440 Header/Head Mounting Bolt

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KOZ45

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What is the thread length and pitch for the header exhaust bolts going in to the heads (#906)

I have a tiny coolant leak I want to try to fix, only near the #6 plug

I think the PO might have used too short of a bolt for mounting the header

I took the bolt out and wrapped it with Teflon tape......still dribbles

Should I drain the coolant past the head and apply a thread sealant to or RTV to the bolt ?
 
3/4” long threads would be nice, how long do you,have now? Teflon tape should be good, try cleaning the threads out first with a tap or thread chaser and drain the coolant down so it goes in dry. RTV is not for this task.
 
I had the same problem, but in several spots. I found a product, permatex i think, a 1400° exhaust bolt sealer, an rtv.
Drained coolant below head level, pulled out one bolt at a time, put on sealer, and reinstalled. Let it sit for a day, problem solved.
 
33IMP said:
I had the same problem, but in several spots. I found a product, permatex i think, a 1400° exhaust bolt sealer, an rtv.
Drained coolant below head level, pulled out one bolt at a time, put on sealer, and reinstalled. Let it sit for a day, problem solved.
Click to expand...

Do you have a link or part number

I only found Permatex Ultra Copper RTV Silicone High Temperature Gasket Maker
 
I think I'd try 33IMP's suggestion. If that don't do it you might check the head for a possible crack from over torque.

KOZ45 said:
I would guess the current bolt threads are easily 1"
Click to expand...

I see TTI uses 1" bolts where as Schumacher uses studs, maybe still available.

B/RB Tri-Y Headers (engine-swaps.com)
upload_2021-5-14_12-43-40.png
 
I'd to find a single bolt or stud and not have to buy a kit

Does anyone know the thread size and pitch?

The headers are all mounted with studs/nuts. The only bolt the PO used is the leaking one
 
The bolts are 3/8-16 coarse. Normal bolt that size has a 9/16ths head, header bolts usually have a 6 point 7/16 head, sometimes a twelve point 3/8 head.
 
KOZ45 said:
....The only bolt the PO used is the leaking one
Click to expand...
Hmmm.........sounds like this issue just may have been chased around previously.

Anyway, if you decide on a stud and you blow up the Schumacher picture, you can make out they are a combination, course and fine thread. Likely 3/8-16 x 3/8-24 stud. Check NAPA or possibly a Doorman parts rack. If you do use a stud make sure the shank portion between the two threads isn't too long to tighten the header flange adequately. If the nut bottoms into a shank that is too long and the shank is driven into the head, it could cause the cast to split, crack, or strip threads.
upload_2021-5-14_13-42-49.png
 
Well since I am going to drain the coolant, I may as well install a new tstat, right? Its been in the there for alteast 5 years

Whats a good temp range 185? 195?
 
KOZ45 said:
Well since I am going to drain the coolant, I may as well install a new tstat, right? Its been in the there for alteast 5 years

Whats a good temp range 185? 195?
Click to expand...
Are you having any issues? If not I would leave it in.
 
No issues, just fear of the unknown.........lol

The coolant I drained out appeared to be in very good/fresh condition, green and not discolored
 
I am still trying to find a good sealant for the threads

I will pick up a single exhaust stud this weekend
 
KOZ45 said:
No issues, just fear of the unknown.........lol

The coolant I drained out appeared to be in very good/fresh condition, green and not discolored
Click to expand...
I would be MUCH more afraid of the unknown new part, than the known-good old part.
The new stuff on the shelves is a coin flip, garbage, or not.
 
I am going to drain the coolant and tap the one mounting hole and clean it out really good

Let it dry and then install a new stud, rather than a bolt

Permatex #2 form a gasket seems to be a preferred product to use
 
KOZ45 said:
I am going to drain the coolant and tap the one mounting hole and clean it out really good

Let it dry and then install a new stud, rather than a bolt

Permatex #2 form a gasket seems to be a preferred product to use
Click to expand...
I think I used the high temp orange stuff.
 
Also consider allen head cap screws for the ones that are "tight" The aircraft industry uses 12 point headed bolts which have a smaller head
 
Permatex High Performance Thread Sealant part #56521 and a 1-1/2" overall length stud with .550" long 3/8-16 thread on one end and .700" long 3/8-24 thread on the other end.
 
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I would not use Teflon tape. Teflon tape is used to lubricate tapered threads so you can tighten until the threads are engaged as far as they can go. Header bolts are straight threads. Use permatex or other sealant.
 
Radiator drained and no more coolant coming out of the lower radiator hose

Seems like the threads going into the head are still wet with coolant

Tried a few q-tips and some paper towels but I can't seem to get it fully dry

Will this be OK for the gasket maker and the stud to cure for a few days?

I also found a stud and nut for $3 locally
 
hum, I thought big block heads had a blind hole
 
Liquid pipe dope is much better for thread sealing instead of tape. Gasket maker always seemed to give up when I tried it.
 
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