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Damn I am green with envy!!! I hope all goes well with your beast. I know I've missed it somewhere in the thread, but what's the stroker going into?
I believe it will go into my 87 daily driver. I swapped an '89 manual with LSD into it recently for the taller gearing. Should be fun.
I think I have everything except the injectors. 85-86 throttle body mounting points have to be removed from the upper block. Ordered Greg's cam cover elbows from Precision yesterday. Gary will be checking the bearing clearances and providing his custom SBC rod end bearings.
968 head gaskets are on their way from Germany. They'll need to be modified to work on the PS head. It involves cutting and plugging holes to match the coolant flow. Greg has been very generous with his time and guidance. I'd still be in the wilderness without it.
More progress on the stroker parts acquisition front. 968 head gaskets arrived from Germany.
Here's a side by side comparison of 968 anf 928 head gaskets The 968 PS little work to properly size the coolant passage holes and cut off the rectangular piece sticking out.
The 968 DS needs a lot more work. In addition to the cutting off the rectangular piece, new holes need to be cut out to match the 928 heads and the 968 holes require plugs to be made to block the coolant passages that normally would be blocked by the head gasket.
The making of the head plugs is quite time consuming and tedious work. I am wondering if I could use JB Steel Stick to close the passages.
Crankshaft dirt traps tapped and plugged. Rotating assembly, flywheel have been balanced. Rod end clearances have been checked, rod end bearings are on order.
Next up I guess is balancing the pressure plate, checking main bearing clearances, grooving the 2/6 bearings and assembly of the block (after removing the 85-86 throttle body mounting points)
So, heard from the shop today. The mains clearance is too big. I think he said by 3 thousandths of an inch. They are going to send them out to be coated to make up the difference.
Anybody ever encountered this? My shop confirmed the crankshaft mains are correct and I am using Porsche main bearings.
So, heard from the shop today. The mains clearance is too big. I think he said by 3 thousandths of an inch. They are going to send them out to be coated to make up the difference.
Anybody ever encountered this? My shop confirmed the crankshaft mains are correct and I am using Porsche main bearings.
Oil clearance at the main bearings according to the Workshop Manual is 0,020 to 0,098 mm. Three thousandths of an inch is 0,076 mm. That is perfect, a stroker engine should not have a too tight clearance.
Åke
Oil clearance at the main bearings according to the Workshop Manual is 0,020 to 0,098 mm. Three thousandths of an inch is 0,076 mm. That is perfect, a stroker engine should not have a too tight clearance.
Åke
Most of the parts are ready. Main bearings go out for coating tomorrow. Once they're back Gary will build a custom fixture to hold the 2/6 bearing while we removes the material.
Gary Grimes, the owner, explains that getting to a tighter clearance nearer 2.5 thousandths will improve oil pressure.
Also, he almost exclusively uses Cometic head gaskets and has never had a failure. He pulled one for me to see. Greg, his machinist, added that he uses a copper spray to coat the Cometic head gaskets and that eliminates the failures. Block with S3 bosses removed Balanced flywheel and pressure plate with instructions Carrillo rods post main bearing clearance check SBC rod bearings
Have the balanced crank, too. The plugs left loose for final cleaning 1/8" threaded dirt trap plugs left loose for final cleaning Plug for balance
I've yet to install a Cometic gasket that did not seep between the layers. Butt smooth surfaces, slightly rougher surfaces, no difference. Not one or two....but every single one I've ever installed seeped. Although I found that I could pour in a can of Stop Leak to "cure" the problem or I could "spray" the gasket (against their recommendations) with sealant between the layers to "cure: the problem. It just seemed like I should not have to do this, to male their product work.
I finally just gave up.
It's so chronic for me, that I finally decided that Cometic's "parent company" must be Rainbird.
There's two other reasons:
1. I like the head gasket to be the "fuse" in the system, should anything go wrong. Stock style gaskets are like putting a 25 amp fuse into a 20 amp load.....they are the perfect match for the surrounding pieces. Cometic gaskets are like putting a 50 amp fuse in a 20 amp load.....something else is going to "melt' before they do.
2. I've got a lot of experience looking at stock head gaskets (don't forget I've got a bunch of 951 experience). I can "read" stock head gaskets. "They "talk" to me.".
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
03-14-2019, 11:02 AM
