Just started rebulding a 1991 Porsche GT M28 47 Engine.
(70 K miles on the clock, was sitting for the last 5 years)

What not to do, and what to do?
All comments/ information / previous experience welcome.
Thanks for all your help.


(My target is optimize; I want to end up with a good engine but I do not want to change each and every part)

 

Why are you rebuilding it?

 

Has been sitting for quite a long time and I started a full restoration of the body , interior and the engine. The car is an empty shell now.

 

I'm not sure I get the "BEWARE" topic...actually I don't. Also, just because the engine has been dormant for 5 years doesn't mean it needs to be rebuilt. As was asked earlier, why? Did you attempt to get it running or perhaps conduct a leak down test?

 

sitting is not that bad. sitting with say, water in the cylinders... ya, thats bad.

leak down done? compression check? did it start/run? how far is it apart? whats the budget?

 

I would only replace the external seals,
the timing belt and the water pump,
and powder coat the intake and cam covers.
new fuel lines and HCV and new dampers
and do an intake refresh new knock sensors and CPS and hall then install the engine.

If it was ruining when it was parked and was in good condition and the coolant was drained it should work well.

OH please change the thread topic,
" beware" is not a great search item to find info for engine refeshing

 

Box it up and send it to Precision in California.

Hire Rob to manage the project as it moves from body to interior to mechanics.

No other solution will result in correct car afterwards.

Will cost about 8 to 10 Submariners.

 

Sorry but wrong thread title here...

 

Why "Beware"?

In general, just sitting for a while doesn't necessitate a complete teardown/rebuild.
Drain the coolant and oil, check the condition, especially the coolant.
Try and turn it by hand, if it won't move put some oil down the spark plug holes and wait.
Check the timing belt to make sure the cams are turning.

Once it's turning without any important parts hitting, do a compression check. Use a scope to take a look at the bores and piston tops.
Pop the pan off, maybe pull a bearing cap to check the crank bearings.

Unless you find something that says there's a problem, then replace the bits Stan (MrMerlin) suggested.

But I have a funny feeling from your other threads that it's a bit late to follow the suggestions here.

 

This.

Before deciding to tear-down, determine condition of the engine. Most sit for years because of something external (ECU/MAF/relays/crank sensor).

Standard procedures for a 928 are to clean all the grounds, clean the electric panel and replace the ignition/fuel relays, replace all the timing belt system parts, replace all the external seals/rubber hoses/sensors/ignition wires, do a tune-up, and make sure the ECU's are working.

That costs about $5k in parts (maybe more like $6k these days - Porsche has raised prices a lot), and will fix pretty much any 32V 928.

The only major internal issues encountered at thrust bearing failures on Automatic cars due to the poor factory flex-plate clamp design.

Like ducman says - unless its been sitting with water inside the engine, odds are its ok and you don't need to open it up.

Good luck resolving your situation! There's plenty of help here from people with lots of experience of these cars.

 

I have cars that had sat for more than 5 years and they all started and ran like clockwork - Why rebuild?

 

Well, now, it's because his mechanic fvcked it up....

 

LFA where are you typing these posts from?
What city does the mechanic that honed you a fine hone job work in?

 

70K miles? The motor is hardly broken in yet! Sitting 5 years? Change the usual fluids, put in some fresh gas and go out for a long, fast ride! The car needs that more than anything else.

 

Bill in the other thread he started the mechanic has already honed one of the cylinders, so at this point the heads are off and we dont know where this OP is or the shop that he is using