problem with aftermarket cylinder heads.
#11
Registered
You need to drop the word agenda.
When you had all the troubles in the Cobra Kit car world and you where speaking out, did you have an agenda ?
When you had all the troubles in the Cobra Kit car world and you where speaking out, did you have an agenda ?
#12
Banned
#13
Registered
#14
Registered
One question for you about your video. You mention determining final length of the pushrod, but I did not see any mention of adding length for proper lifter preload on a hydraulic lifter. Correct me if I am wrong, but wouldn't you want to add the recommended plunger depth to the final determined length of the pushrod?
#15
Banned
One question for you about your video. You mention determining final length of the pushrod, but I did not see any mention of adding length for proper lifter preload on a hydraulic lifter. Correct me if I am wrong, but wouldn't you want to add the recommended plunger depth to the final determined length of the pushrod?
#17
Registered
My problem was being sold a complete set of heads that were misrepresented as ready to bolt on, resulting in wasted time and money. Luckily the rest of the group of friends and professionals helping me, recommended I have them taken apart and setup correctly for my application before they caused a serious problem.
So I shipped them back out to have them disassembled checking and correcting all the guide clearances for a marine build. Mine needed to be opened up as they were to tight. Also checked valve seat run-out and valve depth, and of coarse milling the heads to get the compression we wanted. We also flowed the heads for the custom cam selection. Then they were reassembled with new springs specific to my cam and installed at the proper height. They also mocked up the shaft rockers to get the rocker geometry correct.
750hp 572 n/a AFR 335 CNC
So I shipped them back out to have them disassembled checking and correcting all the guide clearances for a marine build. Mine needed to be opened up as they were to tight. Also checked valve seat run-out and valve depth, and of coarse milling the heads to get the compression we wanted. We also flowed the heads for the custom cam selection. Then they were reassembled with new springs specific to my cam and installed at the proper height. They also mocked up the shaft rockers to get the rocker geometry correct.
750hp 572 n/a AFR 335 CNC
Last edited by offshorexcursion; 10-15-2015 at 10:57 AM.
#18
Registered
My problem was being sold a complete set of heads that were misrepresented as ready to bolt on, resulting in wasted time and money. Luckily the rest of the group of friends and professionals helping me, recommended I have them taken apart and setup correctly for my application before they caused a serious problem.
So I shipped them back out to have them disassembled checking and correcting all the guide clearances for a marine build. Mine needed to be opened up as they were to tight. Also checked valve seat run-out and valve depth, and of coarse milling the heads to get the compression we wanted. We also flowed the heads for the custom cam selection. Then they were reassembled with new springs specific to my cam and installed at the proper height. They also mocked up the shaft rockers to get the rocker geometry correct.
750hp 572 n/a AFR 335 CNC
So I shipped them back out to have them disassembled checking and correcting all the guide clearances for a marine build. Mine needed to be opened up as they were to tight. Also checked valve seat run-out and valve depth, and of coarse milling the heads to get the compression we wanted. We also flowed the heads for the custom cam selection. Then they were reassembled with new springs specific to my cam and installed at the proper height. They also mocked up the shaft rockers to get the rocker geometry correct.
750hp 572 n/a AFR 335 CNC
Didn't you get your heads from Bob Madera? That seems weird that they were not set up correctly for a marine engine.
#19
#20
MarineKinetics
Platinum Member
You are correct, the heads in the collateral valvetrain components were purchased from me. As you can see on the email correspondence from Scott Stinebring the AFR heads would be shipped directly to him complete. That decision was made to purchase them complete because there is very little cost reduction in deleting the spring pack, therefore he was going to repurpose them for a future build. In the line below that you can see “associated valvetrain to upgrade heads for application”. I put together a valve spring package was based on the mass of the valvetrain, rpm level desired, and cam design.
Scott Stinebring would then be required to disassemble the heads, as any proper engine builder would do, measure guide clearances, and any other dimensional measurements he would feel necessary as the lead engine builder, and then provide that information to Kevin. The heads would then be reassembled to the upgraded spec for the engine. This, and multiple other aspects of the engine build were carefully coordinated. As you can see by the second email to Kevin that everyone involved in the processed was apprised of all this information real-time.
I think this makes it quite obvious that the heads were not intended to be “race ready” as delivered out of the box.
Bob