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Author Topic:   oil restriction for dummies ???
brownstone
Dirt Freak

Total posts: 284
posted January 23, 2005 01:11 PM  
Ok, I have to plead ignorance....What do most of you do to prep your blocks for racing concerning oil restriction ?

I have tried the ones that screw in at the back of the block, not much luck, the orings come off while trying to install them.

I have heard that some engine builders drill and tap restrictors under the cam bearings.

What do some of you use and what's the easiest way to go about it ?

We run mod class with a flat tappet cam, and want to put our own together just want to make sure that we do it right.
Thanks !!!!

awkwardjeff
Dirt Forum Champ
Total posts: 562
posted January 23, 2005 03:18 PM  
They now sell restictors for roller or flat tappet cams.... for years they were always for rollers. Then if you had a flat tappet you didn't use restictors or if you did you over heated valve springs and rockers because of lack of oil.

You can use a little oil on the o-rings to help them into the block. If you put your own restictors under the rear cam bearing tap them out 1/4 coarse thread. then purchase allen-head set-screws, drill a hole .090 and thread these into the block.

Me personally I gave up on oil restictors, to many rocker and spring problems. Almost everyone I know has gone this way in the last few years.

stockcar5
Dirt Forum Champ
Total posts: 578
posted January 23, 2005 04:11 PM  
you shouldnt need restrictors because the little holes in the lifter and the pushrod should be plenty small enough to meter the oil to the top of the motor.

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brownstone
Dirt Freak

Total posts: 284
posted January 24, 2005 07:57 AM  
Jeff and Stock:

Thanks for the info. So if I understand right what yall are saying is that you can run a flat tappet cam without installing oil restrictors.

Will there be any starvation issues because of oil staying in the top ?

Also on the restrictors that go in the back of the block I put oil on them no dice, the way it looks is that the block casting has some rough spots that are catching on the restrictor and pushing the o-rings off. I may have to get in there with dremel and clean it up a little to get it to go in without pushing the o-rings off.
Thanks !!!

leapinlizard
Dirt Freak

Total posts: 402
posted January 24, 2005 02:21 PM  
Just run standoff tubes so the crankcase can vent without fighting the oil. Make sure your oil returns in the lifter valley return the oil back to the pan via the timing cover or back of the block.

stockcar5
Dirt Forum Champ
Total posts: 578
posted January 24, 2005 03:29 PM  
yes you can run with no restrictors.
another thing to keep in mind is that your valve spring life will be reduced about 40% when using restrictors. heat is a valve springs #1 enemy and oil is what keeps them cool!! now if you had valve covers with spring oilers thats another story!

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iowatoolman
Dirt Freak

Total posts: 369
posted January 24, 2005 10:51 PM  
one of my sets of heads has the return holes milled out way bigger than stock to aid in the oil leaving the head and fix the front of the block so the oil leaves the valley also

drive hard or drive home

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