairly steep gradients. For the first 300 miles the performance was good. The first sign of roughness occurred at 350 miles and this grew steadily worse until, at 480 miles, two cylinders began to miss badly. At the conclusion of the run, reasonable compression could be felt on all six cylinders.

 

Engine oil pressure was 48 lbs per sq. in. at 30 m.p.h. with an engine temperature of 160° F at the commencement of the test. This dropped to 40 lbs per sq. in. at the same temperature and speed after 150 miles and then remained consistently at this figure throughout the remainder of the test.

 

On completion of the test the cylinder head was removed for examination. It was at once apparent that heavy oil burning had been taking place. The combustion chambers of Nos 3 and 4 cylinders had a heavy deposit of carbonised oil and the sparking plugs were heavily oiled. There was an appreciable hard carbon deposit on all other cylinders.

 

All inlet valves were in good condition but the exhaust valve heads were distorted in all cases, and there were signs of pitting. One of the built-up valves was showing definite signs of leakage. There was excessive oil present on the guides of Nos. 3 and 4 valves.

 

...and here's what I THEN posted up on AHF...

Wally, thanks for that! I'll pass it on to Tom O'Brien for his next hunting expedition!

we did notice that several files are missing we also think we know what may have happened to them

 

Recoverable???

In the meantime - I can move the oil issue along a bit! I've been shown a couple of pages from the REME Official History...and -

There WAS a formal agreement...the Paul-Pryon Agreement - in October 1942 by which the British would move over to U.S.-equivalent "HD" detergent oils! Up to them the British were indeed using a range of straight mineral oils in the "M." series.

A temporary "changeover" regime was put in place to handle the switchover period...and although it was indeed feared that the "flushing" effect of the HD oils in pre-used engines WOULD cause carbon deposits to break away and circulate round the said engines....there was no sign of it happening in practice...

BUT as we now know - Austins did experience problems with their existing piston ring specifications when used with new HD oils Certainly with their car engines post-war...and from the revised-spec piston rings in the Ks being specifically stamped "HD 30" I would guess during the war too.

Hi Wally, did you you have any luck turning up anything more?

Richard, thanks for that.

Piston skirt clearance was increased from .0025" - .0028" to .004" - .0045" to make engines with new pistons immediately suitable for wading through water without fear of seizure. Pistons with original smaller clearance can be used for engines of vehicles which it is known will not be called upon for wading.

 

I would guess that vehicles built for wading with greater piston clearance could have been the ones causing the problems, this may have caused panic at the time and all K5's were considered a problem as it may not have been known how to identify which engines were wading types.

There may still have been a problem with the "wading" types issued to the GT companies for D-Day despite those changes...because from what Tom O'Brien has found they were replaced quite sharpish in the GT companies

"this may have caused panic at the time and all K5's were considered a problem as it may not have been known how to identify which engines were wading types"

I wonder if this could have been mistaken for premature wear??? OR...could wear on top of the increased clearances have led to problems faster than comparable "B" vehicles?

But THIS is real bingo...!

Also there were modified compression and scraper rings which exerted greater pressure on the cylinder walls, these were actually marked HD30 and had to be fitted the correct way up.

Do you know if the new rings were specified to match the HD 30 oil specification???

(Or were the "high pressure" rings used in the "wading" engines with the looser clearances???)

Thanks for that; I knew they held the AFV records, but didn't know they had the softskin record cards too.

Why did it affect the K5 in particular? If the K2/3 and K6 had the same engine why weren't they affected in the same way?

Tht's one of the major planks in the whole debate! Why not...

...and incidently, why didn't it afect the early-production 1943 GS K5s???

But until we get a definitive something on the actual nature of the fault(s)....TWO problems are recorded "thinly" in the 21st AG Admin History...what we're doing now is exploring around the edges of the "problem" with what little there IS available to date.

One thing I'm thinking of now, after seeing something on a forum a while back http://www.network54.com/Forum/433829/thread/1356133544/last-1357131564/Some+interesting+Austin+K5+info+and+a+question

...is that it MIGHT be down to one specific batch of K5s...!

I don't suppose anyone here can put issue dates to those WD number ranges???

Hi Wally, thanks for what you've done so far.

By the way - what was the name of the committee???

That doesn't advance things too much other than to confirm there was a design change.

More than you might think! One of the things we DID turn up many months ago now was that Austins were working with a third-party piston ring specialist company in the last months of 1944 We couldn't find any confirmation that it was specifically to do with the K5, but at the time we regarded it as an amazing coincidence!

NOW we can see that something concrete may just have come out of that liaison with respect to the K5!

Well, here's the thing...

Hmm...Did Austin blame the Yanks for the oil and the Septics got their own back by re-writing history (that's a new one !)...and put it about that Austin were single-handedly responsible for the logistics failure associated with Market-Garden ? What was the U.S. Department of Dirty Tricks called in those days ?

...that's EXACTLY what Tom O'Brien's research is showing up! That Chester Wilmot's "major issue" attributed to the Austin K5 just isn't there!

Why??? Well...

I suspect that the poor old K5 was being thrashed mercilessly to keep up with Ford V8s and Bedford / GM sixes and the 4x4 version simply couldn't take when fully loaded.

 

 

...despite what the Americans said - they didn't get back INTO service in August and September TO be thrashed! The "wear" issue and "defect" issue was discovered when they were being checked through prior to being added to the pool of L of C trucks!

It's clear from the 21st AG Admin History that not only was there ENOUGH lorries in the Reserve - HUNDREDS more "B" vehicles were being landed in Normandy each week! There were enough that several OTHER large batches of "reserve" vehicles could be allocated to other uses temporarily. Yes, the Americans DID on one occasion loan us lorries for a time, but that was later in Sptember IIRC, when the bugbear of too little maintenance on the Lof C HAD eventually raised its head - which was weeks after the K5 problem was discovered!

From Tom's research it increasingly seems like the Yanks heard about the K5 issue and fastened on it...as an excuse? Because they didn't have visibility of the other lack-of-maintenance issues by then? Who knows...now

But one thing is clear from the Admin History - the failed 1,400 K5s weren't actually ever IN use in the L of C to prejudice any performance!

Hi Bryan - indeed I can't help noticing...

As i said above (but in summary form this time ) i am also using info for the K6, which according to the manuals had the same engine, as well as the K2/3

In the August 42 Drivers Handbook it gives no detail of the oil to be used...

...In the October 43 Drivers Handbook, and later editions of the same, it specifies 30HD oil

The Maintenance Manuals from January 44 onwards state 30HD oil

All of these manuals were printed by Austin, so they must have known from at least 1943 that there was a change in the oil type being used.

In fact even up to 1945 they were giving the exact same engine details including those given by NickAbbot above:

...the split - and possible changeover

Like a lot of the "K5" problem, this aspect is at the minute being shaped by what we DON'T see! :-D

79x100...

If the quality of the oil was declining, it may well be that the problems would also have arisen with the earlier 'M' series oils

...although I would have thought that if any problems were ever going to have arisen with the "M"series oils - it would have been 1940-42 in the Desert???

IIRC there was an American "MIL" oil grade directly equivalent to HD 30; I wonder if the specification change was after the Americans began arriving in the UK in numbers, together with their vehicles...? To simplify the supply requirements in the field...

..but that's very much an aside to the K5 issue.

However, it's quite possible that they did test it at the time and found no problems but that there was a lowering of standards or a lack of quality control due to the large number of suppliers and that the problems were caused by this.

But of course that would depend on the nature and duration of the tests...there were some VERY strange testing shortcuts made during the war! Avro Lancaster prototype testing comes to mind...!

Thanks Wally!

The K5 might take some finding, it might be submerged among OTHER 1944 engine failures though Looking at the 21st Army Group Admin History...the L of C "B" vehicles generally had a very hard time hauling stores forward hundreds of miles from Normandy! And of course - as the Admin History notes...all the L of C trucks suffered from not enough maintenance because of all the road time they were racking up!

you maybe lucky the file of papers my well be in my loft the file is to my memory about 3 inches thick and A4 it came from CHERTSY OR CHRISTCHURCH ALONG WITH OTHER FILES it would take time to find but if you can wait...

Certainly! A resolution to this is worth waiting for! :-D

Hi Wally...

over many years I recall getting letters on this subject from members of the public and talked to Bart VANDERVEEN on this very same matter we did find in the papers of a commitee formed by the war DEPARTMENT who where discussing the new range of engines to be fitted to the military fleet of vehicles this went on to be the B range of engines there was referance to engine failures towards the end of world war 2

This is EXACTLY what Tom O'Brien is looking for! 'Cos there's no other sign of the problem showing up yet!

Can you by any chance remember the name of the said committee??? (I take it it's too many years gone to remember the file number!)

{This illustrates an "advantage" of t'Internet - years ago, information found might circulate for a while "in the fraternity"...but unless it found its way into print it was often forgotten again or lost for good. For all its faults, the Net at least "freezes in amber" a lot of material that would otherwise be lost again...}