Machining drawing for twin plug valve covers

[jomalkay]

Anyone have a dimensioned drawing for punching the holes in lower valve cover for twin plug? Thanks, John

[boyt911sc]

Originally Posted by jomalkay

Anyone have a dimensioned drawing for punching the holes in lower valve cover for twin plug? Thanks, John

John,

These are the valve covers for a 3.0 liter SC engine that I'm rebuilding that has been twin plugged. You could see where the drilling is done.




Tony

[Ken911]

i did it the easy way i just bought 964 lower covers

[KTL]

Originally Posted by Ken911

i did it the easy way i just bought 964 lower covers

And drilled the mounting holes out to M8 size?

[turbo nut]

I used 964 upper and lowers and drilled holes out to 8mm. The o-ring style gasket is a plus also.

[bullethole]

Just had my heads twin plugged by Anchor Atlantic, and they included drilling the valve covers in the price. It was something like $550 for all the work (don;t have the reciept handy). You might want to give them a call and see what they would charge to drill the covers for you. Probably cheaper than going through the hassell yourself to do it.

[Gunzel]

I have the lower covers off my 1973 RSR motor. I can trace the plug holes for you

Mike Curnow

[jomalkay]

thanks for the input. My problem is not so much cost, i have a bunch of other parts waiting to get powder coated, need to get them all done at once and i am a week or so until i send out the heads to be twin plugged. I do have a full machine shop at my company (in previous life i was a machinist, so this is a simple task). That said, i am not familiar with the 964 covers, i think they were made both in aluminum and plastic?? one any better than the other? I do like the 964 sealing, looks to be a better. The only set of 964 covers i saw were a complete set for $500 if i recall, I'd spend the money on other items as the motor build is approaching $10k i need to start to pull in the reigns a bit.
Mike,
If not too much trouble, a trace and some measurements would be great. I think i could just punch the holes close enough as this is not critical, but as a former machinist and pretty much full bore anal about these things, well you know.
Thanks again to all.

[Gunzel]

My e-mail is mcurnow@comcast.net
Send me your postal address and I will send a drawing

Mike

[turbo nut]

We clamp them in a mill vise and use a hole saw. Quick and easy.

[Gunzel]

A few pictures of the 1973 RSR valve covers.

[jomalkay]

Mike,
Thanks for sending the trace, i also got another drawing in the meantime as well. I checked in our shop, have a 1.5" end mill for machining the "ribs" away on the turbo style covers, only had a 1 1/16" end mill for the through hole, i think this would work but 1.250" is the "spec. Need to check how much the cutter cutter costs, then will decide. If i jig these things up, no problem to knock one out for you, my question is what happens if i screw it up? I was a machinist in former life so the risk is low. Thanks again.

[Ken911]

Originally Posted by KTL

And drilled the mounting holes out to M8 size?

yes

[Gunzel]

Originally Posted by jomalkay

Mike,
Thanks for sending the trace, i also got another drawing in the meantime as well. I checked in our shop, have a 1.5" end mill for machining the "ribs" away on the turbo style covers, only had a 1 1/16" end mill for the through hole, i think this would work but 1.250" is the "spec. Need to check how much the cutter cutter costs, then will decide. If i jig these things up, no problem to knock one out for you, my question is what happens if i screw it up? I was a machinist in former life so the risk is low. Thanks again.

I'am game,

Mike

[jomalkay]

Mike,
I,ll check the price of a hole cutter, if I get it for $20 or so, I,ll go for it, do your cover/s at the same time. Not familiar with this style, material is aluminum, correct?
I,ll let you know if it's a go and you can send parts to my company address.

[Gunzel]

It is aluminum.

Mike

[scootermcrad]

I hate to bump up a thread this old, but it seemed to be the most relevant.

Can someone please post up dimensions for locating the holes on the lower covers for twin plugs? Quick sketch, maybe? I'm guessing the holes are 118mm on center between holes and 1.25" ID. How about some dimensions to place the holes in the covers?

Also, is there any difference between where the holes would be located on a Turbo type "ribbed" cover, versus the standard type (for example 2.7l covers?). I'm assuming not, but want to check. I have the standard non-ribbed and am thinking of switching to the later Turbo style.

Thanks for any help!

[KTL]

I have a twin plugged lower 930 valve cover with a corner broken off of it. You can borrow it to check size & spacing for the holes if you'd like

[scootermcrad]

Originally Posted by KTL

I have a twin plugged lower 930 valve cover with a corner broken off of it. You can borrow it to check size & spacing for the holes if you'd like

I'll PM you. Thanks!

[cgarr]

If you start with the half hole at the end the edge is the hole center, measure over from that center hole 4.640 for the next center hole then another 4.640 for the last hole.