PHB Posted October 28, 2019 Share Posted October 28, 2019 (edited) 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 October 31, 2019 by PHB Additional information Quote Link to comment Share on other sites More sharing options...
mike30841 Posted October 28, 2019 Share Posted October 28, 2019 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. Quote Link to comment Share on other sites More sharing options...
Nick Johns Posted October 29, 2019 Share Posted October 29, 2019 (edited) . Edited November 8, 2019 by Nick Johns Quote Link to comment Share on other sites More sharing options...
Pete Ashby Posted October 29, 2019 Share Posted October 29, 2019 (edited) 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 October 29, 2019 by Pete Ashby Quote Link to comment Share on other sites More sharing options...
radiomike7 Posted October 29, 2019 Share Posted October 29, 2019 How easy is it to take the valve chest cover off, at least you could rule out stuck valves? Quote Link to comment Share on other sites More sharing options...
Gordon_M Posted October 29, 2019 Share Posted October 29, 2019 I'm thinking something simple but not obvious, like a broken camshaft, or camshaft not driving Quote Link to comment Share on other sites More sharing options...
MB1944 Posted October 29, 2019 Share Posted October 29, 2019 I am with Mike30841 do a full compression test before you open anything up, this will tell you a lot. Regards John Quote Link to comment Share on other sites More sharing options...
PHB Posted October 31, 2019 Author Share Posted October 31, 2019 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? Quote Link to comment Share on other sites More sharing options...
PHB Posted October 31, 2019 Author Share Posted October 31, 2019 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? Quote Link to comment Share on other sites More sharing options...
PHB Posted October 31, 2019 Author Share Posted October 31, 2019 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 Quote Link to comment Share on other sites More sharing options...
Pete Ashby Posted October 31, 2019 Share Posted October 31, 2019 (edited) 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 November 1, 2019 by Pete Ashby missing word Quote Link to comment Share on other sites More sharing options...
Gordon_M Posted October 31, 2019 Share Posted October 31, 2019 (edited) 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 October 31, 2019 by Gordon_M Quote Link to comment Share on other sites More sharing options...
matchlesswdg3 Posted October 31, 2019 Share Posted October 31, 2019 (edited) Not all OHV engines are interference design. But it IS kind of nice to know if it is! Edited October 31, 2019 by matchlesswdg3 Typo Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted October 31, 2019 Share Posted October 31, 2019 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. Quote Link to comment Share on other sites More sharing options...
radiomike7 Posted November 1, 2019 Share Posted November 1, 2019 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. Quote Link to comment Share on other sites More sharing options...
radiomike7 Posted November 1, 2019 Share Posted November 1, 2019 https://p15-d24.com/topic/17152-valves-stuck/ Quote Link to comment Share on other sites More sharing options...
Pete Ashby Posted November 8, 2019 Share Posted November 8, 2019 Any up date on this ? it's always useful to hear what the out come of a problem was Pete Quote Link to comment Share on other sites More sharing options...
Nick Johns Posted November 8, 2019 Share Posted November 8, 2019 (edited) 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 November 8, 2019 by Nick Johns Quote Link to comment Share on other sites More sharing options...
Pete Ashby Posted November 8, 2019 Share Posted November 8, 2019 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 Quote Link to comment Share on other sites More sharing options...
PHB Posted November 9, 2019 Author Share Posted November 9, 2019 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 1 Quote Link to comment Share on other sites More sharing options...
Gordon_M Posted November 9, 2019 Share Posted November 9, 2019 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. Quote Link to comment Share on other sites More sharing options...
matchlesswdg3 Posted November 9, 2019 Share Posted November 9, 2019 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? Quote Link to comment Share on other sites More sharing options...
ltwtbarmy Posted November 9, 2019 Share Posted November 9, 2019 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. Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted November 9, 2019 Share Posted November 9, 2019 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. Quote Link to comment Share on other sites More sharing options...
ltwtbarmy Posted November 9, 2019 Share Posted November 9, 2019 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! Quote Link to comment Share on other sites More sharing options...
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