Valve Stem Lengths and Crappy Service

[Fishcop]

About now I'm pretty p!ssed. Finally got most things ready to put the engine together over the weekend. Fortunately I have received some good advice from others on this board along with Wayne's book, so I 've take the time to "pre-build" this engine without using gaskets and sealant as it has S cams and RS pistons which are new to the engine.

I finally timed the engine and checked for piston/valve clearance which seems fine on the left side, but checking the right side I began to find problems. Basically as I was setting up the intake rocker for #4 and noticed that I had to screw the "foot" right in before it touched the valve stem. I was still able to set the tappet though. I timed that side of the engine no worries, but as I was "graphing" the valve/piston clearances over 720 degrees I found the engine wouldn't turn past a certain point. I found that the camshaft was being prevented from turning because the intake valve was "bottoming out" with no more pivot in the rocker.

The result I've now worked out is that the intake valve stem is too short. The original valves were part number EL91110541500 and were 114mm long. The new valve is part number TRW T3051/1 and 109mm. These heads were sent away and build by a professional.... Surely this should not be a mistake a pro shop makes?

Yet again I'm being held up by vendors and professionals' mistakes. Living 2 hours away from the city makes this even more frustrating and time consuming.

[Wayne 962]

So the foot was hitting the stem seal, or the guide itself?

-Wayne

[Fishcop]

I think it was getting pushed up to the stem seal. Therefore there was no move pivot left to allow the high lift cam lobe to pass.

I got hold of the chap who built them and it appears he used turbo valves on three of the heads on purpose. Something about some damage done by previous work made the tubo versions the best solution, he just forgot to mention/supply lash caps/shim buckets.

Does this seem right?

[Henry Schmidt]

Sorry to hear about your problem. If I understand you correctly he put 49 mm valves from a 3.0/3.3 turbo in your 2.7 46 mm head. I assume he cut the diameter down but this is a horrible repair. If the problem was damage or over cutting of the valve seat ( I'm assuming) he should have replaced the seat/ seats.
If this was my engine or an engine we were building, I would start over at least with those three valves.
If I can help, let me know.

[Fishcop]

Thanks Henry

I will be dropping the heads back to him to go over again and I'll discuss this with him. In his defence he is quite well respected amongst vintage Porsche people and has worked on these engines over 40 years (ex So Cal before coming to Oz). I will hear him out....

[SteveF_911]

Well John I guess you wont have the new engine for the Leyburn Historics.

You will need to drop the heads back, I would suspect that a bit of old stock may have been used.

If you paid the money for new valve I would be demanding the correct parts.

Best to be nice and willing for a long conversation....

I share your frustration, we don't have a lot of Porsche experienced machine shops in Qld...

[Fishcop]

Pretty sure everything is new... The fact is I don't understand valve/seat/guides very well, so if he tells me this was the best repair then I can't really argue. Conveniently he didn't have a receipt available to me at the time and hasn't posted it out to me yet...