Recurved distributor

[Daz1968]

Not sure if anyone can help as I am at a total loss now

I have a 998 Cooper with big valve head and twin h4 carbs similar to downton spec, upon initial start on original Cooper distributor it ran fine other than a small bit of pre ignition on light throttle, I have trusted h and h to recurve it and it’s an absolute nightmare, initially the drive was installed upside down and the timing is still not right has anyone else used them, as I feel they have wrecked an original Cooper distributor and really don’t see point in taking it back to them as I have no confidence in them getting it anywhere near correct,
I have set it as recommended and now adjusted to 5deg btdc as it seems a little better.

It’s the only job I trusted to someone else and I regret it

Is my best bet to get an electronic one it is there anyone else who knows what they are doing

Thanks

[johnv]

Don't worry! Have a chat with Martin at http://www.distributordoctor.com/
he'll sort it out

[111Robin]

Do you have a dial back timing light ?. Are you setting it to 5 degrees static ?, this is just a starting point to allow it to run. It's easier to understand what's happening if you can measure the advance at 1000, 2000 and 3000rpm and also at what rpm it stops advancing. Forget about the advance at idle, set it to 32 degrees advance at the rpm it stops advancing at then see how it runs through the rev range.

[whistler]

I had a 45 distributor modified by them (as recommended by Keith Calver) and found them to be excellent. Maybe you should talk to them.

[Daz1968]

Thanks,

Maybe I should take it back and give them a second chance, I am checking timing with a light at idle not tried any higher rpm settings,
Will take it out for a run first so can give them information regards performance, it felt very flat last time. The original distributor curve felt better.

Just been very frustrating.

Hopefully can get it sorted

[111Robin]

Thanks,

Maybe I should take it back and give them a second chance, I am checking timing with a light at idle not tried any higher rpm settings,
Will take it out for a run first so can give them information regards performance, it felt very flat last time. The original distributor curve felt better.

Just been very frustrating.

Hopefully can get it sorted

Timing at idle isn't relevant though. Run it up through the range and note down the advance. At least then you can give them actual figures. It might be topping out too soon or not providing enough advance higher up. Did they provide you with a plot of the advance curve to compare with and did they tell you to set it to 5 degrees at idle ?.

[Daz1968]

I have no curve graph but I think they said the advance was 22 deg mechanical advance and maxed out at 2.5k distributor revs.
I was told to set it to 10 btdc at idle which I have tried but it pinks more than with the original one, then if I retard to prevent pinking the car feels flat, full throttle appears fine it’s just part throttle.
Mixture is bang on with a colortune and plugs have been a good colour after running so can’t think it’s that.
Temperature is ok now I have fitted a nos sender, the modern repro one was quite a way out.
I just can’t seem to get a good running advance,
Unfortunately my timing light isn’t adjustable but can add some markings on pulley to aid, I presume the circumference of pulley can be divided by 36 to give me some 10 deg intervals.

I am using super unleaded with Castrol valve master plus additive and compression 9.8:1

Pinking isn’t bad though and clears when throttle opened wider.

I was going to try plugging the vacuum advance see if it stops it, that maybe next step

[111Robin]

Ok, so that's maximum advance at 5000rpm engine speed. Do you intend to run it flat out at 5000rpm a lot ?. They are giving you 12 degrees mechanical advance to work with hence setting it at 10 static, to give you 32 all in. If you're retarding it to 5 static you will only be getting 17 degrees all in at 5000rpm, so you won't be getting enough advance anywhere through the range hence the lack of power. I hope I'm getting this correct but it does sound like you're not getting enough advance soon enough unless you're driving flat out all of the time which is unlikely.