The Stovebolt Site Forums The Shop Area Engine Shop Manifolds

Ok, I have cleaned up three sets of intake exhaust manifolds and just snugged them together and the exhaust are warped. its the inner exhaust ports that seem to be the worst. 020 to 030, I don't believe the intake can be milled that much. Trying my best to put this truck back together as stock as possible. I started with an offy and 2 carbs, Fenton headers and shot gun exhaust. looked great but I could not solve the leaking under the intake. I also heard That a triple will run and behave better. I have a new triple offy with three W1 carbs professionally restored with the correct metering rods for this set. Then I am back to trying to heat the manifold. How far can have the GM intake exhaust milled before I get in trouble? Looking for some help on this one. Or whats the answer to heating the intake. I have read and understand why the manifold needs heat per the shop manual. The Triple would look cool.

Stuck
Shade Baby

The only concern with milling the intake is the depth of the counterbores for the alignment rings. The rings can keep the manifold from fitting snug against the gasket if they bottom out in the counterbore. You might need to deepen that cut a little with a hole saw in a drill press, or even some careful work with a carbide burr in a die grinder. The rings don't actually do any sealing- - - -they just keep the manifold aligned with the cylinder head intake ports. I like to make up three individual adapters for the intake ports from aluminum conduit and flat bar stock, and use three Keihin side draft carbs for a Harley Davidson EVO engine.

www.ebay.com/itm/406936508134?

Jerry

An easier way than boring out the counterbore in the manifold or in the head is just to shorten the rings a bit. A belt sander could do that in short order. As long as there's enough counterbore to hold a shortened ring, it will work fine.

I just measured a manifold- - - - -the counterbore is about 1/4" deep, and there's a similar depth to the recess in the port in the head- - - - - -plenty of room to handle a reasonable amount of milling and shortening of the rings if necessary.
Jerry

Has any one checked the exhaust port alignment with the ports. I made a 1 piece gasket using the cylinder head for the gasket template. When the two manifolds were bolted together there was 3/16 inch misalignment. I had to shim between the two manifolds for the exhaust ports to line up. Food for thought.

Joe

The manifolds may have been machined on their mating surfaces. This would necessitate shimming between the intake and exhaust manifolds.

EDIT: another possibility is they were from two different engines machined at different times.

When I was going through all of this back in December/January, one thing that helped greatly to seal any remaining gaps between the manifold and the head was that thick fancy gasket -- Can't remember the name of the vendor -- Somebody help me out and save me from having to search through this forum 8 months ago ...

I believe you are talking about Remflex gaskets. You can purchase one Here at Speedway.

OK so I spent a few hours searching for a machine shop and or someone with a large belt sander within a 75 miles of my home that could surface these manifolds. The ones I did locate only worked on high performance or did not know what a 235 was. The Remflex gasket seems like a good choice and cutting new guides is not a problem. So heres my question, has any one surfaced the manifolds by hand when we are talking .015 to .020 off the manifold and whats a safe tolerance to get it sealed up to the head? I have all sorts of sanders and grinders. I have a24” belt sander with 12” of usable surface. So I was thinking that if I removed the stops or guards, that it may be possible to slide the manifold up and back carefully to get it close to what would seal? I could run it on a timed basis like 15 or 20 seconds and check the Dykem or sharpie like you would with guide coat when doing body work. Body work (LOL) that will be the next challenge. But hey I have nothing but time as long as the Good Lord see fit to leave me here. Any help will work. I realize its needs to be a slow process so we don't overshoot it.

Shade Baby

I watched my local machinist surface my manifold on his belt sander. When he got down to freshly ground metal across the mating surface, he checked it with a straight edge. Seemed pretty straight forward.

Remflex 2027 fits the 235 manifolds. Quieted mine significantly.

https://www.summitracing.com/parts/RFL-2027

Good news I found a machine shop that will surface the manifolds. Turns out it’s a marine shop that work with boat engines. Thanks for the input on this

Shade Baby