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Twiggy - Long Rod Aluminum Block Engine Build-up
https://slantsix.org/forum/viewtopic.php?t=23948		 Page 3 of 25
Author:  Doctor Dodge [ Wed Jul 18, 2007 7:09 am ]
Post subject:  Cam Check
The next step is the checking the cam in the block.
You want to be sure the cam spins freely in the journals and that the rear oil passage to the rocker arm assembly is aligned.

Image

I have an old cam bearing that I use to check the rocker arm oil feed hole alignment. You can also mark the cam journal and block, then look at the index marks.

Image

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The Erson cam's oil feed hole was off by almost the full diameter of the hole. A center punch, drill and deburring job fixed that problem.

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I also check the oil pump drive gear mesh while the cam is being mocked-up in the engine block. With the cam, top timing gear and oil pump installed, use some fine lapping compound to check how the drive gears make contact.

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The pattern was a little off center so I pressed the oil pump's gear onto it's shaft a little more. I also sanded a little material off the back of the top timing gear in order to get the cam deeper into the block.

With all the checks and adjustments completed, clean everything, apply the cam lobe break-in grease and install the cam.
DD
Author:  GTS225 [ Wed Jul 18, 2007 2:15 pm ]
Post subject: 
Doug.....You REALLY need to write a book. This is the kind of stuff that good engines are made of, that the average engine builder, (whether pro or amateur), will miss.

Maybe collaborate with Mike J. about a companion book for headwork?

Put me on the top of the future book buyer's list.

Roger
Author:  Rick Covalt [ Wed Jul 18, 2007 2:15 pm ]
Post subject:  WHY oh WHY ??
Why is it that anyone should have to modify a bad cam blank? I know, so it will work! It just doesn't seem right to me. And if someone does not come here and see this, how would they ever know what all they have to do. Since we seem to have had great dealings with Erson, can we contact them to see if they can see whats up with the suppliers of the blanks? Maybe they can pressure someone into doing some quality control.

It really doesn't set well with me that we have cams with no holes, cams with the wrong holes drilled and cams with rough or poorly ground gears, that can destroy a cam and oil pump gear in less than 500 miles. This was very disturbing to me when my son's cam was wiped out in less than 500 miles 2 years ago. I still don't have a good feeling about putting a new cam in any slant six. I saved a 100,000 mile camshaft ( to be reground) and the matching oil pump off a junkyard motor I got and I think that is the safest way to not have an oil pump / Camshaft gear failure.
But that is not how it should be. By the way. that used cam and oil pump gear with over 100,000 miles was perfectly smooth and looked like it was good for another 100,000. Am I out in LaLa land or what?

Sorry, I just had to vent. I feel better now. Didn't mean to hi-jack the thread. Thanks for your update. I like following along.

Rick
Author:  Dart270 [ Wed Jul 18, 2007 2:31 pm ]
Post subject: 
You are right, Rick. That said, regrind cams work just fine. My 64 motor has had a big one for 10 years with no troubles. Cost me $25 back in 1996.

Cameron Tilley said he ONLY uses regrinds, and look how much power he makes...

Lou
Author:  Rick Covalt [ Wed Jul 18, 2007 2:33 pm ]
Post subject:  Where to get regrind?
Where do you recommend for the regrind? And can you get to .500 lift range?

Thanks,
Rick
Author:  Aggressive Ted [ Thu Jul 19, 2007 1:23 pm ]
Post subject: 
schneidercams.com

These guys will regrind and have some pretty tall lift options available for the SL6.
Author:  Bren67Cuda904 [ Thu Jul 19, 2007 3:08 pm ]
Post subject: 
I thought the cam bearing just had to match the block so the grove cut in the bearing is pressurized. The hole in the cam will only line up twice every rotation regardless of where its drilled (as long as its at least centered in the grove).
I am planning on a cam change and thought the bearing issue is only an issue if your changing the cam bearings. Otherwise just pull one cam and install the other.
Am I wrong?
Author:  Wizard [ Thu Jul 19, 2007 3:20 pm ]
Post subject: 
It is issue of the cam blanks that are mis-drilled at wrong angle. It is not simple drill thru thing, cam have a angled drillings that meets at midpoint.

This is the reason have to dremel a new passage on cam so the valvetrain get the lube. It only get lube flow once every cam revolution.

The oil passage comes up directly from main oil galley to the rear cam bearing then goes at a angle from the bearing to the one rear bolt. Cam is the "turning point for the oil passage". Then up to the head thru one bolt at rear of rocker shaft, this goes to all the rockers that dribbles at both ends. Very complex route.

Cheers, Wizard
Author:  emsvitil [ Thu Jul 19, 2007 3:39 pm ]
Post subject: 
Quote:
It is issue of the cam blanks that are mis-drilled at wrong angle. It is not simple drill thru thing, cam have a angled drillings that meets at midpoint.

This is the reason have to dremel a new passage on cam so the valvetrain get the lube. It only get lube flow once every cam revolution.

The oil passage comes up directly from main oil galley to the rear cam bearing then goes at a angle from the bearing to the one rear bolt. Cam is the "turning point for the oil passage". Then up to the head thru one bolt at rear of rocker shaft, this goes to all the rockers that dribbles at both ends. Very complex route.

Cheers, Wizard
With the solid lifter cams, there isn't continous oil flow to the rocker arms........
You get little pulse of oil flow with each revolution of the cam.

If the passages don't line up, no oil flow........
Author:  Bren67Cuda904 [ Thu Jul 19, 2007 5:09 pm ]
Post subject: 
Does the rear most cam bearing have a center grove cut in it 360? The oil is fed from the bottom of the bearing and the rockers get there oil from the top, right?
Author:  Wizard [ Thu Jul 19, 2007 5:10 pm ]
Post subject: 
No. Read again what I said and look at pic of the bearing shown, it will be very clear to you.

Cheers, Wizard
Author:  Doc [ Thu Jul 19, 2007 5:34 pm ]
Post subject: 
Most of the mechanical (solid) lifter cams do not have a groove in the rear cam journal
These photos will help:
DD
Image

Image
Author:  dakight [ Thu Jul 19, 2007 5:39 pm ]
Post subject: 
All that leads me to this question: why not just machine a groove in the cam journal or use a grooved bearing? Would that draw down too much of the oil pressure?
Author:  Rick Covalt [ Thu Jul 19, 2007 5:54 pm ]
Post subject:  Regrind Price
I just got a price from Schneider to regrind the used camshaft of $100 plus shipping.

Rick
Author:  argentina-slantsixer [ Thu Jul 19, 2007 6:44 pm ]
Post subject: 
I was wondering too if we just can cut a groove like hydro cams have and get plenty of oil on the rockers?
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