working on the a valves and when I went to install the exhaust and intake with the gland rings and a one piece metal clad gasket the rear port would not line up with the gasket.I assume the back of the manifold drooped,I hate to use repro parts but are the new manifolds any good or should I look for a original later model with the hump?
repro exhaust manifold
- Thread starter rocket1
- Start date
Mike Peters
Well-known member
I've installed two or three repro exhaust manifolds and have had no problems with gland rings.
All the old original manifolds I have, including a late 31 with the extra web have drooped and won't work with gland rings. When you install a repro manifold, leave the two bolts that attach the intake manifold loose while you tighten the four big stud nuts holding the manifolds to the engine block. Then snug them up last. No more exhaust leaks.
All the old original manifolds I have, including a late 31 with the extra web have drooped and won't work with gland rings. When you install a repro manifold, leave the two bolts that attach the intake manifold loose while you tighten the four big stud nuts holding the manifolds to the engine block. Then snug them up last. No more exhaust leaks.
ryanheacox
Well-known member
I don't have personal experience with them but have heard they are good quality. If you do get a new manifold you'll have to get it planed with your intake manifold to even the surfaces. You could also get a new intake as well to avoid any machining.
J Franklin
Well-known member
Go for it! How long do you think it might be in production? And in what #s?
Synchro909
Well-known member
I don't make a rod for my own back by sticking with worn out 90 year old stuff. When I rebuild an engine, a new manifold is almost mandatory, just like I wouldn't reuse the old pistons or rings. IMO, it make NO sense not use a new one.
Conaway2
Well-known member
I’ve owned my Model A for over 50 years and never had a droopy manifold issue until this year. It really surprised me, but I learned something new. Also in realizing that the car is almost 90 years old, I think about a bit differently now than I did as a teenager when I bought it.
30 Closed Cab PU
Well-known member
Arm chair mechanic here. Am not agreeing or dis-agreeing, just would like your comments on a different view I've heard a couple of times in the past.
There is a view that it is better to use good used parts, that the parts kinda of get tempered and if still are good are less likely to fail.
Synchro909
Well-known member
I am aware there is a school of thought that original parts are better than new and the way Henry did it can't be bettered. There is some merit in that but I don't subscribe to either as an absolute. The quality of part varies enormously so I'm not saying either is always better or worse than the other.
I have described a number of times here what I think of the RHS of the engine on a RHD car and how difficult it is to do some things that should be easy due to lack of forethought.
His design, while basically good is let down in some places by poor production. To support that, I point to the rear hubs where the hardening is OK at the end nearest to the diff but lousy at the end near the axle nut. You will likley have seen it yourself when inspecting a well used hub - the hardening is worn through down inside the recess.
There was a continuous process of improvement during the production years of the A (and the T). Even today, smart car buyers don't buy the first of a new model - they wait till the bugs have been ironed out. That means the earlier the car, the greater the number of components that are not as good as they could be. Over the years, the standard of those items improved and the later cars IMO, are were better than the early ones. The exhaust manifold is a good example of that.
mhsprecher
Well-known member
Ford did change the manifold in 1931 to provide more material at the last exhaust port to provide more strength to prevent drooping. In my case I had one manifold that was cracked near the bend at the end. I bought a used one and it was drooping, at end, which didn't mate up well at the last exhaust port. I bought a reproduction a few years ago and problems solved.
mike657894
Well-known member
Im on my third exhaust manifold using that logic. Ive got a set of new manifolds on my short list.
Keith True
Well-known member
I've always had good luck with the repro manifolds,even the ones from Argentina.About 10 years ago Stiener tractor had a closeout on Model A exhaust manifolds,I bought 4 of them.I never knew why an antique tractor parts house had Model A manifold,but they did.never had a problem with them,I am down to one left now.I do always go through my manifold pile and marry the new exhaust manifold up to the intake that matches up the closest.Then I have them planed together.I also make sure the surfaces for the cupped washers are on the same plane,so the washer is not cocked off to one side when tightening.I took a mated pair to the machine shop that looked good,the guy said,watch this.He jigged it up,took a light cut,and had me look at it.There looked to be a dozen fresh cut spots,and parts the cutter had not even contacted.Now I have them all cut,even new ones.
I installed the repro exhaust manifold,it is an excellent fit,I would not install it on a show car because the top of the manifold has the cast parting line ground off the entire length of the manifold,would not look original.I now have to work on the idle.