Top end Rebuild
 

Hello, everyone. Please excuse my ignorance, but I wanted to know in a top end rebuild, what is done to the engine and what parts of the engine are replaced, and how would you know if you need one? Once again I'm sorry for this stupid question, I just want to know more about my car and what I can do to take care of it.

Thanks,

Jinkatin
86 Carrera

Sorry, I forgot to ask how much would that cost to have a top end rebuild done?

Thanks,


Jinkatin
86 Carrera

I don't know that there is a hard and fast rule but typically it involves removing the cylinder heads, pistons and cylinders which are then checked to see if in spec. Some might say it only involves the cylinder heads. Anyway, any parts that measure in spec often can be reused. Next is the valve job aspect which also has variables, i.e. can any of the valves be reused. Valve guides are always replaced since they are a weak spot. I got lucky and when I sent my heads out to Walt at Competition Engineering I only had to replace half the valves (exahust IIRC). FYI, I was quoted $8-10k for a top end ONLY by a highly respected Porsche shop here in the Dallas area. That's when I decided to do it myself, except obviously the parts that CE did, and of course I sent the parts out locallyt to be measured and evaluated. If you do it yourself there's no reason to stop at the top end if the engine has a decent amount of miles. You're nearly there once you get everything removed for a top end and all you are staring at is the short block. Do you suspect you need a top end...burning a lot of oil?
Check the rebuild section and you'll get a lot of useful data. Even if you pay someone you'll be a lot better/educated customer after spending some time on this site.

Thanks for the info, but no it does not burn a lot of oil, it smokes when i start it and at a stop when it is at running temp.

A top-end is typically heads, cams and rockers.

$8-10k is patently absurd for this amount of work.

A top-end might include removing and inspecting the pistons and cylinders, replacing the exhaust head studs (very typical) and cleaning the pistons and cylinders and installing new rings.

P&C Service $400 .
Rings $175
Gasket kits $300
Rebuild heads: 3-angle valve job, avg. $750
Regrind cams (stock) $350
Refurbish rocker arms $250
Head studs $200

Parts & Machine (EST.): $2,425

Labor? maybe 20-25 hours bill-able @ ~$90 avg. : $2,250

Somewhere in the neighborhood of $4,500-5,000, tops, from a shop with a pretty high labor rate.

Can you quantify what you mean by "burns a lot of oil"? (qt./___miles?)

Scott...couldn't agree more regarding the price, in fact it made me question the wisdom of owning the car in the first place! In fact what put me over the edge to doing it myself, other than the obvious fact that I could count on this board for help, was when the guy I was talking to casually mentioned that "80% of the job is taking stuff apart and cleaning, mostly just cleaning" The parts that require what I'd call "exceptional skill" (head work and measuring) I just let experts do it. The rest of it is just patient diligence. I'll admit that it's a little stressful when you listen to frank exchanges of ideas about various specific details like sealing surfaces and such. I've been wrenching on cars for 30 years on the weekends but this was a substantial jump in work.

It is very doable, I did it without prior experience (see my thread). After 3,000 miles, I am very happy with the result: no smoke, smooth engine with good power. And now, I`ve got tools and some experience. Go for it yourself !

Aurel

Same here. It's not rocket science. It's Porsche science.

Brian

... with a touch of voodoo.

Not only is it fun to do the work yourself, but it is rewarding beyond words. Lots of resources here and in the form of books. Very doable.

why do you think you need one? do a leak down test and a compression test and check against specs.

That one list is pretty short....

Be prepared that your P/C set may be out of spec and need replacing....
Chains?
Ramps?
Sprockets?
Oil return tubes?
Intake valves worn?
Exhaust valves worn?
Rockers?
Broken studs? Exhaust and head etc....

Etc...

There is a chance you can get out fairly inexpensively, but you need to be prepared for more $$ if required. You really can not know until the motor gets opened up.

Cheers

Thank you all. My 86 Carrera burns about 1qt every 1000 miles or so, it smokes when I started then when I am at a stop after I have been driving it for about 25-30 minutes or so.

Aurel's right. I'd bet you'd find a LOT of people on this board with average wrenching skills who rebuilt their top ends successfully. With "the book" and this forum, it's really hard to go wrong. You live in an area where you'd get a lot of volunteer drop-ins to help out. And, I might add, it's really a lot of fun, and you learn so much.

Currently I'm helping a friend on a complete rebuild of his 3.2. We just got the crank together - next task is to assemble the case. Neither of us has ever done a total before (just top ends), but we forge ahead confidently!

JB

Your oil consumption is excellent, so no problem there. Smoking on startup is perfectly normal for these cars. What's not normal is smoking at a warm idle. What color is the "smoke"? If it's white, it's condensation and you may just have water trapped in your exhaust system. If it's blue, then you're burning oil, but you'd be adding a lot more than a quart every 1000 miles if this is happening all the time.

Don't even think about a rebuild until you've had a competent shop do compression and leakdown tests. They will tell you a lot about the health of your engine. If you have worn/broken rings or worn out valve guides, chances are these tests will reveal them. If the engine tests out good, a rebuild probably isn't indicated and your problem likely lies elsewhere.

How many miles are on the car?