Dead cylinder on my 440. Cam Swap

[timmycharger]

 

I posted on my build thread regarding the noise I have had since startup of my 440 which I refreshed with rings, bearings and new Edelbrock RPM heads. Below are the videos that I posted of it running.  

After 550 miles I did a compression test as I am getting sick of the noise ( I know, should have done that first  ) but regardless I found the #8 cylinder to have 0 PSI reading and a spark plug that looked brand new.   The other cylinders were mostly around 155 PSI except for a few that were closer to 190 but almost an hr passed from when I did one side to the other as the exhaust was burning my hands.  While I am concerned about the readings of some cylinders being more than 10% different, I am much more concerned with the 0 PSI I got on number 8.  

I got some suggestions already on my car thread but I wanted to move it to a separate topic.   Any tips/tricks on what tests I should be performing to be able to pin point it to valvetrain vs. piston/rings?  

I have a borescope, leakdown gauge set, valve spring compressor (overhead type), dial indicator,  and of course the compression gauge for specialty tools.  


https://www.youtube.com/watch?v=sSS5oCcsRaQ

https://www.youtube.com/watch?v=rFh6mxFDMrE

[justcruisin]

Pull the valve cover and see if all is functioning as it should be. Get that piston up on TDC and plug in your leak down tester, identify were the air is escaping, that will show you were you need to go.

[justcruisin]

Just looked at your clips, first thing that comes to mind is a wiped lobe - hopefully not.

[timmycharger]

Thanks for the input.  Actually I am secretly hoping for a wiped lobe LOL,  I made a mistake in re-using that Mopar 284/484 cam in this build. It has terrible vacuum and a pig off of the line.  before the restoration of the car and engine refresh, The car was set up for racing, much lighter than now and with 4:10 gears and a 3000 stall converter.   Now I have 3:54 rear and a 4 speed.

Thanks again for your feedback.

[b5blue]

bent push rod could be all

[justcruisin]

Easy enough to replace a cam if that is the problem, trouble is a strip down, clean out and new bearings would be prudent.

[timmycharger]

Ugh forgot about metal shavings from lobe damage.. I recently changed the pan and there were no obvious shavings or metal in there but who knows.

Hopefully it's just a bent push rod!

[69wannabe]

Get you one of them remote starter buttons and hook one clip to the battery positive and the other to the starter relay wire that engages the starter (smaller wire going to the starter) pull the valve cover and use the button to spin the engine over and watch the rocker arms and see if they all moving the same up and down. If not then you got a valve train issue for sure. The intake on a 440 is one of the easiest intakes to take off and there is no water that runs through it so there is no mess and you can inspect the cam and lifters good with the intake off. Hope you get it figured out soon....

[440]

I would hook up compressed air before I did anything to determine if it was the top end or bottom end.

[metallicareload99]

Ugh forgot about metal shavings from lobe damage.. I recently changed the pan and there were no obvious shavings or metal in there but who knows.

Hopefully it's just a bent push rod!

My memory is fuzzy and I'm not a real mechanic but, when I had a cam lobe go flat, I don't recall "seeing it" show up in a compression test.  Or at least it wasn't obvious to me.  I had one cylinder once with a bad exhaust guide, I don't remember the numbers but it was a good deal above 0 PSI still, and I recall that it was a compression test that led me to conclude that was the problem before taking the head off.

Like has been mentioned valve covers are easy to take off to have a look, and I think the intake is even easier to take off to rule out bent pushrods and to have a look @ the cam.

As much as I hate to say this, the only time I've seen 0 PSI was when there is a major ring issue.  I had the lands between the compression rings crack and those cylinders showed 0 PSI.  Pouring a little bit of oil into the spark plug holes brought one cylinder up to a few PSI, but obviously there is no coming back from that.  Broken ring hopefully and not the piston       ?  I'm hoping for the best, I've been there and it sux.  Good luck!

I would hook up compressed air before I did anything to determine if it was the top end or bottom end.

[timmycharger]

Thanks guys, appreciate the feedback.  Yes, I should have mentioned I have a remote starter button, I have used that several times in the past and used it to do my compression test.   

Agree, step one will be to put some shop air in there and see what happens and yes, I am hoping it has nothing to do with the piston or rings, otherwise it's game over for this summer. 

[c00nhunterjoe]

0 psi is pretty catastrophic. If a wiped lobe is causing 0 psi, there is so much metal throughout that it needs to get hot tanked

[PlainfieldCharger]

wouldn't a wiped cam lobe still give you a pressure reading....

[timmycharger]

Not sure if you would still get a reading with a wiped cam lobe and I would think I would have seen the metal in the oil after the first oil change and then again when I swapped out pans last winter.

Yea, 0 PSI in a cylinder sure is a kick in the junk.. Let's say if my problems are a bent valve or an issue in the head, would that give me 0 PSI? That wouldn't be too bad if that is the case as I would just pull the head and have it serviced.  If it's piston related or a wiped out cam lobe then the engine will need to come out which won't happen until this winter.

[BSB67]

wow

[c00nhunterjoe]

Lets stop guessing and air the cylinder. It should be obvious where its going.

[charger Downunder]

What would happen if a piston ring was put on upside down.

[flyinlow]

O PSI...assuming it was a good test  You have a hole in the combustion camber.  Valve stuck open, hole in a piston, broken head , head gasket blown or a broken block.

Hopefully a push rod issue.     compressed air will tell you a lot.

[timmycharger]

What would happen if a piston ring was put on upside down.

I would be extremely pissed and a little embarrassed 

[timmycharger]

O PSI...assuming it was a good test  You have a hole in the combustion camber.  Valve stuck open, hole in a piston, broken head , head gasket blown or a broken block.

Hopefully a push rod issue.     compressed air will tell you a lot.

Agreed. What sucks is that I can't get to it until this upcoming Tuesday night.  Until then I can't help myself from guessing and obsessing over it.       

[timmycharger]

We put air in the cylinder and couldn't hear anything out of the carb or tailpipe, or out of the valve covers.

Used the remote starter and watched the rockers only to see the exhaust rocker move up and down on that cylinder.

Pulled the intake and lifters and one of them was toast. The cam is wasted on that lobe as well.

What is confusing to me is the noise was there from startup but I changed rockers, lifters, pushrods a few times, adjusting the valves so I don't know how I missed that rocker not moving like the others. I re used this cam from prior to the refresh, maybe it had an issue then and slowly was getting worse? This lifter is not a Mopar one that originally came with the cam. I put a set of comp cam lifters thinking that was my noise.

I'm sure the internet will explode when I just do a cam swap without pulling the motor to be hot tanked and rebuilt due to the shavings and metal. I just did the oil pan on this a few months ago and I didn't see anything concerning on the magnet, same from when I did the oil change before that. 

I plan on changing the oil after the install then again after break in. I'll check the cam bearings while I have it out.  This motor was always a just for now while I have my dream motor built, otherwise I would have done more than just a re ring and bearing. If it dies after 2k miles then so be it, it will make a good platform for another build.

[metallicareload99]

I think that's relatively, a much better situation to be in. I had a similar thing happen, only with a exhaust lifter. I didn't pull the motor. I put in a Lunati 60303, broke it in and changed the oil put at least 20,000+ more miles on it after    Until I had the aforementioned piston/compression problems

[timmycharger]

Good to know. I plan to pull the oil pump off to have s look in there as well. 

[BLK 68 R/T]

I think the problem may have been new lifters on an old cam. I've read and heard stories about avoiding doing that with anything but roller cams. I would also check the lifter bore and make sure the new lifters are able to rotate properly before buttoning it back up.

[68CoronetRT]

Sucks to hear, but atleast you figured it out. I too did an old cam with new lifters and never had an issue.