Original 1957-74 heat riser spacer for FI?

[Joe L.]

Re: Original 1957-74 heat riser spacer for FI?

I just finished removing the old incorrect, rusty exhaust pipes from my 59 FI. The heat riser I found connected to the RH exhaust manifold is pictured below, along with an example picture from Corvette Central of the valve they sell.

Is mine a correct heat riser spacer for my 59 Fuelie? It has a valve inside, which is stuck in the open position and no lever like regular heat risers. Also, the inside diameter is 2". The spacers sold by the parts vendors for 59 have sharper edges and no valve inside. Does anyone know if this is correct or will it at least pass judging?

As always, thanks for the help!

Ian-----


I do not understand how this heat riser valve could have been on an FI-equipped car. The FI adapter (manifold) has no heat cross-over passage. The valve would have to be open at all times or there would be no way for the right bank exhaust gas to pass to the exhaust. The exhaust pressure would probably keep the valve open, but it's a crazy way to configure things. The car would not have had the valve if it was an original FI car. I cannot see any reason why someone would have added one. Plus, the valve looks like it could be an original example. So, that leads to the possible conclusion that the car was not an original FI car but was "converted" at some point (without the valve being removed and replaced by the spacer).

[Stuart F.]

Re: Original 1957-74 heat riser spacer for FI?

Richard;

As I mentioned, the spacer I got from Eckler's does have the "UP" cast into it. It is not real clear, almost as though it came from a very well worn mold, but it is there. I can't imagine an original in any better condition after rusting for 45 years either.

I ground the flats out of the inside of the one I have in preparation for installing it in my 63 (don't need the valve here in Florida). Makes a real pretty piece.

Stu fox

[Joe L.]

Re: Original 1957-74 heat riser spacer for FI?

OK I didn't think what I had was right and you guys have confirmed that for me. I'm not sure thanks are in order, because that means I'm going to have to hunt one down :P

I don't think I've ever seen one come up on eBay. I'll check all the parts houses and see if they have one that matches... Since it was used as late as 1974, I wonder if GM still carries it? hmmm.

Thanks very much!
~ian

Ian-----


Don't bother to check with GM for availability on the 2" spacer. It was discontinued 15 years ago.

[Justin B.]

Re: Original 1957-74 heat riser spacer for FI?

My early production 58' Fuelie was found by me with its' original 290H.P. engine and exhaust manifolds with the spacer. The spacer did NOT have the butterfly valve or any evidence of ever having one.

[John D.]

Re: Original 1957-74 heat riser spacer for FI?

Does 63 FI have the UP on the spacer?

[Stuart F.]

Re: Original 1957-74 heat riser spacer for FI?

John;

I would assume it does. The piece I picked up for mine may be a repro or NOS. At any rate, it looks like it was made from an old mold or tooling as it has the "UP" on it, but it looks rough.

I thought you would be the expert on this. Come on! You just pulling our leg?

Stu Fox

[Ian G.]

Re: Original 1957-74 heat riser spacer for FI?

Hi Joe,

The spacer valve is actually froze open, so it wouldn't be closed anyway. It may have been installed like that. The spacer doesn't have the level on it, or an up or top cast on it either. I think its just some spacer that the guy put in at some point. Are you sure the exhaust doesn't have the crossover passage? I'm pretty sure a 59 FI will have the crosssover -- the Parts House sites seem to indicate it does anyway. I'll recheck my JG.

My car currently has a carb on it -- the fuelie is in a box... There was other stuff on my vette not original, so I'm not surprised the exaust stuff isn't either. All the hangers were wrong for instance. There is other evidence of the car being a fuelie, like the bracket on the inner side of the hood and screw holes for the air filter, and the hole in the firewall for the tach line, and a 6500 redline tach. Also, I had our local judgign chair scope my engine plate and he said it was original... So I'm confident I'm OK there...

[Ian G.]

Re: Original 1957-74 heat riser spacer for FI?

The spacer from Corvette America looks similar to the original pics Joe Mish posted. Paragon doesn't have a pic and Corvette Central's doesn't look right at all.

[Gary C.]

Re: Original 1957-74 heat riser spacer for FI?

Ian, photo of '57 FI exhaust spacer. Gary....

[Ian G.]

Re: Original 1957-74 heat riser spacer for FI?

Is the "top" cast tab flush at the bottom, or is it like the pics from Joe Mish and raised from the bottom a bit?

[Gary C.]

Re: Original 1957-74 heat riser spacer for FI?

Ian, top photo on car, couldn't get good bottom side photo for you. Spacer is approx 1 1/8 inch thick and TOP tab is approx 5/8 inch thick. Which means it's approx 1/2 inch up from the bottom. Gary....

[Ian G.]

Re: Original 1957-74 heat riser spacer for FI?

sweet, thanks a lot

[Joe L.]

Re: Original 1957-74 heat riser spacer for FI?

Hi Joe,

The spacer valve is actually froze open, so it wouldn't be closed anyway. It may have been installed like that. The spacer doesn't have the level on it, or an up or top cast on it either. I think its just some spacer that the guy put in at some point. Are you sure the exhaust doesn't have the crossover passage? I'm pretty sure a 59 FI will have the crosssover -- the Parts House sites seem to indicate it does anyway. I'll recheck my JG.

My car currently has a carb on it -- the fuelie is in a box... There was other stuff on my vette not original, so I'm not surprised the exaust stuff isn't either. All the hangers were wrong for instance. There is other evidence of the car being a fuelie, like the bracket on the inner side of the hood and screw holes for the air filter, and the hole in the firewall for the tach line, and a 6500 redline tach. Also, I had our local judgign chair scope my engine plate and he said it was original... So I'm confident I'm OK there...

Ian-----


Well, my C1 recollections may be quite fallible. However, I just don't recall that the C1 FI adapter (manifold) had an exhaust cross-over passage. Beyond that, I don't see why it would have had one. Does anyone know, for sure? I'm interested in confirming whether my recollection is correct, or not.

John D: you MUST have one of these adapters around somewhere.

[Stuart F.]

Re: Original 1957-74 heat riser spacer for FI?

Joe;

It's as you say. There would be no purpose for it. No, they did not have a heat riser cross over in the manifold plate. The purpose of one is to preheat the fuel mixture and there is no direct way you could possibly do that. That's not to say there shouldn't have been a way, i.e. my 58 fuelie would not start at 2 degrees below zero, but would at 2 above. To this day I don't know if it was the fuel freezing in the spider, fine fuel lines or nozzle blocks, or where ever.

Stu Fox

[Ian G.]

Re: Original 1957-74 heat riser spacer for FI?

Hey Joe & Stu,

If you are correct, then the 58-60 Judging Guide needs an update, because on Pg. 61 it reads:

"290 FI and 270 horsepower engines were specified as using exhaust crossover pipes."

The crossover is just part of the pipes right? I read that it is just an exhaust tube which is cemented over a welded adapter on the pipe itself. There isn't any special adapter on the manifold aside from that?

I do appreciate everyone's input. This has been a really good thread.