Lincoln LS no compression

I had my 4.6 in my Expy bend a valve, broke the spark plug and ran it through the piston.

It would have cost more in just parts to rebuild then it was to grab a remaned.

Those Romeo 2V 4.6's are not cheap.
 
Has been a while since I posted. The owner bought a used engine so we installed it as it was "in good working condition" when he got it.
Long story short, the engine fired up and now there is no compression on cylinders 4 and 8. Already checked it with the dealer scanner and those cylinders are almost flat. Also did a leakdown test to pinpoint the cause and we couldn't figure it out.
I removed the engine again and dissasembled everything. Valves look good and appear to be seating as they should, rings are not broken or seized in the ring lands.
What would you guys do? I'll post some pics in a bit.
 
Where

Do where are the pics and what was the problem. Maybe you should give up.


Imanol Alamillo said:
Has been a while since I posted. The owner bought a used engine so we installed it as it was "in good working condition" when he got it.
Long story short, the engine fired up and now there is no compression on cylinders 4 and 8. Already checked it with the dealer scanner and those cylinders are almost flat. Also did a leakdown test to pinpoint the cause and we couldn't figure it out.
I removed the engine again and dissasembled everything. Valves look good and appear to be seating as they should, rings are not broken or seized in the ring lands.
What would you guys do? I'll post some pics in a bit.
Click to expand...
 
Riccio said:
Do where are the pics and what was the problem. Maybe you should give up.
Click to expand...

What pics do you want? I won't give up, I already have the engine in pieces. Thinking on buying piston rings for that two cylinders and lapping the valves/check seats.
 
You can check compression with a scanner? And what do you mean by couldn't figure out the leakdown test?
 
Please send as many pics as you can as I will need to do the same thing as you. My tensioner a also went but I don't think my chain jumped. How can I tell if it jumped and if I have any engine damage as I hope I can just change the tensioners and fix it on the cheap.

Imanol Alamillo said:
What pics do you want? I won't give up, I already have the engine in pieces. Thinking on buying piston rings for that two cylinders and lapping the valves/check seats.
Click to expand...
 
stugots said:
You can check compression with a scanner? ...
Click to expand...

No, but you can check cylinder balance. (It's a self test that deactivates each cylinder, one at a time. Then it checks to see how much each one slows the engine down. No change in RPM, and you know that cylinder's dead.) That's probably what's he talking about there.
 
Yes, there is a test with the oem diagnostic unit called relative compression, that is how we knew there was a problem with those cylinders.
Apparently the exhaust valves are the problem here, bit I am changing piston rings as well and lapping all the valves.
The assembly process has been good so far, just need to know some torques values for connecting rods and oil sump.
 
Hi guys! It has been a long time since I last posted, but in with some news. Already rebuilt almost the entire engine, checked valve heights, new piston rings, gaskets, etc. I thought it would be ok to share some photos. Did a cleanup on the engine internals and finally was able to restore compression on the engine.
 
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A+ on the cleaning. Looking at how shiny the block is, I'm guessing there was some soft blasting (like walnut or corn husks) and dipping involved. Looks cleaner then a lot of factory crate engines I've seen.

So when you took the engine apart, there was actual build up or something that caused a failure? And what did you do about rod/main bearings on the crank? The bottom end on the LS 3.9 always seemed to be the gotcha for doing rebuilds, although it looked like it was the same as the 4.0 Jag blocks with the exception of the piston rings (Nikasil vs Iron bores)
 
nice.
those look like the old style secondary tensioners though.
there is a newer style, and since the engine is out and everything, i'd be replacing them now.
 
Really cool to see the engine all cleaned up like that. Thanks for sharing!
 
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