trigger wheel pulleys
Turbo Mini Forums

i have seen (trigger wheels) sell a Aseries specific trigger wheel (tophat style) just wondering if any one has one fitted? also does anyone have one fitted with the jonspeed bottom pulley?

also as my bottom pulley is alloy with no dampening what could i do to counter act this? i have spoken to jonspeed and they say that there is nothing wrong with the pulley not having one

Do you mean the bolt on ones? I have one.

sounds like a typical answer from that bunch

If you run without a torsional damper on a 1275 you are taking a risk.

Read Vizard about where the natural frequency of vibration for the 1275 crank is.

I personally doubt the risk is as high as some say but then again, would Leyland/Rover have paid all that extra money if they thought there was no risk ???

Schrödinger's cat - so which one am I ???

My thoughts are as follows, use an mpi pulley with its damper, and get carl to make you a new supercharger pulley. then use something like the specialist components trigger wheel that bolts on top of the existing pulley.

What you would do about the alternator is another issue entirely though! how is it at the moment?

Feel free to shoot me down:)

Edited by minimole23 on 29th Oct, 2010.

i dont really want to buy another pulley,
(miniole23)

what are the risk of running without rod as i am not at home to get to my vizard book (rod s)

another problem i have had is with the jonspeed bottom pulley there is no way of using a lock tab, so i have had to use some locktight which i am not entirely happy about

what i was hoping to do is get the top hat style trigger wheel and use a rubber spacer to seperate the pulley from the wheel to stop vibration there but as above this isnt overcoming the problem that there isnt a damper in the pulley

The problem you might find is having the supercharger bottom pulley and trigger wheel fouls the radiator, have you accomodated for this?

i still do have room between the bracket and the pulley not to much though

If you do not rev your engine above 5700 rpm then in theory you should not need a damper, I think vizard states that the damaging harmonic frequencies occur at 5750 and 6200 rpm, though the resonance is pushed higher up the rev range by the addition of lightweight flywheels and the like. Therefore if you are not caning it all the time you may get away with it, however if you do cane it a lot the fatigue life of the crank will more then likely be reduced, as well as other things.

If the engine does not do much track work, or recieve a pasting much, you will probably get away with it, not all that many people seem to have broken cranks. Personally I would like to think my engine has been endowed with the best chance of holding together so would not run without one.

Best read the yellow bible to be honest as what I've written is probably crap, but you get the idea!

Edit: I'm assuming you have a 1275 engine

Edited by minimole23 on 30th Oct, 2010.

Anyone ever added the damper to a 998? or know the effects.
I wanna do that to give me a trigger wheel.

Haven't got the yellow bible with me to see if it's mentioned.

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

late A+ 998s were fitted fith dampers from the factory.

late A+ 998s were fitted fith dampers from the factory.

I run a damper on my 998... the outside has been machined to take the SC belt. and my trigger wheel bolts between the pulley and the timing cover...

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

but then I dont run an eaton

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!