Changing Heat Riser B'Fly Valve on 63 L-76

[Stuart F.]

Not wanting to impose on another current thread about "Changing Exhaust System", I have a related question that perhaps someone has delt with b4 me.

I want to replace my Heat Riser Butterfly valve with an F.I. spacer that I have ground out round. Can I do this without removing my R.H side exhaust pipe - perhaps loosen and turn to clear manifold studs??? I already have new gaskets and donut, and my studs are not rusted.

Opinions please before I dig into it. Going under a car is no fun any more for someone my age, and I don't like surprises either.

Stu Fox

[Joe L.]

Re: Changing Heat Riser B'Fly Valve on 63 L-76

Not wanting to impose on another current thread about "Changing Exhaust System", I have a related question that perhaps someone has delt with b4 me.

I want to replace my Heat Riser Butterfly valve with an F.I. spacer that I have ground out round. Can I do this without removing my R.H side exhaust pipe - perhaps loosen and turn to clear manifold studs??? I already have new gaskets and donut, and my studs are not rusted.

Opinions please before I dig into it. Going under a car is no fun any more for someone my age, and I don't like surprises either.

Stu Fox

Stu------


I don't think you can do it as you suggest. If you could remove the studs, you MIGHT be able to do it. However, that's a moot point because you'll likely never be able to remove the studs. What I would recommend is just removing the left side exhaust manifold. Just remove the alternator and then the manifold. 6 easy-to-get-at bolts and the manifold is out.

[Clem Z.]

Re: Changing Heat Riser B'Fly Valve on 63 L-76

Not wanting to impose on another current thread about "Changing Exhaust System", I have a related question that perhaps someone has delt with b4 me.

I want to replace my Heat Riser Butterfly valve with an F.I. spacer that I have ground out round. Can I do this without removing my R.H side exhaust pipe - perhaps loosen and turn to clear manifold studs??? I already have new gaskets and donut, and my studs are not rusted.

Opinions please before I dig into it. Going under a car is no fun any more for someone my age, and I don't like surprises either.

Stu Fox

i faintly remember back in the day removing a heat riser valve on a 61 vette that some one put in upside down so the exhaust was blocked and would not run over 4000 RPMs. i flipped it without removing anything just by pulling the head pipe down.

[Stuart F.]

Re: Changing Heat Riser B'Fly Valve on 63 L-76

Ah Clem, those were the good old days with the C-1's and tri 5's. I think Joe has the right idea because the C-2 (at least the 63) looks to me to be less compliant with the exhaust pipe passing through the cross member just back of the engine (at the tail shaft mount). I was hoping that maybe it would be easier with the 63 hanger which is quite different than the 64-67, but I think that the size of the hole in the cross member is probably the limiting factor, specially with the 2-1/2" pipes. I believe I need at least 3" of drop to clear the manifold studs, then perhaps with the pipe joint loose, I could rotate it clear and allow the valve to drop enough to clear the studs too. Probably too much to ask for. Joe's idea to just remove the manifold may be my only sure option. May also be a good time to refinish them.

Thanks fellows for the opinions. I appreciate it.

Stu Fox

[Barry H.]

Re: Changing Heat Riser B'Fly Valve on 63 L-76

Stu, I have replaced the heat riser, (or block off) plate many times on my mid year corvs by just removing the three nuts, flange, then pulling down on the head pipe to get enough clearance for the heat riser to drop down. On occasion I have had to loosen the "c" clamp at the transmission mount to gain some extra drop for the head pipe.
If you are talking about "sideipes" it is easier, just loosen the exhaust mount nut at the rear, on the frame, then remove the three flange nuts & flange, & drop pipe to clear studs & remove the heat riser.
Just an afternoon project.
Barry Holmes

[Joe L.]

Re: Changing Heat Riser B'Fly Valve on 63 L-76

Ah Clem, those were the good old days with the C-1's and tri 5's. I think Joe has the right idea because the C-2 (at least the 63) looks to me to be less compliant with the exhaust pipe passing through the cross member just back of the engine (at the tail shaft mount). I was hoping that maybe it would be easier with the 63 hanger which is quite different than the 64-67, but I think that the size of the hole in the cross member is probably the limiting factor, specially with the 2-1/2" pipes. I believe I need at least 3" of drop to clear the manifold studs, then perhaps with the pipe joint loose, I could rotate it clear and allow the valve to drop enough to clear the studs too. Probably too much to ask for. Joe's idea to just remove the manifold may be my only sure option. May also be a good time to refinish them.

Thanks fellows for the opinions. I appreciate it.

Stu Fox

Stu------


I also think you'd find that unless you have a stainless steel exhaust system that rotating the forward pipe (with the crossmember clamp loosened) won't be so easy. This joint rusts up pretty solid, especially if it's not been separated in a long while.

[Bob J.]

Re: Changing Heat Riser B'Fly Valve on 63 L-76

Stu, I have replaced the heat riser, (or block off) plate many times on my mid year corvs by just removing the three nuts, flange, then pulling down on the head pipe to get enough clearance for the heat riser to drop down. On occasion I have had to loosen the "c" clamp at the transmission mount to gain some extra drop for the head pipe.
If you are talking about "sideipes" it is easier, just loosen the exhaust mount nut at the rear, on the frame, then remove the three flange nuts & flange, & drop pipe to clear studs & remove the heat riser.
Just an afternoon project.
Barry Holmes

I've used the same method and its worked everytime.Bob

[Stuart F.]

Re: Changing Heat Riser B'Fly Valve on 63 L-76

Thanks Barry and Bob. Sounds like it's worth a try, specially if as Joe says the joint may have rusted shut. Mine are aluminized pipes (not SS) and I don't imagine the coating has held up this long inside the pipes, if there's any there at all. The reason I kind of didn't want to break the joint anyway is that I feared it would allow the welded pipe back to the muffler hanger to twist or move, and I have a perfect fit now and don't want to risk messing with it.

Thanks again Guys. So, I have a choice to make on whether it's time to remove the manifolds to clean them up and replace the spacer at that same time, or try to just drop the pipe to change from the valve to the spacer. Great! The second option sounds like the place to start.

Stu Fox

[Timothy B.]

Re: Changing Heat Riser B'Fly Valve on 63 L-76

Stu,

Along with what everyone said, if you have the one piece shield on the engine and decide to remove the manifold, that shield is a bear to remove. This is necessary to remove the exhaust manifold, I can see why the design changed.

[Stuart F.]

Re: Changing Heat Riser B'Fly Valve on 63 L-76

Tim;

Yes, I do have the one piece shield and you are so right. It is a bear to remove. The last time I had it off, I believe it was when I had the battery out to change the tray. But, there is a trick to it and it can be done. Trouble is, each time I figure it out I forget to write it down (stupid old techwriter me) and have to re-educate myself again the next time. Seems to me it comes out the bottom easier, so to speak.

I recall to this day the first time I removed it to change plugs soon after I got the car and was stationed down at White Sands in NM (back in the points days). I was at the hobby shop taking up rack space on a weekend. I used every tool they had and recited every swear word I knew a thousand times. Finally ended up bending the shield, from which it still has some kinks in it.

Thanks for reminding me.

Stu Fox

[Bob R.]

Re: Changing Heat Riser B'Fly Valve on 63 L-76

If you take out the exhaust manifold then you have to remove the spark plug shield and as said above that is a pain in the neck to get out. I always remove it from under the car in the small opening between the battery and the starter.
I installed the heat riser from under the car by releasing the exhaust pipe from the manifold. There was enough play in the exhaust pipe to allow the installation of the riser. I would certainly try that method first. If you need a little more movement as stated above just unhook the exhaust bracket at the transmission.
I think you will be sucessfull with this method.

[Stuart F.]

Re: Changing Heat Riser B'Fly Valve on 63 L-76

Thanks Bob. That will definetly be my first approach. Also, thanks for the point about removing the shield from underneath. That's what I was thinking, but it has been awhile. With electronic Ignition, I seldom change the plugs anymore. So I guess I'm spoiled.

Thanks to all for your help. I feel confident this will go well.

Stu Fox

[Domenic T.]

Re: Changing Heat Riser B'Fly Valve on 63 L-76

I have done it also by pulling down while loosening the clamp at the cross member but dont rule out double nutting the studs after a little penetrating oil on the top and bottom. You might get lucky, I have about a 70% sucess rate but it boils down to how long were they in there and do you want to risk breaking a rusted stud.

DOM

[Stuart F.]

Re: Changing Heat Riser B'Fly Valve on 63 L-76

Dom;

Thanks for reminding me. My current pipes were put on in 1995, or about 6k miles ago (I just checked). In anticipation of this project, I began cleaning and spraying the studs since our last cool season. It's hard to evaluate properly with your nose on the pipe using a trouble light, but I think they are quite clean and should come off without any trouble (the car hasn't seen any inclement weather). One question though, these being brass nuts on steel studs, can they be reused effectively or should I plan on replacing them.

I just had the car out for a run to the Gas station via the highway as we have a show tomorrow at our Old Town (October Vettefest). The car runs so sweet now that I don't feel pressed to make the change until the weather cools down more.

Thanks for your advice.

Stu Fox

[Domenic T.]

Re: Changing Heat Riser B'Fly Valve on 63 L-76

Stu,
I reuse the brass nuts over and over on my aircraft and see no problem, but I would not use them when you double nut.
Your post made me remember why I ordered SS studs yesterday with my new SS exhaust system.
I found SS nuts that also look stock. I use anti sieze when I put exposed nuts, bolts, and studs in place that could be a problem down the line.

DOM