Trick for extended high RMP survival

[TimT]

OK...8000 RPM plus...the engine needs some "oiling" help.

have the crank cross drilled... Its mentioned in BAs book..I havent read Waynes book so I cant say if he mentions cross drilling the crank.

To compliment the cross drilled crank, you have to modify the center main bearing..

Made a fixture to hold a bearing (this can be reversed one end holds a 3.3 the other a different main) A finished bearing is in the fixture in this pic



fixture and bearing in the 40 year old lathe



Finished product



The bearing pictured is going in a 964 turbo engine..... DE/Street/ Club Race car..

[TimT]

WOW 115 views and not a peep?

anyhoo, maybe if I typed RPM correctly instead of RMP (royal mounted police?)

The title to a thread cannot be edited?

[Tim Walsh]

Is this the bearing that sends the oil to the conrods? I'm a little confused on how this helps

[garibaldi]

That is a good approach, here is another approach to be considered. This method does not reduce the bearing surface area, but still allows the oil volume to get to the main. The bearing shell can just be drilled radially to allow the extra lubricant to get in.

[TimT]

I like your method as well. However I am limited to what I can accomplish with a lathe, I dont have a mill, but am thinking off finding a used Bridgeport somewhere. Ive heard you can get pretty good deals at machinery auctions, now where would I put it?


Tim: This mod assures the 2&5 rod bearings get oil. They tend to starve for oil during extended high rpm running. That is not a good thing.

[garibaldi]

I actually did this mod in a Sunnen CK-10 honing machine. I used a boring bar in a locked position to cut the groove. I know what you mean by being limited, but here is a cheater way if you dont have a mill or a boring drive.

You can use your lathe to make two biscuts from brass or 7075 aluminum that are sized on their OD to your main. Get a suitable boring bar, or you could make one from a piece of solid steel tubing and drill some holes to hold your bits with threaded cross drills for set screws to secure them. I made the tool bit I used for this from a piece of drill rod and shaped it with radiuses in the corners and locked it into the boring bar. You could do the same thing. Take light cuts, .010 at a time. I did each case half individually. SO all you do is lock the biscuts in the mains at either end of the case, run the bar through the biscut so they act as the bearing for the bar, set the toolbit, and clip a little more with each cut. You can drive the bar with a drill if you have to . Just be sure that the rigidity is in the setup and that the bit is stable. Try it if you like.

[TimT]

This is funny, as soon as I posted my last post, I thought about using a boring bar to cut the case... Ill have to see if I can get a case half on the bed of my lathe

More than one way to skin a cat..

[garibaldi]

No, I wouldn't use a lathe, too much power. You won't have the right feel for the tool in a lathe, you can only cut a bit at a time and you need control over the tool that a lathe wont give you. You could rotate it by hand if you had to, but I wouldnt recommend trying it in a lathe.

[TimT]

LOL, I wouldnt turn the lathe on... just use its bed, and head and tailstock.... and do the cutting by hand..

I nvested a few hours making the fixture so I think Ill stick with it . The fixture I made a can do another dia bearing if you flip it over...

[Max van Sabben]

I was thinking it to do it the way on the picture!
Anyone did it that way?


Tim can you please take a picture from youre cross drilled crank?

Max

[TimT]

Max,

the engine that bearing and crank went into is already completed and on the road..

There is another one in the works though!