Cam bearing oil mods

Cam bearing oil mods

Joined: August 28th, 2002, 6:51 pm

April 8th, 2008, 9:26 pm #1

I did some searching for this answer, but gave up.
Somewhere here I read about two oil passages to the front cam bearing and an oil mod to block one off.
Can you guys elaborate on that please? I have the standard Moroso oil restricters but nothing is restricting the front cam bearing.

Thanks
Danford1
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Joined: December 5th, 2004, 11:36 pm

April 8th, 2008, 10:17 pm #2

There is only one oil feed to the front cam bearing but 2 feeds to the front main.

To restrict the front cam bearing you need to tap a deep thread past where the cam bearing oil feed passage intersects the mains/lifter oil gallery and install the restrictor just under the cam bearing, same size as the moroso restrictors for the other cam bearings.

Things to consider:

The front cam bearing oil feed also supplies oil to the bottom of the dissy shaft and underside of the dissy gear and rear of the cam sprocket.

Depending on your application you may or may not need this supply restricted. On drag engines I have the front cam bearing installed far enough clockwise so that oil feed to the dizzy shaft is restricted to around .020 and leave the bearing as far forward as you can to minimise the feed to the back of the cam sprocket.

This stuff is hard to describe in words and I dont have one apart to take pics of. Grab your block and look at the oil feed path from the filter across the block and you will quickly see it. There is another thread here somewhere from an Aussie bloke who is circuit racing a clevo that explains it better than I have.

PS when all the cam restrictions are done you can then block off completley the second feed to the front main.
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Joined: December 16th, 2003, 1:59 am

April 8th, 2008, 11:17 pm #3

I did some searching for this answer, but gave up.
Somewhere here I read about two oil passages to the front cam bearing and an oil mod to block one off.
Can you guys elaborate on that please? I have the standard Moroso oil restricters but nothing is restricting the front cam bearing.

Thanks
Danford1
there's a lot going on at the front cam bearing, i haven't taken a look at it for a while and may've missed some of it last time i did.



"Enlightened statesmen will not always be at the helm" ~ James Madison
Last edited by tinman351 on April 17th, 2008, 1:34 am, edited 1 time in total.
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Joined: December 5th, 2004, 11:36 pm

April 8th, 2008, 11:36 pm #4

The drill a new restricted feed hole in in the bearing will work very well in all bearings but No1. It may not work with No1 because the groove on the cam side of the bearing (extends about 3/4" of the inner radius of the bearing) on No1 is a transfer passage to supply oil to the gallery that feeds the bottom of the dizzy shaft. To re drill and re position the bearing will probably cut all oil to the bottom of the dizzy shaft. I am going of memory here and open to correction.
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Joined: May 7th, 2005, 1:24 am

April 8th, 2008, 11:51 pm #5

there's a lot going on at the front cam bearing, i haven't taken a look at it for a while and may've missed some of it last time i did.



"Enlightened statesmen will not always be at the helm" ~ James Madison
If you install the front bearing upside down, then how does the bottom of the distributor get oil from the transfer slot? I think a better way to restrict oil to the front cam bearing is to install a moroso restrictor between the crossover passage and the front cam bearing. I drill out the cam bearing passage from the first main bearing to 5/16 inch only as deep as the crossover passage in the front of the block. Then I use a 5/16 tap to tap the cam passage below the crossover passage when the block is upside down. If you need to make an extra oil restrictor just drill out a 5/16-18 set screw with a 1/16 drill bit. Most set screws nowadays are soft enough to drill.
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Joined: December 16th, 2003, 1:59 am

April 8th, 2008, 11:58 pm #6



"Enlightened statesmen will not always be at the helm" ~ James Madison
Last edited by tinman351 on September 24th, 2009, 5:10 am, edited 1 time in total.
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Joined: September 8th, 2006, 3:49 am

April 9th, 2008, 2:22 am #7

I did some searching for this answer, but gave up.
Somewhere here I read about two oil passages to the front cam bearing and an oil mod to block one off.
Can you guys elaborate on that please? I have the standard Moroso oil restricters but nothing is restricting the front cam bearing.

Thanks
Danford1
I also taped the BIG hole and plugged it...no problems and I run as hard as 8400...
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Joined: July 26th, 2002, 1:52 am

April 9th, 2008, 2:57 am #8

I just put a solid set screw in the little hole that goes up , or comes down from the crosshairs depending on how you look at it.

The way I look at it I want to close that loop where oil could just go around and around . Blocking the big hole would do that too.

I'm willing to write off the oil that goes to the no 1 cam bearing/gear but I seriously strive to keep the front cam bearing real close to the thrust plate .

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Joined: November 28th, 2007, 4:51 am

April 9th, 2008, 3:23 am #9

I did some searching for this answer, but gave up.
Somewhere here I read about two oil passages to the front cam bearing and an oil mod to block one off.
Can you guys elaborate on that please? I have the standard Moroso oil restricters but nothing is restricting the front cam bearing.

Thanks
Danford1
main problem with the oil system is in the front cam bearing oil feed. If you study it closely you will see that the oil feed hole to the front cam bearing is supplied directly from the main oil pump feed, the oil goes to the cam journal in one direction and back down to the crankshaft main journal from the oil feed hole that is supposed to supply oil to the cam journal. Study it closely and you will see what I mean. Putting the oil restrictor in the no 1 main does not do a thing . What you have to do is tap the oil feed hole for no 1 cam journal riht behind the bearing, this requires a very long tap, you then put the restrictor right up there. You then plug the hole in the no 1 main journal with a screwin plug.Put the other restrictors in the other mains as normal. And while your at it you can also make a restrictor for the no 1 main bearing oil supply to make it the same size as the rest, if you look at it you will see that it is about 20% larger than the rest. If you do some serious racing have the lifter bores bushed as well because the restrictor in the mains only work for one side lifter bores, if you study this closely you will see what I am talking about. We found this out the hard way, and a very costly way. We now race all season and do teardowns at the end and you can use the bearings again

This is from Tony-T. I did this to mine plus some, roll-pins in the pushrods, and closed off the back cross over in the block and run a external line. I didn't have the lifters bushed. to much $
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Joined: December 17th, 2003, 4:14 pm

April 9th, 2008, 3:36 am #10

I bought some rollpins of the suitable size, but with the stock pushrods the opening is very short and the pushrods main tube is larger in the inside diameter, so if I did attempt to push them in they would end up rattling around loose in the main body. I have two sets of aftermarket prods and no go with them too.
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