which Head Gasket to get??
- Thread starter suprafanatic
- Start date
When I had my 7M-GTE out, I basically just cleaned the block down really well. I didn't cut it, or lap it, just cleaned it down to good metal. The head was machined, but not the block.
I put ina stock Toyota head gasket, and torqued down my ARP studs to 90 ft-lbs. I plan on bringing the boost up to 15-18 lbs eventually. I feel that theis should be fine as long as I take care of the cooling system.
I base that on the fact that Reg Reimer's 7M-GTE in his Mk2 is running with a stock Toyota head gasket, on stock bolts torqued to 72 ft-lbs, and I know he runs more than 18 lbs boost on it.
If I'd had the time to do a complete rebuild, I'd have had the block decked and put in a MHG, but I didn't have the time or the funds at the time, so I did what had a reasonable chance of lasting at least a few years.
I put ina stock Toyota head gasket, and torqued down my ARP studs to 90 ft-lbs. I plan on bringing the boost up to 15-18 lbs eventually. I feel that theis should be fine as long as I take care of the cooling system.
I base that on the fact that Reg Reimer's 7M-GTE in his Mk2 is running with a stock Toyota head gasket, on stock bolts torqued to 72 ft-lbs, and I know he runs more than 18 lbs boost on it.
If I'd had the time to do a complete rebuild, I'd have had the block decked and put in a MHG, but I didn't have the time or the funds at the time, so I did what had a reasonable chance of lasting at least a few years.
Dan_Gyoba said:
This statement makes me seriously wonder about reading comprehension among Mk III owners. :3d_frown:
You DO NOT want to over torque ARP studs or bolts...ARP specifically says not to do this. Torque specs for ARP studs is 80 ft/lbs and bolts are 75 ft/lbs on an aluminum head...both specs are based on using moly for lube. It's on the instructions every new ARP hardware set has in the box and is easily available if you lose the spec sheet. Just use the ARP spec for heavens sake and stop making this kind of thing up as you go!
Actually, I have a related tech question: Is the cut from a cbn(?) mill good enough on the block and head, or will it still have to be lapped?
I know that the old grind stone cutter used by some out dated shops is a pretty rough cut, but the cbn(?) has a really smooth, almost mirror, finish.
I know that the old grind stone cutter used by some out dated shops is a pretty rough cut, but the cbn(?) has a really smooth, almost mirror, finish.
It's easy to find out, just get a sample cut and have them measure the RA. All good shops can do this.
It's CNC and the cuts are measured in the # per inch...the more cuts per inch, the smoother the finish. There are diamond cutters available that produce a very fine finish cut vs the carbide fly cutters. Like Grim said, get a sample.
Thanks 
I was pretty sure he called it a CBN mill, but I could be mistaken. So if I know the number of cuts per inch, and what type of bits are being used, the RA can be determined? Just trying to verify the data I'll get.
I was pretty sure he called it a CBN mill, but I could be mistaken. So if I know the number of cuts per inch, and what type of bits are being used, the RA can be determined? Just trying to verify the data I'll get.
No, you could guess with that information. There is a tool that measures the actual output and gives you a number.
Yeah, I know there is some sort of measuring tool, was just curious. Haven't had to deal with mls gaskets until recently, as I'm starting to find them more in production vehicles. Been researching the local shops as to what type of machines they use, and what type of cut they give. Just wanted to see if I could verify the information they give me without having to buy the tool and learn how to use it.
You do NOT want to buy the tool yourself. They are damn expensive - expensive enough that the only people who can justify owning them are either independently wealthy or a business.
Cuel - Sorry man...I thought you were referring to the machine.
Yes, there are CBN (Cubic Boron Nitrate) end mills...they are almost as hard as PCD (Poly-Crystalline Diamond) and should produce a very fine finish. Typically you see a machine shop use carbide end mills.
Yes, there are CBN (Cubic Boron Nitrate) end mills...they are almost as hard as PCD (Poly-Crystalline Diamond) and should produce a very fine finish. Typically you see a machine shop use carbide end mills.
unless you guys want to keep talking its ok, i have no more use for this thread, as i dont think i have a BHG so i wont be needed a new hg. thanks for all the advice tho guys.
so i wont be needed a new hg. thanks for all the advice tho guys.
Thanks JDub. By the way, its Cuel(cool). no "r". A lot of people do that...
I had a bookmark to a thread where IJ discussed lapping in depth, but can't seem to find it. I think it was somewhere in his build thread, but don't really remember.
A lot of people do that... I had a bookmark to a thread where IJ discussed lapping in depth, but can't seem to find it. I think it was somewhere in his build thread, but don't really remember.
Fixed
Go here:
http://www.mcmaster.com/
They have lapping plates...search at the top left. And the diamond paste that makes short work of lapping a block that's been fine finished. The key to lapping is keeping the plate flat and using even strokes.
Here's a .pdf of the pattern Reg Riemer recommends when using the lapping tool he sells:
Lapping Plate Pattern
Go here:
http://www.mcmaster.com/
They have lapping plates...search at the top left. And the diamond paste that makes short work of lapping a block that's been fine finished. The key to lapping is keeping the plate flat and using even strokes.
Here's a .pdf of the pattern Reg Riemer recommends when using the lapping tool he sells:
Lapping Plate Pattern