Date: Tue, 26 May 1998 07:17:16 -0400 (EDT)
From: Simon Trickett
Subject: Question
Is it ok to use a Comp dizzy with a Sport cam?? does anyone have a sport cam knocking around that is for sale??
Simon Trickett
Date: Tue, 26 May 1998 16:01:19 -0400 (EDT)
From: Nickcleak
Subject: Re: Question
Well it will work but be quite inefficient ... just use the proper one !
The comp one is only suited to competition use , ie rpm over 7000 on road use it's best to stick with the sport one with vacuum advance ..
Nick ...
Date: Wed, 27 May 1998 12:49:09 +0100 (WET DST)
From: Simon Trickett
Subject: RE: Question
Nick,
The reason I need to use the Comp dizzy is that my R17 is cracked. So I am going to run a Sport cam for a while!!! I take it 'inefficient' means bad fuel consumption????? Who cares!!
The comp dizzy is matched to the 0.360" camshafts though out the rev range, I have had no probs running around with a comp dizzy. It was matched to my engine (R17 good mid range power i.e. less than 7Krpm)
The Vacuum advance only makes an engine more fuel efficient at high engine speeds. As far as I can tell apart from the vacuum advance the centrifugal advance is very similar in its curve between the Comp Dizzy and the Sport dizzy. I do not have a sport dizzy to use at the mo you see.
I know you run electronic ignition, do you use a dizzy less system (Volvo?)
see yer
Simon Trickett
Date: Thu, 28 May 1998 07:06:25 +0100 (WET DST)
From: Gary Harding
Subject: RE: Question
Simon,
That all depends. What fuel are you using, what is the compression ratio and what fuel/air ratio are you using? Well, the answer is yes it will work but you will need to set the static timing to a point that pinking is just avoided at all times. Good luck and let me know what that static timing is as I'm about to do the same.
You can to a degree simulate this by blocking off the vacuum advance pipe to the distributor. Not the same but very close.
Gary
Date: Thu, 28 May 1998 14:17:54 -0400 (EDT)
From: Nick Cleak
Subject: Re: Question
Hi Simon ,
> The reason I need to use the Comp dizzy is that my R17 is cracked. So I
> am going to run a Sport cam for a while!!!
well the engine will be like a little sewing machine now .. !
> I take it 'inefficient' means bad fuel consumption????? Who cares!!
Inefficient also means not getting the most energy out of the fuel so less power ..
yes , i ran a Comp distributor on the clan for quite a while , then a sport one and the consumption reduced by 10% ...
Well i care about fuel usage .. i do 300 miles a week at an average of 47 mpg at the moment ! Of course if you are wealthy or don't do a great mileage it doesn't matter , have you got 2 x 40 DCOE carbs ? I got 38 mpg in the Clan with those and R 17 and big valve head .. ..
> The Vacuum advance only makes an engine more fuel efficient at high
> engine speeds.
no , it is load sensitive not speed sensitive to be exact between say 5% throttle open to about 20% throttle open and interpolates between progressivly ...
In other words when you are just cruising along with hardly any throttle opening .... depending on the state of tune depends on when the vac advance works , ie a standard Imp it will not work very often as you will be over half throttle most of the time !
On the other hand a high compression Imp sport spec 930 which i am using , cruises from say 40 mph up to 70 mph on strombergs with hardly any throttle opening ( 18 in Hg . ) so the cruising advance is high ...
> As far as I can tell apart from the vacuum advance the
> centrifugal advance is very similar in its curve between the Comp Dizzy
> and the Sport dizzy. I do not have a sport dizzy to use at the mo you
> see.
i think the max advance on the Comp dist is about 36° @ 6000 rpm . ( + the static advance of course )
yes i can understand Imp sport distributors don't exactly grow on trees these days do they !
>I know you run electronic ignition, do you use a dizzy less system (Volvo?)
No i am using a management system where you can have any degree of advance at any rpm and again there are 8 different throttle positions mapped so quite comprehensive . there is also temperature compensation so that you can modify any part of the curve depending on temperature of the engine , eg advance the timing if the temp goes up over say 100°C to cool it down , or retard slightly overall from cold to warm up quicker etc ...
I have some EXCEL spread sheets which i compiled with details of various advance curves including the comp distributor if you would like me to attach them for you ...
Regards ,, nick ...
Date: Fri, 29 May 1998 05:25:41 +0100 (WET DST)
From: Paul Greville
Subject: Re: Question
Hi fellow Impers,
Can anyone sell me a distributor suitable for my IMP. The engine is 998cc, twin 40 Webers, R22 cam and big valve head.
Many thanks,
Paul Greville
(Western Australia)
Date: Fri, 29 May 1998 06:46:22 +0100 (WET DST)
From: ABryson@sperry-sun.com
Subject: Re[2]: Question
I have used the Special Tuning Comp distributer with no vacume advance. Timing is set for max advance of between 38-42 deg at 4000 RPM. As you are using an R22 there is not much power below 4000, therefore in the rev range you are running the distributer will be full advanced.
Hope this helps.
Andy
PS. Do you know what happened to the Blue Race Imp which Brian Taylor used to own. I rebuilt the engine & gearbox before I moved to Jakarta in 1994.
Date: Fri, 29 May 1998 03:48:57 -0400 (EDT)
From: Darcy Maddock
Subject: Re: Question
Hi Paul, I strongly recommend contacting Brian Bradshaw in New Zealand. His phone number is (03) 348 7979. Of course you dial the international bits first. He built a comp. dizzie for my 930cc, special head and R20 cam. I have nothing but good to say about his work. All you need to do is give him your exact specs. and he will do the rest. Ask him for a price list as well. Good stuff like Kevlar bonnets and boots and lots of others right up to full comp. parts. All the best Darcy.
Date: Fri, 29 May 1998 11:59:29 +0100 (WET DST)
From: PIETER.POSTHUMA@nlrtm.ponl.com
Subject: RE(2): Question
Nick,
For some time I am looking at engine improvements, fuel injection, etc. I am interested in the set-up on your car. What exactly have you installed ?
Regards
Pieter