Topic: Connecting new dual to heat riser ?
in Forum: C3 Fuel, Emission Control, and Exhaust Systems
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Hi Guy's, I just got my new dual exhaust from Corvette Central with Magnaflow muffler's.
No problems getting the old system off, even though I working on my back with a creeper and the Vtte on blocks.
The left side has gone together real easy, fits like it should.
The problem I am having is the "sleeve and donut ", Corvette Central say that I should be using these on both sides on the manifolds, as I said the left side was no problems, but now I am on to the right side I can't see how the sleeve and donut can go on.
The old Y- PIPE that came off only had a sleeve and donut on the left side and none on the right,
Has any one else put one of these systems on and worked out how to get around this, or does the new engine pipe go on to the heat riser WITHOUT the sleeve and donut.
Andy from down under
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Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
If the heat riser has a chamfered bottom, where the pipe goes, and the pipe is flared, then no gasket/dognut is used. If the bottom of the heat riser is flat, then there should be a sleeve, with a dognut for that...
Joel Adams
C3VR Lifetime Member #56 
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
Mine had the chamfered heat riser and no donut was needed. But, I decided the heat riser was ugly, useless, and didn't help performance so it got canned. Now I use the donut and all works well. Just check to see if the pipes are set up for the heat riser or not - simply a matter of length.
Good luck...and remember a Day Working on a Vette is better than a day doing anything else but driving one!
C3: 1979 Corvette Coupe, Auto, L-48, Red/Doeskin (my wife's fave);
C4s: 1986 C4 coupe (SCCA road race car), satin black, 4+3, Z51 package, L-98; & 1993 C4 coupe, white, 6-speed, LT-1.
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Mounds View, MN - USA
Joined: 5/24/2007
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Vette(s): 70 LT1 coupe, 69 350 HP coupe, 69 390HP 427 coupe, 71 LS5 convert, 85 coupe, 93 coupe
The 79 system used a heat riser and gasket to the manifold, with a chamfered bottom on the heat riser. I am almost certain that you still use the heat riser.
Larry
Larry
Hey Aussie,
Mine is a '79 with true duals and it still has the heat riser.
Due to installing a new intake manifold w.o. an EGR, I wired the (heat riser) flap at the exhaust manifold in the open position. It works for me. No complaints.
Hope this is helpful to you.
Kevin
Thanks for the feed back, really it was only common sense to sit back and look at the connecting engine pipe and heat riser to see that it did not need a sleeve and donut, its just that the support guy from Corvette Central was so sure in his email that I neeeded to use them. When I emailed him back with year of the vette then he agreed that I did not need them.
All in all it was a pretty painless job, I took the engine y-pipe off first, then droped the cross member and the whole system was easy to remove in one piece, alot easier than trying to undo the rusted bolts on the original cat and remove the mufflers while lying under the car.
The new dual went together well, all the right bends and curves in the right place, I suppose it took 3 hours to put together including new centre clamps and making sure it wasn't going to hit or rub on the body.
When I finally started it up and checked for leaks, I found one very tiny leak coming from the weld on the right hand side engine pipe were the 2" goes to 2 and a half. how frustrating had to take off the pipe and spot weld the hole (luckily I have a welder in the shed), put it back together and all is good.
Now I have a V8 that sounds like a V8 should, at idle it gives out a nice dual note and rumble when applying the power, not tooooo loud as to get the attention from plolice but just enough that people look and also hear a great looking Vette
Now on to the next project of putting a new transducer on for the cruise control and getting that sorted
Regards
Andy
Lifetime MemberModerator
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
Joel Adams
C3VR Lifetime Member #56
My Link
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
What is the easy way to get the pipes back apart once they have been clamped for a few years? They don't just slide back out!
I have my heat riser wired open too, with vintage '72 coat hanger wire.
F4Gary 2009-08-18 08:46:37
I have my heat riser wired open too, with vintage '72 coat hanger wire.
in Forum: C3 Fuel, Emission Control, and Exhaust Systems
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