Heat riser valve delete

amy

I have a few of these left over so I will take advantage of this new forum to advertize them.

The heat riser delete will eliminate the valve altogether while still retaining the geometry of the exhaust attachment point.The main body of the part is machined from round stock steel and the ears are flat bar construction and TIG welded on a fixture for good fitment.

Price for the part is $60.00 shipped in the US and Puerto Rico,others will be actual shipping included.PM or post here with any questions.Thanks.Here's a few old valves from 350,430 and 455 Buicks and the delete on the lower right.These are detailed pictures of the part

350 manifold with delete and gasket

455 manifold with delete and gasket

This is a gasket that I found to work for this application if the manifold surface is not nice and flat.The Gasket is not included with the purchase.

Hi, what does this thing do? what does it replace?  sorry, super noob.


Originally Posted by waijo355Hi, what does this thing do? what does it replace?  sorry, super noob.

It replaces the heat riser valve.Look at the first picture on the upper left,that's a complete valve out of a '76 455 Buick engine.The valve,as intended,routes hot exhaust gasses to the top of the engine during cold weather operation for faster starts and to keep the intake charge warm.The valve acomplishes that by closing the flapper,the problem is that after years of operation they deteriorate and get stuck in the closed position or only partially open creating an exhaust obstruction.For mild weather areas or for cars that only see good weather,some people just eliminate the valve altogether by either removing the flapper or using something like this item.

Not all vehicles were equipped with the heat riser valve,so if you don't have one there's no worries of it becoming stuck.For vehicles equipped with it,you will find it on the left side of the engine(driver's side)between the exhaust manifold and the exhaust pipe attached to it.Hope that answers your question.

Is there a performance gain from eliminating the flap?


Originally Posted by BigBlock68Is there a performance gain from eliminating the flap?

I like to think that eliminating the restriction to the exhaust path that the valve poses,even in the open position,should help performance somewhat.That's the reason that I made the pieces to begin with,I used to do a similar modification to the sbc's in my past life.Notice also that I made the internal diameter of the part slightly larger than that of the manifold in case that someone wanted to open it up a little,again,for improved exhaust path.

I can not make any claims as to the performance or lack of it that will come as a result of using the part since I have never tested or measured any engine's power before and after installation.I made the part for my own use and made a few extras in case anyone else wanted to replace an old defective valve or felt the same as I do about the stock part choking the left manifold's flow.To answer your question directly,I don't know.

Keep in mind also that there's a shool of tought that states that the heat riser should always be present on the engine in order for it to perform well.I will agree to that but only on a case by case application with the weather temp being the major factor in making that call.Then again,think headers.

Oh, so it's more about eliminating the headache of the valve being stuck open?

Or stuck closed..


Originally Posted by SmartinOr stuck closed..
Hector,
My '71 doesn't have this valve. It's a US car from Texas. My Canadian GM Parts Book doesn't show it anywhere.
What applications was it put on as new?


Originally Posted by Steve CraigHector,
My '71 doesn't have this valve. It's a US car from Texas. My Canadian GM Parts Book doesn't show it anywhere.
What applications was it put on as new?

I don't know what criteria the factory used for the incorporation of the valve or which years.I believe that some models were built both with and without the valves on the same year.I know that both my '69 and '79 came with them as well as a '76 that I parted out a while back.Maybe the original destination of the vehicle dictated wether the valve was used or not,just my speculation.Perhaps someone else can shed some light in the subject.

71's didn't have them, that's all I can confirm for sure.


Originally Posted by SmartinOr stuck closed..

My mistake.

Great product! I have bought several 350s for dirt cheep with the owners claiming they were worn out and rattling.... Really the noise was the heat riser stock shut and flaping as the exhaust tried to push past! After I wired them open more power and no noise!!!

I had a chance to work on my '69 this past week and since it was sitting on jackstands I figured,if the bolts come loose I'll replace the valve with the delete and take a few pics.
I've been spraying some PB Blaster on the threads for the last year sporadically and the nuts and bolts all came off smoothly.Notice that somebody has been here before,they replaced a stud with a bolt and there was RTV on both mating surfaces of the valve and they also used a gasket.

The valve was stuck,not  in the closed position but not open all the way either.
I decided not to use the gasket and used some Hi Temp RTV to coat the sealing surfaces.The deed is done.If the nuts/bolts holding the exhaust pipes on the manifold come loose it is a 10-15 minute job to change the part.


ttt

What is the purpose of the delete? Couldn't you simple remove the offending flapper, then bolt the pipe to the exhaust manifold?

Thanks


Originally Posted by drspencerWhat is the purpose of the delete? Couldn't you simple remove the offending flapper, then bolt the pipe to the exhaust manifold?

Thanks

The delete is keeping the attachment point on the manifold for the pipe,you need the radiused surface for the pipe to seal.Without the valve or the delete there's only a flat surface on the manifold.


Originally Posted by HecticThe delete is keeping the attachment point on the manifold for the pipe,you need the radiused surface for the pipe to seal.Without the valve or the delete there's only a flat surface on the manifold.

Would a 71 350 come stock with a valve?

Thanks


Originally Posted by drspencerWould a 71 350 come stock with a valve?

Thanks

According to Adam's post above,no.

Is there any reason this plate woiuldnt work on a 401 Gran Sport? Are the manifolds the same ID as the 350/455 manifolds?
Rhett


Originally Posted by Bigpig455Is there any reason this plate woiuldnt work on a 401 Gran Sport? Are the manifolds the same ID as the 350/455 manifolds?
Rhett

I did not have a NH manifold to compare when I was making these.I don't know the spacing for the studs on the NH ,the overall length or thickness of the part may be different,I just don't know.Can you PM me the dimensions from your valve?

Any update on fitting the 401?
Still avalible?

I still have a few of the parts left but no idea if it will fit the NH exhaust.

It would be good to know; if, this will fit 322 and/or other nailheads.
I need to replace the gasket at the Roadmaster's Y pipe. I would like to get rid of the flapper at the same time.
Will I be the guinea pig?


Originally Posted by bhambulldogWill I be the guinea pig?

Either you or me.