327/365 bang and now ok????

[firstgear]

Got side pipes put on the 64 this past winter and today was really the first time I was able to get her out and get moving....moved it from our house 40 miles awawy to the new house (old house has 8+ attached garage and for sale, new house only 2....but more space on the way)....every time I would accelerate in any gear through about 2500 rpm or so, I would hear the loudest bang coming out of what I thought was the right exhaust....the car would kinda stumble and then this bang like someone was hitting something in the exhaust or the engine...after about 32 miles of this, all of a sudden it was gone....just took her out again, and it is still gone and runs a lot better.....something stuck in a carb jet? bad winter gas? ideas?

She runs real good now.....I just hope it was eomthing caught in the fuel stream that is now gone......what do you think? By the way, with the exhaust opened up, she really does scoot a lot better than she did before.....

 

[Tyler Townsley]

Heat riser stuck closed then poped open.

Tyler

 

[firstgear]

Heat riser stuck closed then poped open.

Tyler

Where is it and how do I make sure that in the future it doesn't do it any more? Pcictures? Suggestions? Or does this happen from time to time and it will eventually free itself up? or will it come back and be a PIA?

 

[ßill]

The heat raiser is located in the exhaust manifold at the flange that connects to the exhaust pipe. If i remember right it is only in the passenger side. There is a shaft sticking out of the pipe with a counter weight on it. you should be able to move it with your fingers WHEN COLD.

 

[Tyler Townsley]

The heat raiser is located in the exhaust manifold at the flange that connects to the exhaust pipe. If i remember right it is only in the passenger side. There is a shaft sticking out of the pipe with a counter weight on it. you should be able to move it with your fingers WHEN COLD.

Depending on the environment it tends to rust if the car sits for a time. You should be able to push it open very easily with one finger.

Tyler

 

[paul67]

Mine is welded open.

 

[firstgear]

she ran fine again today....so, what ever the problem....must be over with now....just glad that it isn't an ongoing problem....really made some racket inside the car and made the car spit and sputter....feels good now.....thanks

 

[JohnZ]

Make sure your heat riser moves freely; if it's stuck shut, it forces all the exhaust from the right bank through the small crossover passage under the intake plenum and out through the passages in the left side cylinder head - MAJOR restriction!

 

[Viet Nam Vett]

It looks something like this. This is not a Corvette Heat Riser.... but the weight and spring on the left will look something like this for a vette on the passenger side exhaust manifold where it meets the exhaust pipe.

 

[ctjackster]

she ran fine again today....so, what ever the problem....must be over with now....just glad that it isn't an ongoing problem....really made some racket inside the car and made the car spit and sputter....feels good now.....thanks

Instead of welding or wiring it (the heat riser valve) open, you might also consider taking the heat riser out (save it for Mr. NCRS) and replacing it with the FI-spec spacer, assuming you are not running your Vette in the cold winter months - a very easy job, no welding or wiring required.

And that's how mine is set up

 

[allcoupedup]

You can also wire it open or bed the tab on the thermostatic sprint so that it always hangs open. I went the FI spacer route because I have 2.5" pipes. Not sure they make one for 2" pipes.
Brian

 

[ctjackster]

the "327/ 365 bang" title tells me the FI spacer will work for Firstgear ; )

 

[Mike McKown]

Sounds to me like you had/have a fouled plug. If a heat riser hangs shut, it won't cause any explosions. Your car will just be real sluggish.

 

[firstgear]

It looks something like this. This is not a Corvette Heat Riser.... but the weight and spring on the left will look something like this for a vette on the passenger side exhaust manifold where it meets the exhaust pipe.

Is this gizmo's sole function in life to assist in getting the car up to temperature faster? Before I heard the banging (pre-side pipes), and don't hear it now, I know that the car used to run like crap until it got warm and then she ran real good, when it was cold she would like hesitate on acceleration....I don't really want to do anything to it right now, as it seems to run real good....idles good, smooth acceleration....good starts...I am actually amazed that it is running this good as it never ran this good before the sidepipes....go figure....

 

[firstgear]

You can also wire it open or bed the tab on the thermostatic sprint so that it always hangs open. I went the FI spacer route because I have 2.5" pipes. Not sure they make one for 2" pipes.
Brian

I have 2.5" pipes....went for 2" sidepipes and when we went to change to them, opps, found out I had 2.5".....what is a FI spacer and where do I find that gizmo and who sells it?

 

[JohnZ]

Is this gizmo's sole function in life to assist in getting the car up to temperature faster? Before I heard the banging (pre-side pipes), and don't hear it now, I know that the car used to run like crap until it got warm and then she ran real good, when it was cold she would like hesitate on acceleration....I don't really want to do anything to it right now, as it seems to run real good....idles good, smooth acceleration....good starts...I am actually amazed that it is running this good as it never ran this good before the sidepipes....go figure....

Nope, has nothing to do with how fast the engine warms up, but has everything to do with improving cold driveability until the engine warms up. Its function is to heat the floor of the intake plenum via the crossover passage at cold start to improve atomization of the air-fuel mixture; when the engine is cold, the air-fuel mixture tends to "wet out" on the cold walls of the intake, causing poor mixture distribution and all manner of cold driveability problems. The bi-metallic coil spring on the end of the shaft opens the valve fully as the exhaust manifold and valve casting heat up - only takes a few minutes.

All the vendors have the 2.5" FI spacer, or you can just wire the valve open in warm weather, and take the wire off and let the valve do its thing if you drive the car in cold weather.

 

[ctjackster]

I have 2.5" pipes....went for 2" sidepipes and when we went to change to them, opps, found out I had 2.5".....what is a FI spacer and where do I find that gizmo and who sells it?

Section 33 item 22D in the LIC catalog ($25); or item 322113 at Corvette Central ($24) among the usual sources. Frankly, if you put your car up for the winter, or live where you never take the car out when it's in the 40s or below, this is the way to go, in my little opinion:

 

[firstgear]

Section 33 item 22D in the LIC catalog ($25); or item 322113 at Corvette Central ($24) among the usual sources. Frankly, if you put your car up for the winter, or live where you never take the car out when it's in the 40s or below, this is the way to go, in my little opinion:

thanks for the picture and information...I moved the 64 back to our old house (35 miles away) :-( tonight so that I could pick up my 350 cu in motor that came out of the '60 vette....hopefully tomorrow or Friday I will be able to get the '60 vette to the new house (it is at the shop that pulled the motor for me and will be putting it back in)...my gal wants to build a new attached garage to the new house, about a 40X32 figuring we can get 6 cars in and coupled with the old 2 car, there should be room for all the cars).

I will be glad when the old house sells......will take some pressure off the budget and give me more time to work on the cars (got 3 lawns to mow now....)

thanks again for the info....