Intake Manifold bolt torque (aluminum head)

[Aiken Racing]

I am going to put studs in my new aluminum head instead of bolts so I don't have to worry about wearing out the holes in head if I have to take the intake on and off. I would rather just put studs in one time and leave it.

With an aluminum head what kind of torque should I be using on the studs or bolts on the intake and exhaust? I assume that it should be less then a iron head and that is why I am asking.

Thanks,
Chris

[Jerry Sloot]

try this....call Curtis Farley at Farley Engines, nice guy and I'm loving the alum head on the last motor from him

[Aiken Racing]

Well I just found out something interesting.

The intake bolts on the ford (and aluminum) heads are 1/4 18 threads!! Non-standard so places like Fastenal can't even get them. They said they were custom made for ford to use on their engines so you have to get their factory bolts.

Does anyone know a source for these? I want to get a stud that is 1/2" longer then the stock bolt instead of using the normal bolt.

Thanks,
Chris

[Rick Brannon]

I think if you check again, you will find that they are 5/16 X 18.

[Ferris11]

Chris,

Umm, .. the service at my cylinder head business doesn't stop after you buy a head, .. any time you need anything call ( 703-541-0565 ) and if I'm not in the shop the message has my cell phone number.

I'm in the service business.

That said, the bolts should be 5/16x18

If you are using the green intake gasket torque to 15 - 17 Foot Pounds, .. exhaust the same.
You'll have to chase this a little till the gaskets settle, .. so check it after every session or two till it stays put.

Curtis
Racing Flow Development

[Aiken Racing]

geeze.... I didn't even measure them myself as I took them directly to Fastenal and they measured them. When he stuck them in the hole chart he must of read them in the wrong direction..... so I just called him back and he appologized for the mixup. He just ordered 5 studs and locking nuts.

Thanks for clearing that up. I should of measured the bolts to begin with because I didn't think they were 1/4" bolts but I didn't question the guy.

Chris

[Aiken Racing]

Thanks Curtis!

I knew I could of called you but I also knew that the response of the message board is pretty quick plus this is a question that I haven't seen in the past so I figured having it on the board for later dates isn't a bad thing.

I am only putting studs in the intake so that I can put them in and not have to remove them every time. Now that I am thinking about it....I may have a small problem doing this.

If I torque the studs down to 17 and the nuts on the end down to 17 when I back them out there is a good chance the studs will back out too since I am using nylong locking nuts. Isn't it true that locktite doesn't work in high temps? If so is there any else i can put on the threads of the studs to keep them from backing out when I take of the nut off? Or can I torque the studs down more? An idea how much more then 17?

Thanks again,
Chris

[mjs]

Chris,
I have used Loctite 266 (high temp grade) on intake studs and it worked well. No problem with the studs backing out. It works pretty well even on header bolts.

Paul Derov
CF #12

[Jeff Smith]

Chris,
I dont think the nylock nuts will torque the same as regular nuts. I am not sure of the exact difference, but the locking ability of the nylock has to add to the torque needed to hold the same compressive strength.
Just for giggles, why would you be removing the intake so often that you feel you need studs?

John

[Chuck Gillis]

Chris: Torque is analog for fastener tension. Aerospace practice is to measure run-in torque, with a dial torge wrench, and add that to the torque value required to properly tension the fastener.

gm

[Ferris11]

Chris,

I'd use high temp locktite on the studs, .. but be carefull going over 17 ft lbs on them, .. the aluminum head is fairly soft.

I'm not sure how hot those studs will get, .. it may soften your nylon in the lock nuts.

I'd use the bolts myself, .. .. and use the time saved to find more power on the flow bench, . ;)

Curtis

[Aiken Racing]

Alright, that is what I wondered about. I didn't want to over torque them. I will just go a pound or two over 17 on the studs and keep the nuts at 17.

As the nylon lock nuts.... I was wondering about them melting too on the head but I think the nylon on grade 8 nuts are tougher then other grades though I can't be postive. Jim Justice gave my nylon lock nuts for the rocker stands which I am sure is hot inside there too. If those don't melt the ones on the end of the carb shouldn't melt either.

I don't plan on taking the intake off that often plus it is easier slide the intake on the studs then hold it there while i put a bolt in. HAHAH. wow i am lazy!

I just don't like taking bolts in and out of soft aluminum that is why I would rather just put studs in them and forget about it.

Thanks everyone,
Chris

[Charles Warner]

If you can get them, use MS21042 Jet Nuts. I'm not sure they come in coarse threads, but in the fine series, they work fine in hot areas.

You should be using them on calipers and wheel rims.

[Mike Ahrens]

I recall reading something in the Coast Fabrication catalog that studs should not be torqued into the block or heads of engines. They should be put in hand tight and secured with locktite. I believe this is because the stud will bottom in the hole and then as it is tightened it will essentially apply a "jacking force" (for want of a better term) to the threads. When you then torque the nut, this force will then add to the jacking force already applied which could overload the threads.

BTW doesn't the GCR specify the use of the original fasteners for this application. I thought some creative engine builders were using bolts with undersized shanks to allow them to optimize the position of the intake manifold.

[Aiken Racing]

Very good point!

I don't have my GCR handy until this evening. Anyone else know if it is true about using the stock bolts?

Thanks,
Chris

[USF2000]

Chris, if I am not mistaken, intake bolts are open now,but you need to use the stock diameter for your studs or bolts which is 5/16.-Dave

[PRSCHMN]

if you are that worried about the threads in the aluminum head, then replace it with a standard head then you won't have to worry. (wink...wink)

[PRSCHMN]

just checked 2002 GCR. i don't think this has changed for 2003.

see FCS page 55.

section D.2.s.2.A ...fasteners unrestricted except for intake manifold.... ... fasteners may be of socket head or hex head configuration...