Autotest cam

[wantafaster1]

Can anybody recommend an autotest cam, or better a good engine spec? I'm kind of hoping nobody says SW5, too obvious. Are there good alternatives?

[Chalkie]

Piper 276?

but sw5 always a good upgrade

[davidnutland]

Std 's', metro mg, 997 cooper.

[PaulH]

the only cam to use is MED HT. Time it at 108 with Standard pressed steel rockers or 106 with 1.3:1 roller tips. works best on a 1380/1430. aldon yellow timed max advance 28deg. compression circa 10:1 stage 2/3 head. If you plan on doing fast test look at fully lightened and balanced bottom end with the heaviest flywheel you can get your hands on
cheers,
Paul

[In the shed]

Hmmm. I wonder about an MG Metro cam with 1.5 rockers on a 1380. 11:1CR. 3.7FD with a 2.54 first. Possibly fed through a HIF44 of all things.

[wantafaster1]

Think I have to give this metro cam a go, besides here a few other folk have personally recommended them to me. Sadly I have an MG engine stashed away but I think the last owner put a 286 in it.

Thanks for any suggestions so far. What about piper 255 or kent 256?

Then again, the irish are damned good at autotesting so have to take into account Pauls recommendations. By the way its for a full weight car, not a light special. Not currently got the bits for a 1430 but yes I see the point of having one as far as torque goes.

[mk1]

As an alternative the Minispares HiTorque jobbs seems to work well.

[PaulH]

I wont harp on here. I will advise you to steer clear of the MG metro cam. its is not a torque cam. MED HT, Mini spares HiTorque and if all elce fails a std 998 A+ cam timed in at 110 Full lift.

1.5 roller rockers are you enemy, so is anything that makes the engine operate lake anything other than an 850 at idle.

and you are right we have autotesting down to a fine art here. If your car is full Weight you need the mildest engine you can achieve to have any hope of getting slow speed response. Any thing elce will simply brake traction constantly and you will be sitting there as the seconds tick by.

are you planning to run a 2 speed box in this ??

[wantafaster1]

Thanks for the reply Paul.
No actually, no 2 speed box, I want to do Targa rallies and multi venue autotest events so its road legal and maybe heavier than ideal. Planning to bore plus 60, near standard S head, use an Hif 44 on an MG inlet. Hopefully a standard pre a plus box if I can find one.
I'm sure you have seen the way the above sort of events have exploded on our side of the water recently! You will know the kind of lanes rallies I mean too. Don't know anyone involved in this and would hate to be mis informed, without wishing to seem paranoid! Would like to get something pretty close straight away and then it will be up to me to steer the damn thing.

[PaulH]

Thats a hell of a lot of different disciplines, Autotesting is basically an completely different discipline to every other Trials driving discipline. Here in Ireland we normally in fact nearly everyone I know is running two cars now. one for pure autotesting and the other for tials drives.

trials driving is a lot more forgiving on the type of motor you run any of the above specs would work for a trials car. but the spec i talk about would be a motor that would compete well in an autotest.

[mk1]

PaulH, I would be interested to hear why you don't like the MG Metro cam.

[PaulH]

Hi Mark,
I have tried the metro cam several times and it just wont work. The Metro cam is an old idea from ST. its one of these weird cams with a 252 inlet and a 268 exhaust duration it is ground of a split LCA. inlet 110 and exhaust 105. In theory it should perform well. in practice it does not however. From a lot of study on wave dynamics and gas dynamics My self and some other very knowledgeable people have come to a similar conclusion the A series 5 port motor does not like a cam witch has a long exhaust duration and a short inlet. these motors are very much starved of gas flow on the inlet side as a rule and this gets worse the slower the motor spins (generally) to achieve maximum torque in a A series low down you need a short fast cam cycle on the inlet and the exhaust even less. This will achieve a higher gas velocity and greater cylinder filling which in short will yelled more power. This is what the HT cams try to achieve. big lift, fast valve speeds low durations. The Metro profile is. slow on valve speed, short on lift and long on duration. its all works better when higher engine speeds are achieved and this cam can start to work but generally it is not suited to the NA application. Now days there is much much better profiles available for relatively small money. This cam however is a great starter profile for beginner turbo motors as the long exhaust gets a turbo moving quicker and the slow valve speeds are vary favourable for cylinder filling in a positive pressure environment.

hope that helps mark,
cheers,
Paul.

[mk1]

Thanks PaulH, very interesting.

[wantafaster1]

Sorry for causing confusion, thought that the like of Eamonn Byrne or the Fergusons would have been using an autotest engine tune in the trials car. Ignore the autotest bit then!
Every day is a school day! Thanks for your time Paul

[PaulH]

No problem lads always glad to help. Eamonn does run a similar spec to an Autotest engine in his trials car but it is much less tame and would be closer to a fast road spec than an auto test spec. Norman could have anything in his car, God only knows. normally they run a sort of 1430/1460 fast road spec tho. He tends to be a bit secretive about what he is running who can blame him he has a winning formula.

[wantafaster1]

Are you related to Dave Hickey, bikes?

[PaulH]

My father is David Hickey, but hes not a biker

[wantafaster1]

A chap I know Paddy Hoey used to mention Dave Hickey to me, maybe he did some work on classic race engines or something. Quite a while ago now.

[PaulH]

Hmm thats interesting I do know a Few Hoey's who are mini heads unless he meant me and just got the name confused and I some times use my full name Paul David Hickey. its a small world