Looking for help with botched head work

[Dave Whittick]

I sent the heads from my 64C off to a local shop (2 hours away), recommended to me by other Porsche owners in the area. The shop had the heads for 9 months and I lost communication with them 3 months ago. After a dozen failed attempts to get in touch, I finally drove to the shop to retrieve my heads. I'm happy to have my heads back but I'm a little upset with what had been done to them. Can anybody suggest what direction this guy may have been heading in? He's loaded a tonne of weld into the combustion chambers of each cylinder and cut a chamfer into each edge.


I'd appreciate any suggestions to save the heads as well as a reputable shop to do the work.

[Ron LaDow]

Dave,
WIH was he instructed to do? I'm wondering what sort of piston dome he had in mind.

[Dave Whittick]

I told him that I had a big bore kit to go in. He recommended a super 90 cam and he was going to oversize the valves a little. These weren’t to be a radical head redesign.

[Martin Benade]

It is good that you got them back before he did more. I can't imagine it would have gotten any better, but I hope he wasn't finished. I am pretty sure you will spend less and have better results buying another pair of heads, although they will not be cheap. I hate to even look at what he did.

[Mike Wilson]

I'd check with Walt Watson at Competition Engineering. Maybe send him the pics and see what he says.

Mike

[Dave Whittick]

I have to assume that he planned some sort of chamber reshaping. It doesn’t do me any good. Still doesn’t explain the chamfer.

[Dave Whittick]

I'd check with Walt Watson at Competition Engineering. Maybe send him the pics and see what he says.

Mike

Thanks.

[Jon Schmid]

No idea where you are located, Dave, but maybe Ollie's can help? I assume they are still around...

[Martin Benade]

He resurfaced the sealing surface before opening them up for larger bore, I don't think he listened to you much.

[Ron LaDow]

Since I'm only seeing one side of the issue, it's not where I'm gonna beat on the guy doing the work. Nor on you, but so far, it kinda sounds like he was given cart blanc.
I'd suggest Vic as the resident head-work guru, but 'un-shrouding' the intakes to that degree suggests he was aiming at some real crank speeds. And it will take a big lump on the piston to get the chamber back to a decent CR with that big "holler" over there. Did you give him any sort of RPM or CR targets?
Also, the sealing surface is far too wide as it stands (dunno if he was done); you'll get an un-wanted peripheral chamber from that:

Dunno who failed to communicate, but when I send a set of heads out for work, it's under specific constraints and numbers.

[C J Murray]

It's safe to say the guy hasn't a clue how to make a engine work properly.

It looks like be was welding so did he say why? Welding the heads for increased squish area can be beneficial but you wouldn't then machine away the weld except in a way that smoothed the surface. This guy appears to have welded then removed the weld along with the original squish. It looks like an experiment gone wrong, very wrong. Are you certain that those heads are the ones you sent him? Could he have tried some "genius rocket man" modifications on another customer's heads and had to use yours to finish that previous disaster? I think you will be buying new heads because rebuilding those chambers will not be cheap.

Have him replace the heads or go to small claims court.

Who are these butchers?

[C J Murray]

Also, the valve sizes used in the C/SC/912 are about optimum for street use. The exhaust port flow is lazy so the exhaust valve needs to be big and a too large intake valve slows down the mixture flow at the valve curtain and that reduces turbulence which inhibits combustion. Racing or very large displacement street engines may need larger valves and other tricks to improve performance but not a typical street engine.

[Mike Horton]

Ollie's is now in Lake Havasu, AZ, Len Hoffman is on the East coast, others?

… again, your location?

[Thomas Sottile]

I am sorry for your problems hope things work out .

[Dave Whittick]

Dunno who failed to communicate, but when I send a set of heads out for work, it's under specific constraints and numbers.

I'm a little unclear myself where this went off the rails. I was mearly looking for a shop to go through the heads and make sure they all looked ok. I gave him permission to repair or replace parts as required. I was quite clear that this was a street engine with a slight bump in displacement (86mm big bore kit). He recommended a Super 90 cam and slightly larger valves to go along with the 86's.

The shop builds engines for some well known Porsche race teams up here in Toronto. His reputation amongst the local aircooled Porsche guys is that he's excellent but not very quick. I was OK to wait but became concerned once he stopped communicating with me. The last text I received from him, when I checked in, was that the heads were almost done and he anticipated completion in a couple of days. Everything seemed fine. He stopped responded to me after that.