4 replies to this topic

[Diag]

Hello all,

 

First post from me, hope it’s in the right place.

 

I have built a few A series in the distant past but am far from up to speed on what works with what. I am trying to help out a friend who has tried and failed miserably to build a quick engine. He went wild with his credit card buying parts and paid a few local mechanics to bolt it all together. I have inherited the failed parts list and am trying to put something together for him without going over the top on budget. He has blown a huge lump of money on this already.

 

This engine is for a show car. He wants to be able to travel to shows, keeping up with traffic, and not being hassled by trucks on the motorway. He wants a decent bit of acceleration and to be able to travel at the speed limit without revving the nuts off it. Mid range power is more important. It also needs to pass an emission test.  

 

I am looking for suggestions based on what I have to hand.

 

The block I have to work with is an A plus 1275 that is bored to 20 over.

The head is 12G940 that he says is “stage 3”. It is certainly ported and the chamber volume is 21.5 ML but the chamber shape looks pretty standard to me. .

He had a 285cam but that is damaged so I need to buy a cam. Not sure which one?

He was running a standard duplex and I think a new vernier duplex is the way to go.

He has twin 1 ½ SU’s. I wonder if it is over carb’d? Maybe a single SU would be better for low to mid range power?

It has an LCB and what looks like an RC40 or similar system.

He has a recently rebuild box with a 2.7 diff running 10 inch wheels. I am wondering if we should go for a shorter diff? Lots of mid range with the low diff might work for cruise without lots of revs? I am unsure if the relatively basic spec of the engine will pull that diff well enough.

I am thinking about 10 to 1 CR. We have 98 octane fuel here.

 

He would like it to idle well and i expect it should with a relatively mild Cam.

 

Sorry for the length of the post but I thought I should add as much info as possible.

 

Thoughts on the above would be more than welcome.

 

thanks

 

 

[danllew]

In terms of a good well rounded cam, I think Swiftune SW5 is a decent torquey cam.

[panky]

I'm running a very similar engine (nice head, allegedly stg 3) in my '91 Cooper but have an MG Metro cam and single HIF44 with a BDL needle and K&N element in a drilled airbox. I did fit vernier timing gear to dial in the cam. The car goes well, very torquey, and will cruise at 70 pulling 3500 rpm with the 3.44:1 final drive. Not had it on a rolling road but hope to soon to fine tune.

[Diag]

I have read a bit about the SW5 and I think it may be the cam to go for. 

panky, 12 inch wheels? 10 inch on this would make a difference. With the setup I have it should be geared for 70mph at about 3200rpm. 

[panky]

I have12" wheels, but 10's with a high profile tyre will be very similar.

Edited by panky, 26 October 2017 - 07:30 PM.