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Leave the Holbay set-up!

Kristian Jonsson

Kristian Jonsson

Donation Time
There are a lot of question about how to make the engine work without the Holbay head but just the Holbay camshaft. Why not use a standard head, preferably a Hunter (Arrow), do some combustion head modifying, and buy an fast road/rallying (or similar) camshaft from one if the clever camshaft company you have in US. Just leave that Holbay camshaft who is obviously very specialized for just the detuned Holbay engine.
I have an new Holbay cam on the shelf (Anyone interested?) but I don't think I am going to use it.

What camshaft company's in US can be recommended if I want to order one?
 
alpine_64

alpine_64

Donation Time
Kristian,

Depends which holbay cam you have... H120.. Marathon... E128.

There are several cam companies in the UK that offer grinds for the cars KENT cams, coltec (ex- holbay) alpine racing specialist like cottee power and mass racing developments, crane cams etc.

Delta in the usa have a good rep on the forum ( and are obviously local to stateside owners)

Be worth speaking to the UK guys if you are in europe... Also a lot more guys in UK race alpines.
 
R

RootesRacer

Donation Time
Kristian Jonsson said:
There are a lot of question about how to make the engine work without the Holbay head but just the Holbay camshaft. Why not use a standard head, preferably a Hunter (Arrow), do some combustion head modifying, and buy an fast road/rallying (or similar) camshaft from one if the clever camshaft company you have in US. Just leave that Holbay camshaft who is obviously very specialized for just the detuned Holbay engine.
I have an new Holbay cam on the shelf (Anyone interested?) but I don't think I am going to use it.

What camshaft company's in US can be recommended if I want to order one?
Click to expand...
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.
 
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...

Come to think about it, a while ago I did put an engine together with a used Holbay cam (H120 probably), modified head, and a DCD 28/32. It was difficult to start, had no low revs whatsoever, did sing above 3000 rpm. I didn't continue with any tuning . I did take the engine out of the car, it also had a unreasonable low oil pressure and I was going to move to anther part in the country. The engine is sitting in my garage. Can we say it is an difficult case and I should put in another camshaft? Maybe the Harrington Le Mans cam? I just have the change the oilpump drive.
 
Kristian Jonsson

Kristian Jonsson

Donation Time
Just for fun I did look at the proposed DCOE jetting for the Holbay engine, to compare with the 3 pairs of DCOE I have. They are all different depending on where I am looking. The jetting on my DCOE are between themselves also different.
 
alpine_64

alpine_64

Donation Time
The holbay jets are very lean and the holbay dcoe different ventialtion to stock. If you use stock holbay jets on an alpine it will run poorly amd lean... The holbay motors have a big airbox and filter... If thr hoses split on the filter housing thw cars run super lean...
Your dcoe should have matching jets per pair...AND matching progression holes... Or they will never run right
 
Jay Laifman

Jay Laifman

Donation Time
Dan, I'm using the stock H120 cam, H120 head, and now H120 Webers. I was using 151s. The two things I've noticed are (1) with the 151s, I'd get a spit out the carbs at odd times. That's completely gone. I believe those long tubes addressed that. (2) At light throttle, I mean, cruising along with the lightest of touch - so probably at the transition holes, it flutters a little. I've tried different idle jets and idle mixtures with the screws and have minimized it, but not gotten it to go away.
 
alpine_64

alpine_64

Donation Time
Jay... What jets are you running in the motor... The factory holbay jets are VERY lean and dont work in an alpine.. Also the factory holbay motor had the big airbox/ filter and if removed the cars ran like.....
You have a holbay head.. And iirc you bored the intakes out to match an alpine manifold.. Is it running flat tops and a holbay spec distributor.. If not assume you mains are now in the 120-130 range?
 
Jay Laifman

Jay Laifman

Donation Time
Correct, the intakes were bored out. Slightly dished, not flat.
120 mains, F16 emulsion tubes, 140 air correction (probably could go leaner, don't have just now), 35 pump jet, and 50F9 idles (also have done 55F8 idles - ok; 45F9 - not good).

And FYI, this is what I had with the 151s, that didn't have the light throttle flutter:
115 main, F11 emulsion tubes, 200 air correction, 45 pump jet and 55F8 idle jets
 
spmdr

spmdr

Diamond Level Sponsor
Jay, don't you have the SS "Holbay" cam?

That's not the same as the original H120 cam.

DW
 
spmdr

spmdr

Diamond Level Sponsor
Ok, I'm confused... When did you have the Sunbeam Specialties cam in the engine?

Didn't the SS cams specs come from you?

DW
 
Jay Laifman

Jay Laifman

Donation Time
I purchased an NOS H120 cam in a Chrysler box from SS in 1990, and it was up and running before 1993. I don't recall who I might have provided the specs to. I do remember the guy who helped me build the engine (Lotus John Kuba, the VARA tech inspector) said it was "an odd" cam. Ha! I can try to find what specs I have on it now.
 
spmdr

spmdr

Diamond Level Sponsor
Jay, OK, so you DID get the cam from SS. I thought/remember (weak) you stating that on several occasions.

I just don't remember SS selling an Original spec H120 cam.

I thought SS only sold a revised "Holbay" cam.

I thought SS sold a Stock cam and then only could get the "Holbay" cam, out of the UK.

I also recall SS/Rick didn't have the specs of that "Holbay" cam and you came up with the specs.

...my weak memory thing.

But, then again, maybe Rick didn't really know what he was selling, so you MAY have an original spec H120 cam.

DW
 
Last edited:
Jay Laifman

Jay Laifman

Donation Time
I am out of town this week. When I get back home, I'll look up what I have on the spec. The thing is that this cam was a one off for Rick. When I got the H120 head from him, he did not have the cam. A year or so later, he contacted me and said he got one H120 cam from the UK on its way in a container. So it could be different from what he might have had before or after. As I said, all I recall now is that it was sealed in its original Chrysler box, and marked "H120 cam" on the outside.
 
Jay Laifman

Jay Laifman

Donation Time
Also, as noted above, my pistons are not flat topped. They are slightly dished. I was not part of that process. I don't know if a mistake was made or there were other details. I believe that the mechanic did cc the head. He also designed the pistons for my 55 over size to fit his rings. I recall a conversation with him about compression numbers he was coming up with, and the need to lower it a little.

At this point, it could have been a mistake he made. Or he could have thought a lower compression made sense. All I know is that it runs beautifully, and has done so for almost 30 years now. So if it has been reliable because the compression was lower, then I'm ok with it. I don't have it on the track. So I have no need to wring out every bit of HP.
 
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