Jump to content
PHB

Dodge WC engine help

Recommended Posts

I have a Dodge WC 6cyl petrol engine which was running well but on a return back from a short drive it has seemingly lost all compression. 

I've had the front timing chain cover off and everything is in order, the engine turns over but at a constant speed and will not start again - there is no compression when tested.

Having driven the vehicle into the garage and turned it off in the usual way I'm at a loss as to why this might occur but it seems like the valves have stopped functioning or are open all the time.

Any guidance or advice would be appreciated.

Peter

 

THANKS to all those of you who have responded so far.

We've had the side covers off the engine and all valves appear to be stuck open! there is nominal compression on one cylinder only! Very strange how this has occurred!

The timing shaft does not appear to be broken so I'm not sure why the valves would stick open! I'm assuming they cant be bent as its a side valve?

Edited by PHB
Additional information

Share this post


Link to post
Share on other sites

When you say there is no compression, do you mean there is no compression on any of the cylinders, and have you verified this by checking each cylinder with a compression tester? Reason I ask is that I can't think of a likely fault that would cause a loss of compression to all cylinders at the same time, short of a massively catastrophic failure.

Share this post


Link to post
Share on other sites
18 hours ago, PHB said:

I have a Dodge WC 6cyl petrol engine which was running well but on a return back from a short drive it has seemingly lost all compression. 

I've had the front timing chain cover off and everything is in order, the engine turns over but at a constant speed and will not start again - there is no compression when tested.

Peter

Do you mean the front timing cover ? or the valve chest cover on the side of the block ?

A slipped timing chain will certainly give you problems starting and running but will also be associated with other indications like spitting back up the carb and/or back firing at the exhaust.

If you can provide a bit more information regarding what tests you have carried out to determine the complete loss of compression  it will help people provide more accurate suggestions as too the cause of your problem and what the solution might be.

Pete

Edited by Pete Ashby

Share this post


Link to post
Share on other sites

How easy is it to take the valve chest cover off, at least you could rule out stuck valves?

Share this post


Link to post
Share on other sites

I'm thinking something simple but not obvious, like a broken camshaft, or camshaft not driving

Share this post


Link to post
Share on other sites

I am with Mike30841 do a full compression test before you open anything up, this will tell you a lot.

Regards

John

Share this post


Link to post
Share on other sites
On 10/28/2019 at 10:47 PM, mike30841 said:

When you say there is no compression, do you mean there is no compression on any of the cylinders, and have you verified this by checking each cylinder with a compression tester? Reason I ask is that I can't think of a likely fault that would cause a loss of compression to all cylinders at the same time, short of a massively catastrophic failure.

Thank you for replying.

We've had the side covers off the engine and all valves appear to be stuck open! We also did a compression test on all cylinders and there is nominal compression on one cylinder only!

The timing shaft does not appear to be broken so I'm not sure why the valves would stick open! I'm assuming they cant be bent as its a side valve?

Share this post


Link to post
Share on other sites
On 10/29/2019 at 9:30 AM, Nick Johns said:

Is the timing chain very slack? it could have jumped over several teeth and put the valve timing out

Hi - thank you for your reply - Yes it was slack - but it is still in the correct position. Plus there is no compression on any cylinder - unless it had jumped a full half cycle?

Share this post


Link to post
Share on other sites
On 10/29/2019 at 10:03 AM, Pete Ashby said:

Do you mean the front timing cover ? or the valve chest cover on the side of the block ?

A slipped timing chain will certainly give you problems starting and running but will also be associated with other indications like spitting back up the carb and/or back firing at the exhaust.

If you can provide a bit more information regarding what tests you have carried out to determine the complete loss of compression  it will help people provide more accurate suggestions as too the cause of your problem and what the solution might be.

Pete

HI - Thank you for your reply.

We removed the front cover to reveal the timing chain - we checked the to cogs and they align as expected - so unless the who chain allow a jump of a full rotation of the smaller cog - coincidentally?

We have done a compression test on all cylinders and nothing - save for pot 1

What I'm struggling with is the fact that the engine ran normally until I switched it off - now nothing!

Peter

Share this post


Link to post
Share on other sites

I agree very strange indeed but do not be be tempted yet to strip any more of the engine ,   

So you saying 5 out of the 6 pairs of valves appear to be stuck open with the springs compressed ?

If you look in at the valve chest the cylinder with compression this has the pair of valves that are operational ? 

Which cylinder is this ?

What was the reading?

Looking at the other pairs of valves that appear open you should be able to see the cam followers and tappet blocks moving up and down can you see this ?

Have you tried very gently tapping the valve springs of the valves that are open ?

When you crank the engine over if your valves are stuck open you should be hearing all sorts of wheezing and blowing from the exhaust pipe and also from the carburetor can you hear any of this?

that will do for starters have a think about the answers and come back here and we can all take it from there

Pete

Edited by Pete Ashby
missing word

Share this post


Link to post
Share on other sites
1 hour ago, PHB said:

We have done a compression test on all cylinders and nothing - save for pot 1.     Peter

Ah, that would be the cylinder right at the front then, immediately behind the cam driven gear?  ( some people number the cylinders from the firewall end ... )

I think you have a broken camshaft, and the break is between cylinders 1 & 2, so cylinder one is opening its valves normally and giving some compression, but the other five cylinders are on strike - or at least their valves are.  Hold the driven camshaft gear and try to rock it slightly - it should feel a bit more wobbly that you would expect - it may even pull out a little if you tug on it.

The slightly less bad news is because you have a flathead / side valve, the pistons have not come up and wrecked the valves, which is what would have happened with an overhead valve engine.

Edited by Gordon_M

Share this post


Link to post
Share on other sites

Not all OHV engines are interference design.  But it IS kind of nice to know if it is!

Edited by matchlesswdg3
Typo

Share this post


Link to post
Share on other sites

Easy way to check the camshaft is to take the valve chest cover off and see if all the cam followers are moving when the engine is spun over.

Share this post


Link to post
Share on other sites
On 10/28/2019 at 4:08 PM, PHB said:

I have a Dodge WC 6cyl petrol engine which was running well but on a return back from a short drive it has seemingly lost all compression. 

I've had the front timing chain cover off and everything is in order, the engine turns over but at a constant speed and will not start again - there is no compression when tested.

Having driven the vehicle into the garage and turned it off in the usual way I'm at a loss as to why this might occur but it seems like the valves have stopped functioning or are open all the time.

Any guidance or advice would be appreciated.

Peter

 

THANKS to all those of you who have responded so far.

We've had the side covers off the engine and all valves appear to be stuck open! there is nominal compression on one cylinder only! Very strange how this has occurred!

The timing shaft does not appear to be broken so I'm not sure why the valves would stick open! I'm assuming they cant be bent as its a side valve?

I have seen it several times on vehicles that are infrequently used which was why I made the suggestion, usually it is just one or two but you seem to have a full house. The short run probably didn't help either.

Share this post


Link to post
Share on other sites

Any up date on this ?

it's always useful to hear what the out come of a problem was 

Pete

Share this post


Link to post
Share on other sites
1 hour ago, Pete Ashby said:

Any up date on this ?

it's always useful to hear what the out come of a problem was 

Pete

There is an update added to the first post at top of this page

Edited by Nick Johns

Share this post


Link to post
Share on other sites
11 hours ago, Nick Johns said:

There is an update added to the first post at top of this page

Thanks Nick I did see the added comment after you pointed it out,

what I should have said is 'Has the fault been identified yet',  it 's always useful to hear the outcome of an unidentified problem both for personal interest and also for others who may find the diagnosis and identification process useful.

I've noticed on other forums that some times threads like this are left hanging with several suggestions provided but the originator never comes back with the result.   I just find it a bit disappointing when this happens as the web provides a huge resource for all of us to enhance our mechanical knowledge and fault finding abilities but without a definitive answer there is always room for uncertainty on the advice offered. 

Pete

Share this post


Link to post
Share on other sites

Thank you for the ongoing replies.

I'm working on this at weekends so apologies for no further updates so far.....however.....

I've now established that by removing the covers on the side of the engine to expose the valve springs that the can tappets are rising and falling as the engine is rotated - suggesting the cam is not broken.

There was some piston compression on the pot nearest the bulhead - so I'm again reasonably happy at this stage that the cam is fine.

So it appears that almost all the valves have stuck or are sticking! 

I'm now trying to see if these can be freed off without taking the engine out and opting for a rebuild - but if I'm correct and they are all sticking open I'm thinking the odds might be against me!

Please bear with me as I continue to explore this!

Thanks

  • Like 1

Share this post


Link to post
Share on other sites

Well if the cam is OK and all the valves just happened to stick at once, I think you should be looking at the oil supply to that area.

Share this post


Link to post
Share on other sites

I guess a useful question to ask is, has the engine had a recent rebuild or recent work on it......or stood idle for a long period......or has it been running happily for a long period prior to this?

Share this post


Link to post
Share on other sites
5 hours ago, PHB said:

I'm now trying to see if these can be freed off without taking the engine out and opting for a rebuild - but if I'm correct and they are all sticking open I'm thinking the odds might be against me!

 

Hi, I have just done all the valves on a civilian 1949 230 cubic inch dodge engine. It is basically the same as the military engine and so can confirm that to take the valves out, you don’t have to take the engine out. One thing I will tell you is, ignore all the shortcuts mentioning hammers and wd40 etc. Take all the valves out, exhaust and inlet, and clean all of them off. Start by draining all the coolant because when you get the manifolds off, the coolant will leak out.

Then take the cylinder head off and also get the exhaust and the manifold off. Watch out for the hidden center bolts in the manifolds, just under the carb. Then cover the holes which are between  the cam followers, and make sure the floor is clean under the vehicle, then just compress the each valve with a compressing tool, and get the collets off. The main faff is actually removing the springs, but if you are reasonably certain that they’re not the cause of the sticking, then Leave them there. Get a reamer of the appropriate diameter, and ream the valve guides yo clean them up. Clean the valves, check for trueness, and then pop everything back in. 

When they’re all back in then you have to set the gaps. If the military dodges are the same, there will be a panel in the body directly opposite the valves which can be removed so that you can do the gaps. The 49 coronet has an access panel which is removed by taking off a few self tapping bolts to make life easier.

Share this post


Link to post
Share on other sites
4 minutes ago, ltwtbarmy said:

 Clean the valves, check for trueness, and then pop everything back in. 

 

All good advice, but I would add that while you have the valves out, get them faced, ensuring the edges of the valves are not too thin (the edge of the valve can burn away if they are) and get the seats cut. Then lap the valves in to the seats. It is likely if the valves have been sticking the faces and seats could be burnt if the valves were not right down on their seats when closed.

Share this post


Link to post
Share on other sites
29 minutes ago, Richard Farrant said:

All good advice, but I would add that while you have the valves out, get them faced, ensuring the edges of the valves are not too thin (the edge of the valve can burn away if they are) and get the seats cut. Then lap the valves in to the seats. It is likely if the valves have been sticking the faces and seats could be burnt if the valves were not right down on their seats when closed.

Totally agree, definitely face the valves and lap them in while they’re out.  sorry, i forgot that bit. Been a long day cutting rust out of a mini moke and my brain is shutting down!

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...