HELP CCKW Engine knocking

[deadline]

I'm still going with valve guides.

 

There are some TB's that were released in 43 regarding the crankshaft hitting part of the lower engine casting. If your bearings are worn you might have been hitting that. I can look up the specifics.

 

But I still say valve guides.

[R Cubed]

bit of an update to this thread, had a couple of hours free today and made a start to rule out the noises on my engine.

 

started by disconnecting the vacuum line to the hydrovac to rule out air leaks on that, also the vacuum line to wipers, no change on either.

then dropped off the fan belt to rule out the alternator and water pump, no change on that either.

 

The first is a squeak this now seems to be a wheezing sound and it looks as though it's a vacuum leak on the far ends of inlet manifold ports to the cylinder head joints !!!

 

The second noise which is a knock this now sounds like an exhaust blow as it is much louder on the manifold side than the other side of the engine, the two could be connected as the exhaust manifold is very close to being beyond any use and the fact that the lnlet is bolted to it might mean I need to change both !!!!!!!!!

[Degsy]

Hi Richard, From past experience with my 352 I think you could well be on the right lines Richard, I went through 2 exhaust manifolds before I found a brand new British made one still in its original wooden case which dated from the 1950's but was much more strongly made than the original and was webbed for extra strength. It took me a while to realize why it could be Brit made until it dawned on me that at that time the British Army still operated large numbers of DUKW'S but I have never heard of another or anybody knowing about the manufacture of them. I'm sure the wooden box which was obviously made specifically fit the manifold had a manufacturer's name on it but at the time I thought nothing of it and have no recollection of what happened to the box. I was reminded if it today at Malvern as Rex Ward had newly made 'heav duty' manifolds on his stall with an eye watering price tag over £400 but since secondhand ones which are usually warped seem to fetch in the region of £200 and usually seem to come from Holland then it does put the price for something new and not simply fit for the scrap pile not all that pricey after all. I just wish I could come across a shed load of those Brit ones at the price that original one cost mr, it would be better than winning the lottery. If you do have to change the manifold even if yours will repair make sure you fit a new copper/asbestos/copper type, not the cheapest but anything else is rubbish and not worth having. If Rex hasn't got any good gaskets Wildenberg in Holland normally stock them but they also have cheap stuff so if yyou do go down that road make it clear to them what you want. I have dealt with them a no of time over the years an always found them 'on the ball' with their product knowledge on 'jimmy's'. If you need contact details let me know I have email and phone no's and they do have English speakers.

Does your engine have a pipe running from either the top of the rocker box or the oil filler pipe to the throat of the inlet manifold just below the carb? most do except what I believe to be very early engines. If yours does I need to talk to you on the phone or on Skype if your'e on there,PM me for a contact number , it is important but I can only explain it to you verbally.

Regards

Degsy

[shopnut]

bit of an update to this thread, had a couple of hours free today and made a start to rule out the noises on my engine.

 

started by disconnecting the vacuum line to the hydrovac to rule out air leaks on that, also the vacuum line to wipers, no change on either.

then dropped off the fan belt to rule out the alternator and water pump, no change on that either.

 

The first is a squeak this now seems to be a wheezing sound and it looks as though it's a vacuum leak on the far ends of inlet manifold ports to the cylinder head joints !!!

 

The second noise which is a knock this now sounds like an exhaust blow as it is much louder on the manifold side than the other side of the engine, the two could be connected as the exhaust manifold is very close to being beyond any use and the fact that the lnlet is bolted to it might mean I need to change both !!!!!!!!!

 

 

You may already know this, but make sure the guide collars/rings are fitted between inlet manifold and head, if they are not fitted the whole manifold can slip down, and cause some interesting problems, I know because it happened to me many years ago.

 

Regards

[deadline]

Take the manifolds off and lay a metal straight edge (ie ruler) to check for warp/flatness.

 

You could correct it somewhat by hand with a file and a surface plate and some india ink (scrape it flat). Being you're in the UK there may be a larger source of knowledgeable scrapers available to you. Its not rocket science. Whenever you rebuild a tranny or transfer case one step is to file the gasket mating surfaces to remove metal that has been pulled up due to bolt torque. Then polish out file marks.

 

Its just a piece of metal.. it can be made to do your bidding.

Edited November 21, 2011 by deadline

[N.O.S.]

..Its just a piece of metal.. it can be made to do your bidding.

 

Agreed, but it as been my experience that some HMV metal has a serious attitude problem...

[diamond-t-steve]

One way to find a vacume leak is to have the engine running and then to spray a little easystart around suspected leak locations. If a leak is present the revs will pick up a little as the easystart is drawn into the engine.

 

Hope this helps. Regards... Steve.

[deadline]

That will help with vacuum leaks, but not exhaust.

 

If the engine is cold you can just use soapy water. The engine will 'steady out' if its a vacuum leak (because the water is plugging the leak until it get all sucked in) and for a pressurized leak it will bubble... as long as the engine stays cool enough. Run the engine for a minute or two (won't get hot enough in that short time) and you can spray away.

[R Cubed]

Hi Richard, From past experience with my 352 I think you could well be on the right lines Richard, I went through 2 exhaust manifolds before I found a brand new British made one still in its original wooden case which dated from the 1950's but was much more strongly made than the original and was webbed for extra strength. It took me a while to realize why it could be Brit made until it dawned on me that at that time the British Army still operated large numbers of DUKW'S but I have never heard of another or anybody knowing about the manufacture of them. I'm sure the wooden box which was obviously made specifically fit the manifold had a manufacturer's name on it but at the time I thought nothing of it and have no recollection of what happened to the box. I was reminded if it today at Malvern as Rex Ward had newly made 'heav duty' manifolds on his stall with an eye watering price tag over £400 but since secondhand ones which are usually warped seem to fetch in the region of £200 and usually seem to come from Holland then it does put the price for something new and not simply fit for the scrap pile not all that pricey after all. I just wish I could come across a shed load of those Brit ones at the price that original one cost mr, it would be better than winning the lottery. If you do have to change the manifold even if yours will repair make sure you fit a new copper/asbestos/copper type, not the cheapest but anything else is rubbish and not worth having. If Rex hasn't got any good gaskets Wildenberg in Holland normally stock them but they also have cheap stuff so if yyou do go down that road make it clear to them what you want. I have dealt with them a no of time over the years an always found them 'on the ball' with their product knowledge on 'jimmy's'. If you need contact details let me know I have email and phone no's and they do have English speakers.

Does your engine have a pipe running from either the top of the rocker box or the oil filler pipe to the throat of the inlet manifold just below the carb? most do except what I believe to be very early engines. If yours does I need to talk to you on the phone or on Skype if your'e on there,PM me for a contact number , it is important but I can only explain it to you verbally.

Regards

Degsy

 

PM sent.

[R Cubed]

You may already know this, but make sure the guide collars/rings are fitted between inlet manifold and head, if they are not fitted the whole manifold can slip down, and cause some interesting problems, I know because it happened to me many years ago.

 

Regards

 

Yes thanks, could not work out why they were there until it dawned on me that the fixing studs dont stop the manifolds slipping down so they put some sleeves in the inlet ports as a type of dowel.

[R Cubed]

Take the manifolds off and lay a metal straight edge (ie ruler) to check for warp/flatness.

 

You could correct it somewhat by hand with a file and a surface plate and some india ink (scrape it flat). Being you're in the UK there may be a larger source of knowledgeable scrapers available to you. Its not rocket science. Whenever you rebuild a tranny or transfer case one step is to file the gasket mating surfaces to remove metal that has been pulled up due to bolt torque. Then polish out file marks.

 

Its just a piece of metal.. it can be made to do your bidding.

 

Thanks for all the suggestions in this thread of mine of possible faults, it is always good for alternative suggestion.

 

 

The problem I have is that the exhaust manifold ports are very thin round the mating faces where they contact the cylinder head, this has resulted in them corroding and flaking away to the point now that with the two manifolds bolted together at the base of the carb I cant get the exhaust manifold to bolt up tight before the inlet manifold is tight, so I have to split the two manifolds and try to make some room, or make some new manifolds :cool2:

[R Cubed]

The new rings we just put in after a very light cylinder hone were 15 gap You can get rings which are not gapped - you have to grind a little of to gap them correctly. This could be a way of taking up any wear, but would not have thought it was worth the trouble.

 

Just out of interest (I'm not qualified to comment further :-D), what is your biggest gap in the working area of the cylinder?

 

See my edited post No 77

[deadline]

Filing or scraping the mounting surfaces flat is a few .001s of an inch (.01mm).

 

Snapping the flanges off are the result of trying to torque a warped manifold to a flat mounting surface. Bolting a flat manifold to a flat surface will not snap anything.

 

Having a knowledgeable scraper flatten the manifold is significantly cheaper than a new manifold.

 

If you are not into perfection, there are PLENTY of post war 270 engines that use the same manifold. I have one from a civvy 270 and other than the casting marks they bolt right up.

[R Cubed]

Over the weeekend I have removed the two manifolds and split them appart, of the four fixing bolts one came undone due to the threaded hole in the inlet manifold being cracked, one was corroded so badly there was only about 5mm dia of stud left, and that sheared off, the other two sheared off, yes level with the manifold. The last two exhaust ports nearest the firewall both are corroded beyond use ( no more material to machine off to create a flat level surface) and can be seen to have been blowing badly ( this I susspect is the knocking noise ) ...... Also the exhaust manifold casting between ports 3 and 4 has a crack in it about a inch long although there is no sign of black exhaust soot from it.

Due to the fact that both manifolds have been bolted together for many many years the corrosion on the exhaust ports has now meant that when they were pulled up tight it distorted the inlet ports so would not seal properly (now proved before stripping down) both end ports of the inlet manifold had air leaks, these of course feed two cylinders each (the squeeking / weazing sound) so this has had an effect of weakening the fuel / air mixture to cylinders 1, 2, 5 and 6 so out of the 6 cylinders only 2 were getting the correct mixture, no wonder it seemed sluggish :shocked:

[Vulture]

Over the weeekend I have removed the two manifolds and split them appart, of the four fixing bolts one came undone due to the threaded hole in the inlet manifold being cracked, one was corroded so badly there was only about 5mm dia of stud left, and that sheared off, the other two sheared off, yes level with the manifold. The last two exhaust ports nearest the firewall both are corroded beyond use ( no more material to machine off to create a flat level surface) and can be seen to have been blowing badly ( this I susspect is the knocking noise ) ...... Also the exhaust manifold casting between ports 3 and 4 has a crack in it about a inch long although there is no sign of black exhaust soot from it.

Due to the fact that both manifolds have been bolted together for many many years the corrosion on the exhaust ports has now meant that when they were pulled up tight it distorted the inlet ports so would not seal properly (now proved before stripping down) both end ports of the inlet manifold had air leaks, these of course feed two cylinders each (the squeeking / weazing sound) so this has had an effect of weakening the fuel / air mixture to cylinders 1, 2, 5 and 6 so out of the 6 cylinders only 2 were getting the correct mixture, no wonder it seemed sluggish :shocked:

 

Wow, that sounds a right combination ! So what's your current thinking ? Replacement inlet and outlet manifolds ? Also will you need to take the head off to drill the studs out, or do you think you can sort that in-situ...

 

Kind regards

 

Ian

[deadline]

That's the problem with fixing stuff... its always worse than you hope it to be.

 

At least there is an upside.. as you noted you should see a little more pep from the engine once the manifolds are replaced and all the discrepancies repaired.

[R Cubed]

Wow, that sounds a right combination ! So what's your current thinking ? Replacement inlet and outlet manifolds ? Also will you need to take the head off to drill the studs out, or do you think you can sort that in-situ...

 

Kind regards

 

Ian

 

I am still a little aprehensive about the Knocking sound but we shall see on that point. With what I have found the exhaust manifold definatly needs replacing, the inlet I am going to check for flatness, although it should be ok as it does not suffer with the heat that the exhaust manifold does. The broken studs are all in easily accessible places so will be done in-situ.

[R Cubed]

That's the problem with fixing stuff... its always worse than you hope it to be.

 

At least there is an upside.. as you noted you should see a little more pep from the engine once the manifolds are replaced and all the discrepancies repaired.

 

I am very surprised with how bad the inlet air leaks were and considering this how well the truck went even with the gun on !!! good old GMC...

[RMS]

Hi Rich

 

this will wet your whistle!!

 

 

http://www.cliffordperformance.net/Merchant2/merchant.mvc?Screen=PROD&Store_Code=CP&Product_Code=52-0040K&Category_Code=C235

[N.O.S.]

Hi Rich

 

this will wet your whistle!! .....

 

Oh no, you've gone and 'blown' it well and truly now! :whistle:

[R Cubed]

Hi Rich

 

this will wet your whistle!!

 

 

http://www.cliffordperformance.net/Merchant2/merchant.mvc?Screen=PROD&Store_Code=CP&Product_Code=52-0040K&Category_Code=C235

 

Oh no, you've gone and 'blown' it well and truly now! :whistle:

 

 

 

errrrrrr stay " tuned".............

[rosie]

Cough cough!

Hmmmmmmmmmm get back to work you!

 

 

Love from Rosie x

[P Marriott]

Check out this advert for fabricated 270 exhaust manifold, rather than a cast one.

 

http://www.milweb.net/dealers/trader/dave_roe_halftrack_parts/

[R Cubed]

Well I have been also going thorough the bits and bobs connected to the inlet manifold. I have checked the hydrovac non return valve, which was fine holding good vacuum some time after the engine had been stopped. The steel pipe from the rocker cover to the inlet manifold via a metering valve can quite often get gummed up with oil and carbon deposits, my one was un blocked and the valve inside was free to move. Below are some pics of the valve unit this is detailed in the TM to be regularly checked to ensure it does not get blocked up. NOTE: the thread on the right hand side in the pic screws into the elbow on the inlet manifold, the thread on the left hand side ( Brass ) screws to the steel tube with the other end screwing to the elbow on the rocker cover.

 

 

This is the complete valve removed from the inlet connection and the steel tube to the rocker cover.

 

 

 

 

This is how it splits in half.

 

 

 

 

This is what is inside it.

 

 

 

 

Here is the main valve part and return spring. There is a small hole in the centre of this valve and can sometimes get gummed up with oil deposits. ( in TM for regular cleaning ) There is also a larger hole in the side of the valve to allow more air to pass under higher vacuum loads.

 

 

 

 

Here is a view of the back of the valve and spring.

 

 

 

 

Here is the inside view of one half of the valve housing, (this is the half which screws into the inlet manifold connection) where the valve and spring in the pic above go in spring first.

 

 

 

 

Last of all the other side of the valve housing.

 

 

Edited December 2, 2011 by R Cubed
To make explanation more clear.

[Jack]

I can see I am going to have to come up there and sort that Mans Truck out in a minute!!