Hi all
Just had my car on a dyno to have the engine run in.
Had some problems and I could do with some advice.
Spark Plugs: NGK bp6es
Dist: Hitachi D4R85-16
Engine: A+ 1275 block rebored to 094, MOWOG 12G940 head
Carby: HS6 SU (I had the carby completely rebuilt in dandenong, melbourne. This included new needle supposedly matched to engine 1360cc etc etc.) on heated minisport alloy inlet.
Fuel: premium unleaded

So the car was put on the dyno after warming it up to normal operating temp.
(I had previously sought advice on the forum re running an engine in on the dyno)
Analyzer was placed in the exhaust.
First problem, analyzer was reading high (too lean I was told) so off with the damper housing, the needle removed and a different needle put in. Still too lean and lots of detonation.
So what the guy does is after each of a long series of runs removing the damper
housing and filing the back of the needle (at approx the correct part of the needle, determined by sitting a rod in the damper pot instead of the damper as a guide to the part of the needle sitting in the jet needing filing) adjusts the needle by filing to achieve the correct mix at differing loads/rpm.

Ignition advance was retarded to try to alleviate detonation (which does not occur during road use/test) but still occurs on the dyno under heavy load.
In the wash up the chap tells me BHP approx 80 and maybe look at changing plugs to a cooler running plug to alleviate detonation, doesnt want to retard timing any further.

To begin with cant say I'm too impressed with the carby specialists needle selection forcing the need for the replacement of and subsequent filing of the needle, however.

What are your thoughts on my dyno experience?

1. Should I try to get the correct needle or accept the modified needle?

2. The detonation under heavy load on the dyno worries me, should I be worried and what sort of corrective measures do you advise?

Thanks for your replies in advance.
Wish the doc lived in my neck of the woods!

This is because the pulsar dissy is the wrong curve. It is far too advanced for a mini. the one you hve is 18* and it should be more like 10*. Either get the pulsar one modded (call graham russel who will do it for you for $30 Ausmini special price) OR go back to your old dissy.

Discussed here:

http://www.ausmini.com/forums/viewtopic.php?

and here

http://www.ausmini.com/forums/viewtopic ... &start=240

don't run it as is, it will ruin your engine if you keep running it too far advanced for too long

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Lillee - 1969 Morris Mini K

Can you please supply contact details for graham eg email, phone etc. Thanks

Graham's phone- (02) 9630 2195.

<edit> in the meantime put a timing light on, rev motor to ~4000 rpm and check MAX advance (with vacuum advance disconnected)- make sure it's then firing at about 30* BTDC.
If so you won't hurt it in the meantime.
Reconnect the vac line.
Graham's mods to the dizzy will improve low and midrange torque.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

we gotta stop people from putting these pulsar dizzy's in

I am actually impressed with your dyno result. It sounds like a clued in dyno bloke.
I also have no bad things to say about the carby specialist as picking the correct needle out of thin air is never ever going to work. They will get close but it will never be spot on.

i am damned impressed you have found a dyno guy who is willing to try and file your needle to get it right, that is a skill I haven't seen for a long time most dyno people these days are only good for shootouts and bugger all else, sounds like a winner to me

Jon

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Roundies and Clubbies(except vans) are both ugly that is why I have Midas and a van
1293 Mini Midas Bronze,1275 Clubman van