Offenhauser manifold
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Offenhauser manifold
I am going to be putting an offenhouser manifold on my 79 inline 6 and was wondering what the torque specs. are for it? if any. Also is it the same torque spec for the headers? thanks
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From: LaGrande,Ore
Same bolt holds both on,same torque. Use quality gasket, retorque several times (2 maybe 3). "MOTORS" manual says 20 to 25 ft.lbs. Start in center and work out. alternating sides. Might want to check flange thickness on both manifold and header, they should be close to the same or you will get uneven clamping and possably a leak. OBCB
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From: Boise, Idaho
If you don't have it, here's the tightening sequence. It'll be the same with the Offenhauser and header.
As oldbrokecowboy said, each bolt spans a tab on the intake and on the exhaust, so there's no way to torque them differently. The torque spec for the stock intake/exhaust is 26 ft/lbs, but I've heard a little less for the Offenhauser.
General rule of thumb. Torque during install, re-torque after the engine's first warm up / cool down, re-torque one more time after 100 miles.
As oldbrokecowboy said, each bolt spans a tab on the intake and on the exhaust, so there's no way to torque them differently. The torque spec for the stock intake/exhaust is 26 ft/lbs, but I've heard a little less for the Offenhauser.
General rule of thumb. Torque during install, re-torque after the engine's first warm up / cool down, re-torque one more time after 100 miles.
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If the o.e. washer sits crooked, as it usually will, clamp it in a pair of vise grips and grind down one side as needed to make it sit flat.
I used high temp rtv silicone on both sides of the exh ports on the gasket. Maybe I made a mistake, but with heads, manifolds, etc. I always torque starting in center, with a clockwise spiral. Do the first pass with w/half the torque. I have 2500 miles on the engine w/o probs. If you are using headers, I would think long and hard about either studs, or the Stage8 locking bolt system. You may be glad you did.
I used high temp rtv silicone on both sides of the exh ports on the gasket. Maybe I made a mistake, but with heads, manifolds, etc. I always torque starting in center, with a clockwise spiral. Do the first pass with w/half the torque. I have 2500 miles on the engine w/o probs. If you are using headers, I would think long and hard about either studs, or the Stage8 locking bolt system. You may be glad you did.
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From: Boise, Idaho
Not headers, necessarily, but shows the studs. It's one thing I was very glad I did. Makes installation so much easier since you can hang things on them. It's a lot easier getting a nut onto the stud when you're holding up two exhaust manifolds and an intake, than it is to hold all of them up, and try to get a bolt to go in a hole.
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Thanks for all the info guys. Yea when i went to take the old intake off this morning i saw that the bolts were holding on both the manifold and headers. Where can i get those studs from? and what size are they?
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From: Boise, Idaho
Do you have a local place that specializes in hardware and stuff? We have one here, and that's ALL they sell, is all the different size bolts, washers, nuts, etc. you'd ever need in every shape, grade, and size. It's great. Call a local exhaust shop and ask who they buy their stuff from when they have to replace or upgrade bolts for a customer.
Take one of your bolts down and have them match the thread. I don't remember the size off the top of my head.
Avoid places like Ace Hardware, etc. Before I found the place I mentioned above, I originally bought all my studs from them and specifically requested "automotive grade" and the hardest steel they had. They were almost $4 a stud, but I figured the extra strength was worth it. I had one snap in half under 20 lbs of torque. During the process of working the broken stud out, two more snapped and shot off just from sitting under the torque. Complete junk.
When I got the ones I have now, they were much stronger and cost about $1 a piece.
Take one of your bolts down and have them match the thread. I don't remember the size off the top of my head.
Avoid places like Ace Hardware, etc. Before I found the place I mentioned above, I originally bought all my studs from them and specifically requested "automotive grade" and the hardest steel they had. They were almost $4 a stud, but I figured the extra strength was worth it. I had one snap in half under 20 lbs of torque. During the process of working the broken stud out, two more snapped and shot off just from sitting under the torque. Complete junk.
When I got the ones I have now, they were much stronger and cost about $1 a piece.
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Do you have a local place that specializes in hardware and stuff? We have one here, and that's ALL they sell, is all the different size bolts, washers, nuts, etc. you'd ever need in every shape, grade, and size. It's great. Call a local exhaust shop and ask who they buy their stuff from when they have to replace or upgrade bolts for a customer.
Take one of your bolts down and have them match the thread. I don't remember the size off the top of my head.
Avoid places like Ace Hardware, etc. Before I found the place I mentioned above, I originally bought all my studs from them and specifically requested "automotive grade" and the hardest steel they had. They were almost $4 a stud, but I figured the extra strength was worth it. I had one snap in half under 20 lbs of torque. During the process of working the broken stud out, two more snapped and shot off just from sitting under the torque. Complete junk.
When I got the ones I have now, they were much stronger and cost about $1 a piece.
Take one of your bolts down and have them match the thread. I don't remember the size off the top of my head.
Avoid places like Ace Hardware, etc. Before I found the place I mentioned above, I originally bought all my studs from them and specifically requested "automotive grade" and the hardest steel they had. They were almost $4 a stud, but I figured the extra strength was worth it. I had one snap in half under 20 lbs of torque. During the process of working the broken stud out, two more snapped and shot off just from sitting under the torque. Complete junk.
When I got the ones I have now, they were much stronger and cost about $1 a piece.
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on the offenhauser manifold there are two threaded holes on one side of it. anyone know what hooks into them? they are several places on there to bolt stuff anyone have any instructions on what goes where?
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From: Boise, Idaho
The threaded holes are for vacuum ports. I got mine used, so it already had them in there, but I think you can probably just get them at parts stores. It gives you an assortment of ways to hook up manifold vacuum to various accessories, PCV, cruise, etc. etc.
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abandoned
do you have a pic with your manifold on? Where did you bolt down the throttle cable? seems like there is a spot for it on the manifold but the carb is in the way of it. Am i gonna have to purchase a throttle kit? I have a bunch of lines that came off the 1 bbl but dont know where they hook on at with the 4 bbl
do you have a pic with your manifold on? Where did you bolt down the throttle cable? seems like there is a spot for it on the manifold but the carb is in the way of it. Am i gonna have to purchase a throttle kit? I have a bunch of lines that came off the 1 bbl but dont know where they hook on at with the 4 bbl
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From: Boise, Idaho
There are a few throttle cable kits that people use, and I'm sure they can give you guidance as to which ones. I believe Lokar makes them.
As for me, I went the cheap route and made my own out of some $5 plates from Home Depot. I bolted it to the two bolt holes in the back where the exhaust was to bolt to the intake:
I also replaced the stock throttle cable with a generic from Schucks and got an assortment kit of random springs and found one that clipped onto the linkage and my homemade plate. It's a poor mans way of doing it, but it's worked great for 2 years.
As for me, I went the cheap route and made my own out of some $5 plates from Home Depot. I bolted it to the two bolt holes in the back where the exhaust was to bolt to the intake:
I also replaced the stock throttle cable with a generic from Schucks and got an assortment kit of random springs and found one that clipped onto the linkage and my homemade plate. It's a poor mans way of doing it, but it's worked great for 2 years.