36 replies to this topic

[Burgerdale]

That's what I'm thinking, keep the compression ration to 10.5. Those pistons will be fine, then I need to make a decision on the cam.
This is what I'm really stuck on.
The 3.6 diff, Lightened and balanced bottom end will help it rev. The lightened flywheel will help it accelerate but the lower inertia impare setting off. The 286 cam I had in at 1380 didn't like it unless it was given full chat everywhere.
I'm thinking 276 but the power really drops of at 6k. Not sure what the 1.5 rockers would do for that.
I'm tempted by a 266 or sw5 but I don't want to waste too much much from the top end. I know there's no magic cam so I'm trying to get the balance right first time.
Not sure if there's a better profile out there that will offer a good midway between 266 and 286 but doesn't drop off as much as a 276.

Edited by Burgerdale, 15 October 2015 - 08:09 PM.

[Mrpeanut]

heres my spec you may get some ideas from
 
stage 3 head
maniflow 1.75
mg metro cam
balanced flywheel crank rods  pistons
standard flywheel pre verto
uprated clutch plate
standard lucas electronic dizzy
hif 44 itg filter and MED substack
10.5 comp
shell v power
 with millers octane boost = 101
3.44 dif
revotec electronic fan
 
goes nicely lots of low down/mid range power very happy

Bob's engine is fantastic. Very, very driveable with the power where you need it - down low and through the mid range. My 1330 with a minispares evo1 cam made 84bhp and pulled like a train from down low (much better than Bob's ;)) If you want to save some money that's a cam wort looking at. I also kept costs down by fitting the county +60 pistons. My engine builder said he'd fitted loads as the triumph boys love em. He's never known one to fail and reckons they're on a par with a 21253.

Edited by Mrpeanut, 15 October 2015 - 08:06 PM.

[Mrpeanut]

Not sure if there's a better profile out there that will offer a good midway between 266 and 286 but doesn't drop off as much as a 276.

Swiftune SW8, or an AC Dodd RS or RS+ may suit. Neil Slark says good things about them, he reckons AC's grinds are particularly good.

[Burgerdale]

Are the county pistons fine with the 10.5 compression? Mine are rated to 8.8. They are a triumph thing normally, these are labelled as mg midget 1275+60.
If I need buy 21253 then so be it, I can use the county ones for when I rebuild my gt engine. That's going as standard as possible but it needs a rebore and it's already had one.
I'll go check ac dodds cams out too thanks.

[Mrpeanut]

Are the county pistons fine with the 10.5 compression? Mine are rated to 8.8. They are a triumph thing normally, these are labelled as mg midget 1275+60.
If I need buy 21253 then so be it, I can use the county ones for when I rebuild my gt engine. That's going as standard as possible but it needs a rebore and it's already had one.
I'll go check ac dodds cams out too thanks.

You'll have the low compression ones which are the cheap alternative to a 21251. You'll need the 21253 or equivalent to get a higher cr. AC sends some really good info about his cams, plus will give some great advice on the best cr for cam application. PM him on here.

[Burgerdale]

Thanks, I'll pm him as I can't get the website to load.
Best get on with ordering some 21253s now.
Hopefully I'll get a good recommendation from him and I'll eventually build a tidy little motor.
Can't wait to drive it again.

[gazza82]

Do you need +60? What is the block now?