RED SHARK 1990

I had sent a pair of cylinder heads from my 1990s4 for a valve job, new guides,stem seals and surfacing from 928 motorsports. Here is the thing when we removed the oil check valve in the heads there are debris inside the spring and ball bearing so we cleaned them out ,is it typical of the job for the machine shop to clean them out and put back cleaned? When i ask Carl he said we supposed to clean them after they came back.....Then why do we pay for the job that should have done the cleaning ? Is this the way most shop do their work? I just wanted to know.

BC

Luan - The proper way to work on a set of our Porsche 928 32V heads is to completely disassemble them, and specifically remove the check valve as well as the "plugs" that set at both ends of the pressure pipe which has been machined into the heads at production.

Many... MANY people simply are not aware of this and for this reason, when heads are rebuilt, these oil passages are clogged with crap.

928er

That is correct. it is missed by many shops.

RED SHARK 1990

I paid 928 motorsports for the complete job,and i thought they would do the cleaning all the parts on the heads and re-assembled? Is that supposed to be done if you paid a shop to do the work..

BC

Honestly, not speaking about anyone here or elsewhere in particular - as Sterling said not many people even realize this. Further - trust - actually TRUST, "mechanic, contractor, knowledge, know-how-wise" about 3 people in this country for these things. And I have met and dealt with a much larger number than that.

Mike Simard

If you're getting assembled heads then yes, they are supposed to come clean and ready to bolt on, assembled in a clean area with care and packaged well.

A bare block or heads from a machine shop is understood to be cleaned by the builder but assembled heads are completely different.

It's not surprising to hear that someone is getting filthy assembled heads and that's not unique to your source or 928s. There are very few shops that actually do that well. The majority of rebuilt heads out there are packed with abrasive crap.
I've seen it time and time again, nice looking shiny heads wrapped in plastic but when you look close and take the valves out there is the bad abrasive kind of grit that will screw things up. It's that way in the majority of machine shop rebuilders and half hearted engine builders.
It's alot more time to build a head well. Nobody understands the importance of workmanship when shopping around and this lack of consistant quality has tainted the whole trade so that consumers look at crate motors as superior because of the wide range of quality among builders.
Anyway, sorry for the rant, it's a subject dear to me. If I had to have a set of heads rebuilt right now it would be a dilema. There are shops around here but I know what would happen. There are only about 3 folks in the world that I trust enough to build a set of heads without packing them full of dirt and then there's the other stuff that's really important like seat runout etc. It would be much easier to find reliable brain surgery.

BC

That's funny Mike - you mention "3 people" as well.

I wonder if its the same three people. Probably not, as you are one of mine. So maybe if the other two are different, I can get yours, and have 5?

Mike Simard

Well Greg Brown is obvious. Another is a customer who builds racing engines, KSS Motorsports. Sterling may have a good source too.
The key is for it to be someone who is serious and has a reputation to nurture. There are alot of half hearted car guys and local machine shops out there that are just not going to put alot of effort into it.

Mrmerlin

this situation will also happen when you have the crank polished ,
the oil journals will fill with the polishing compound though the crank may look all clean,
a cursory check of the journals with a few cans of brake cleaner may prove otherwise.
I would say that the heads are the same way,
everything must be cleaned after the machine and cleaning work is done ( grit blasting)
NOTE you will find that every bolt hole has to be traced with a tap as the grit blasting materials will fill the threads.
Pay close attention to the intake manifold bolt holes and the exhaust manifold bolt holes and the water bridge,
as any exposed bolt hole will get grit in it and should be cleaned prior to installing the heads

and all of the oil passages should be flushed with brake cleaner and then blown out with compressed air,

hopefully the head was washed before final assembly so the valves and guides are free of abrasive materials.
The oil passages should be triple cleaned to include removing the tapped in caps then the bores are cleaned with a bore brush similar to what you use to clean a gun barrel

GregBBRD

This is easy.

If there is dirt in the oil valve, there is dirt everywhere in the oiling passages. You can't clean it out, after the heads are assembled....the dirt will run out the oil holes where the lifters go and get all over the valves and new guides. If they bead blasted the heads, the silicon beads will ruin the engine.

You need to start over.

928mac

I dont know where else you guys get your stuff done, but as greg said it will distroy your engine.
It was obviously not disassembled properly, it was obviously not high pressure steam tanked, which is part of the job so this would make me believe that the rest was not done correct.
Do it right or not at all
Sorry Carl but to send back an unsteam'd head is shoddy work. End of story

FBIII

If your rebuildimg an engine you can't assume everything has been done correctly and completely. You need to check work for cleanliness and accuracy. You get a block or crank back from a machine shop you don't just throw a set of oversize rings or bearings on. You check clearances and double check. Its part of the process. You were fortunate in that you were doing just that, double checking someone elses work.

Mrmerlin

though you can see how much dirt comes out by spraying some brake cleaner in the lifter bore oil feeds this will run into the main oil feed galley and then rinse out ,

but the head should have been cleaned prior to final build

RED SHARK 1990

Well i thought i will give people benefit of the doubt, Mark Anderson has a source for me as it was too late as i had the heads already sent out to 928 motorsports. Before the heads were sent out i spoke to Carl and he assures me that the machinist was one of Carls best? The check valve cap we saw had some wear and debris inside the spring ,ball etc. After the head were sent back they told me it was ready for the install,we decided to see if the are clean or not and they are not....I paid for a complete valve jobs,new guides install and seals.....how could you clean the heads after when everything are fully assembled????? people like money but they dont deliver the goods anymore,except for the very few that cares....

Imo000

What does Carl has to say about this?