The Stovebolt Site Forums The Shop Area Engine Shop No Compression on Three Cylinders

Finally getting to test start the engine...no compression on cylinders 3, 4 and 6.

Project came with the story the the engine was a crate engine...I noticed some repainting on the engine so I figured that (maybe, if I was lucky) it had been rebuilt. (The block and the head have casting dates that indicate they were cast on the November 10, 1953. Numbers on the block by the distributor indicate that the engine was intended for a car with a Powerglide transmission.) The oil looks very clean and the area behind the pushrod cover looked very clean as well. So, I had my hopes up.

Yesterday I finally attempted to start the engine (12 volt system, 6 volt starter, no alternator/generator connected, engine cold).

I did get a backfire or two, but mostly nothing but cranking. Fuel was getting to the carburetor and accelerator pump was functional. I pulled the spark plugs several times, but they never appeared wet at all. Checked the timing and points...and was getting a strong spark.

Gave up last evening and today I decided to pull the plugs and check the compression:
#1 = 100
#2 = 110
#3 = 0
#4 = 0
#5 = 125
#6 = 0

All the valves appear to be opening and closing when I watch the rockers.

Perhaps I adjusted the hydraulic lifters incorrectly, but I think I really was paying attention!

Any suggestions about what to check next?

I was really hoping to not have to pull the head off.

Thanks!

Back off all the valve adjustments, or loosen the rocker arm shaft stands until all the valves are closed.

Lock the flywheel with a couple of pairs of vise grips at the bottom of the bell housing and put air pressure into the cylinders one at a time.

Listen for air leaks at the carburetor, tailpipe, and oil fill cap.

Adjust the valves again, but this time, don't tighten the adjustments past the "zero slack" stage.

Start the engine. The valves will probably rattle a little, but the lifters will fill with oil so you can do a proper valve adjustment.

Then yank the hydraulic cam out, and throw it as far as you can. Install a Melling CCS-1 and solid lifters.

Jerry

Here's a Youtube video with hydraulic lifter failure on a brand new engine. This is the new normal, unfortunately. I personally know of two people to whom this happened.

https://youtube.com/shorts/r5SIOzwBi-w?si=8vUG9sTf5rXJ9Jwr

Is there some inherent flaw with hydraulic lifters on this engine, or is it just part of the rash of cheap Chinesium that flooded the aftermarket several years ago? (I suspect the latter).

Meanwhile, you could also get a borescope-they're remarkably cheap these days-and look down into the cylinders and see if the walls are fresh. Probably what's happening is you've got a stuck valve from sitting, and once it barks off it'll free up.

Thanks for the responses!

After I read Jerry's suggested steps, I started out to pressurize the cylinders and realized that I needed a way to do that. (I had thought my compression test setup would be able to be repurposed for that, but the pneumatic fittings wouldn't connect to my air hoses.) I went to the local NAPA store where the people seem to actually know something about what they sell and three of the guys understood what I was trying to do (and that I really didn't want to spend the money for a leak down tester). Eventually, they had me talk to their machinist and he asked if I was local...then lent me HIS leak down test kit!

I did as Jerry suggested and backed all of the adjusters off, and for good measure, I loosened the rocker shaft stands.

When I ran air into cylinder #'s 3 and 4, you could have blown up balloons if you stretched them over the carburetor. The leak down test gauge showed that whatever air went in was going straight out (basically no resistance). On cylinder #6, there was more resistance, but it was still pretty sad. I could hear the air hissing somewhere, but I couldn't be sure it was not just coming out around the sparkplug hole threads.

Since all the valves were loose, I figured that if I gave the intake valves that were leaking so badly a whack with a rubber mallet, perhaps whatever was holding them open would let go. So, I went ahead and did that and saw the gauge indicate that there was an improvement (increase) in the resistance. I did that a few more times to the other offending valves and then adjusted the valves to the "zero slack" stage as Jerry suggested.

I reconnected everything (made sure that the manual crank was removed from the front of the truck (!)) and called my wife in as a witness to see what the result might be...

That thing started on the first touch of the button! It ran quietly and smoothly with a slightly fast idle. I was dumbstruck! Not only did it start right up - but it sounded really smooth!

I had taken the advice several folks had offered about how to set things up for the first test run, and I had gotten some steel flex exhaust pipe and the muffler that Otto had suggested. The thing just purred!

(I have to admit I was stressing. When the compression test showed 0 compression on three cylinders, I was thinking I might have to give the whole project up due to finances.)

I have attached a photo my control panel...Light Switch as ignition, oil pressure, water temperature and volt meter (although I have not connected an alternator yet).

I wish I could post a short video...it started up in less than 2 seconds!

Next step is to get it driving & seat the rings! Full throttle / full decel, try not to attract the cops.

That's awesome, Nick. Were the valves stuck as a result of varnish or were they misadjusted?

That engine looks nice.

Outstanding results Nick and I like your "control panel"!

BC, thanks for the suggestions about getting the rings seated! The rest of the truck is a long way from being ready to drive. I have not even pulled one brake drum to see what that situation is, and the only usable wires on the truck are those few that I installed to test the engine. Until I get it a lot further toward being drivable, would idling it occasionally for a minute or so to prove to doubters that it runs, be harmful to the engine? (The truck is in an attached garage so it doesn't get too cold and it is very dry here, so condensation should not be much of a problem if I keep the demonstrations short and of a limited number, I would think. BUT, what do you think? My knowledge is not very deep!)

Otto, my guess is that it was varnish, because when I used the leak down tool to run air into the cylinders, the adjusters were all fully backed off and the rocker shafts were loosened as well. My guess is that if the engine was gone over before I received it, that they did the bottom end and left the top end as it was.

Dan, the control panel was created to make sure I could shut things down quickly! I was concerned that my ADD would result in something I overlooked causing dramatic results! (The fire bottle being right there was the result of 46Sparky's (Lee Esparza's) suggestion to have one handy! - I had more than one nearby! I am glad I didn't need it!)

If you do start it up occasionally, let it run to reach full operating temperature and let it go for 30 minutes or so as if it were being driven.

Short runs allow blowby gases and condensation to settle in the crankcase, turn to acid, contaminate the oil, and cause rust and pitting on internal parts.

I think I would leave the engine off and sealed up

I'd suggest doing a good sealing job on intake and exhaust, fog the cylinders with some type of preservative oil, and do little, if any running until the truck is road-ready. Loosen the valve adjustments to close off all the cylinders, regardless of camshaft position. Piston rings don't seat properly until they get run under load for several cycles. Perfect Circle used to recommend 10 full throttle pulls from 30 MPH to 50 MPH, preferably uphill. Other than creating a smoke screen that's rough on the local mosquito population on the first startup, putting an engine in sealed long term storage doesn't cause any problems.

www.ebay.com/itm/397595251700?

A friend who owned a salvage yard would store take-out engines upside down after draining most of the oil out of the crankcase, to allow residual oil to puddle in the combustion chambers and piston ring area, after blocking off the intake and exhaust manifolds. Those engines could be stored indefinitely, without locking up from rust.
Jerry

Thanks Jerry!

Nice save Nick!