question The "Austin K5" problem...a new direction....

[phylo_roadking]

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

 

 

Recoverable???

[wally dugan]

HI

 

l have just been to a reunion with my old boss and l told him about the missing files he has given me abox of files

and i have come across one of the missing files its part one of two files in this file it tell us who attened the meeting

about a range of post war engines

the chairman SIR GEOFFREY BURTON MINISTRY OF SUPPLY

SIR CHARLES BARLETT VAUXHAULL MOTORS

[wally dugan]

SORRY THING POSTED before l finished the list

 

SIR MILES THOMAS NUFFIELD GROUP

MR R ROOTES OF ROOTES GROUP

MR T SKIPPER OF DENNIS MOTORS LTD

 

MR A A LAIRDET OF LEYLAND MOTORS LTD

 

 

no one from AUSTIN l know other manufactures where not present date of meeting 14/12/1945 file number GS[W] 2291

 

PART ONE OF TWO

 

 

REGARDS WALLY

[phylo_roadking]

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

[phylo_roadking]

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...

[phylo_roadking]

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.

 

Obviously they wanted to check the efficacy of various possible repalcement strategies depending on the results of the test;

it's a pity they didn't specify WHAT cylinders

each type

was fitted to

....

 

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.

 

HOWEVER - what I'm seeing here, now....I should have asked before, right at the start of the thread when you first found this, Tom...is signs of

ALL THREE

of the problems we've been discussing!

 

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.

 

Unfortunately, the one thing I HOPED to see from the account was missing - quite literally

the colour

of the smoke the engine was undoubltedly puffing out by then! Blue smoke= valves and guides, white smoke = rings! As sadly THAT section doesn't specify

where

the oil was coming from...above or below!

 

But THIS is the most interesting section...

 

 

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 -

bu

t 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

- is valves burning. That looks like the octane rating vs. ignition timing issue rearing its head...

 

THIS -

T

here was excessive oil present on the guides of Nos. 3 and 4 valves

-

is a high wear issue I.E. the engine oil was dirty/carbonised/graphited up...I.E. the

high-detergent

oil was carrying

blow-by on the rings

around the engine, causing wear at the valve guides.

 

There's

the smoking gun all right - but it's more like "

Murder On The Orient Express

", there are signs of several culprits

ALL working hand-in hand

 

Now...

 

There's one more VERY interesting sentence in that report

It's

THIS

...

 

This vehicle had been fitted with new standard pistons and rings

 

The 1,400 "wading" Austin K5s didn't have "standard" pistons and rings fitted! To be exact - it had rings of THIS specification...

 

"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."

 

...and that was the same spec in 1943 as in 1945! So

those

details didn't change...

 

But I know from Tom's work early in the thread - at the very least the

material used

did!

 

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".

 

...it ALSO looks like the "design" of the rings themselves changed

- not only have we that comment from above..."

new and interchangeable piston rings of improved material

and design

should be incorporated into production now

"...but we have THIS from the HMVF thread -

 

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

 

...from - the "

Austin Service Journal - War Department Issue

" !!!

 

So - THIS

"

Ring gap ·008/·012-in. Groove widths: Compression ·1265/·1270-in. Oil Control ·1577/·1582-ins. Groove clearance, ·002-in. to ·0025-in

" remained the same, but

other

design aspects of the rings themselves were changed as well as the material they were made from.

 

***But what was it about the "wading" K5's engines that

MADE

these changes necessary to stop carbon "blowby" past the rings heavily contaminating the HD30 oil, that in turn was being circulated around the engine and causing the high wear visible on the valve guides???***

 

 

 

[phylo_roadking]

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.

 

So...the new rings sealed better (due to the extra pressure - I'm guessing the change in material was to make the increased-pressure rings

last longer

...)...

AND were specifically designed to cope with HD30 oil and its effects/attributes

. And it's these modified rings -

particularly I would assume the oil control ring?

- that had to be fitted the correct way up as indicated by the "HD30" mark.

 

That must therefore have been one of the "design" changes to the modified rings -

whatever

was changed about their design, they became "single faced", only useable/fitable one way round.

 

And finally...

 

[phylo_roadking]

....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...???

Edited November 17, 2013 by phylo_roadking