Top vs. Full Rebuild?

28tbsfan · 28tbsfan's Garage

New owner here and I need some advice. The PPI stated that I had several oil leaks (rear main seal and crank pulley) to name a few. My mechanic wants $3500 to do the work because it requires the engine to come out. It is an 89 911 Targa with 114k miles on it, great paint job, good trans + clutch, and just recently had a full brake job.

My question is would it be worth it to do an entire top rebuild since the engine has to come out? What does that entail, how does it differ from a full rebuild, and how much will that improve the performance? Also, what is the average cost for that kind of work?

Thanks!

yelcab1 · 09-26-2009, 09:59 PM

Rear main seal is easy, but crank pulley requires the engine case to be split for a proper rebuild. $3,500 is about right for that. If that is the case, then $1,000 more would give you a full top end rebuild since the labor is already included. A full rebuild would be a little too early with 114K on the clock, in my opinion.

logan2z · 09-26-2009, 10:01 PM

Quote:

Originally Posted by yelcab1

Rear main seal is easy, but crank pulley requires the engine case to be split for a proper rebuild. $3,500 is about right for that. If that is the case, then $1,000 more would give you a full top end rebuild since the labor is already included. A full rebuild would be a little too early with 114K on the clock, in my opinion.

I see you're in San Carlos. Which shop in the Bay Area does a top-end rebuild for $4500??

yelcab1 · 09-26-2009, 10:05 PM

I did not say that !.

What I said is if his mechanic is splitting the case to repair the crank pulley seal then the heads are already off. He can send the heads off for a valve job for $750 at German Precision in Sunnyvale and bring them back for assembly by this mechanic. That would be $1,000 more than $3,500.

My valve job is $1,000 with all free labor by me. I got all 12 used steel studs in the process for free.

28tbsfan · 28tbsfan's Garage

Quote:

Originally Posted by yelcab1

Rear main seal is easy, but crank pulley requires the engine case to be split for a proper rebuild. $3,500 is about right for that. If that is the case, then $1,000 more would give you a full top end rebuild since the labor is already included. A full rebuild would be a little too early with 114K on the clock, in my opinion.

Thanks! Would the performance improve with this being done? What exactly does a top rebuild entail?

yelcab1 · 09-26-2009, 10:10 PM

No performance improvement with this job. A simple valvel job means disassembly of all heads, clean all components, re-cut the valve seats and valves, fly cut the heads, re-assemble with new seals and valve guides. If you want more performance, you would ask for port and polish (mucho money). In your case, you may just want to add a Steve Wong chip and be done,

28tbsfan · 28tbsfan's Garage

Quote:

Originally Posted by yelcab1

No performance improvement with this job. A simple valvel job means disassembly of all heads, clean all components, re-cut the valve seats and valves, fly cut the heads, re-assemble with new seals and valve guides. If you want more performance, you would ask for port and polish (mucho money). In your case, you may just want to add a Steve Wong chip and be done,

The problem is my car smells like a NASCAR from the oil leaking. I have to get these oil leaks fixed to truly enjoy the car. Although, if the top rebuild will do nothing to improve the performance of the car, then I'm not sure it is worth it.

RoninLB · 09-26-2009, 10:44 PM

valve guides wear

test your specs valve guide to valve stem

also test thrust main bearing clearance

Bobboloo · Bobboloo's Garage

$3500 is crazy in my opinion to replace those two seals. Splitting the case is not necessary to replace the crank seal. Removing the crank pulley is, but splitting the case is not necessary.

The case would only need splitting if you needed to replace the #8 bearing O-ring seal but that's not the same as the crankshaft front seal which can be pried out after removing the pulley.

To bad you aren't close by. I'd do a top end overhaul and fix the leaks for $3500 provided no valves or valve seats need replacing. Oil consumption should determine whether or not you need a top end overhaul anyway.

Let's do the math on replacing the two seals. R+R the engine and tranny. 4 hours. Replace the two seals. 2 hours. So that's 6 hours plus the cost of the two seals. How can this be over $1000?

Shop around.