Merc 420 to 525sc in a Formula 242.
02-12-2016 | 06:33 AM
#71
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Joined: Nov 2004
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From: On A Dirt Floor
Well its been a while since I have updated.
The build is as follows:
Stock forged crank. Reconditioned forged rods with ARP bolts. Melling HV oil pump. TRW 2399 pistons .060 over. The heads I got are stock HP500 Carb heads. They have Manley Severe Duty intakes with inconel exhaust valves. I used a crane 134561 cam with their matching triple springs.
The build is as follows:
Stock forged crank. Reconditioned forged rods with ARP bolts. Melling HV oil pump. TRW 2399 pistons .060 over. The heads I got are stock HP500 Carb heads. They have Manley Severe Duty intakes with inconel exhaust valves. I used a crane 134561 cam with their matching triple springs.
Motor looks sharp..
02-12-2016 | 07:02 AM
#72
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Joined: Oct 2012
Posts: 896
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From: Buffalo NY
Its has 2 springs and a damper spring. For regular use Crane 99893 is ok. For extended high RPM use Crane recommended 99896 springs. They were $256 vs $89 for the cheap springs. It seems like valvetrain is not the place to try to save money.
03-14-2016 | 08:41 PM
#74
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Joined: Jul 2004
Posts: 11,332
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From: chicago
The 99896 spring is for a hydraulic roller camshaft, and will have way to much pressure.
99896 is 150 psi @ 1.900,and has a rate of 528lbs lbs/in. With your cam, it would have around 450lbs of open pressure. That will kill the cam quickly.
03-14-2016 | 08:55 PM
#75
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Joined: Oct 2012
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From: Buffalo NY
Those are the part numbers Crane specifically recomended.
I hope that was a typo on those springs.
The 99896 spring is for a hydraulic roller camshaft, and will have way to much pressure.
99896 is 150 psi @ 1.900,and has a rate of 528lbs lbs/in. With your cam, it would have around 450lbs of open pressure. That will kill the cam quickly.
The 99896 spring is for a hydraulic roller camshaft, and will have way to much pressure.
99896 is 150 psi @ 1.900,and has a rate of 528lbs lbs/in. With your cam, it would have around 450lbs of open pressure. That will kill the cam quickly.
