manifold

[Rich Chandonnait]

Well I finally bit the bullet and pulled the old intake/exhaust manifold out of my Pearson/Wanderer and lo and behold I have a hole by the exhaust pipe exit, could this be the reason that my engine could not hold a steady RPM,I don't know but I suggest it is, my question it if I buy a new manifold does it come with the gaskets, or do I need to buy separately, second question the 2 bolts that hold the exhaust pipe on are they metric as I could not get a wrench on them so, I had to pull the whole thing out

[Don Moyer]

Rich,

You will need to order the gaskets separately, since we have never built in
their cost in the price of our manifolds. We may have to revisit this
rationale in the future, but historically, most of our manifold sales
occurred during a major rebuild in which case the purchaser already had a
complete gasket kit.

The retaining bolts for the exhaust flange are standard 3/8" coarse threads.


Regards,

Don Moyer

[sunnnnseeeker]

Don,

I have been meaning to tell you that the manifold studs I purchased from MMI were 1 thread too short, just to be flush with the nut, with your new after market manifold. I did not install any washers under the nut. I don't think it is a big problem and I am not really worried about it on my engine but it would be better if the studs were 1/4 longer for the manifold you are selling.

I think you can see what I am saying in the picture attached. Nuts are torqued to 25ft lbs.
Nathan

[Don Moyer]

Nathan,

Thanks for the intell. I'm not aware of any change in our stud length.
Given the tight quarters along the side of many engine compartments, we've
always tried to keep manifold studs from getting any longer than necessary.
It may be that our manifolds have picked up an extra .020" or so in cross
section. I'll check with our shop folks and let you know.

Don

[Don Moyer]

The mystery is solved and we have a bit of egg on our face. We inadvertently got a few manifold studs into our inventory stock that were dimensioned to fit earlier OEM manifolds.

There has always been a small difference (about .025") through the cross section along the stud holes in OEM manifolds made prior to the mid 1970's and those made later. We added .025" to our manifold studs years ago to accommodate this additional cross section. Later, when designing our aftermarket manifolds, we opted to stay closer to the later manifolds for a number of reasons, mostly because they had slightly thicker cross-sections around some of the water jackets.

In any case, the original factory studs which we apparently sent you will fit on the later OEM manifolds (and our after-market manifolds) exactly as you're showing in these pictures. I don't think there is any functional issue, but if you'd rather replace them, I'll be happy to send you three longer studs.

Don