Should I rebuild the bottom end?

[KillerDynoSoar]

Originally posted on the other forum but I guess this is the right place for this kind of post.

I have a 85 3.2 of unknown mileage in my 77 backdated Carerra 3.0
I am currently having the top end rebuilt and so the engine will be in tip top condition.


I have a dilemma, should I split the case and have the bottom end rebuilt too? The engine was driving fine apart from some worn valve guides and rings. My engine seemed to be getting good oil temps and pressure when I have been running it and oil consumption isn’t excessive. However, I am not sure how well my Carerra 3.0 gauges are reading the 3.2 vitals.

The top end is costing me bucks because of the things that I have to have replaced. My engine builder knows my budget and has told me to that the top end rebuild should be fine. He is warning me that the bottom could cost me a lot more. It seems fine so don’t do it.

I am however a little worried. What if my bottom end lets go after the rebuild? Will I have wasted all my money?

What have all you guys done with regards to the top end vs top&bottom rebuild choice?

There seems to be no immediate problem with my car, will the top end rebuild suffice?

I need advice or reassurance...


This is what another forum member said...

Originally posted by JeremyD
If it has unkown mileage - then for piece of mind, I would split the case. I hope you are doing rod bolts too.

I'll bet you $500 that your layshaft bearings are showing copper.

Does anyone agree?

[cstreit]

Well bottom ends just don't "let go" unless there is a problem.

I believe the current factory hours difference between and R&R top end and a complete rebuild is about 16 hours (60 vs. 44). So it might be worth discussing this with your mechanic regarding cost. 16 hours plus parts should be a reasonable amount, and in actuality may be closer to 10-12 hours. Add in seals, bearings, and a line-bore/oil-pump check and I don't think you've added an astronomical amount.

I would also recommend a bottom end if you're going this far and don't know the mileage in your engine... If only for the piece of mind and a documented history. THis is all assuming you plan on keeping the car a good long while. If your oil-pressure was good and you're only going to keep the car for 20-30k miles then it's probably not worth it.

The 3.2 case is pretty bulletproof so there isn't a lot of risk in splitting it vs. the older magnesium cases.

[Scott R]

I had to pull the top end apart on my 3.0, and I found that it had been apart before for headstuds. I decided to crack the case at that point and I'm happy I did, the intermediate shaft bearings were a mess and the mains were pretty shot as well.

In the end it was an an extra two hours to tear it down and now I'm having everything balanced, checked and rebuilt for a good piece of mind.

[KillerDynoSoar]

My oil pressure seems to be ok showing
6druck at cold
4+druck warm and driving
6druck on full load
2 druck at Idle.

This is in very hot weather too.

My Mechanic told me that because I have a 77 Carerra3.0 gauges that they may be reading alittle high.

He has stressed to me that its not worth rebuilding the bottom end of this engine. He says the 3.2 motor is a strong well engineered bit of kit.

Perhaps I am worring too much. Also I doubt I'll be keeping this car longer than a couple of years. Its a weekend driver.

A