valve guide job -- leave engine in?

[luigisdad]

Hi:
I found a friend of mine, a mechanic, that has offered to do the valve guide job on my 1989 911 Carrera for super cheap -- $400. He is planning to do it leaving the engine in. Any dangers of doing it this way?

Thanks
Roy

[dtw]

Run.

[OldTee]

and hide. I dropped a 79SC engine with 3 hours of work and I am 71. Forget it, have it done right.

[BoxxerSix]

Find a better mechanic. There is nothing he can do to the guides with the motor in then car, period. Anything being done to the guides(reaming or replacement) requires head removal, and anyone doing it right would pull the motor as such.

[cgarr]

Maybe he was just gong to replace the seals and call it good? In any case its a lot more work to pull the heads with the engine in than out. Was he going to reuse the antifreeze or putting new in?

[equality72521]

Roy, I suggest you search this site and learn as much as you can about this subject. Only then will you realize just how ridiculous and stupid his offer is.

[BoxxerSix]

Originally Posted by cgarr

Maybe he was just gong to replace the seals and call it good?

Even that'd be damn near impossible in the car. You have to remove all the stuff to get to the rockers and rocker shafts and remove those as well. then and only then could you pressurize the cylinders at TDC(locked) to remove the valve springs/retainers/keepers to get to the seals.

Could be done, but should still be far easier with the motor out and in a stand, or at least sitting down secured on something. And surely not for $400, unless he's a REALLY good friend.

[sww914]

You cannot replace valve guides with the heads on the engine. The valves must be out of the guides to replace the guides. Only somebody with no Porsche experience would be afraid to pull the engine to remove the heads. I on't think that it's possible to remove the heads with the engine in the car. These are not small block chevys. You don't want anyone without any Porsche experience working on the engine.

[lindemans]

Heads must come off.
My main concern reading this: if a guy does not know the details around correctly putting a 911 engine back together, he will never be able to get the heads and all back as they should.

This will easily create consequential work to be done or even damage that may well cost you 10x 400 to get the cheap valve job corrected ...

Don't let someone who is afraid of dropping the engine work on your car.
Dropping the engine is about the easiest task on a 911 ......

Do it right, do it right later or don't do it at all.
No alternatives.

Hint: buy Wayne's book and get a sense of the build up of the engine and the specific care that you MUST take at some points. I still don't understand why they made it so complex in Stuttgart, but it is what it is...

[TibetanT]

Run, Forest...run!!!!

[cstreit]

I actually saw someone remove the heads from a 911 engine with it still in the car... Once.

I suspect that this guys is a domestic car mechanic who's used to doing it this way... Trust us, it's a LOT easier to yank the engine and do it.

[911pcars]

In case anyone was wondering, the heads must be removed from the engine in order to replace valve guides. Reseating valves to valve seats is part of the job.

Chris said it. It's easier to remove the entire drivetrain. However, it's not impossible to remove the cylinder heads and leave the engine in the chassis (He might have to drop it a bit). Perhaps your tech friend doesn't realize the time and convenience of dropping everything for easier access. However, if he prefers it that way and can perform the job to spec, who's to say he won't do it properly? I'd get some add'l reassurances first though. It helps if he's a real good friend and an equally good tech. Many shops charge $400 just to R&R the drivetrain.

Sherwood

[ChrisBennet]

Is there some miscommunication? Perhaps he/you is confusing valve adjust with valve job?
-Chris

[Aurel]

I thought about that, but he wrote a valve guide job, so...Otherwise, yes: a valve adjustment would cost ~$400, and is done with the engine in the car.

Aurel

[timc]

Originally Posted by luigisdad

Hi:
I found a friend of mine, a mechanic, that has offered to do the valve guide job on my 1989 911 Carrera for super cheap -- $400. He is planning to do it leaving the engine in. Any dangers of doing it this way?

Thanks
Roy

Roy, I think I used to own a car that your mechanic worked on. When I pulled the engine out, and the fan shroud off, the cylinder deflector tin was installed correctly on the pass side, but on top of the cylinders on the dr side, thus blocking all air flow to those cylinders.

If I would have continued to drive this car with the above, it would have ruined all three pistons and cylinders, among other possible damage.

Find a new mechanic.

[930gt-40r]

Originally Posted by luigisdad

Hi:
super cheap -- $400. He is planning to do it leaving the engine in. Any dangers of doing it this way?

Roy, was there drinking involved when he told you this?

[stevepaa]

take it to henry schmidt and get it done right.

you get what you pay for. and in this case you'll get a damaged engine the first time you start it.