Heat Riser - 250

[T and S]

I have two exhaust manifolds, one the heat riser is fubar, the other it is functioning but the pin for the spring is all but rusted off. I was thinking of just eliminating the heat riser and pluging the hole. Will this effect cold starting, or just take a bit longer to warm up?

[TJ's Chevy]

I left the heat riser stuck open all the time with mine and I had no problem. Even during the winter.

[Lugnutz65]

The heat riser diverts exhaust to warm the intake manifold. A warmed intake helps prevent the vaporized fuel from condensing on the inside of the intake, especially true during hard acceleration when vacuum increases. Tom Langdon sells intake warmers that work with engine coolant. Use Landon's warmer with headers.
In warm climates the stock diverter is less important. My spring and holding pin were shot but it can be repaired very easily and new springs are sold by vendors. I'd try running it as it is now. If performance is poor then fix it. The flap inside might bang around a bit and be annoying.

[jdl71]

If you want it to work, this would probably be the easiest way:

http://www.summitracing.com/oh/parts...make/chevrolet

I just got one a few weeks ago, and seems to be pretty good quality.

[ACK]

Originally Posted by Lugnutz65

The heat riser diverts exhaust to warm the intake manifold. A warmed intake helps prevent the vaporized fuel from condensing on the inside of the intake, especially true during hard acceleration when vacuum increases. Tom Langdon sells intake warmers that work with engine coolant. Use Landon's warmer with headers.
In warm climates the stock diverter is less important. My spring and holding pin were shot but it can be repaired very easily and new springs are sold by vendors. I'd try running it as it is now. If performance is poor then fix it. The flap inside might bang around a bit and be annoying.

I'm curious as to how you fixed the pin.

[Lugnutz65]

We drilled a hole and drove a new stainless pin into the hole. Then cut the pin to length.

[T and S]

We drilled a hole and drove a new stainless pin into the hole. Then cut the pin to length.

I was thinking about doing that. How hard is it to drill out the old pin and put in the new one. Seems like a verily easy job.

[jdl71]

Cast iron is very, for lack of a better word, brittle. It can be drilled, but be very careful not to bang or whack it anywhere. Especially an exhaust manifold that has been through thousands of heat cycles. I ruined 2 trying to fix broken studs.