today i recieved a call from the machine shop that i sent in my intake manifold, cylinder head, and exhaust manifold to. the guy says that the cylinder head is all machined with the oversized valves installed along with the new springs, rockers, lifters, OEM cams, and adjustable cam gears. intake manifold is port matched. yay.

then he went on to say that he needs an extra day to fix the exhaust manifold because it was warped...?

crazy. i had no idea that it was warped... probably explains why it leaked so bad near the thermostat housing.

i know a few people have dealt with cracking and warped STAR manifolds, but i haven't heard of many HRC manifold warping. what are the causes for this?

my hrc warped. it just does it over time from intense heat and shifting of the motor. its only metal.

actuallt the HRC has more complaints. The STAR manifold is quite beefy and will hold a bit more.

only probs that I heard were of a couple of people with cracked STAR manifolds.

yea, quite a few people have had their manis warp...

hmmm there's probably a reason for it, the best guess i can come up with is that when the crappy hex bolts that come with the kit fall out (which mine did, even if i used red loctite and torqued them until i thought the head was about to strip) i bet the manifold expands unevenly because it's torqued down only in some spots.

coupled with the weight of the whole assembly. is your downpipe bracketed to something? Mine really wasnt and that was a contributing factor in the stupid hex bolts coming out over and over and over and over and over and over and over again. :)

yeah my downpipe is definately NOT supported at all, although it has a flex section...

gravity is not your friend LOL

I ordered the stud kit from ARP to try to keep the mani on! $80 damnit. I don't have anything supporting the downpipe. Oh well :7

Yeah, my HRC mani warps CONSTANTLY. I've had it milled flat so many times that it just keeps happening more and more frequently.

According to RRE, this is caused by
1) Manifold flange too thin to begin with.
2) Uneven tightening/backing out of fasteners.

I use GST mani studs and copper nuts, with blue loctite and it helped immensely. I think if I had been doing that from the beginning, as well as uniformly torquing down the studs, the mani would never have warped.

Originally posted by thedawg
Yeah, my HRC mani warps CONSTANTLY. I've had it milled flat so many times that it just keeps happening more and more frequently. According to RRE, this is caused by 1) Manifold flange too thin to begin with. 2) Uneven tightening/backing out of fasteners. I use GST mani studs and copper nuts, with blue loctite and it helped immensely. I think if I had been doing that from the beginning, as well as uniformly torquing down the studs, the mani would never have warped.

Fuck that great information So the 1st Mod when buying an HRC kit is to pick up GST manny studs

Originally posted by Skrilla

Originally posted by thedawg Yeah, my HRC mani warps CONSTANTLY. I've had it milled flat so many times that it just keeps happening more and more frequently. According to RRE, this is caused by 1) Manifold flange too thin to begin with. 2) Uneven tightening/backing out of fasteners. I use GST mani studs and copper nuts, with blue loctite and it helped immensely. I think if I had been doing that from the beginning, as well as uniformly torquing down the studs, the mani would never have warped.

Fuck that great information So the 1st Mod when buying an HRC kit is to pick up GST manny studs

yes, 8mm 4g63 studs and bolts. get them from RRE

Originally posted by ner947
hmmm there's probably a reason for it, the best guess i can come up with is that when the crappy hex bolts that come with the kit fall out (which mine did, even if i used red loctite and torqued them until i thought the head was about to strip) i bet the manifold expands unevenly because it's torqued down only in some spots.

HAHAHAHA the fuckin hex bolt Geezuz! I cant find enough negative things to say about those fuckin bolts.

True I've heard (and seen 2) HRC Mannies warp but they can be machined back still I like the HRC manny over the star.

I'd like a Star Kit with the FastFab manny though

Just about every star manny I've ever seen cracks but that's it, no leaks and it's quite common for iron mannies to do this (even stock 4G-63 mannies crack). For the most part there isn't any need to worry about it and if you do just get it welded. I remember Manek1 (OG from back in the day) his was cracked and RRE welded his for him at a SoCal meet

Mine warped as well. At the same damn thermostat housing hole. USed GST mani bolts and thus far its all good.

I think alot of people do not utilize the DP bracket to help support the weight of the turbo, hence there is undue stress on the manifold.

I think I might give the Chill factory manifold a shot when the HRC goes.