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Post by jkdv8 on Mar 6, 2015 19:57:23 GMT -5
Is there a sequence to tighten the bolts. Kinda like torquing lugs or tighten the center set first the the outer four. Also, what about the torque specs. Some cars you tighten down to certain point then back it off and tighten it again. Second time around using less force. I will look at the service manual and sees what it says. Would think the tolerances would increase and decrease dramatically from cold to hot. Especially if they are cast iron like the block. Something to keep in mind.
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Post by dclambertt on Mar 9, 2015 17:51:18 GMT -5
Ed, have not checked the head flange but this crack is not hard to see and is in the same damn place as photo in this thread, right after the first port from the back. I think it could even have something to do with the sheer weight of the exhaust system hanging on this diminutive manifold. May try fabricating some sort of hanger up near the manifold. This last one lasted just over a year.
Dan
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Post by dclambertt on Mar 9, 2015 18:01:19 GMT -5
jkdv8, I did consider the sequence of tightening although i did not check the torque on these but just did them by feel using a small socket wrench. From previous experiences I decided to carefully tighten them slowly and together to keep from stressing the manifold any more than necessary. Please let me know what the proper torque turns out to be and I'll try that next. -Dan
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Post by dclambertt on Mar 9, 2015 19:30:13 GMT -5
I'm finding 22 ft-lbs for the exhaust manifold bolts, and no gasket sealer on the gasket. I think I used exhaust gasket sealer on my last install.
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Post by dclambertt on Mar 14, 2015 23:59:23 GMT -5
Well I got the new manifold installed today. That entire side of the engine is new.. starter, alternator and manifold. Sounds like a new car. The manifold I just replaced after one year? Made in China.
Will post some pics when I can.
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Post by ES_97Sport on Mar 16, 2015 18:26:56 GMT -5
Well I got the new manifold installed today. That entire side of the engine is new.. starter, alternator and manifold. Sounds like a new car. The manifold I just replaced after one year? Made in China. Will post some pics when I can. When you do can you also get me a pic facing the flange? One of the entire flange and one zoomed into the center and right port so I can get a good look at the surface. Also one from the top and one from the bottom. Yea, I bet. I just got my big Sport back with the new down pipes. Still have a leak at the flange to the CAT but it sounds SO nice. Even with the existing leak. There is something weird going on here. The torque specs sound right. From pictures previously posted it LOOKS like a stress crack and my first thought is stress applied on the exhaust down pipe but it looks to me like that crack started on the inside and went up over the top around down the outside. That would be the least likely place for it crack on an impact from the bottom on a down pipe. The other thing that makes me question an impact is the fact I'm on my 4th or 5th full exhaust and I've never had a manifold crack even though I've beat the crap out of the pipes on rocks - AND I do not have the clamp on the driver side down pipe that attaches to the bell housing so my down pipes are only supported at the manifold flange and the stock pipe flex mount points. The two manifolds (DR/PS) I've had to replace on my big Sport cracked from being immersed red hot in the South Platte River. So, somewhere around 50 degree water. Neither cracked in the same place and neither cracked where the pictures show. I might be able to tell more with your pics to compare, but from these pics it looks like maybe the flange on the head isn't true. What concerns me is that the crack in the picture appears to be spreading. Wider inside the radius and narrows around the outside. Both cracks on my manifolds were hair lines and never spread or widened even after being driven for at least a year/year and a half. That indicates to me that there's something's 'pulling' on the metal in that area. Which leads me back to wondering if the manifold face on the head isn't true. That's the only thing in common among all the manifold replacements. Different manifolds but same heads points to the commonality - the heads. I'm going to take a closer look at my spares when I get home. Something's not right here. MAYBE its a torque issue, but the more I look at the design the less inclined to believe that's it. Is your exhaust stock? Do you have the clamp on the driver side down pipe attached to the bell housing? Did you notice any tweaking of the down pipe counter to the exhaust manifold when you were reassembling everything? Did everything seem to bolt straight up without stressing anything? Edward
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Post by jkdv8 on Mar 17, 2015 12:01:28 GMT -5
Sorry for the late response. According to an '03 service manual the torque spec is 33 ft lb. Regardless of 3.0/3.5. All the manual mentions is making sure the flange isn't warped like Edward was saying. Said to use a straight edge and a feeler gauge to check for distortion. Standard value of 0.15mm or less. Limit being 0.20mm. If that helps any. Not sure how nessecary all that is. Seems a bit excessive. However if that's the case, it doesn't take much to be considered warped. Also, it being a Chinese knockoff could've contributed.
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Post by dclambertt on Mar 17, 2015 12:11:52 GMT -5
No problem jk, I used 22 ft lbs and it was definitely more than what I applied the last time by feel. The spec sheet I found called for 22 ft lbs for a 3.5L manifold and 33 ft lbs for the 3.0 manifold.. mine is a 3.5.
Ed, I think the support for the down pipes and cats was fine, and all connections were straight and absent of any twisting. Didn't verify the bell housing clamp but will do that next time I look, but I imagine it's connected or the pipes would have dropped far more than they did when I pulled the bolts out.
Thanks again gents.
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Post by ES_97Sport on Mar 18, 2015 18:01:14 GMT -5
No problem jk, I used 22 ft lbs and it was definitely more than what I applied the last time by feel. The spec sheet I found called for 22 ft lbs for a 3.5L manifold and 33 ft lbs for the 3.0 manifold.. mine is a 3.5. Ed, I think the support for the down pipes and cats was fine, and all connections were straight and absent of any twisting. Didn't verify the bell housing clamp but will do that next time I look, but I imagine it's connected or the pipes would have dropped far more than they did when I pulled the bolts out. Thanks again gents. jkdv8: Sounds about right. Deviation in the face when bolting cast iron to something can't be much. Unlike aluminum, its brittle and there's very little flex so its sensitive to stress under heat/cooling. Really, kind of a PITA. Good. I can't see it being the clamp. I haven't had one hooked up or on for years and I've never had an issue which is surprising considering the abuse the exhaust has taken on the rocks. Pipes won't drop at all with the clamp bolted up. Edward
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Post by dclambertt on Mar 19, 2015 16:49:45 GMT -5
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Post by ES_97Sport on Mar 20, 2015 16:54:04 GMT -5
Okay, the clamp is bolted to the bell housing properly as expected. I think it could have been several things that caused this last manifold to go. Made in China, no proper torque control, and exhaust sealant applied to a very thin metal gasket. I used Felpro gaskets (no sealer) this time around for both the manifold and flange, which may have provided a little more leeway for any slightly irregular surfaces. Just a theory. .... Good. FWIW, of course. At least it can't hurt. Mmmmmm. I don't know ... "Made in China", I'd expect anything to happen. Torque, maybe. Sealer? Mmmm. I've used the spray on copper sealer on the metal exhaust gaskets for cast manifolds for other vehicles without any issues. These are cast manifolds on cast blocks. Maybe a combination of uneven torque and the sealer and maybe the gasket itself? What kind of gasket is that? Is is a thin metal sheet gasket or a 'fiber' type gasket? The down-pipe gasket you show is identical to the half dozen I just bought from the dealership. I just picked up another 3.5L passenger side pipe and I took a good look at my spare passenger side manifold. No way could that gasket cause this, so I think its back to the head/manifold/gasket/torque. I'm going to talk to the tech next week and see if he has any brilliant theories. BTW, do you have a heat shield that bolts over the passenger side manifold? Forgot how well the factory down pipes are made. HEAVY. Way heavier material than the cheap stuff the muffler shops use. Edward
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Post by dclambertt on Mar 20, 2015 17:02:12 GMT -5
Very thin metal sheet gasket was used previously, so I'm thinking that I might have created an uneven surface using the thick paste sealer I applied by finger, coupled with the torque issue. Agreed, the down pipes are beasts. Hoping this manifold does as well.
Dan
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Post by jkdv8 on Mar 20, 2015 17:08:10 GMT -5
Bet it was the Chinese knockoff. Fiber gasket would probably suffice as well.
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Post by ES_97Sport on Mar 20, 2015 17:19:52 GMT -5
Very thin metal sheet gasket was used previously, so I'm thinking that I might have created an uneven surface using the thick paste sealer I applied by finger, coupled with the torque issue. Agreed, the down pipes are beasts. Hoping this manifold does better. Dan Ok. That's what it should be. I still think no, but .... More likely the torque issue combined with the China manifold. I still worry about the surface. Do you still have the old manifold? Be interesting to lay a machinist straight edge across that thing and take some measurements. jkdv8: No. I can't remember why, but you're not supposed to use the thick fiber gaskets on cast exhaust manifolds between the block and manifold. I do know that using them will completely change the torque spec. Edward
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Post by jkdv8 on Mar 20, 2015 17:23:56 GMT -5
Hmm. Interesting. Good to know. Pressure issue I suppose.
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