help please on 389 stroker
sooner_disciple73
02-25-2006, 08:53 AM
My brother is building a stroker and we are having a few problems first the block is bored 60 the heads are shaved 40 and the cam is crane 302/302 blue racer with.50 lift on exhaust and intake and we need to know what would be best cam to put in it cause the intake valves are hitting the piston. any help on this subject would be appreciated
TLBLZER
02-25-2006, 04:11 PM
My brother is building a stroker and we are having a few problems first the block is bored 60 the heads are shaved 40 and the cam is crane 302/302 blue racer with.50 lift on exhaust and intake and we need to know what would be best cam to put in it cause the intake valves are hitting the piston. any help on this subject would be appreciatedyou should contact uldradine cams an tell them about your set up you are using and the problems your are having:smokin:
bobss396
03-03-2006, 11:39 AM
The problem is not with the cam. A .500 lift cam is not that radical by any means. You have an incompatibility issue between your crank, rods and pistons. I tend to talk people out of DIY stroker experiments and steer them to buying complete proven kits. Often the rods have different center to center distances and/or the piston pin hole is offset, or the pistons are machined for valve clearance. Have you checked for rod and block interference?
If you do go the DIY route, the rule of thumb is to assemble one cylinder only, use the bearings but not the rings. Spin the crank and see if the piston is above the deck height, if so, stop right there.
If all was well, you would then slip in the cam, one pair of lifters, rockers, timing gears, chain, etc. Install the head with the head gasket, but just let the weight of the head hold it down, do put in a couple of bolts but back them off about 1/4". You can also put a ball of modeling clay or plumber's putty on top of the piston.
Turn the engine over slowly by hand, if the valves hit the piston, the head will lift off the block deck, causing no harm to anything. If it doesn't hit, you can measure the compressed clay thickness to see what your piston to valve clearance is.
Bob
If you do go the DIY route, the rule of thumb is to assemble one cylinder only, use the bearings but not the rings. Spin the crank and see if the piston is above the deck height, if so, stop right there.
If all was well, you would then slip in the cam, one pair of lifters, rockers, timing gears, chain, etc. Install the head with the head gasket, but just let the weight of the head hold it down, do put in a couple of bolts but back them off about 1/4". You can also put a ball of modeling clay or plumber's putty on top of the piston.
Turn the engine over slowly by hand, if the valves hit the piston, the head will lift off the block deck, causing no harm to anything. If it doesn't hit, you can measure the compressed clay thickness to see what your piston to valve clearance is.
Bob
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