Bobacuda Posted June 2, 2014 Report Posted June 2, 2014 The heat riser is frozen in place and the plate has been removed from it in the exhaust manifold I will be using on my truck. While this project is still at a relatively easy stage to get to the manifolds, should I split them apart and install a thin piece of sheet metal (a block-off plate) between the intake and exhaust manifolds, or is it OK to leave this open? I was wondering if the intake would get too hot without a block-off plate. Any ideas or experiences? Quote
greg g Posted June 2, 2014 Report Posted June 2, 2014 I have mine blocked with a thin piece of stainless steel. My flap and pivot are gone, and the pivot holes are welded closed. I have not encountered any diveability issues eve with temps dow into the 20's. Quote
1941Rick Posted June 2, 2014 Report Posted June 2, 2014 The only time you need a heat riser is if you drive in cold conditions....Mine is gone due to headers and never had a problem right down to freezing. Block it off. dont leave the hole there as you will have fuel problems...... Quote
48Dodger Posted June 2, 2014 Report Posted June 2, 2014 (edited) Blocking off the heat with a plate will help with hard starting once the engine has been running and then shut off (vapor lock, etc). The assist from the exhaust manifold for a cold start is for coooold climates, like where Mark and Ed live Mini-so-cold-a ....lol. Don't know where you're living, but the extra minutes getting it warmed up without the riser is usally not a problem. Don Coatney has a few pictures of his block off somewhere..... 48D Edited June 2, 2014 by 48dodger 1 Quote
Don Coatney Posted June 2, 2014 Report Posted June 2, 2014 Tim is sort of correct and Greg left out one important piece of information. My plate is blocked open to the intake but acts as a separator for dual exhaust. I have dual carburetors same as Greg so heating the center of my intake manifold is not a problem for me as there is no carburetor mounted in the center of my intake manifold. Quote
55 Fargo Posted June 2, 2014 Report Posted June 2, 2014 Yes block this area off, you do not wan a warmed up engine, on a hot day allowing hot exhaust going up under the carb base. I have now had 2 flatties in a row with this problem, and it is a pain in the a$$. Get it blocked off, and you will be much happier on warm days... Quote
MBF Posted June 3, 2014 Report Posted June 3, 2014 Yup-what they all said. Did it on my 36 Plymouth several years ago. Quote
Bobacuda Posted June 4, 2014 Author Report Posted June 4, 2014 Thanks to all for the info. I wanted to mark this solved and credit everyone, but it looks like Fernando got the nod from the computer. Anyhow, thanks to all...now I just need to find a thin piece of metal to make the block off plate. Quote
Bradley S. Posted June 4, 2014 Report Posted June 4, 2014 Is it possible for this flapper plate to rot and start leaking exhaust gas into the intake? Seems like I hear some exhaust noise coming from that area on my truck. It goes away when I turn the flapper plate to the open position. I don't remember hearing that noise before. Brad 1 Quote
Don Coatney Posted June 4, 2014 Report Posted June 4, 2014 Is it possible for this flapper plate to rot and start leaking exhaust gas into the intake? Seems like I hear some exhaust noise coming from that area on my truck. It goes away when I turn the flapper plate to the open position. I don't remember hearing that noise before. Brad Only way that is possible is if the intake manifold is cracked. The heat riser hot exhaust gas heats the underside of the intake manifold and the hot gas and fuel charged intake manifold gas do not comingle. Quote
Merle Coggins Posted June 4, 2014 Report Posted June 4, 2014 It could be exhaust leaking past the shaft that you are hearing. There may be more wear in one spot that allows exhaust gasses to leak out and when the shaft turns it reduces the gap areas and restricts the leak. 1 Quote
Young Ed Posted June 4, 2014 Report Posted June 4, 2014 It could be exhaust leaking past the shaft that you are hearing. There may be more wear in one spot that allows exhaust gasses to leak out and when the shaft turns it reduces the gap areas and restricts the leak. Correct I had this on my p15. A heatriser kit took care of it. I managed to do it in about a weekend without breaking off any studs. I did ruin one though and had to replace it. Quote
Bradley S. Posted June 5, 2014 Report Posted June 5, 2014 Thank you for the technical advice. When does one find this heat riser kit? Vintage Power Wagons perhaps? Thank you! Quote
Bradley S. Posted June 6, 2014 Report Posted June 6, 2014 I checked it out, you guys are spot on. Exhaust leak past the shaft when the valve is closed. Stops when the valve is flopped over to open. Thankk you! Brad Quote
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