exhaust manifold question
#1
07-31-2017, 06:13 PM
Join Date: Jul 2017
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
exhaust manifold question
Hi folks - 86 dodge d150 318 727auto
I made a big mistake yesterday. I grew tired of a exhaust leak ticking and the smoke getting in the cab when at a red light so I got to my farm and under the shed and started checking exhaust manifold bolts. Everything was loose but two. Anyways , I wish I would have just tightened and went on but I kept digging and piddling and took them off. Oh lordy it was a big pain. I ended up taking to the saw zaw to the smog tubes because it was rusty and could not detatch. Also the donut flange blots too. So hard ugggg. Anyways, I need advice...... The studs that go in the water passages seem to have two different thread pitches on either side .. Also, Looks like some bolts are longer then others. I assume previous owner could have mis and matched bolts an they are not original. The auto parts places cant find in computer or online by year make model.
1. Anyone know the bolts sizes/length/thread pitch/grade for the manifolds ???
2. Should I coat the studs in water passage with ATV or something else?
3. Lastly, unless you guys think otherwise, I am going to hit the manifold and head with a belt sander and clean with brake cleaner sound ok?
4. What should I torque them back to?
I made a big mistake yesterday. I grew tired of a exhaust leak ticking and the smoke getting in the cab when at a red light so I got to my farm and under the shed and started checking exhaust manifold bolts. Everything was loose but two. Anyways , I wish I would have just tightened and went on but I kept digging and piddling and took them off. Oh lordy it was a big pain. I ended up taking to the saw zaw to the smog tubes because it was rusty and could not detatch. Also the donut flange blots too. So hard ugggg. Anyways, I need advice...... The studs that go in the water passages seem to have two different thread pitches on either side .. Also, Looks like some bolts are longer then others. I assume previous owner could have mis and matched bolts an they are not original. The auto parts places cant find in computer or online by year make model.
1. Anyone know the bolts sizes/length/thread pitch/grade for the manifolds ???
2. Should I coat the studs in water passage with ATV or something else?
3. Lastly, unless you guys think otherwise, I am going to hit the manifold and head with a belt sander and clean with brake cleaner sound ok?
4. What should I torque them back to?
Last edited by flboy0638; 07-31-2017 at 06:16 PM.
#2
08-01-2017, 05:41 PM
Join Date: Jul 2017
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
9421360 - Dodge calls it a screw - 5/16 x 2 1/8 x 18pitch Hex ( longest bolt )
6034643 - Dodge calls it a stud - pitch is 18 coarse side goes in engine , other side thread that nut goes on is finer
6031857 - Dodge calls it screw - 5/16 x ?length? x 18pitch Hex ( small bolt ) <<<<<< match length up with old one, remember shorter is better then longer
Ended up getting all bolts from Fastanal and studs from oriellys. No where had the funny washers that go on longest bolts. No where had the exact length so I got 1/8 shorter on bolts but exact size on stud
Teflon is suffice so they say, for the stud going into the water jacket but you can use whatever sealing compound you choose.
Get some anti seize for bolts
Also got a 5/16 thread cleaner and wd 40 cleaned thread holes in engine
took my manifolds to muffler shop and got all smog holes welded shut, while there they verified double checked no cracks and a flat surface and belt sanded mating surface
soaked in "the works" toilet bowl cleaner from family dollar to de-rust and remove inside carbon
6034643 - Dodge calls it a stud - pitch is 18 coarse side goes in engine , other side thread that nut goes on is finer
6031857 - Dodge calls it screw - 5/16 x ?length? x 18pitch Hex ( small bolt ) <<<<<< match length up with old one, remember shorter is better then longer
Ended up getting all bolts from Fastanal and studs from oriellys. No where had the funny washers that go on longest bolts. No where had the exact length so I got 1/8 shorter on bolts but exact size on stud
Teflon is suffice so they say, for the stud going into the water jacket but you can use whatever sealing compound you choose.
Get some anti seize for bolts
Also got a 5/16 thread cleaner and wd 40 cleaned thread holes in engine
took my manifolds to muffler shop and got all smog holes welded shut, while there they verified double checked no cracks and a flat surface and belt sanded mating surface
soaked in "the works" toilet bowl cleaner from family dollar to de-rust and remove inside carbon
#3
09-19-2017, 10:17 AM
The outside studs are longer, and yes use some RTV to seal them or you will have leaks. You will need to plug up all the holes in the head from the smog pump air passages. You are also going to need to plug the other end of the smog pump pipe in the back so it does not leak from the exhuast pipe and other head.