26 replies to this topic

[lawrie124]

Hi.

Hopefully a simple question.

It says 8 degrees static, and I have confirmed with them that is 8 degrees at idle with vac advance removed (and blocked off at carb).

The thing is that at full revs it advances to about 48 degrees.

Surely that is way too advanced?

We usually set our cars at 4000rpm at about 38 degrees so 48 sounds dangerous to me?

Any suggestions and advice much appreciated.

Mike

[Spider]

The Aldon yellow should give only 24 Degrees, measured at the Crank (12 on the Distributor).

 

Given you're seeing 48 degrees, which is double the 24 degrees that the Distributor should be, with respect, I suspect you maybe measuring it incorrectly.

 

How are you measuring it?

[lawrie124]

Timing light. And double checked with another timing light.

[GraemeC]

Does sound very wrong - don't thinkt Hey even do 20 degree bob weights
I wonder if the baseplate is moving?

[Spider]

Something is way out of kilter then.  Depending on the head fitted, generally total advance should only be around 28 - 32 degrees.

 

If you bought it new, send it back with an explanation and ask them to kindly check it and rectify or replace it. If you bought it used, anyone could have done anything to it.

[Earwax]

I have seen another yellow that was way  out of spec- in the same dangerous zone..... .  sent back and replaced . Mike even 38 at 4000 seems a bit much for me.  Again i have seen a dyno operator set timing for a mini at 38 saying it gave best power and didn't hear pinging ( race engine).... BUT lots and lots of experienced mini people recommend 30-32 total......( talk to moke spider about the curve before what as these can also be not ideal for a 1275)

[nicklouse]

Some engines do seem to run with stupid advance as people who don't know just don't worry.

One car I looked after (well I did after this) the people looking after it a shed the engine builder what the timing should be. The engine builder said 24 degrees at 1500 rpm. The guys said back 40 degrees at 1500 and all was agreed.

They said it went but had no real go.

I did not know about this until we were at a sprint.

Owner did not really believe me so would only allow me to reduce the timing by 1/2. 20 at 1500 rather than 14 at 1500.

Let's just say I was I charge of the engine from then. And had it set correctly.

You need to understand what is in front of you rather than what you normally work on.

[lawrie124]

Ok. Thanks all. I will have one last play tomorrow then send it back if faulty.

Cheers

Mike

[Midas Mk1]

When I was at the dyno recently, the operator commented that my yellow wasn'y acting like a normal yellow in terms of bob weights, and he commented he'd seen alot of aldon yellows on the rollers with variances..

Starting to think this is the reason behind my car just refusing to run, no matter what the timings at.

Edited by Midas Mk1, 02 August 2016 - 07:39 AM.

[Spider]

Oh dear,,,, I hope that Aldon aren't going the way of so many others,,,,

[Dusky]

Intresting. I set my timing at 8 degrees at 1000 rpm a few months ago and found it at 25 yesterday. I wonder if there s a faulty batch of dizzies?

[ACDodd]

Simple fix, send them back. If the supplier does not know there may be a problem, nothing changes.

Ac

[lawrie124]

Simple fix, send them back. If the supplier does not know there may be a problem, nothing changes.

Ac

 

can't disagree with that. Just wanted to check I wasn't being a complete idiot with my timing light.

 

I will give them a call.

[lawrie124]

Spoke to Aldon.

 

a very helpful chap said set timing to 8 degrees with vac off, and block off vac on carb (HS4) and I will be fine.

 

it's a 998 with a 266 cam.

 

I think the implication is that I don't need to be using the vac advance, and it should spin up to (I think he said) 22 degrees, or was it 32 degrees? sorry, can't remember..

 

seems a bit strange that it's a dizzy with a vac advance unit, but hey ho will give it a try and see what it advances to at say 4,000rpm

[nicklouse]

you did tell him there is a vac advance unit on it didn't you.

 

as the base plate does need locking in place or it will move as the diaphragm vibrates as it no longer has "load" on it.