Forged 7 bolt 4G63T crankshaft STD 88mm Stroke
- Thread starter EVOCPE
- Start date
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IMO the cheapest option is starting to look like going with another stock crank. George did some work with his 7-bolt block to try and avoid crankwalk, even on his forged stroker engine. Something about plugging up the oil-squirters and improving the oil pump.
4piknup
master of none
Maybe a Torrington roller on the crank thrust face.
Maybe could cross drill the oil feed for the thrust surface? I haven't had a look to see what the standard setup is like.
Maybe could cross drill the oil feed for the thrust surface? I haven't had a look to see what the standard setup is like.
7 bolt???
BMGTZ
Grumpy old man from the school of hard knocks
On the centre main bearing there aren't any holes drilled in the crank to supply oil to the big end pins. So all the oil that goes to the bearing is uses to lubricate the crank and the thrusts.The problem as I see it is that the bearing shell isn't fully grooved and the oil is only escaping in the two small spots where it is grooved.
for many years when dealing with old rally engines{these aren't the only engines that suffer thrust wear} we have drilled additional holes in the bearing shell to allow a great flow to that area. whilst the oil feed has two outlets on that area....the block is grooved behind the bearing shell. So drilling a hole that aligns with that groove get you more oil to the bearing surface. That in turn escapes to the thrusts.
I once tried to groove some shells to flow oil out to the edge of the thrust area....wasnt a good idea. So I have just stuck with the extra holes. I usually put two holes in the block side and one in the cradle side.
for many years when dealing with old rally engines{these aren't the only engines that suffer thrust wear} we have drilled additional holes in the bearing shell to allow a great flow to that area. whilst the oil feed has two outlets on that area....the block is grooved behind the bearing shell. So drilling a hole that aligns with that groove get you more oil to the bearing surface. That in turn escapes to the thrusts.
I once tried to groove some shells to flow oil out to the edge of the thrust area....wasnt a good idea. So I have just stuck with the extra holes. I usually put two holes in the block side and one in the cradle side.
BMGTZ
Grumpy old man from the school of hard knocks
I am building an engine now...so will take some snaps later
BMGTZ
Grumpy old man from the school of hard knocks
here is a pic of the block side..
