Questions on Re-build

Groesbeck Hurricane · 12-12-2001, 07:43 PM

I finally have the engine out to replace the broken head studs. I am also doing the update to the timing chain tensioner. I note the timing chains look in excellent condition for 100,000+ miles in an '83 911, but also note they were made in France. Is this normal?

My concern other than actually being able to get out the studs is the condition of my valves. I have some photos that did not turn out very good, and are JPEG over 100K. I have the ancillaries taken off the motor and have exposed the studs, valves, chains, etc... I note the following about the valves:

Cyl Exhaust Intake

1 Valve has white powder Valve is black
Chamber is clear chamber is black

2 valve has white powder valve is black
chamber is clear chamber is black

3 valve is oily valve is caked black
chamber is black chamber is white

4 valve is white powder valve is black
chamber is black chamber is clear

5 valve is white powder valve is caked black
chamber is black chamber is almost clear

6 valve is white powder valve is caked black
chamber is black chamber is almost clear

The crank had some initial resistance to moving to top dead center (vehicle sat for several months prior to working on her) but after initial movement the motor turns easily.

What should I be looking for further into the engine? Any ideas, thoughts, or prayers (if necessary) would be helpful.

I had photos of the engine removal and how we raised the car, but the developing place has conveniently misplaced them. If they show up and are small enough or I can get small enough, I will post.

RoninLB · 12-12-2001, 10:21 PM

What do you want from this engine. Street, track, bullet proof, or good enough?

Ken Gentry · 12-13-2001, 04:06 AM

Boy at 100k I'd replace the timing chains, guides, and associated gears for sure.

jabb · 04:57 AM

I would definitely have the heads redone at this point....
You can send them off to EBS. Since you have broken head studs
the heads may have been moving around a little when the cylinder fires resulting in uneven sealing surface between the head an cylinder

Groesbeck Hurricane · 12-13-2001, 05:39 AM

Ronin,

I'm looking for a street car with an engine as close to bullet proof as possible. Money has been the issue as we have had to put it into the farm. I am mostly concerned with what I should be keeping an eye out for with the blackened valves. Should I be looking at replacing with Sodium? The PO had some work done at a dealership in Houston and they overtorqued some stuff and stripped out the heads of bolts. I have been cutting and cussing for several weeks.

Ken,

I looked at replacing everything, but it all looks very good. Any other ideas? I always heard chains can last for 1,000s of miles.

Joe,

That has been my fear. I noted something was definately wrong when we heard a loud noise from the engine (sounding like timing chains) and had smoke from burning oil coming through the vents (for those that remember).

THANKS TO ALL!

Jim Sims · 12-13-2001, 06:11 AM

I believe your exhaust valves are already sodium filled. I would get a complete head/valve job done at this point. I would also change the timing chains and ramps at this point. Chains are relatively cheap and the wear is deceptive; it is a real eye opener to hold out a new and used chain and note the greater lateral sag in the used chain. I have received new OEM Porsche parts from Spain, the Czech Republic, France and of course the Fatherland. How do your P&C's look? Have you checked the piston ring lands for wear? How's the cam tower stuff look? Are you going to go into the bottm end? A data point: given where you are now I have to believe at the minimum you're looking at $2000 to get the engine back together using new parts (studs with nuts, gaskets, chains, ramps, tensioner upgrade kit, etc.) and quality head and cylinder end machine work. Good luck, Jim

Jim Sims · 12-13-2001, 06:26 AM

David, In my opinion there is no substitute for a good collet type stud remover/installer. I have used the SnapOn version with good success. If you are going to replace the studs yourself you really need to have one of these with the proper collet for the stud thread. If a stud is broken, then the cam/jamming type is useful but I would only install new studs with a collet type tool.

Jim

Jim Sims · 12-13-2001, 06:50 AM

My error, sodium cooled exhaust valves apparently were not OEM after '77. If your exhaust valves have a "divot" in them they are sodium filled. If not; replace them with sodium filled units. Cost of head/valve job just went up! Jim

Groesbeck Hurricane · 12-13-2001, 02:17 PM

Jim,

Thanks for the input! My original estimate was $2,500, but I feel closer to $3,500 right now. Do I just send one of the horses straight to Wayne? (Wonderful, fast, one horsepower Medium Bay Thoroughbred mare. Likes women.) I will be spitting out money for sodium filled valves.

Anyone have inputs on who does the best work for the pistons? John, any costing information here? This is far beyond what I am capable of. I can tear down and put back, but no machining.