Good evening everyone and thank you for reading! Looking for some input from those who’ve done this before me. Around 260,000 miles my engine developed a miss. Upon checking I discovered it was the number three exhaust valve leaking. I did not do a compression check on the cylinders but I did a leak down test with the engine cold and every cylinder held 92 psi with 100 psi input (except number three of course which only held 79 psi). The heads are off of the engine and at the machine shop. My question is, should I pull the engine and rebuild the bottom end? Cylinders appear to be in pretty good shape, you can see the cross hatching and you can’t feel a ridge at the top of the bores where the rings stop. Just curious what the folks who have already been down this road would say.

 

In my opinion, bolt your reman heads back on and keep driving. I pulled my 3VZ at 365,000 to do a 3.4 swap. Still no sign of bottom end trouble at that point.

 

If it ain't broke, don't fix it. Leave it alone.

 

Same here. I left mine alone in the same situation also. After 10000 more miles it is not using oil or doing anything bad at all. I spent the money I saved not doing the bottom end on long tube headers instead.

 

When Larry at Yodaman did my head gaskets, he said the bottom end looked nearly perfect, so we left it alone. This was at 196,000 miles.

 

When I rebuilt my 3vze I also reused the bottom end. It looked perfect at 225k miles. Same for the pistons. I was very impressed. Nothing these days can match the quality of the Japanese old school metal casting.

 

I concur with the others here. Leave it be. If you want to get THAT much into things, you are probably better off just going 3.4 rather than rebuilding the bottom end on your 3.0. Unless there is something blatantly wrong with your 3.0, just slap your heads on and go.

 

hey if you did replace the bottom would you replace the bolts too or just reuse?

 

I rebuilt the top end and put as many new parts and gaskets on as I could during the rebuild. I left the bottom en alone with the exception of the front crank seal. After 5000 miles I’m pleased to report that it runs fine, doesn’t smoke and is getting about 17 miles per gallon. I do have one small leak that I suspect is the rear main seal. It all seems to drip. Not much at that.

 

If you don't put those half-moon seals into the valve cover with the right sealant, they'll leak. Every time. Probably where the leak is coming from...
Pat☺

 

If the leakdown % in the good cylinders is under 10% you should be golden. When a cylinder is over 20% the risk of oil consumption after installing the heads is pretty high.
When you have numbers are under 10% or over 20% making a decision is easy, it's the 11-20% range that gets risky. Most techs are ok with 11-15%, but 15-20% they'll advise the customer of the risks involved and the possibility of oil use from the increased pressure from the redone heads.

And like a compression test, you want to see little deviation from the high/low numbers. No more than 10%