engine overhaul

[hotrod351]

my 73t is doing a bit of smoking and oil driping, with 140,000 miles on it. i was thining of just reringing it and having the heads done, also replacing the rod bearings. anyone had any success with this. i know it wont be perfect be the car only get driven a couple months during the winter out of the year. there is a place in phoenix that says they can regroove the pistons for different rings and bore the barreles and that will save me a lot of money, but then the pistons will be loose in the barreles. any other opions. thanks.

[Groesbeck Hurricane]

Hotrod,

Have you checked to make sure the head studs are not pulled? I would do this prior to making a decision on working with the rings and heads. Are you familiar with how to check the studs?

[Wayne 962]

A top end job will almost certainly result in pulled studs and a complete rebuild about 10,000 miles later. There really isn't such a thing as a top-end rebuild on a mag-case engine - it just doesn't work (95% of the time).

-Wayne

[Groesbeck Hurricane]

Noah,

No offense taken! If I'm wrong it is better to correct me than let someone do something that is incorrect. I appreciate knowing when I'm wrong. I rushed to the idea as that was the part failure that caused my engine to leak oil. Rings were good, top end was fine, bearings were in spec, but oil was leaking out and burning on my heat exchangers. Five broken lower studs....

[hotrod351]

well im sure that checking the head studs wouldnt hurt anything, how would i go about checking them.

[crashr]

Wayne, I don't understand your comment. Your saying that if you do a top end rebuilt, that you will only end up with pulled head studs later. I'm sorry I just don't understand what you mean?

[Wayne 962]

crashr, that's exactly what I'm saying.

To explain it a bit further, when you do a top end rebuild, you're using new components, mixed in with old ones (the bottom end). You're retightening the heads and placing new stresses on the engine that weren't there before. This causes disruption to the case, and makes the (already fragile) head studs pull out. They don't need much coaxing to pull from the case, and disturbing the top end almost always results in pulled head studs later on down the road.

Make sense?

-Wayne

[emcon5]

Just to clarify, Wayne is talking only about Magnesium cased engines, aka 2.7 and smaller.

Right Wayne?

Tom

[limble]

When replacing the head studs what is done to the mag case prior to installing the new head studs? If the case i.e. threads on the case are stressed then adding new studs won't help. Do you install an insert?
Do they come with the new studs?

[Wayne 962]

Yes, I'm only referring to magnesium cases, and the top end 10,000 mile failure is most seen on the 2.7 engines...

You install case savers into the case that have a bigger and coarser thread. They will not pull out unless something goes really wrong...

-Wayne