no engine compression

[tutilee]

Hi looking for any technical help.

I have a 1996 bayliner engine: mercruiser Alpha 1 3.0/Lx 4cyl. inline

last year I decided to change all the gaskets on the engine cause they were all pretty mush leaking, and also clean the engine compartment of all the oil biuldups. happy to say that I did a incredible job. I tear down the engine to the bear block and cleaning it and painting replacing every gasket on that motor. It looks brand new. So happy to have finished it only to be disappointed with what happened when i crank it for the first time to hear the engine spin like a top. absolutely no compression. I'm completely lost. I know that i didn't missed any gasket. The only thing is that a whole year went by before I crank it after i did the work due to health reasons. My problem now is that i cant think whats my best process of elimination to finding what i did wrong beside replacing the gaskets in the first place. lol is all I can do at this point. The only thing I can say on my behalf is that I'm not a dummy, I've rebuild engines before quit a few times.

Any help would be greatly appreciated. For i am lost at this point.

Thank you. tutilee

 

[Maclin]

Re: no engine compression

Does it spin real evenly as well as too fast? Could be valve lash setting, too tight keeping the valves open. What can you hear while it is spinning? Any puffs out the carb?

Does it spin unevenly? Could be cam timing off a tooth or more and valves not closing at the right time.

Are you sure the engine is moving and not just the starter spinning?

Are all the spark plugs in it?

 

[havasuboatman]

Re: no engine compression

When you cleaned the engine parts, did you soak, or blast, the oil out of the lifters?
If there is no oil in the lifters, the valves wont move, if the intake valve doesn't open, there is no way to draw air/fuel into the engine, therefore...No compression.
To check this, pull off the valve cover and try to push down on the pushrod side of the rocker arms with your thumb. If they move, sorry dude, you have to pull out the lifters and fill them up.
If the motor sat for a year, you will want to pull the distributor, fashion a tool and spin the oil pump using a drill. That will pump oil throughout all of the oil passageway and bearings before you do anymore damage to them.

 

[robjen1019]

Re: no engine compression

did you put the plugs back in?

 

[tutilee]

Re: no engine compression

Thank you all for such a quick response. Yes the plugs are in lol.

As far as the engine cleaning I only meant on the outside, No soaking or blasting
the oil out of lifters. please let me check again tomorrow to hear if it spins evenly or not, but yes the engine spins and spins very fast. not just the starter.,

Again thank you all. will update tomorrow when I can check it better. Thx.

 

[tutilee]

Re: no engine compression

P.S. no buffs from carb. thank you.

 

[havasuboatman]

Re: no engine compression

Thank you all for such a quick response. Yes the plugs are in lol.

As far as the engine cleaning I only meant on the outside, No soaking or blasting
the oil out of lifters. please let me check again tomorrow to hear if it spins evenly or not, but yes the engine spins and spins very fast. not just the starter.,

Again thank you all. will update tomorrow when I can check it better. Thx.

If the engine is rotating with the starter, your next step is to check for valve movement.

 

[superpop]

Re: no engine compression

Did you actually remove the head or modify any settings on the bottom or top half of the motor. If you cracked the motor in half and installed a new Head Gasket then you need to start with the head, pop the valve cover and see if the valves are moving. Not sure if this is an interference motor or not but if it is you may have bent valves due to bad timing setup and now there is no compression even if the valves move a bit. Still lots of questions.

 

[tutilee]

Re: no engine compression

Hi, I sorry but I was not able to remove the valve cover today, It rain for the most part but will remove it tomorrow. But I did check for "spark" thats ok plus look thru oil cap hole and saw oil on the first rocker arm if thats any kind of sign. again ty tutilee.

 

[tutilee]

Re: no engine compression

Hi, yes I did removed the head. Don't really know what you meant by interference motor but will remove cover tomorrow
and let you know if the valves move when it's cranked. Ty.

 

[Bifflefan]

Re: no engine compression

Timing belt, chain or gears (which ever). Cam timing is off.

 

[tutilee]

Re: no engine compression

Hi, so are you saying that no matter what do i need to remove the timing cover. to reset the cam timing

 

[Bt Doctur]

Re: no engine compression

Cam timing should not have changed unless you removed the cam itself.
most likely the valve lash is adjusted way too tight.

 

[Maclin]

Re: no engine compression

I agree that valve lash makes the most sense given the work actually done to this engine. When I first posted I was thinking overhead camshaft for some reason and that is why I mentioned cam timing :redface:

 

[Fordiesel69]

Re: no engine compression

Timing is fine unless you had the cam out. Your valve lash is way too tight or way too loose. You need to pull the valve cover and have a look like others suggested. I had to bleed the oil out of my lifters on my diesel to keep them from having the valves hit. It took forever for them to pump up. Only half the cylinders fired for like 3 minutes. If this is your problem, they will eventually pump up.

 

[tutilee]

Re: no engine compression

Hi all, Ran a compression test and came back ZERO compression on all 4cylinders, Can.t imagine what could have gone wrong. like i explained in the beginning i took engine apart to replace ALL gaskets only. Than boat sat for about 1.5 years w/out ever starting the engine after reassembling.

Can anyone please guide me to what i should check next to try and find the problem.

Thank you all for all your help. tutilee.

 

[mvoellinger]

Re: no engine compression

Hi all, Ran a compression test and came back ZERO compression on all 4cylinders, Can.t imagine what could have gone wrong. like i explained in the beginning i took engine apart to replace ALL gaskets only. Than boat sat for about 1.5 years w/out ever starting the engine after reassembling.

Can anyone please guide me to what i should check next to try and find the problem.

Thank you all for all your help. tutilee.

Did you pull the cover like you stated previously and check the lifters/valves?

 

[cr2k]

Re: no engine compression

this is NOT an interference engine.

Most likely your lifters have bled down.

Did you crank it prior to the work you did? If so was there compression then?

If not run for year or so there might be gunk in the oil passages too.

Check for valve operation and we can go from there.

 

[tutilee]

Re: no engine compression

actually no.4 cyl. is reading 100psi. that's the only one, the rest of the pistons
are reading ZERO.

The engine ran well before i did the work.

Question what's a "interference engine." that you mentioned?

thank you.

 

[mvoellinger]

Re: no engine compression

actually no.4 cyl. is reading 100psi. that's the only one, the rest of the pistons
are reading ZERO.

The engine ran well before i did the work.

Question what's a "interference engine." that you mentioned?

thank you.

Interference refers to whether the space the valves occupy when open is also the space the pistons occupy when at the top of their travel. On a properly timed engine, the valves and piston will never be in this same space at the same time. On an improperly timed engine...well...physics has taught us no two objects can occupy the same space at the same time, and one will give (usually a vent valve and a ding in the piston).

You still havent answered us as to what the valves are doing. For you to lose ALL compression in 3 cylinders, Im guessing something with the valves.