#99342, "cutting the hahn mani(cuts to prevent warpage)"
Ok i have i guess what you can call the first gen of the hahn turbo mani. It does not have the slits cut into it to prevent warpage/shearing of the bolts. Anyway i was just seeing if it would be wise before i install it to do the same on mine. I was just going to take a cut off wheel to it
Also if anyone did how big of a cut did you make? I would think a 1/4 gap is good
thanks, kevin
___________________________________________________________________________ 13psi on a built bottom end with a stock now mtx, check mate.
#99347, "RE: cutting the hahn mani(cuts to prevent warpage)" In response to Reply # 2
If you do bother to do this, go with Quadman's recommendation. However, I don't think it is necessary. The bolt holes are sufficiently large to keep you from shearing anything and the manifold is compact enough that warpage is unlikely. I ran a first gen HRC manifold for 6 1/2 years without expansion cuts and it never warped. I was careful about my torque sequence and settings, but nothing out of the ordinary. Or maybe I was just lucky.
Corbin
'95 ESI-T Now with more power and fewer leaks
Gimme fuel...Gimme fire...Gimme that which I desire
#99351, "RE: cutting the hahn mani(cuts to prevent warpage)" In response to Reply # 3
I warped mine 5x (original 1st run HRC manifold before they started using a thicker head flange) and had to resurface it 2x. Each occasion was preceded by the stupid HRC hex bolts vibrating out or not being torqued correctly and the exhaust manifold gasket blowing out. It takes about one day of a blown gasket to warp the manifold.
Once I switched to 4g63 manifold studs and copper crush nuts it stopped warping mostly.
Another Socal 2GNTer cut bandsaw width gaps in his 1st run manifold with 4g63 studs/nuts and hasn't had any problems since. I'm going to do the same on my next manifold.
#99359, "RE: cutting the hahn mani(cuts to prevent warpage)" In response to Reply # 4
Originally posted by thedawg I'm going to do the same on my next manifold.
Yeah, whatever.
______________________________ If a sentence found online has 35% misspellings or greater and includes at least two racially charged expletives, chances are it is a YouTube comment.
'95 Eclipse TurboGS (garage deco) '95 TSi AWD (restoring a survivor) '97 Talon ESi-T (poor impulse control) '99 Eclipse RS-T (daily beater) '13 Evo X (mostly stock) '17 Sienna (Middle Aged Dad Mobile)
#99363, "RE: cutting the hahn mani(cuts to prevent warpage)" In response to Reply # 4
Originally posted by thedawg Each occasion was preceded by the stupid HRC hex bolts vibrating out or not being torqued correctly and the exhaust manifold gasket blowing out.
Now, that I would believe. I never used the hex bolts. Most of the time, I used jam nuts on studs. Never blew out an exhaust manifold gasket.
Corbin
'95 ESI-T Now with more power and fewer leaks
Gimme fuel...Gimme fire...Gimme that which I desire
#99367, "RE: cutting the hahn mani(cuts to prevent warpage)" In response to Reply # 7
Originally posted by thedawg I even managed to blow the copper TTI exhaust mani gasket ...and FU dino, she's down for a 5spd swap right now in preparation. Send me a clutch.
Want my Clutchmasters? I think it has some disc left.
______________________________ If a sentence found online has 35% misspellings or greater and includes at least two racially charged expletives, chances are it is a YouTube comment.
'95 Eclipse TurboGS (garage deco) '95 TSi AWD (restoring a survivor) '97 Talon ESi-T (poor impulse control) '99 Eclipse RS-T (daily beater) '13 Evo X (mostly stock) '17 Sienna (Middle Aged Dad Mobile)
#99368, "RE: cutting the hahn mani(cuts to prevent warpage)" In response to Reply # 7
Originally posted by thedawg I even managed to blow the copper TTI exhaust mani gasket ...and FU dino, she's down for a 5spd swap right now in preparation. Send me a clutch.
thats why BANME!s shouldnt touch theese cars.
Member # 751
FOUNDER of the Central Cali chapter of 2GNT! (I got kicked out after I refused to go Cow tiping) - Hehehe you know who this is for
#99515, "RE: cutting the hahn mani(cuts to prevent warpage)" In response to Reply # 9
I'm the one Dan is taking about. I cut the manifold using a bandsaw in three places between each runner. Then I cut a copper exhaust gasket into 4 pieces, one for each individual port. I could never get the manifold to seal on the outermost edges no matter how flat it was cold. The manifold would almost seal when hot, but would pull away due to the contraction when cold. I could not longer put any torque on the studs. So anyways, when i cut the manifold and seperated all four ports, they moved into their relaxed position. None of sections of the head flange were in line with each other. Eg. the flange was no longer flat. This totally revealed that the manifold in its static state was already slightly misaligned when made, and the whole manifold was under load in itself. Well, I surfaced the mani after and I have not had a leak for the past 6 months.
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