The Stovebolt Site Forums The Shop Area Engine Shop Manifold to Head fit

My Exhaust Manifold is alightly bowed, and when brought up to the Head with no Gasket...the middle two Manifold Ports are about 1/16th away from the Head, when the end two are flush and snug.

Should I expect this to bend "in" and be okay, when Bolted down?

Or, should I get it surfaced so they are all on the same plane?

That's a long way for a piece of cast iron to bend. You're inviting a leak or a crack unless you get it milled. How about the intake? It's usually a good idea to leave the bolts where the intake/exhaust manifolds meet slightly loose until the whole assembly is snugged against the head a little.
Jerry

Take it to a machine shop and let them true it on a belt sander. It is cast and it will not bend. I always bolt the intake and exhaust together and have them surfaced together. Otherwise you will have exhaust leaks and you will gradually burn away at your exhaust manifold. It is common for inliner manifolds to be warped and it is very common for people to either never measure them or just use them and then they wonder why they have vacuum leaks and exhaust leaks. Having them trued has been an almost standard thing for the over 50 years I have been working on these old machines.

Well, I definitely did not feel good about trying to cinch that gap closed!

I had the Exhause Manifold held snug to the Head by hand, and, could see that the two inner Ports had a roughly 1/16th gap, which looked perfectly parallal, no taper to it.

My Intake Manifold is now independent of the Exhaust Manifold, I had eliminated the Bolt-together and I have closed off the Heat Riser Box opening, so the Exhaust Manifold is a sealed thing, and the two Manifolds do not need to bolt together any more...

In order to get my Intake Manifold to fit, it had to some up about 1/4 inch...hence, eliminating the Bolt-Together Heat-Riser connection.

So, being seperate entities now, I tried fitting the Intake Manifold by itself to the Head, and it fit perfectly...no wayward Flange Faces...really nice fit.

So, being as I had a second Gasket Set, I decided to just double the Gaskets for the two inside Exhaust Ports.

This seems pretty well perfect as for taking care of that gap.

So, I just went ahead and Bolted every body down tight, and saw no movement of the two inner Exhaust Faces, while I was cinching things down.

So, I am just going to try the double Gasket deal for the two inner Exhaust Ports, and, see how that does.

I called around Town, and looks like only a few places will 'Surface' Intake-Exhaust Unit Flange-Faces...and, it is a $100.00 ( and some driving time and delay for me to get the old Beast on the Road ).

So, if my Double Gasket does not work out, I will go get the Exhaust Manifold's Flange Faces Surfaced.

Thanks for the input everyone!

I love this forum!!

If you can find some soft sheet copper the right gauge, another option might be to fabricate correct-thickness copper gaskets for the inboard exhaust ports- - - -in case the double-gasket arrangement doesn't work out.
Jerry

Hi Jerry,


That sounds like a really good idea.

I think the Hobby Stores sell small rectangle Sheets of various Gauge Copper, so, would not be too hard to get some.

As it is though, the 2nd Gasket seemed to my Eye to be just perfect for the Gap which needed to be filled...so...it's all on and snug now and waiting to be test run.

Anyway, got a bunch more done to-day on the Van, and am taking a fast breather now for a few minutes ( time & temp claims 107 out ) since I am working outside in the Sunshine on Gravel...and, going to fire it up here in a few minutes...( well, if it starts anyway! We'll see...)

Fingers crossed!

Well, long story short, she fired right up, idles beautifully, super quiet, no intake/vacuum l;eaks I can find, no exhaust leaks.

I literally had a Tear or two start welling up, I am not kidding...

Man, this had been five long weeks of 110 degree outside on Gravel Work on the old Girl, getting all these various things brought up to Snuff!

Image showing the wonderful old 235 at a nice Idle -

http://images16.fotki.com/v388/photos/9/901917/4085747/IMG_0300-vi.jpg

Come on, man! There are kids who visit this site. You had 'smoke' in your eyes. There's no crying in trucks. Thanks for getting back with us with your fix!
Carl

I do not move easy either!

But, it got to me a little...sure enough.

Just an overwhelming feeling of "Gratitude" and humility...rolled into one.

And hey, it has ben 108, 110, 112 out, and I been five Weeks all day every day out in the Sun working on the old girl.

And, I will say, I was lucky the 'Double Gasket' appears to have done the deed there with that pesky Gap the two inside Exhaust Manifold Faces had...that worked out just dandy...the extra Gaskets were just the right thickness.

Sure idled nice!! And quiet!