I have a Heat insulator for the carb. #3973231, can anyone tell me what applaction this is for?
Thanks, Michael
Thanks, Michael
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Re: Carb. Insulator
Michael-----
Try as I may, I can't come up with a specific application for this piece. However, I can tell you this about it:
1) It was released about late 1969;
2) It was used only on Chevrolet vehicles;
3) It was not used for any Corvette application;
4) I think it's very likely it was released for some NA-9 (1970 California emissions) application;
5) It was discontinued without supercession in April, 1980
6) A very strange thing here is that besides Corvette, I checked full size Chevrolet, Chevelle, Camaro, Chevy II, and series 10-30 light trucks and I can't find any application for this piece in the 70-72 period when it would have HAD to have been used. So, that pretty much only leaves medium duty/heavy truck (which I doubt) or Corvair.
Can you post a photo of it?In Appreciation of John Hinckley -
Re: Carb. Insulator
Michael------
I received by e-mail your photo of the insulator. I tried to attach it to this response but I was not able to. However, I am attaching to this response a photo of an NOS example of a GM #3969837. You will note that the aluminum shield is virtually identical to your GM #3973231. The difference appears to be the fact that the 3969837 has gaskets stapled to BOTH sides of the shield whereas the 3973231 has none. However, from your picture, it looks like there might be staple marks about where I'd expect them to be if there were originally gaskets attached. If that was the case, then I don't know what the difference would have been between the 2 parts.
The 3969837 was used for Corvettes for 1970 Corvettes with EEC (i.e. California emissions) except LT-1. In general, this configuration shield was used only for 1970 with EEC applications. So, as I surmised in my previous post, I'm virtually certain the 3973231 was used for some 1970 with EEC application. Now I also know that application was with a Q-Jet carb, just like the 3969837. So, now we know it's NOT Corvair which was a possibility I mentioned before I knew the configuration of the shield.
All I can say now is that this shield was almost certainly used for some 1970 with EEC application involving full size passenger car, Chevelle, Camaro, Chevy II or truck. I couldn't find any such application for it, but there must have been one.
I see what the difference is now between the shields. Note the difference in the "cutaway" area on the lower, left side of your 3973231 versus that on the 3969837. That extra cutaway must have been done to provide clearance for some manifold mounted or otherwise ENGINE RIGHT SIDE mounted accessory. It might have been done for AC-related clearance. However, I have no information it was ever used for 1970 Corvettes so-equipped. So, it remains a mystery.In Appreciation of John HinckleyComment
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Re: Carb. Insulator
Joe -
May have been a service-only part; I remember having a new Q-Jet-equipped early-80's IROC Z/28 Camaro company car that was plagued with vapor lock issues, and a no-charge TSB was issued on those cars that included installation of the same kind of plate and some modification to the fuel tank vent system, which cured the problem.Comment
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Re: Carb. Insulator
John;
I had an 83 Z-28 H.O. w/5-speed (one of the first ones delivered), and it would shut down on acceleration. The tank venting system was sending all the fuel from the pump back to the tank.
Is that the same problem of which you speak?
Basically, I understood the problem was that the fuel line was designed to suit a V6 application, but on the V8, the line had to cross from the V6 L.H. side to the V8 R.H. side and did so too close to the engine.
I couldn't wait for the factory service fix and instead diagnosed/fixed it myself. Primarily, I inserted a drilled out Holley carb jet in the return fuel line to act as a restrictor and added some insulation to the fuel line. Cheap trick, but it worked. Factory fix wasn't really effective until the 84 model run, as I recall.
Stu FoxComment
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In Appreciation of John HinckleyComment
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Re: Carb. Insulator
Stu -
I don't recall the specifics other than the big aluminum plate and three pages of instructions on the vent system changes that the mechanic left in the car.
I had three '85 IROC Z/28 company cars - the first one was stolen from a mall parking lot while I was Christmas shopping, the second one was stolen right out of the Exec garage on a Saturday, and I took the third one to my first day at Chrysler when I left GM (and had the Chrysler Exec garage guys take it back up Van Dyke later that morning and drop it off at GM). Car thieves LOVED the IROC Z/28's.
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Re: Carb. Insulator
John:
Wasn't the early 82 + Camaro chassis based on the Monza platform? I seem to recall a number of deficiencies were encountered with the V8 application besides the fuel line, not the least of which was the rear end. That delayed the 83 Z-28 H.O. for me, and I finally had to accept it w/o posi (open rear end). The basic "Monza" rear axle posi was fine for the standard V8's in the 82, but couldn't handle the torque of the H.O. - so I was told.
Stu Fox
P.S. Don't mean to steal the thread, but it seems like a slow night.Comment
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Re: Carb. Insulator
Stu -
Nope, the "F"-body had its own all-new platform in '82; we built a whole new Body Shop building for it at Norwood (and had to buy and demolish a Shell station and a 3-story Salvation Army headquarters building adjacent to the land-locked plant to get the land to do it, then write a check to rebuild them both about a mile away). The "F"-body diff was smaller than the previous generation, but was larger than the "H"-body diff used in the Vega and Monza.Comment
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