|
|
Post by brigond on Mar 29, 2014 16:02:21 GMT -5
when I was changing my spark plugs . I noticed this wheel on the passenger side manifold . There is a heat activated spring like a choke spring. I have and idea of its function . Can someone explain its function ? Could it be restricting my exhaust flow ? Here is a random internet picture . Thanks  |
|
|
|
Post by daytona71 on Mar 29, 2014 17:09:46 GMT -5
The function of the heat riser assembly is to assist in warm up when the engine is cold. Hot exhaust on the right manifold, is blocked by the closed valve of the riser. The exhaust then travels through the crossover of the intake, to the left side exhaust. This hot exhaust helps pre-heat the intake which will allow better fuel atomization below the carb, and also helps control the positioning of a mechanical choke. Once the riser is satisfied with the exhaust heat, the spring will open the valve. Upon hard acceleration, the valve will be forced open until the spring activates the valve to the open position. If the riser is stuck open, it will take a longer time to warm up the engine, if stuck closed there will be a significant loss of power. Hope that helps
|
|
|
|
Post by brigond on Mar 30, 2014 1:08:12 GMT -5
Yes thanks Dave.
I understand that some folks block off the port that leads to the base of the carb to avoid vapor lock. I believe the modification is just a gasket without the port cut out.
Won't the hot exhaust fumes still travel through the intake manifold port even with the valve open upon hard throttle?
I'm curious about those with headers . If the heat riser is eliminated because headers
Are installed , does the header gasket have a block off to the port going through the intake? Or does the port still remain un blocked?
Sent from my PC36100 using proboards
|
|
|
|
Post by Nacho-RT74 on Mar 30, 2014 10:36:07 GMT -5
that heater riser was as far I know eliminated for 73 and later cars. The intake port mixture heating system will keep working but less flow going through though. Maybe for that, to help to the engine warm up with less fumes going throught the intake crossover, in 73 the electrical choke assistance was incorporated with a control unit, single or dual stage ( with exterbal ballast ) depending of engine. t1.gstatic.com/images?q=tbn:ANd9GcS69uDxrnk3gxiImiJwqykvk8PLZq6CSef4t9tUhAJThq6z_KBUYAheaders of course will eliminate this piece since is a manifold piece. Will keep working like 73 and laters cars though yes, intake block port with the gasket ( or unexistant manifold or heads provision ) will eliminate even more the mixture preheat system... |
|
|
|
Post by brigond on Mar 30, 2014 12:08:21 GMT -5
Thanks Nacho.
Does anyone here have the gasket that blocks the port?
Negative......So the affects of eliminating (blocking the port with gasket ) Will be a long warm up time?
Benefits...... Also possible heat reduction and vapor lock reduction at the top of the engine ?
Sent from my PC36100 using proboards
|
|
|
|
Post by odzking on Mar 30, 2014 12:43:59 GMT -5
|
|
|
|
Post by brigond on Mar 30, 2014 15:39:07 GMT -5
What a bargan. That's some eBay special.
I think ill eventually take that contraption out and go with headers.
Though, after changing spark plugs I couldn't imagine how tight the headers will make it . For all other engine work as well.
Sent from my PC36100 using proboards
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Mar 30, 2014 20:45:58 GMT -5
That price, though hard to swallow, is somewhat normal. Unlike some things that you see on eBay, listed at what you perceive to be insane prices...it will sell, probably sooner than later. Some shop doing a $50k restoration won't care about that price. They will be happy to find it at any price. It's kind of surprising that more repro's are not made. Looking around, I only see them made for Hemis and 67-69 Big Blocks www.megapartsusa.com/proddetail.asp?prod=199-DR071&cat=514www.megapartsusa.com/proddetail.asp?prod=107-HRK101&cat=514 I was reading that the new repro exhaust manifolds come with the heat riser.....but they don't work!  That sounds about right for Mopar reproduction parts. |
|
DynoDave
CO-ADMINISTRATOR
Motown Mopar-Wizard
Posts: 11,150
|
Post by DynoDave on Mar 31, 2014 13:15:03 GMT -5
|
|
|
|
Post by Nacho-RT74 on Mar 31, 2014 23:56:26 GMT -5
And it was not eliminated. My 73 400 has one. They were on big blocks through the 70's and thru 80's on small blocks. ok, corrected... somebody told me that on Moparts. my car and no one I have seen locally assemblied got it |
|
