Compression=0...what would you do?

[Moat Creek]

Hello:

I have a 1960 series 2-88 rover that I have been working on for some time that I bought from a fellow here in S. Cal that had not used the vehicle for many years. A year or so back I got the rover running with the intent of checking out he mechanical systems before tearing the whole thing down when I had money to replace frame/bulk head. Before I started the tear down I was having issues with the carb. One fine afternoon I replaced my BV carb with a rebuilt one. I took the rover out for a spin and it ran really, really well for five blocks & the the starter gear locked onto the flywheel (very loud sound down by my feet) & rover coasted to a halt.

When the starter gear/spring failed I decided it was a sign that the tear down should start since I would need to inspect flywheel. My plan was to have a local series rover engine expert (Pat) rebuild the engine while the rebuild was going on. As it turns out he was busy with projects so I decided to re-install the engine since it was running well & I could pull it later (less then a six pack of beer job) if there was an issue or if engine rebuilder schedule cleared.

To make a long story shorter I got my rover friend reassembled & fired up the engine. After working through a few vacuum leaks I have a steady idle but I believe at this point I have a stuck/bent valve (caused by sitting/gum?). The ignition system is working well & I set timing by Green bible & verified with timing gun (mark is rock steady). Engine idles nice but is loud & lacks power. I am positive when I replaced carb I did not drop anything in intake manifold & complete engine sat in a corner of my garage while I rebuilt frame, etc. Compression in #4 cylinder is zero and it is a 8:1 head. See below info gather after engine was warmed up with a decent screw in type compression meter....new starter was used to crank:

# PSI PSI after oil squirted in cyclinder
1 115 125
2 135 140
3 140 150
4 0 0

It seems like I could get a rebuilt head and install it but I am not sure if based upon compression readings & age of other components it may make sense to either get a rebuilt engine or try to find someone to rebuild. It has new fuel & water pump but timing chain/tensioner/distributer were not replaced. I do not have the knowledge or time to learn to rebuild engine (house is for sale). So the way I see it my optons are:
1) I can replace head & see what happens (if does not solve issue then I may have wasted money & time).
2) Get a rebuilt engine (solves problem but costs $)
3) Try to find someone to do engine rebuild (any names in LA area would be appreciated) not sure of what the cost would be on this option..any thoughts? Engine may not be original and must ahve been rebuilt before...how many times=unknown.
My goal is to drive drive rover to next house vs a sad trip on a flatbed . I plan on keeping my rover friend very long term & use for running to Home Depot, fishing, camping,,,,

Sorry for long post but I appreciate your feed back!!

Eric

[LaneRover]

When you run the engine - or just turn it by hand with the valve cover off can you see the valves for #4 moving?

[willincalgary]

When you run the engine - or just turn it by hand with the valve cover off can you see the valves for #4 moving?

I would strongly suspect a stuck valve. Check that first before you spend anything.

[ignotus]

Sounds like it could have been the connecting rod or something else in the motor.
do as been suggested^^^ pull the valve cover and turn the motor with the crank handle and see if the valves move. If they do pull the plug from #4 and put a piece of wire in it and see if the piston moves up and down using the hand crank.
Any metal in the oil pan?

good hunting!

[SafeAirOne]

Eric,

I'd avoid replacing item after item till it's fixed. It may be a simple $200 (including parts) head job. It might be a whole new block. I'd suggest that you troubleshoot and identify the exact problem as described in a few of the other posts. That way you'll know if you're in for a simple, fast and cheap fix or whether the engine is toast.



Just trying to run through scenarios where compression would equal zero on one cylinder...

Valve stuck wide open

Piston not moving at all

Large hole in cylinder wall/block

Large hole in piston


I can't think of any more off the top of my head. I'd think that without any rings installed you'd still get some sort of reading on the compression tester.

[73series88]

yep gotta get that head off.
keep us updated
aaron

[Les Parker]

Could be a displaced push rod or valve tappet.
Remove the valve cover and have a look see.

[mongoswede]

Put a small squirt of oil into the cylinder and check the compression again. If the compression comes back its a sign that the rings are bad or not sealing. If there is no change then suspect valve train.

[fubog]

I would remove the rocker cover and inspect the valve operation, as has been suggested, and (pending the results of the visual) set the bad cylinder at TDC compression and air it up. This is just a crude form of a leakdown test.
HTH
Glen in Fla.

[SafeAirOne]

Put a small squirt of oil into the cylinder and check the compression again.

He did in the OP. That's the second number in his compression readings.

[mongoswede]

He did in the OP. That's the second number in his compression readings.

who reads the original post

[Moat Creek]

Update on zero compression

Thanks all for your input an comments. I did a liitle work tonight and following are results.

1) I borrowed a fiber-optic borescope from work and checked cyclinder #4 which had the zero compression. From what I could see (2/3 of top) the piston has no holes and seems to move up and down freely when cycling starter. With the borescope I could also see both valves open in sequence with no sticking apparent. The valve heads look normal from the side view. I also looked at all the cyclinders and they seem consistent with #4. Piston crowns have some areas that are pretty rough and look like metal was splattered on them (all four)...not sure if this is normal or not.
2) I pulled valve cover and rotated engine by hand and then with starter and all rocker arms/valves seem to cycle as one would expect. No parts seem bent or damaged.
3) I rechecked compression and verified that #4 was still zero. I checked # 3 just to make sure gauge was working and it held at 150PSI and pressure did not degrade for the few minutes I was watching.
4) Not sure what the probelm could be other then crack in block or bad head gasket at this point. If it was head gasket could it just impact one cyclinder?

Anyway let me know what you think!

Eric

[LaneRover]

Is there oil in the coolant at all?

[SafeAirOne]

If it was head gasket could it just impact one cyclinder?

Yes.

[bkreutz]

Since you've got the valve cover off.... measure the heights of the valves on #4 and compare that measurement with another cylinder. Make sure the rocker arms are loose when you measure them (rotate engine until you can "rattle" them. If the height is not the same I'd suspect a bent valve, even though you can see the valves move with a borescope, it's almost impossible to verify sealing using that method. It doesn't take much of incomplete valve sealing to cause this (another possibility is a burnt valve which would be hard to see unless the burnt spot aligned with your borescope). I think the next logical step is to take the head off and inspect, you've done about all you can do short of pulling the head.