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Leave the Holbay set-up!

Kristian Jonsson

Kristian Jonsson

Donation Time
RootesRacer said:
A true H120 cam with a stock head and anything other than DCOE webers will be next to impossible to tune.

H120 is a package, not a component.
Click to expand...

But what is so special with this profile? Can it be re-profiled (to H128 for instance) to make it more usable for other configurations? I understand that Holbay put a lot of effort to make the car and it's engine to behave like a standard family car.
 
spmdr

spmdr

Diamond Level Sponsor
The lobe centers are the big difference with the H120 cam, 103 vs 110 ( sV ).

So you get more overlap between the intake and exhaust valves being open at the same time.

...makes for harder starting and less low RPM torque.

I guess you could call it a cheater way to get more valve overlap WITHOUT all the cam duration that you would usually have with big valve overlap.

I have a couple H120 cams I'm wondering what to do with also...

I guess I NEED to see how an H120 runs before I decide.
 
spmdr

spmdr

Diamond Level Sponsor
I have seen few Holbay heads, but I thought I remember a smaller Exhaust port.

And this head flow chart would tend to confirm it.

BUT, I would add, not seen a Holbay head in over 25 years....

holbay[1].jpeg
 
Jay Laifman

Jay Laifman

Donation Time
I can assure you 100%. I even ported out the SV exhaust manifold to match - at least at the initial opening. I looked at earlier headers. But they too were too small. It wasn’t until I got a junked Alpine with what appeared to be racing headers in it, that measured larger that I swapped those in.

Mine was NOS from Rick in 1988. I have no idea if it represents all H120 heads.
 
alpine_64

alpine_64

Donation Time
The holbay heads had smaller intake ports and thats why the holbay manifold tapers quite a bit in section from carb to head.

Iirc they did this and calmed the cam in development to help low end torque and drivability as the test motors were more powerful but peaky
 
Last edited:
Jay Laifman

Jay Laifman

Donation Time
spmdr

spmdr

Diamond Level Sponsor
Just looking for all the Alpine Hop-up info I can find...

I assume the Original H120 cam would make the engine more Peaky.

BUT, considering all the other mods, no telling until it's tried.

I'm guessing, performance wise, you may be as good as it gets, for a street car, ....and not a stroker, etc.

BTW, still wondering what header you have?

Also, and I think I made this threat before, I need to stop by and get a ride in ....oh ya, my old car...

... I think for the first time.

DW
 
jdoclogan

jdoclogan

Platinum Level Sponsor
Based on my performance experience with the KB grind from Delta Camshafts in Tacoma, Washington for my Promotional Harrington Le mans. As well as, the research I have done and conversations with DW. I just packaged up two sets of 1592 cams and rod assemblies to be sent to Delta Camshafts today. Ken, at Delta assured me I would get the exact specs from Delta Camshafts 2002 Performance report on KB grind. This includes the intake and exhaust Lobe Center line of 106.0 and 106.4 respectively.
 
Jay Laifman

Jay Laifman

Donation Time
spmdr said:
BTW, still wondering what header you have?

Also, and I think I made this threat before, I need to stop by and get a ride in ....oh ya, my old car...

... I think for the first time.

DW
Click to expand...

Ha! True, your old car. My rear self-adjusting brakes stopped adjusting well, and bind up. I gave up and now have what I need to swap back to manual adjusting or discs. But I don't know when I will get to it. I will let you know when it is done, so you can feel free to drop by when you are out and about in the area.

As to the headers, right now I'm running the cast SV manifold, that I opened up at the openings, to smooth the transition for the exhaust to flow, rather than have a ledge of the manifold lip. The headers I have were just sitting in a shell of a SIV or V I got once. On hindsight, it was probably an old race car and I should never have given it up. But it went to someone with needs for a Tiger. It looks just like an early tri-y system, but the tubes were larger than stock - matching the Holbay size. I got them jet coated and they sound great and work great. They just are not perfectly flat, so I blow the exhaust gaskets. That's why I went back to the cast manifold.
 
Kristian Jonsson

Kristian Jonsson

Donation Time
Back again to this newer ending story.
What shall I do with my Holbay 120 camshaft. The Holbay head has probably to much pitting or corrosion problems, and I have learned by reading hundreds of treads in this matter that I can't use my standard heads. I was going to sell it and instead order a camshaft from some of the cam produsers that can grind a "little more then standard cam"
But I hesitate. Can't there be some set-up that is reasonable.
 
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