Slant Six Forum :: manifold issues

Hi and welcome to the forum! It sounds like you managed to get a hold of two warped exhaust manifolds. It is also possible that you found an exhaust manifold that is actually slightly different from your original. Recent discussions amongst slant owners have revealed a surprising number of different slant six exhaust manifolds maufactured over the years with subtle differences, one of them being the height of the manifold "tower" below the carb..

It sounds like you managed to get a hold of two warped exhaust manifolds.

Recent discussions amongst slant owners have revealed a surprising number of different slant six exhaust manifolds maufactured over the years with subtle differences, one of them being the height of the manifold "tower" below the carb.

The big difference i find is not many manifolds were supplied with the same shutter mechanism as mine.

alot of the newer manifolds seem to have a whole bunch of junk installed on them. some kind of vacuum operated valves or such. I have another parts motor, but the manifold has two or tree devices attatched to it.

as to tower height, I am told by a local mopar fiend that some had a spacer for an EGR valve, and that's what he wanted to attribute my gap to. That makes no sense because a 1/16 area wouldn't be enough for an EGR valve.

as to trash on the manifold, I can go out and take pics of one of the two motors on the parts truck.

Is there a machining operation that can correct the problem?

Author:	heviarti [ Sat Feb 04, 2006 11:26 pm ]
Post subject:	manifold issues
I am having a bit of trouble with all of the sealing surfaces on my manifolds mating properly at the same time. I had originally had trouble with the number one leg of the exhaust manifold being about 1/2 inch out of phase with the exhaust port on the head. Also, the lugs sat high on all of the legs of the exhaust manifold. I initially thought to replace the gasket, and did, but it was short lived. I bought an exhaust manifold off a 1964 D100, which is correct for my '62 W200. I found the shutter mechanism in my old manifold was stuck when I finally seseperatedhe intake from it. When I installed the replacement assembly, i found that i could either have the lugs sit high, or a gagap ofbout 1/8 inch on the inner side of the mating point of the manifolds. I ended up bolting the exhaust up and filing the surface closest to the fenderwell . This improved things, but it still wasn't good enough to solve the problem. The crush gasket would completely flatten on the fenderwell side, and not contact on the inner side. It leaked there, and i had to put the manifolds on sepeseperatelyore i bolted them up. I ended up fashioning a wedged bail from brazing rod to seat in the channel of the crush gasket, and it held until this week. None of the mopar people around here have any clue as to this problem, one even suggested it was due to a warped head (ZZZZT! wrong, head surface is fine, plus it would only be out .002 or .003, which wouldn't be enough to cause that gap.) When installing the manifold I did use the proper washers and nuts, i did bring everything to torque gradually, using a tightening pattern, and did put the head side to 10 foot pounds. I went for 15 at the joint between the manifolds to retain my brass bail. has anyone seen this problem before, and if so, does anyone have a way to solve it? Neither headers or Dutra Duals are a valid option for my vehicle, because I would not be able to run a second pipe around my PTO shaft. I really want to fix this problem once and for all.

Author:	Reed [ Sat Feb 04, 2006 11:37 pm ]
Post subject:
Hi and welcome to the forum! It sounds like you managed to get a hold of two warped exhaust manifolds. It is also possible that you found an exhaust manifold that is actually slightly different from your original. Recent discussions amongst slant owners have revealed a surprising number of different slant six exhaust manifolds maufactured over the years with subtle differences, one of them being the height of the manifold "tower" below the carb. The good news is that you should be able to replace your exhaust manifold with an exhaust manifold off of any slant six engine. I would try to find the newest manifold you could to minimize the potential for warping and to get he strongest manifold you can. Good luck! New manifolds pop up on e-bay from time to time.

Author:	heviarti [ Sat Feb 04, 2006 11:46 pm ]
Post subject:
The big difference i find is not many manifolds were supplied with the same shutter mechanism as mine. that's what i'm looking for. also, alot of the newer manifolds seem to have a whole bunch of junk installed on them. some kind of vacuum operated valves or such. I have another parts motor, but the manifold has two or tree devices attatched to it. I want as little extraneous machinery as possible.

Author:	Charrlie_S [ Sun Feb 05, 2006 5:29 am ]
Post subject:
Quote: Hi and welcome to the forum! It sounds like you managed to get a hold of two warped exhaust manifolds. It is also possible that you found an exhaust manifold that is actually slightly different from your original. Recent discussions amongst slant owners have revealed a surprising number of different slant six exhaust manifolds maufactured over the years with subtle differences, one of them being the height of the manifold "tower" below the carb.. I agree, it sounds like two warped manifolds. New manifolds are available. Reed, I am aware of some differences in exhaust manifolds (choke pocket, heat riser, extra ribs, etc) but am unaware of any difference in the hight of the "tower". Can you document this in any way? Or is this an "urban legend", like the super six manifold being better then the standard 1bbl manifold (not).

Author:	SlantSixDan [ Sun Feb 05, 2006 8:52 am ]
Post subject:
Quote: It sounds like you managed to get a hold of two warped exhaust manifolds. Quite possible. It also sounds as if the original poster may have some bent manifold studs. Quote: Recent discussions amongst slant owners have revealed a surprising number of different slant six exhaust manifolds maufactured over the years with subtle differences, one of them being the height of the manifold "tower" below the carb. Don't believe so, no. All \6 exhaust manifolds are physically interchangeable with one another. The differences are relatively minor: Different styles of heat riser valve and choke pocket, differences in stiffening ribs in the casting, studs vs. threaded holes for the headpipe flange and central intake-to-exhaust location, and presence/absence of a threaded port for an O2 sensor.

Slant Six Forum https://www.slantsix.org/forum/

manifold issues https://www.slantsix.org/forum/viewtopic.php?t=16039	Page 1 of 1

Author:	SlantSixDan [ Sun Feb 05, 2006 8:55 am ]
Post subject:
Quote: The big difference i find is not many manifolds were supplied with the same shutter mechanism as mine. The later heat control valve (what you are calling 'shutter mechanism') is less prone to seizing. No big deal here; the late-type valve will work fine on your engine. Quote: alot of the newer manifolds seem to have a whole bunch of junk installed on them. some kind of vacuum operated valves or such. I have another parts motor, but the manifold has two or tree devices attatched to it. There are no vacuum-operated valves or other 'junk' attached to any exhaust manifold. Perhaps you are looking at extra stuff on an intake manifold, such as EGR valves and vacuum ports. You can use your original intake manifold (free of any bolt-on widgets) with whatever exhaust manifold you wind up with.

Author:	heviarti [ Sun Feb 05, 2006 11:00 am ]
Post subject:
as to tower height, I am told by a local mopar fiend that some had a spacer for an EGR valve, and that's what he wanted to attribute my gap to. That makes no sense because a 1/16 area wouldn't be enough for an EGR valve. As to studs, I replaced the bulk of them. and as to trash on the manifold, I can go out and take pics of one of the two motors on the parts truck. I've got several manifolds around, but without some definite test to check them for true without bolting them on.... who knows. Is there a machining operation that can correct the problem?

Author:	SlantSixDan [ Sun Feb 05, 2006 11:18 am ]
Post subject:
Quote: as to tower height, I am told by a local mopar fiend that some had a spacer for an EGR valve, and that's what he wanted to attribute my gap to. That makes no sense because a 1/16 area wouldn't be enough for an EGR valve. It also makes no sense 'cause it's wrong. I think your Mopar fiend is really a Ford guy in disguise (some Fords used sandwich-mount EGR valves, IIRC). The EGR valve, on slant-six engines so equipped, was mounted on the intake manifold. The exhaust manifold neither knows nor cares whether the intake sitting atop it has an EGR valve or not. Quote: as to trash on the manifold, I can go out and take pics of one of the two motors on the parts truck. Sure, toss some pictures up! You may be seeing e.g. the heat stove for the '70-up thermostatic air cleaner. That actually bolts to the '70-up throttle linkage bracket, but sometimes that bracket is left attached to the exhaust manifold. Either which way, it's easy to remove. Quote: Is there a machining operation that can correct the problem? The exhaust manifold can be machined for flatness to correct minor gaps, but you're talking about gaps of fractions of an inch, not thousandths, so something's majorly torqued that probably cannot satisfactorily be addressed by machining (machine enough metal away to correct a ½" gap and there's no flange left on that runner!)

Author:	Reed [ Sun Feb 05, 2006 12:03 pm ]
Post subject:
The only case I have personally observed of an exhaust manifold being a different height was on an exhaust manifold purchased by Matthew Neerman for his 74 Valiant. the manifold mated to the cylinder head fine, but there was about a 1/2 inch gap between the bottom of the intake and the "tower" on the exhaust. He got another exhaust manifold and it sealed fine, so it wasn't a warped intake. I suppose that the "short" exhaust manifold may have just had an odd warp to it. Matt, you still out there? Chime in here buddy. As far as extra mechanisms being attached to the exhaust manifold, th eonly item I am aware of ever being attached to the exhaust manifold is the O2 sensor. The intake maifolds had other things added to them, but you aren't using the intake, right? As far as the counterweight on the heat flapper, the later round style was actually an engineering improvement over the old retangle one. Why not use it?

Page 1 of 1	All times are UTC-08:00
Powered by phpBB® Forum Software © phpBB Limited https://www.phpbb.com/