Feeding the lifters.

[TurboDave]

Well, finally got all the holes completed for the lifter bore oiling holse in "INDY1". Fortunately, a previous owner had done the really hard part by drilling the holes on top the oil gallery so a longer .125 bit could be used to go through the other side of the oil gallery down into the lifter bores. I drilled those and gave the lifter bores a quick hone.
They also drilled valley drain holes down into the block for each pair of lifters.
This picture better shows what I'm trying to describe.
http://community.webshots.com/photo/80287028/86896713kVbzxS

Now, the other block "INDY2" doesn't have any of the lifter bore oiling holes drilled or the valley drain holes bored. Not sure what they made those drain holes with. Maybe a machine shop, or if drilled, it had to be a very long bit to reach down in there, without the drill chuck hitting anything.

On INDY1, my .125 bit is a long 6" bit, permitting me to complete the process where the access holes were.

On INDY2, my #21 bit (for the access holes so that I can use the 10-32 plugs I have) isn't long enough (and can't find a long #21 bit) to do half of the holes without the chuck coming in contact with parts of the front, rear, and valley braces.

Now, here's my point. If I move the holes at the ends of the block enough so the drill chuck doesn't hit anything, the final oiling holes down into the lifter bores would be offset from bore center by about half the radius of the bore. So the oiling hole into the bore would be somewhat eliptical because of this offset.
Would that eliptical shape make the hole affectively too large????????????

Here's a picture of INDY2 with no valley machining done. There's drill chuck interference that occurs with one lifter one each end of the block and one at each of those four vertical block stiffeners (particularly the top where it's fat).

http://community.webshots.com/photo/80287028/80288772rGHkve

 

[KendallF]

Dave,

I don't think the size of the hole will matter too much..the stock block has a huge slot for each one. If you are really anal retentive (and we all know you are! ) you could step the through-hole size down from .125" to, say, .100" or thereabouts. You are certainly getting to do some unique work on those...good luck!

 

[TurboDave]

Originally posted by KendallF
Dave,

I don't think the size of the hole will matter too much..the stock block has a huge slot for each one. If you are really anal retentive (and we all know you are! ) you could step the through-hole size down from .125" to, say, .100" or thereabouts. You are certainly getting to do some unique work on those...good luck!

Good, that's what I was thinking, I think I'll just drill off center with my .125 bit. Should be OK.
It's drilling those drain holes that will present the largest problem, unless I can find an extra long bit for that.

UNIQUE! That's an understatement!!!

You'll never guess what I discovered this last weekend!! I thought that I had it figured that there wouldn't need to be any real unique machining done to these blocks. HOWEVER, I noticed how "meaty" the lower section of the blocks seemed, so measured across the block at the engine mount pads. These aluminum blocks are a total of .880" wider than the stock/stage blocks, so, I'll have to have .440" machined off each side of the block where the engine mount bolts to.
Makes life interesting though! Shouldn't be too tough for a good machine shop, but we have none here.

 

[turbodave231]

Dave,

Do you really want to take that much off the block in the engine mount area? Maybe making custom mounts would be better. Paul Ferry might have some ideas how to accomodate the extra thickness with motor mounts. He helped me with a custom transmount.

Dave Roland

 

[re-evaluating]

Not in a million years

Dave the biggest reason I passed on those blocks myself was concern about the strength in the motor mount area.. The last thing I would ever do would be to remove material from such a critical area.. Just deal with fabricating custom mounts even if they are solids, but don't do all this work and then rip a hole in it.. Just my 2 lbs worth. Dave

 

[sumnerw]

Dave -

From looking at the first pic, it appears that the lifter bores for the bottom center cylinder (#3?) are farther apart than the rest of them. I can't tell from the second pic if there is any difference for that block. I have checked the lifter bore spacing on both of my two stock blocks so far and all except #3 are the same and #3 is about 1/8" greater in both cases. Just curious (as is my camshaft with a flat #3 exhaust lobe) if you can confirm that this spacing weidness has infected more than just stock turbo blocks.

Thanks,
Buzz White in Houston, TX (sumnerw@flash.net)

 

[TurboDave]

Originally posted by turbodave231
Dave,

Do you really want to take that much off the block in the engine mount area? Maybe making custom mounts would be better. Paul Ferry might have some ideas how to accomodate the extra thickness with motor mounts. He helped me with a custom transmount.

Dave Roland

Well, that decision is still up in the air. Those motor mount bosses on these blocks are incredibly thick!!! I compared that area with the width of the stock/stage block, and removing the .44 from each side would bring it down to the size of the stock/stage.
But I like the idea of talking to Paul also. It's just that whatever mount has to be fabbed, I would like it to bolt right into a stock GN frame/mount area. If I decide to sell one or both, I'd like to have enough parts and machining done so the perspective buyer can just "drop it in".
The motor mount thing seems to be the only "big" machining job to accomplish, or a newly designed motor mount for them.

 

[TurboDave]

Originally posted by sumnerw
Dave -

From looking at the first pic, it appears that the lifter bores for the bottom center cylinder (#3?) are farther apart than the rest of them. I can't tell from the second pic if there is any difference for that block. I have checked the lifter bore spacing on both of my two stock blocks so far and all except #3 are the same and #3 is about 1/8" greater in both cases. Just curious (as is my camshaft with a flat #3 exhaust lobe) if you can confirm that this spacing weidness has infected more than just stock turbo blocks.

Thanks,
Buzz White in Houston, TX (sumnerw@flash.net)

I think what you're seeing is more a "camara perspective" thing than anything else.
As near as I can tell, all the lifter bores are spaced equally.
Kinda hard with the calipers I have, so I'll have to try and figure a better way to measure the bore spacing.
One good thing, they're all perfect .842 bores, so finding lifters definately wont be a problem!!!

 

[FHW]

Number 3 lifter spacing on stock and stage blocks is 1.615 vs 1.515 on the other cylinders.Buick did something very wierd here and when i talked to Ken D. about this even he did not know why.

 

[FHW]

Dave you can buy drills in long sizes try an machine shop supply. If you have access to a lathe an need a long length but your drill size does not you can drill a piece of steel rod and braze or epoxy the drill to the rod. hth

 

[TurboDave]

Originally posted by FHW
Number 3 lifter spacing on stock and stage blocks is 1.615 vs 1.515 on the other cylinders.Buick did something very wierd here and when i talked to Ken D. about this even he did not know why.

As a followon, sure enough, I just measured the lifter bore seperation. They're all 1.5, except the #3 bores. They're 1.6, just like them all.

 

[sumnerw]

Dave -

Thanks for taking the time to check that lifter bore spacing out. That really is weird.

I suspect it is a factor (not quite sure how, though) in the demise of so many 3# exhaust lobes. I guess it isn't that much of any issue with non-stock blocks like yours since I'm guessing you'll be going roller cam and lifters (which is what is going into my stock block to replace my wiped cam).

Best regards,
Buzz White in Houston, TX (sumnerw@flash.net)