Holbay Eater

K

kiwi_commer

0
Has anyone here driven, or been driven in a Holbay Commer?

See, I have this Rapier lump, and I have these Dellorto's, and I want to build an engine something like a Holbay replica.

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I know the Holbay engine has been put in a Commer before, but has anyone driven such a van and can compare it to a standard van and can comment on the performance?

I've seen what the Holbay engine can do ( http://www.youtube.com/watch?v=BJuYXO0wn4Q ), and the internet tells me that the Holbay is all done by 6,000 rpm, which sounds ideal for a camper. The internet also tells me the Holbay head ] has smaller inlet ports than the standard Hunter/Rapier head to improve slow speed inlet velocity, which let the factory fit a bigger cam while maintaining low end torque. I don't have a Holbay head, but I do have the carbs and I can have my cam re-ground.

What do I tell my cam people so i can get a Holbay-spec cam? I have this information:

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I think the E128 cam is probably too big for a camper, but a Holbay H120 is probably ideal. Will the info in the above pic be enough to tell my cam grinder?

Any info most gratefully received.




Commer in Some go quicker than others. http://www.youtube.com/watch?v=be3T2AcjFN8
 
Corrrrr this looks interesting but wouldn't you loose the low end torque by fitting the Holbay cam with the larger inlet ports of a standard head? I'm no expert on this but you could end up with an engine that's got nothing at low revs - but boy would it go when you booted it:p

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Harvey & Bonnie
 
Im still collecting the bits for a GM Redtop conversion from Tim, no worries of loss of power from anywhere :)

Hasta la supervista baby
 
my Chrysler competitions van is running a full holbay with twin weber 40's. You will need to chop the engine bay slightly to get the carbs in. Some one more computer savvy should be able to link the build thread for you.
It goes like a train to about 60mph and then dies due to the back axle gearing but I can spin the wheels in 3rd.
 
Your best bet is get the cam people to grind your base circle down and get all the lift possible. Holbay cam is too long a duration really, concentrate on torque spread. Lobe centres are too close to give the bottom end you will need, especially if you're using a Rapier head. :)

4650583641_dba2503b41_o.jpg

"You,re only supposed to blow the bloody SLIDING doors off"
Founder of the 6 speed club
 
As the ports on the rapier head are larger, the inlet ports on the manifold wont match the head making a large step which is'nt good for flow. Ive got a holbay marathon engine in my rapier which has been over bored to 1840cc, it has a different cam profile and different size valves in the head. Coltec racing did two different tuning upgrades which were "Rally" and "Marathon" so if you contact them im sure they can point you in the right direction. But be ware when we go for a drive in Riches comps van you need ear defenders with them 40 webbers on full chat! It could do with one of tims 6 speeders bolting to it;)

th_c286f0ee-63c4-4297-a0e1-bed3864c542e_zps27c68fe0.jpg

JON'S AUTOS the garage that comes to you...
[email protected]
www.jonsautos.co.uk
www.facebook.com/jonsautos
 
quote:
Originally posted by steve williams

my Chrysler competitions van is running a full holbay with twin weber 40's. You will need to chop the engine bay slightly to get the carbs in. Some one more computer savvy should be able to link the build thread for you.
It goes like a train to about 60mph and then dies due to the back axle gearing but I can spin the wheels in 3rd.



Aha that's what I wanted to hear, wish I could have a ride in that van. Thanks for the link Panky.

Racer - have you driven a Rapier/Hunter engine with a Holbay spec cam?
 
Yes, but it was a long time ago :I


4650583641_dba2503b41_o.jpg

"You,re only supposed to blow the bloody SLIDING doors off"
Founder of the 6 speed club
 
quote:
Originally posted by Jon

As the ports on the rapier head are larger, the inlet ports on the manifold wont match the head making a large step which is'nt good for flow. Ive got a holbay marathon engine in my rapier which has been over bored to 1840cc, it has a different cam profile and different size valves in the head. Coltec racing did two different tuning upgrades which were "Rally" and "Marathon" so if you contact them im sure they can point you in the right direction. But be ware when we go for a drive in Riches comps van you need ear defenders with them 40 webbers on full chat! It could do with one of tims 6 speeders bolting to it;)

th_c286f0ee-63c4-4297-a0e1-bed3864c542e_zps27c68fe0.jpg

JON'S AUTOS the garage that comes to you...
[email protected]
www.jonsautos.co.uk
www.facebook.com/jonsautos



Yep those Dellorto's will let them selves be known, I'm sure. I wonder if I can jimmy up some sort of airbox to help with the induction roar? Hmmm, the manifold I have was off an Avenger so I don't know if it will fit the 1725, being different engines I assume not. Sounds like I will need some flat top pistons. Anybody know of any that will do the job?
 
The hunter 1500cc ones do the trick I think, speedies sell them as flat top hi comp

http://www.speedyspares.co.uk/ROOTES/HUNTER/hunter%20reportPage2.html

I've got a kent 'rally' cam which is pretty useable at low revs

m_5ab8dd55b2c2c84c5ce92d6090469c78.jpg
 
quote:
Originally posted by Jon

As the ports on the rapier head are larger, the inlet ports on the manifold wont match the head making a large step which is'nt good for flow. Ive got a holbay marathon engine in my rapier which has been over bored to 1840cc, it has a different cam profile and different size valves in the head. Coltec racing did two different tuning upgrades which were "Rally" and "Marathon" so if you contact them im sure they can point you in the right direction. But be ware when we go for a drive in Riches comps van you need ear defenders with them 40 webbers on full chat! It could do with one of tims 6 speeders bolting to it;)

th_c286f0ee-63c4-4297-a0e1-bed3864c542e_zps27c68fe0.jpg

JON'S AUTOS the garage that comes to you...
[email protected]
www.jonsautos.co.uk
www.facebook.com/jonsautos



Been a while on the engine front, but Jon, you must be running a 100 thou-over bore in your Rapier to get 1840 cc right? I bet that car is fun. How thick are the bores on these engines (generally)? I saw someone suggest not to go more than 60 you over, yet the Sunbeam Alpine guys have gone to 1900cc + ?
 
I've see roller tipped rockers with various lift ratios advertised on ebay:p They are expensive though - and in the USA:I

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Founder of the Non-Facebook Club
 
http://forum.commervanfan.co.uk/topic.asp?TOPIC_ID=7887&SearchTerms=liner :)

4650583641_dba2503b41_o.jpg

"You,re only supposed to blow the bloody SLIDING doors off"
Founder of the 6 speed club
 
quote:
Originally posted by commeracer

http://forum.commervanfan.co.uk/topic.asp?TOPIC_ID=7887&SearchTerms=liner :)

4650583641_dba2503b41_o.jpg

"You,re only supposed to blow the bloody SLIDING doors off"
Founder of the 6 speed club



Oh wow. I was thinking of doing that myself (got the spare engine) but don't need to now.:)
 
quote:
Originally posted by Panky

I've see roller tipped rockers with various lift ratios advertised on ebay:p They are expensive though - and in the USA:I

41fa30c8-22ce-43e8-bd12-188475a80292.jpg

Founder of the Non-Facebook Club



Crickey those rockers are a bit pricey. [:0] Look flash though.
 
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