For the last few days I was working on my 1926 engine and had to remove the intake manifold. About 2 years ago, I had to replace the exhaust manifold, because the old one was warped and I burnt a hole in it trying to straight it. As I recall I had some trouble installing the manifolds then. Well this time I have a new aluminum intake and it will not go on with the exhaust in place. It fits fine with the exhaust off. So, after inspecting, I found that the two manifold were interfering with each other, not by much but enough so I could not (even force) the rings and sleeves into their holes. I solved the problem by marking the points of contact and slowly grinding away at both the exhaust and intake.
I maybe toke 1/16" total to get them to fit.
I have had the same problem with the high volume intake manifold. I told Glen and he said he had never seen it. Actually it has happened twice on Model Ts I have worked on with the Hi Vol intake. I was not brave enough to grind the exhaust manifold and just ground the intake just behind the mating flange.
So glad that I am not alone.....
Same problem here with a repro. alloy intake. I had to relieve it to clear the exhaust manifold. The problem is worse if you are battling to fit an exhaust manifold with even the slightest downward bend at the rear.
Allan from down under.
Got both intake and exhaust from Chaffin's this summer. The intake is high volume aluminum and the exhaust is cast iron standard. They fit together and after I ran it for a short time, about 3 miles it started leaking exhaust. I didn't even think of a problem with the fit, as both manifolds seemed to go on and the rings fit. Anyway I torqued it hot and then again cold. I could see down between the head and the exhaust. The copper rings were crushed. No leaks since I torqued. It is a little different because with iron you torque hot and aluminum you torque cold, so I did it both ways. Seemed to fix it and have put on about 250 miles since with no leak.
There was some conversation previously regarding the width of some of the repro steel glands being too wide thus not letting the copper ring crush totally evidently resulting in leakage !
Same problem here with the high volume intake from Chaffins. Additionally mine had a pin hole leak that had to be welded. I could have put a screw in it to plug the pin hole but that would have looked like poo.
Same problem with mine also. Also sticks out further from the block and the clamps now do up on a bit of an angle and are not on as many threads.
And it's not just with the repro intake manifolds. I had to grind some away on a new repro exhaust manifold when using it with an original aluminum (dogleg) manifold. The new exhaust manifolds work OK with a skinny "standard" intake but not with the higher-volume ones, new or old.
Did use the oversize alum intake once, and had to grind away some too.
Just installed a new exhaust on Dixie, used the iron intake. No metal fit interferences anywhere.
One thing I check carefully is the gasket fit and placement. Like to use the new copper sandwich 3-1 type, just easy for me. And use the steel gland rings with it. Fit each gland ring, and check fit of 3-1 too.
One thing needed is to 'mash' the overhanging cylinder head gasket, where it overhangs on the manifold side.
Bit of gasket hanging over, mash it flat along the block with a hammer.
Then after test fitting, add some gasket cement to hold the 3-1's in place too.
A bit extra around the intake is just 'security' for preventing intake leaks, or wishful thinking
Align and fit the manifold, setting them into the gland rings.
Then snug up the clamps and all is done. No leaks!
My exhaust manifold is straight, the ports line up. When I put an original aluminum intake on mine, it was a very tight fit between the two. It mounted up just shy of grinding any material off.
Make sure the recess for gland rings is clean in the block and manifolds then do a dry fit. The gland ring just need to bridge the gap between the two not be crushed.
We are well aware that our high volume intake manifolds interfere a small amount with some exhaust manifolds. Not all but some. Obviously if the intake is bigger to make it high volume you are going to have more of a possible interference problem. But that is the price you pay for gaining 2 horsepower. If you are opposed to removing a small amount of material from the outside of the intake or exhaust manifold then you don't need 2 horsepower. The area where you have to remove a little material is not even visable and it does not damage the manifold. The net gain in power is well worth the little effort it takes to make them fit. We have sold thousands of these manifolds to satisfied customers. If you are unhappy with yours please return it for a full refund.
Mine fit fine. No grinding needed. If I had to grind a small amount off I would have done it and not griped about it. There is a difference between cheap crap parts (like the 26/27 stop light switches) and things like castings that involve large expenses and the variables of fitting every single flipping T made. I am glad that there are a couple of vendors that risk large capital dollars to supply the hobby with parts that we can just order on the phone without going to every swap meet in the country and slowing up the driving experience. Try buying a fender at a swap meet and seeing if it will fit your car without some sort of fitting.
Sorry for the rant but do you really think there was 0% rejection of parts on the Ford assembly line? I bet that manufacturing tolerances 100 years ago were "slightly" higher than today. Thanks Glen for what you do for the hobby!
Forgot to add I have a new exhaust manifold as well. Perhaps the combined thickness of the two new items is thicker than the original on both counts? I like my new alloy inlet and the straight exhaust was a breeze to fit. Small price to pay to remove a little material and have a non leaky exhaust and the extra two horses!
In my younger days, when I was cobbling together race cars, lots of parts had to be modified to get to fit. When ever a non standard or different make model or year part, and I used a lot of junk yard stuff, was added, many times they had to be cut and/or ground up to fit around other parts. I was not belly aching about this, just pointing out that I had a problem getting a seal on the intake manifold, in an effort to alert others that an adjustment may be needed. I don't have a problem with adjusting these parts. I only had to grind about 1/16" off, on my race cars that much was considered cleaning up a part. Mike