Bob Garretson's idea 3 piece Carrera Cylinder Head work completed.

[Ibrahim Kuzu]

Martin,
We are casting them here in USA. Foundry specializing on cylinder head casting.
Wil,
Thank you for the good words, It was and is very challenging project ,makes you happy when successfully done after many tries.....

Harlan,You are fully correct. Bob told me to take over the project...Was very complicated...Took us some time and many changes on the 3 section design
Yes we will be doing the smaller intake and exhaust passages to optimize the power band lower in later dates..We wanted to start with an original spec first.

As Joris mentioned ,now days you can get plain bearing crank on 547 engine case with special bearings.
IK

[Richard Emerson]

I’m interested in all of the above.

[Jacques Lefriant]

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Hi Harlan
Plain bearing crank replacement has been done for at least 10 years by utilizing the 692/3A crank shaft. This requires a PB flywhell and sifferent countershaft and some critical machining for the center bearing. Al Cadrobbi and David Kopf had me source a Hybrid 2.0 ltr(74) that utilized the roller crank crank gear and the roller crank flywheel to be used in a PB case. I am making a run of these in the 66mm stroke to facilitate the conversion and will use the ball bearing thrust to eliminate the modyfing of the center journal for the thrust. this way it is completely reversalble to the roller crank and does not require the sourcing of a flywheel and countershaft. it is still recomended that the oil pump be enlaged to the 2.0ltr one. Some nuanced modifictions are required to the oil galleys and special main bearingss are being manufactured to preserve the anti shuffle charackteristics of the RB bearings. I will offer this conversion as a service but the proprierty parts will not be available for distribution.
j

[Greg Bryan]

This is quite amazing! Great job, Ibrahim.
Now that John Willhoit and AA Performance are each creating new cast heads for 616 motors and others have billet cnc heads, the head shortage seems to be over.

[Ibrahim Kuzu]

Hi Richard,
For the Cylinder head,
We need to go thru a tough testing first .Than we will make it available to 4 cam Racers, mechanics or individuals wanting spare on the shelve
1500cc,1600cc or 2000 cc or custom port or cc
Thank you,

Jacques,
That is the way to go...I always hated hitting the crankshaft with a chunk of brass hammer to get those weird rings seat on the flywheel of plain bearing crankshaft.
Superb Idea and engineering .Thank you. We need it.

Hi Greg,
Thank you .Appreciate it.You got it... Hope now 4 cam owners get the cars out and drive and race to the floor....In comfort ...
Here is one over revved factory original head,only good area is one of the cylinder head ....
IK

[Mike Smith]

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I have just heard that Bob is in Hospital - Wish him well guys

[Harlan Halsey]

Mike,
I'm sorry, although not surprised to hear that. I'll check with Del Sessions when I see him tomorrow. I have known Bob since we were both 40 and both here on the peninsula.

[Mike Smith]

He went in yesterday - so it is really early days

[Harlan Halsey]

Jacques,
What you describe is sort of the way I would have gone about it. I would have used the 692 crank as a starting point, but had SCAT do a custom utilizing a 6 bolt flywheel interface-if there's room or room can be made-and the stock Porsche roller thrust bearing. Making a custom flywheeI is easy. I didn't get into the main bearings, sizing the crank to fit shell bearings in the original bore, or sleeving the roller bearing bore to fit smaller bearings. I would have no compunction over reversibility. I'm sure it can work, with the Garretson/Ibrahim heads, and new LN aluminum cylinders, and no one should ever want to go back. In fact I do have a spare 547 case around here.....

[Mike Smith]

Jacques,
What you describe is sort of the way I would have gone about it. I would have used the 692 crank as a starting point, but had SCAT do a custom utilizing a 6 bolt flywheel interface-if there's room or room can be made-and the stock Porsche roller thrust bearing. Making a custom flywheeI is easy. I didn't get into the main bearings, sizing the crank to fit shell bearings in the original bore, or sleeving the roller bearing bore to fit smaller bearings. I would have no compunction over reversibility. I'm sure it can work, with the Garretson/Ibrahim heads, and new LN aluminum cylinders, and no one should ever want to go back. In fact I do have a spare 547 case around here.....

We have been supplying the 692/3A crank for at least 8-years for the Roller to Plain Conversion
Absolutely no problems that I am aware of

[Ibrahim Kuzu]

Mike ,
Thank you and Thank you for the info on Bob.
Talk to Ruth this morning .Bob is in good spirit, he went in for colonoscopy.
Wishing and praying fast recovery and soon he gets home in 100% health.
IK

[Jacques Lefriant]

Hi Mike
Yes that is the current way to convert but it requires a different crank gear and flywheel which uses the problematic expansion cones, also extensive machining to the center main to accommodate the #2 flanged bearings and locating it axially. this creates an incremental cost upwards of $2000-$6000 and does not allow the retrofitting of the roller crank.
j

[Jacques Lefriant]

Hi Harlan
i still haven't figured out to machine the crank for the gear to use a flanged #1 bearing for the flywheel. i think my current solution is very elegant.
j

[Mike Smith]

Jacques Lefriant » Wed Feb 24, 2021 6:55 pm

Hi Mike
Yes that is the current way to convert but it requires a different crank gear and flywheel which uses the problematic expansion cones, also extensive machining to the centre main to accommodate the #2 flanged bearings and locating it axially. this creates an incremental cost upwards of $2000-$6000 and does not allow the retrofitting of the roller crank.

Point taken Jacques,
It is not something that we, as a company, have been carrying out. We have just been the supplier of the cranks
I was only really letting the guys know that, it is carried out in Europe on a fairly regular basis and it is an option.

I have absolutely no doubt that whatever you come up with will be a good way of getting around the various problems

[Ibrahim Kuzu]

On KG ( Kuzu/Garretson ) cylinder head ,we have the center fins fully casted for better cooling.
IK