I'd like to go back to using the stock intake gaskets for my twinscrew. Bill Ball (and others) have machined 1/8" spacers to allow the appropriate gasket compression without squishing it completely.

Does anybody have any or would be willing to machine them easily and cost effectively?

I guess you also need to put studs back in, since it would probably be a nightmare to align bolts back through everything.

Anybody done this and could walk me thru the process to make it as idiotproof as possible? When you reinstall studs, do you double nut them to seat them in the heads, use blue loctite on the threads, and to what torque value?

My idle is somewhere ~1000 and I think it's due to leaking intake gaskets--when I spray starting fluid around the rear passenger side of the intake, it calms down some.

I would've posted to the twinscrew thread, but it's a bit unwieldy given the >1000 posts...

 

Turns out you can buy 1/8" spacers (1/2" OD) thru McMaster Carr. Geez, they have everything. Part #93013A961. In case anyone else is considering doing this...

 

Brian:

Good find. Also, to make this work properly you need to use spacers inside the manfold so the thin bottom will not warp. My manifold walls were exactly 1". So, I bought some 1" long tubing/spacers at OSH (McMaster Carr has them as well). These should go around the bolts inside the manifold. It's no easier to do this with studs - in fact, it's harder. I positioned the spacers inside and dropped the bolts in on the workbench before mounting the manifold so they stayed in-place just fine. Using the stock gasket, I dropped the torque to the factory 11 ft lbs, and went around a few times until it held torque.

 

Thanks, Bill, that's probably good advice. I was going to PM you to ask if you went back to studs or kept the bolts--now I know. I ordered some 1" spacers too.

Did you need any trick to keep the 1/8" spacers from dropping out of the gasket when you were positioning the manifold, or were they snug enough to stay in place?

 

I only have a mental image of how the longer spacers fit inside the bloser manifold, but it sounds like a careful dose of JBWeld on the ends of the spacer sleeves is an answer. Do them on the bench with bolts through them and just snug until the epoxy sets up, and they will be there pretty permanently. That would also eliminate possible air leaks around the bolts, and make Brian's stud option pretty reasonable.

Brian, use weak loc-tite on the studs when you install them. There are several stronger grades, including 'stud and bearing mount' and 'sleeve retainer'. Don't use those! Your goal is to have the studs in there snug enough to let you use Nylok or similar locking nuts, and be able to remove the nuts without backing the stud out. Clean and prime the studs and the threaded holes in the heads for best results. You may want to remove those studs someday.

 

One quick question for Bill--I'm curious as to why the inner spacers would be required when going back to the original gaskets--if we're using 11 ft/lbs of torque rather than 30, it seems like the load being placed on the manifold would be considerably less. Or were you just acknowledging the tendency for the manifold to warp, period?

 

I think I just laid the gasket and spacers on the heads and dropped the manifold on and found everything lined up OK. I don't recall a problem or any clever solutions. Oh, you could tack the gasket down with a few dabs of gasket goop in a few places.

 

Right, I wasn't as concerned about the torque as heat warping. Now, the thick rubber gasket could cover a lot of warping, but the internal spacers/sleeves are good insurance. The guys in Denver had their kits professionally evaluated and the recommendation was to make the base thicker and brace it inside. As I left my base the same, I thought the internal spacers were a real good idea. Also, there are a few other bolts/studs in the lid that I changed so they went through the bottom and lid and had the same 1" spacers/sleeves so they acted as extra braces.

 

https://rennlist.com/forums/5446996-post1757.html

An Excerpt from my post above (5/26/08) in the twinscrew thread....you can go there and see the photos. This improvement worked very well for the entire track season.

While I had the intake off, I port matched the intake to the cylinders. It took me about 20 hours with a dremel tool, but I would guess that I picked up just under 2 square inches of intake opening.

I insulated the bottom of the intake where the intercooler resides. Keeping the cool part cool helps.

One of the problems with the "early Andy" manifold is the lack of support in the middle of the intake. My solution was to put in place 1 inch tall 3/8 diameter sleeves. (Just on the center 3 bolts on each side...the ends are fine)

I can attest that this solution works great. At just 10 pounds of torque the intake and sleeve were in compression and I did not have to exceed the factory torque spec for the manifold. Unlike the initial installation.

Ken

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1/8" thick spacers? What thickness gasket material is everybody using? Would't the spacer prevent the gasket from getting a good seal?

 

Pizza,

I think that we are talking about spacers within the intake in the 3 center intake to head bolts where there was no internal support in the manifolds. (see the photos in my link above)

Without the "spacer" the upper portion of the manifold did not want to remain flat and transfer its fastening force to the bottom portion of the manifold that was in contact with the gasket and head.

Using the spacer as I did, allows the torque of the fastener to be transferred to the lower portion of the manifold and eliminate leaks and or the need to over torque the manifold.

Not a bad fix for about $5.00.

Also, there was mention about retaining the sleeve or spacer in place with JB Weld. I would vote against that, since if you have a little glob of JB Weld that fractures and drops, it is going to go under a valve or directly into the cylinder. I just retained mine in place with short bolts that just "peeked" into the lower manifold bolt hole and then when the manifold was positioned, I carefully withdrew the short bolt and placed in the correct length bolt.

I will admit to bumping one out of alignment and then I just used a bent magnet to realign and hold in place until I could drop in the fastener.

Regards,

Ken

 

I previously posted picitures of the studs and spacers on the twinscrew thread. It is probably 3 or 4 pages before the last page. I used a stock gasket and have had absolutely no problems. I also think the 1 inch spacers are very important.

 

The 1/8th inch thick spacers under Andy's manifold allow us to use the stock manifold gasket. The stock manifold gasket is 0.18" thick. The 0.12" (1/8th") spacers under the manifold assures the same 1/3rd compression as seen with the stock sleeves that go over the stock studs and through the stock manifold mounting legs. Mine were cut from 1/2"OD pipe, with the ID large enough to accomodate the manifold bolts or studs.

Andy originally used thin cork gasket material then changed it to a harder material. He kept upping the torque value he recommended on the manifold bolts he provided in order to get this to seal. My system ALWAYS had a idle miss once it warmed up and I suspected heat warping of the thin base plate in the manifold combined with the hard gasket material. Even 30 ft lbs of torque wouldn't overcome this and was dangerously close to pulling these small steel bolts out of the aluminum heads. In fact, some of the bolts would not torque further than 22 or so.

I believe Ralph and/or Dave Roberts came up with this solution. Dave Roberts is using spacers that are machined to fit into his manifold base. Ralph alerted me to the simple 1/8" spacer idea to use with Andy's manfold and it has worked perfectly with the stock manifold gasket. Combined with the 1" internal sleeves to help maintain the original distance between the top and bottom plates, this has eliminated my warm idle miss.