building an engine but cant find answers :)

[Machi san]

Hi everyone.

I have recently got hold of a prefacelift k10.

Iam going to be building an engine for it very soon. I will be getting the head worked slightly, will get 3 angle job and small amout of work done on the ports. Whilst searching i found a figure of how much to skim to bring the CR up to a decent level. i cannot find this figure now and cannot remember it either. anyone know off of the top of theyre head?

also i was planning on using ma12 pistons or ma12 overbore pistons but i cant find any info on piston dimensions and whether the block can take the extra diameter. anyone shed any light please?


lastly i have a set of old gsxr 750 carbs that i intend to use. have people that have carried out bike car s conversions got any feedback they can give on. whether itll run well enough to get me too the rolling road?

thanks peeps
kev

 

[superls]

you will struggle to find much info on ma tuning, purely as not many people do it, if you have the head off it would be easier for you to work out how much to skim off, if using ma12 pistons use an ma12 block, and there isnt much room for an over bore, as essentially the ma12 is an bored up ma10.

the bore of the ma12 is easily found, it tells you in the haynes and also on wikipedia, without me searching, i think the bore is 71mm and the stroke is 78mm

i used a set of cbr600 carbs on my ma12, it ran fine with the only tuning being balancing the carbs, ran for something like 6 months no trouble what so ever, they were by no means perfect but more than driveable for every day use.

 

[Machi san]

you will struggle to find much info on ma tuning, purely as not many people do it, if you have the head off it would be easier for you to work out how much to skim off, if using ma12 pistons use an ma12 block, and there isnt much room for an over bore, as essentially the ma12 is an bored up ma10.

the bore of the ma12 is easily found, it tells you in the haynes and also on wikipedia, without me searching, i think the bore is 71mm and the stroke is 78mm

i used a set of cbr600 carbs on my ma12, it ran fine with the only tuning being balancing the carbs, ran for something like 6 months no trouble what so ever, they were by no means perfect but more than driveable for every day use.

Thanks thats some great info

I was more concerned about whether the deck heights would match and whether there was enough meat for an overbore. So with that answered would you know whether i can fit an ma10 crank into an ma12 block and adjust the deck height to suit, also use ma10 cambelt to overcome the adjustment in deck height.

I want a short stroke motor because i like revs and not keen on lazy engines. Plus i intend to keep 4 speed for lower weight.

I read that cams are available for 70quid, is that a piper cam or a privateer cam?

Thanks again
Kev

 

[superls]

id assume the ma10 crank will fir the ma12 block, but the ma12 block is physically taller than the ma10 one so custom con-rods would be needed, and then you would need an ma12 timing belt.

i doubt there will be alot of difference in the 4 and 5 speed weight to be honest.

i dont know about cams i never got around to getting one, i just ended up fitting a cg engine out of a k11 micra, theres a place in birmingham that will regrind cams for £80 if i remember correctly.

 

[Machi san]

Yeah i think thats supersprint in birmingham. They are good i think

RE. block height, i would just mill the top of the block to get the height right. will be about 10mm give or take a little.

cheers matey
kev

 

[Machi san]

Yeah i think thats supersprint in birmingham. They are good i think

RE. block height, i would just mill the top of the block to get the height right. will be about 10mm give or take a little.

cheers matey
kev

 

[superls]

I dont know how suited the block yould be to just milling 10mm off the top, not sure what effect that would have, sure worth a go if you have the equipment and a spare block, while your at it, flat top the pistons and take an extra couple of mm off the block.

i have a cheap ma12 up for sale if your interested?

sent you a pm about the flywheel also

 

[Machi san]

I think its possible to do the above, couldnt be 100% without investigation but its an old trick people used to use on the old mini a series engines. You can use a 1275cc block and short stroke crank to build a high revving 1070cc engine ect.

But also changing the rod length could also be a good idea because altering the rod length to crank stroke ratio can alter the caracteristics of the power band.

And also if the ma12 is a bored out ma10 block but an extra 1/2 taller. would it not be possible to bore out the ma10 to ma12 piston diameter, its only 2-3mm bigger is it not.

but then i wont be finding out because iam buying your cg fitting kit lol.

 

[Machi san]

Saying that though. i may hunt down some ma12 pistons and have a tinker with the old ma10 when i rip it out.

 

[diggs112]

Speak to Dave Walker he is a autograss engine builder and he builds all the top ma12 engines he would be able to answer your questions and piont you in the right direction im sure!! not got his number to hand but should find it on google.

 

[bobsp16]

dave number is 01636 671277