Fantasy 1275cc engine build spec suggestions.

Post by **heathy12** » Tue Nov 18, 2008 7:20 am

Just sorting out collecting my two engines so can build my ultimate spec over the christmas break and it got me thinking.

If you were to build a Hot engine for a Minor what'd the spec be. Pistons, cam, oversizing, head gaskets and spacers, Cams and pumps.

Mines a little different being a Metro Turbo 1380cc lump which im overhauling but got me thinking what everyone else classed as their ultimate spec!

Could be a good read and reference point!

Post by **PSL184** » Tue Nov 18, 2008 7:56 am

For me it would be strong and reliable and just the same as one I've just built....
Standard rebuilt bottom end with balanced crank.
MG Metro head.
266 cam
HIF44 on MG inlet
LCB outlet into 1 1/2" system....

Post by **bmcecosse** » Tue Nov 18, 2008 10:49 am

Ultimate road build ? Would be whatever capacity you like (but overbores become dramatically less reliable as the bore size increase) - biggest valves you can fit, so probably a Cooper S head (the original - not the last-of-line) and a 649 cam with the best carbs and exhaust you can afford. The crank should be EN40B nitrided, the rods Cooper S, and the pistons forged ! All carefully balanced of course - and flywheel lightened as you wish. Duplex steel gears and a crankshaft damper will be required - and perhaps megajolt ignition - or a 123 dizzy seems to work well too.

Post by **superchargedfool** » Tue Nov 18, 2008 11:25 am

mines as bmc's but with an eaton on it blowing at 10psi making 140bhp with strong torque from 2000 rpm. Oh and not blowing up too soon after being built would be nice as well. OH and 30 mpg would be nice as well. OH and no oil drips would be lovely.

Post by **bmcecosse** » Tue Nov 18, 2008 12:38 pm

Ahh well - if blowing is allowed - a much less dramatic cam would be required! With a 649 the overlap would allow the blower to blast fuel and air right through the engine into the exhaust. MG Metro cam would be about the ultimate - although on the Metro Turbo they used the rather more staid normal 1275 cam.

Post by **alainmoran** » Tue Nov 18, 2008 3:34 pm

I assume you've had a read of David Vizard's book?

Post by **MartinB** » Tue Nov 18, 2008 3:40 pm

If it is fantasy we are talking about, it has got to be a KAD 16 valve with turbo!

Martin

Post by **downsey** » Tue Nov 18, 2008 4:34 pm

or sr20 turbo hehe

linearaudio · Post by **linearaudio** » Tue Nov 18, 2008 8:14 pm

No- it would have to be a supercharger, turbo's are sooooo common. And make sure it whines good and loud! Trouble with going down the fantasy route too far is you end up with something thats not really an A series any more, so might as well save a lot of money and chuck a K series in. (still the right parentage though!) The main feature I would go for would be blueprinting/balancing. Makes the plot much sweeter. How about a short stroke screamer instead of the usual 1380 route? Frantic fun!

Post by **heathy12** » Tue Nov 18, 2008 11:03 pm

Okay, wrong end of the stick guys.

I purely ment engine specs or if you could build an engine with a decent spec what'd it be.

Theres so many different car parts you can make fit into an A series to make improvments...eg, my engines got Herald 13/80 pistons in it, maybe a slightly different Cam fitted from another car so was just wanting to see what the specs of the engines would be along with where the bits came from.

Kind of like a big alternative parts list with different build specs and combinations really.

Needing some ideas to go with my new Turbo build.

Post by **Mogwai** » Tue Nov 18, 2008 11:09 pm

Nitrous oxide

to hell with the big ends

Post by **heathy12** » Tue Nov 18, 2008 11:12 pm

bmcecosse wrote:Ultimate road build ? Would be whatever capacity you like (but overbores become dramatically less reliable as the bore size increase) - biggest valves you can fit, so probably a Cooper S head (the original - not the last-of-line) and a 649 cam with the best carbs and exhaust you can afford. The crank should be EN40B nitrided, the rods Cooper S, and the pistons forged ! All carefully balanced of course - and flywheel lightened as you wish. Duplex steel gears and a crankshaft damper will be required - and perhaps megajolt ignition - or a 123 dizzy seems to work well too.

This fellas got the idea!

Sounds a hot little engine there!

Post by **bmcecosse** » Wed Nov 19, 2008 3:30 pm

Should manage reliable 100 bhp without using 'stupid' revs!

Post by **minor_hickup** » Wed Nov 19, 2008 6:07 pm

Well I was looking to aim for 100bhp myself if the budget will allow such a build for my morris, this is once I've finished restoring it. I've got a very big valve 11 stud head (can't remember the sizes but the valves almost touch) that's well ported. I may get my friendly local engine builder to look it over for improvements. I've also got a set of 1.5:1 rollerised rockers.

I was thinking a fairly sorted bottom end, well lightened and dynamically balanced with a lightened flywheel and forged pistons +60thou to 1330cc. A piper 285 camshaft driven by vernier adjustable duplex gears and suitable tappets. A nice high compression, say 10:1 or maybe a smidge higher. A cranshaft damper, decent crank ventilation system and fast road distributor. I see aldon do one designed to work with the 285 camshaft. As for carbs I can't decide between twin 1.5" SUs on a tubular manifold or a Weber 45 on a maniflow long manifold. As for exhaust I was thinking a maniflow or similar LCB manifold and a 1 3/4 or 2" exhaust with a single silencer exiting in front of the rear wheel out the side.

Better get saving! However I doubt the midget 1275 'box I have would put up with that!

Post by **callyspoy** » Wed Nov 19, 2008 7:32 pm

you mentioned roller rockers and a weber...don't let roy hear you!!

Post by **minor_hickup** » Wed Nov 19, 2008 8:12 pm

What's wrong with webers? On a highly tuned engine its a damned site easier to get the fuelling right with a weber around here. Its something the proffesionals like to use and have great experience and stocks of spares for. Makes sense really, especially if theres a small performance advantage.

Post by **wanderinstar** » Wed Nov 19, 2008 9:40 pm

Well I have heard of Hillman Imp pistons fitted to 1098, but Herald 13/80 pistons. Pray tell more. Or is it supposition??

Post by **callyspoy** » Thu Nov 20, 2008 1:22 pm

minor hickup...i have 1.5 rollers and a dellorto...Mr BMC is not a massive fan though! that said...i think even he would aprove on a well tuned engine!

Post by **bmcecosse** » Thu Nov 20, 2008 1:33 pm

Certainly not the 'rollers' - there may be trouble ahead!

Post by **callyspoy** » Thu Nov 20, 2008 2:26 pm

there maybe trouble in the head...HAHAHAHAHAHAHAHAHA!