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carb vs exhaust manifold?
https://slantsix.org/forum/viewtopic.php?t=48327		 Page 1 of 1
Author:  kielbasa [ Wed Mar 28, 2012 3:57 pm ]
Post subject:  carb vs exhaust manifold?
is there any difference between exhaust manifolds used with certian carbs? im going to use a stock 1barrel holley, and i have a couple manifolds to chose from, they seem to have different heat riser flap setups /counterweights/springs what not? or does it not mater?
Author:  Aggressive Ted [ Wed Mar 28, 2012 6:32 pm ]
Post subject: 
No, choose one that is warped the least or have it trued up. Make sure the mating surface is not pitted between the manifolds.
Author:  kielbasa [ Wed Mar 28, 2012 7:13 pm ]
Post subject: 
well im trying to figure out how to set them up. when i tighten the 3 hot box bolts just enough for "contact", i cant fit the manifolds over the studs. i have to losen up the 3 bolts quite a bit in order for the exhaust manifolds 2 end holes to fit over studs.

when i then try to tighten everything, it seems the manifolds want to bind. they would sit flat on head surface, but would be crooked with eachother on the hot box section.

common? fix?
Author:  Aggressive Ted [ Thu Mar 29, 2012 9:47 am ]
Post subject: 
How much are they off? Is it a flatness issue?

The Remflex hot box gasket helps in some instances because it is so thick.
Author:  Doc [ Thu Mar 29, 2012 9:54 am ]
Post subject: 
Sounds like a warped manifold issue...
DD
Author:  kielbasa [ Thu Mar 29, 2012 10:54 am ]
Post subject: 
I bought 2 remflex hot box gaskets from dusteridiot. I just wanna make sure I can get the best possible fit.
Any tips on surfacing everything? What to use, where to take it. Certian way to chuck it up for getting it on the correct angle?
Author:  Doc [ Thu Mar 29, 2012 11:56 am ]
Post subject: 
Do the trial fit, (as you already did) bolting the intake to exhaust manifold, at the heat box with-out the gasket.
Use a manifold to head gasket at the port openings, to show you where the alignment is off...
Badly warped manifolds will usually have one of the end ports higher then the others. (caused by extended running of the engine with a broken end stud)

See if you can angle grind the heat box surfaces to get better port alignment, across all 12 openings. (basically, "split" the amount of warpage, across all 12 port openings)
Once you have full contact at the heat box and the best port alignment possible, re-surface the port face surface.
DD

http://www.slantsix.org/articles/manifo ... unting.htm
Author:  kielbasa [ Thu Mar 29, 2012 12:41 pm ]
Post subject: 
thanks doc, i have 1 more manifold i can use, the hotbox bolt holes are non existant, ill need to helicoil 2 of them, but the flapper is in far better working shape then the first manifold im trying.

ill try the helicoils, and mock that one up, see which one is less warped.

for resurfacing, do i need to find someone with a blanchard grinder? or is there an easier way?

and for the hotbox, you say use a angle grinder... that woudnt get thinks perfectly straight/flat does that mater much on the hot box area?
Author:  Doc [ Thu Mar 29, 2012 1:07 pm ]
Post subject: 
That surface needs to be pretty flat to keep the gasket sealed.
"Angle Grind" as in... grind at a different angle.
That usually means taking some additional material off the outer-front edge of the heat box mounting surface so the intake's #6 port opening moves upward, in relation to the exhaust port next to it.

Basically, this is "fuss with it" work...
Do try the other exhaust manifold you have, it may-be a lot closer to being "right".
DD
Author:  kielbasa [ Thu Mar 29, 2012 1:27 pm ]
Post subject: 
ahh read it wrong, sorry, and thanks for advice.
Author:  kielbasa [ Fri Mar 30, 2012 11:47 am ]
Post subject: 
i got the helicoils in, and mocked it up, this manifold fits so much better, there are a few gaps here and there

at the port ends, the biggest gap is .015, which is #4 exhaust port. but this isnt torqued down, just till the nut stopped. ill be trying to use the Felpro manifold gasket, with that halomayr blue gunk. ive had a tube for a while, and never really used it on anything. does .015 still sound like too much?

and at the hotbox area, there is a slight gap, but again not torqued, just till the bolt stopped. and its with out gasket. i do have a remflex gasket for that part, which seems like it will work beautifuly.

id really like to avoid buying a manifold gasket, thats more expensive then a head gasket :-D, but if .015 is way overkill for a felpro gasket, let me know.

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Author:  Wizard [ Fri Mar 30, 2012 12:27 pm ]
Post subject: 
No good, HAVE to mill the sealing surfaces flat first on that heat box then bolt both manifolds and have this assembly ground at the shop.

Cheers, Wizard
Author:  SlantSixDan [ Fri Mar 30, 2012 2:41 pm ]
Post subject: 
Quote:
ill be trying to use the Felpro manifold gasket, with that halomayr blue gunk (…) id really like to avoid buying a manifold gasket, thats more expensive
Another way of saying that is "I'd prefer doing the whole job all over again because an inferior gasket glooped up with gunk didn't get the job done". Are you sure? Figure out how your lower back will react to another afternoon spent leaning over the fender wrestling a heavy chunk of cast iron out of and into place, and calculate what your time is worth in dollars per hour, then compare that to the price of buying the good manifold gasket in the first place.

Food for thought.
Author:  kielbasa [ Fri Mar 30, 2012 2:45 pm ]
Post subject: 
just going off of docs reccomendation on his article, thicker softer gasket will be more prone to cracked manifolds, but seal better.

and also it does state he used hylomar in the article. which he had much success with...
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