Alexander Posted July 29, 2009 Report Posted July 29, 2009 I seem to have suddenly lost all compression in cylinder #1 (0 PSI) adjacent cylinders show near 100 what could this be? engine ran well 3 weeks ago when started last. whats the best way to determine if its the head gasket or perhaps a valve? you thoughts would be greatly appreciated. Thanks Alex Quote
jd52cranbrook Posted July 29, 2009 Report Posted July 29, 2009 Its been my experience when a head gasket blows on one cylinder, it blows into the adjacent cylinder, ending up having low compression in two instead of just one cylinder. Plus rarely, for me anyway, will the compression go all the way to 0. Quote
rolliejoe Posted July 29, 2009 Report Posted July 29, 2009 (edited) with 0 PSI it sounds like a stuck valve. Edited July 29, 2009 by rolliejoe Quote
dezeldoc Posted July 29, 2009 Report Posted July 29, 2009 Try this oldtimer trick, put a piece of paper up to the tail pipe with it running, if it stays you have a bad valve or stuck one. don't laugh it works! Quote
55 Fargo Posted July 29, 2009 Report Posted July 29, 2009 I just tried this as a iget a piff-piff, puff-puff rap at an idle with my engine, I am running 2 inch pipe, and a single Smithy muffler. The paper blew right out my hand like a rocket. Does this rule out a bad valve in my case? My compression is 100 to 105, except cyl#5 was 96 on the last time I did a compression test on this engine, about 2 years or 2000 miles ago.............Fred Quote
Plymouthy Adams Posted July 29, 2009 Report Posted July 29, 2009 rules out a good grip on the paper... Quote
rolliejoe Posted July 29, 2009 Report Posted July 29, 2009 Being the #1 cylinder makes it easy to bring it to TDC if you want to do a blow by test. Quote
dezeldoc Posted July 29, 2009 Report Posted July 29, 2009 The idea behind it is the bad valve will pull a vacuum just like in the intake. if you want the best and sure way is to do a leak down test. Quote
Alexander Posted July 29, 2009 Author Report Posted July 29, 2009 thanks guys these are all great ideas. i will look in to in to it and will let you know what i found Quote
kencombs Posted July 29, 2009 Report Posted July 29, 2009 Leak down test is best, but a quick and easy test is similar. Make/buy an adapter that screws in the spark plug hole and allows you to attach and air hose. With pressure applied, listen at the tailpipe, carb intake and oil filler tube. That should point you in the right direction, exh valve or intake stuck (or a piece of carbon holding it off the seat) or a piston/ring failure. Quote
Alexander Posted July 30, 2009 Author Report Posted July 30, 2009 As mentioned, turns out it was a stuck exhast valve. It took for ever to free it. had to flood the cylinder with PB blaster. all is good now and engine runs great. I am back to my main project. Swaping out the M6 semi auto trans with a 3 speed manual on the 51 coronet. Thanks for all the tips Alex Quote
55 Fargo Posted July 30, 2009 Report Posted July 30, 2009 Alex, I have also now have a 3 spd trans, and dry clutch rather than the OEM M6 Trans and fluid dirve in my 47 Chrysler. The clutch housing frame mount had to be moved forward, the clutch rod had to be shortened, other than that, no other real concerns. I am not sure I would ever switch back, even though I have an M6 trans and fluid drive in a parts car. I can see how a fluid drive could be convinient in town though. I love the off the line power with a dry clutch and 3 spd trans, I have a 3.73 rear end....Fred Quote
Alexander Posted July 30, 2009 Author Report Posted July 30, 2009 I agree, nothing beats the dry clutch for off the line torque. In my case I hope to get by with only swaping out the M6 with a 3 speed manual and reatin the fluide drive. If I dont forget Ill take before and after pictures to share on the board. cheers Alex Quote
greg g Posted July 30, 2009 Report Posted July 30, 2009 If you have a car with valves sticking, I might add a pint of Marvel Mystery Oil or some Rislone the next time you ned to add oil. Quote
55 Fargo Posted July 30, 2009 Report Posted July 30, 2009 I agree, nothing beats the dry clutch for off the line torque. In my case I hope to get by with only swaping out the M6 with a 3 speed manual and reatin the fluide drive.If I dont forget Ill take before and after pictures to share on the board. cheers Alex Alexif the 3 spd trans is from a fluid drive set-up, it should bea fairly simple swap-in. Would be a matter of disconnecting the wiring for the M6, install 3 spd trans, the shifter linkage should fit and work just fine, as it is. The speedo drive gear in the trans should match your current rear end, if possible, remove the gear from the M6 and use in the 3 spd, if it fits, don't think it does though, as I have tried this before........Fred PS, when my engine idles, once warmed up, I get a piff-piff sound from the exhauyst, evn though she is idling smooth or pretty smoooth under hood. Is this a case of my Smithy muffler, or do you guys think, I have a problem with an exhaust valve.....................Fred Quote
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