Can someone mic a VH crank snout???

[tmorgan4]

Just spoke with ATI again and they need me to mic the crank snout to .0001". This wouldn't really be an issue other than the only 1-2" mic I've got only goes to .001" and I don't really trust it. I should just order a new one but that will take another week. Anyone want to do me a favor and get me an ACCURATE measurement? There has to be a few machinists on here.

[David Steele]

I'll do it for you whats ATI making and can I add a cog belt drive for a dry sump?

[tmorgan4]

That would be great! I actually thought of you when I posted this...aren't you a machinist??

ATI is building a damper for me. I thought I was going to have ROSS do it but things didn't quite work out and I just wanted a solid answer that it could be made. I sent ATI my factory damper for measurements but they still want crank measurements. If possible they asked to measure in 3 places to .0001".

What I spec'd on my damper is to get rid of the 4 and 7 rib (inner and middle) belts, and only keep the outer 6 rib. If you're still keeping your factory water pump and alternator, flipping the water pump pulley around lines it up almost perfectly with the alternator on the outermost 6 rib. I'll probably have a thin spacer made to make it perfect.

I'm having a HTD pulley for a dry sump(from my research HTD seems superior to Gilmer drives) built into the pulley that will sit just inside the 6 rib (between the 6 rib and timing cover). This takes an estimated 60-90 days to build AFTER I approve their drawing. Once I give them these measurements I should have a drawing in a few days. I could post it up here, and if it will work for you I'm sure a 2nd could be made.

Cost is $775 total. I already paid their non-refundable $250 engineering fee for the drawing, so there's a chance future units will be cheaper since this won't need to be done again.

Thanks David!

[tmorgan4]

Ricky at ATI sent me this drawing of an LS1 pulley with a similar belt setup. He said it would be very similar. Just something to reference until i get my drawing, anyway.

[David Steele]

Front .34071''

Mid .3477''

Rear .3413''

Did you even determine what diameter to make the dry sump drive gear it needs at least 50% engine speed.

There is one thing I think that should be revised in what your pulley would be.
The oil pump is most important and the belt should be the most accessible.. not being stuck
behind a belt and in between the timing case.

One reason is if you want to change the speed of the pump you have to reset tension for other belts because the
oil drive is behind a serpentine belt so you have to remove both to get to one. There is a good reason why the HTD drives are always outer most and the serpentines are always behind.

[tmorgan4]

Thank you doing this David. Just to be clear, did you measure the part of the crank that protrudes from the timing cover? The measurements seem correct if they are 1.XXXX". Just want to make sure!

It's up to me what size pulley (how many teeth) get put on the damper. I've been looking through the available dry sump drive pulleys, to make sure that I end up somewhere in the middle and have adjustment for faster or slower pump speeds. I've mainly been looking at Peterson since they're somewhat local and they make nice stuff.

They have dry sump drive pulleys available in 32-49 tooth counts (with not every size being available in between). Their crank drive pulleys are available in 18-33 tooth counts just for reference. I think I will have a 20 tooth put on the ATI.

This way I can buy a 40 tooth dry sump drive (it's available) and have my 50% of engine speed. I can go up or down from here if need be.

I do think that would be nice to have the HTD drive on the front, but it's all a big compromise. Putting the HTD drive on the front will either mean A) relocate all the accessories (alternator, power steering, water pump) to move them close to the timing case OR B) Have a longer assembly with the accessories mounted in the factory position and the HTD drive hanging off the front.

I don't think it's going to be a big deal to loosen the single serpentine belt to remove the dry sump belt whenever I need to. I'm not racing this car so being able to quickly prep the car isn't as big of a deal (although it would still be nice). The only reason I should be pulling the HTD belt off is for maintenance (which should be done fairly regularly...if it breaks I'm screwed), or to change the size of the drive. Neither one is all that often that I'm worried about putting the HTD belt behind the serpentine.

I do appreciate the criticism. It makes me double check my thinking. It sucks when you get an expensive part and wish you'd have done something different.

[David Steele]

I measured from just in front of the cranksprocket to the tip before the chamfer and inbetween.

Yes it's ''1.xxxx''

I have to move factory accessories regardless.

[tmorgan4]

Thanks again for the measurements David. It REALLY helped me out, and definitely saved me waiting another week. Hope to return the favor someday!