Kristian Jonsson
Donation Time
Is it worth the effort to replace the cast iron manifold from the S V to the earlier tubular manifold!
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Exhaust manifold
- Thread starter Kristian Jonsson
- Start date
Jay Laifman
Donation Time
A few thoughts:
The stock alternator from a SV won't fit in the earlier stock tubular headers, but will with some of the Hitachi ones.
I came across an odd early tubular headers that were slightly larger OD. I believe they were former custom race headers. I liked that they were larger OD, because the Holbay head has larger ports, and stock is too small. I had them Jet Coated and loved them. They sounded great too. But they leaked a little.
So I went back to the stock SV cast manifold, and dremeled out the edges to make the flow better from the larger ports. The sound is a little different. I think it is a little quirky. But it is more like what I always had with my Alpine before the Holbay engine (which was about 20 years worth).
I might try to resurface the headers, re-JetCoat and try again some day.
Finally, that all said, I happen to have a new stainless SV tubular headers that I think has the front tube altered for the alternator to fit. I'd be happy to sell them if you were interested. I'd be even happier if you were in LA and I didn't have to ship them. I don't know that they will leak like the others I have. The bases are much thicker.
The stock alternator from a SV won't fit in the earlier stock tubular headers, but will with some of the Hitachi ones.
I came across an odd early tubular headers that were slightly larger OD. I believe they were former custom race headers. I liked that they were larger OD, because the Holbay head has larger ports, and stock is too small. I had them Jet Coated and loved them. They sounded great too. But they leaked a little.
So I went back to the stock SV cast manifold, and dremeled out the edges to make the flow better from the larger ports. The sound is a little different. I think it is a little quirky. But it is more like what I always had with my Alpine before the Holbay engine (which was about 20 years worth).
I might try to resurface the headers, re-JetCoat and try again some day.
Finally, that all said, I happen to have a new stainless SV tubular headers that I think has the front tube altered for the alternator to fit. I'd be happy to sell them if you were interested. I'd be even happier if you were in LA and I didn't have to ship them. I don't know that they will leak like the others I have. The bases are much thicker.
husky drvr
Platinum Level Sponsor
Jay,
Were you able notice a difference in drivability or power with the headers over the manifold, other than sound?
Jay Laifman
Donation Time
I kind of sort of might have felt it spun a bit faster at the higher RPMs. But without actual dyno, there is no way to tell. It kind of sounded smoother too.
jdoclogan
Platinum Level Sponsor
The Alpine engine's exhaust engineering from the Rootes factory was not the best. The head design restricted the exhaust gas flow. The header design needed to be such that the system created maximum scavenging of the exhaust molecules as they entered the exhaust pipe. Here is the physics and the math on Alpine headers. They need to be 1 1/4" OD and 1" ID. All tubes need to be 20" in length. Ceramic coating will assist to reduce any heat loss through the header. Titanium header wrap will provide for reduced heat loss as well. Heat loss is the neminus of scavenging in an exhaust header. I have made a prototype and the "seat of the pants" dyno indicated a significant increase in power. I'm looking to have a professional version made implementing the use of the mandrel process.
Jay Laifman
Donation Time
I am traveling now. I know that I have the exhaust port size for the stock Alpine versus the H120 at home. When I get back, I'll take a look to see where 1 1/4" falls. It would be interesting to know.
Jay Laifman
Donation Time
Ah. I found an old email of mine where I mentioned the sizes. According to my old email, I measured the stock port at 1.12" and the Holbay port at 1.21". So your 1.25" ideal size would still work for the Alpine. I believe the racing headers that I found and got JetCoated were about 1.25". That I won't know until I'm home. I'll measure the runners too. They were definitely close to 20".
If you are going to make a set I'd be interested in buying one.
If you are going to make a set I'd be interested in buying one.
Jay Laifman
Donation Time
Oh I misread your post. At 1.12" ID, I'm not interested. As I said, the Holbay port is 1.21". So the stock manifold creates a step, which is the worst thing to do.
bernd_st
Bronze Level Sponsor
While coming back to the original question and trying to keep things simple you can or even should replace the SV cast iron affair with aftermarket stainless tubular exhaust headers. I'm running that combo on my SV and it works a treat. No interference with the original Lucas 10AC alternator. Other than improved gas flow the main obstacle is the heat storage of that cast item which will excessively heat up the inlet manifold/twin Strombergs leading to significant power loss...
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Whether it’s worth it or not depends on how “stock” your current motor is and how much a few extra hp is worth. I read a bunch of previous posts on this topic last year when faced with the same dilemma and a stock motor. Several people much smarter then me had commented that the current manifold is a pretty efficient design already, and heat is the enemy as stated above.
I had my exhaust manifold ceramic coated in black (black is the most effective) to retain as much heat inside as possible. I also did the downpipes and the Y to reduce engine bay and footwell heat. Have not road tested yet but very optimistic.
At the same time I had the intake manifold ceramic coated with a version designed to reflect as much heat as possible to keep air coming into the engine as cool as possible . All 4 pieces coated cost less than the set of SS tubular headers!
Jay Laifman
Donation Time
Interesting comment about the cast manifold retaining and distributing more heat than the tubular headers. I always understood the cast manifold to keep the heat flowing further down before dissipation through the pipes.
I did have my pipes ceramic coated. So perhaps the best of both. Though maybe fireroad's ceramic coated cast manifold is even better for heat flow.
Just a possible warning here. Bernd_st's headers do not look like stock factory pipes. His front pipe has a kink in it. The factory ones I've seen are straight down there:
I did have my pipes ceramic coated. So perhaps the best of both. Though maybe fireroad's ceramic coated cast manifold is even better for heat flow.
Just a possible warning here. Bernd_st's headers do not look like stock factory pipes. His front pipe has a kink in it. The factory ones I've seen are straight down there:
RootesRacer
Donation Time
Im gonna guess that Bernds is a 4 branch.
bernd_st
Bronze Level Sponsor
It's a Standard 4 branch Aftermarket S&S manifold. The kink is as it comes -to make room for the generator/alternator. It's different from an original early exhaust manifold which anyway won't fit on a Series V w/o modifications, because of the Zenith inlet manifold joint holder extensions. Furthermore it's made from stainless ( rust proof) with bigger tube diameter = more power. By the way I'm running the same 4 branch on my S1 with twin Zenith's. It does perform extremely well there either - again better than the tubular early style...
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Jay Laifman
Donation Time
Yes, that's my point. Factory stock will not fit. I do have a stainless set, unused, with the extra kink, if anyone wants to buy it. I should put it up on the for sale section.
alpine_64
Donation Time
Jay is that a falcon one bought via Sunbeam specialties?
Kristian Jonsson
Donation Time
If factory don't fit, it can be "adjusted" by making a "kink"?
alpine_64
Donation Time
The kink is not just a small bend.. Needs a different length pipe