13 replies to this topic

[Shane.spears.91]

i want power, but i want reliability aswell.
im a hard one to please i know ha.

can you help?

[Turbo Nick]

stage 1 1275, keep it simple and it'll be fun more of the time.

[Beej123]

In theory, the bigger you go, the less reliable, less gap between bores makes it more likely to blow a gasket for instance. But any engine built well will be reliable. In most cases, the most reliable route to power is with a turbo because you get the boost without having to have the engine on the limit all the time and below the spool up RPM it will drive like an NA engine.


1310 and 1330 are popular sizes with 1380 being considered as big as you want to go. But going for a turbo charger 1275 is a reliable way to get good power.


Unless you drop a VTEC lump in haha

[Cooperman]

1330 is a good size, that's 0.060" oversize. Pistons are reasonably priced (P21253) and the block can be re-bored if necessary or can be sleeved back to 1275. So when worn the block is not scrapped, as it can be with a 1380 cc overbore.

[Shane.spears.91]

i already have a 1340 engine with +60 piston. but it shattered number 2. yet the sleeve was unharmed.

[Cooperman]

i already have a 1340 engine with +60 piston. but it shattered number 2. yet the sleeve was unharmed.

That's 1330 cc actually.
Why not just hone the bores and fit a new set of pistons?

[Shane.spears.91]

sorry i meant 1330* hit wrong button.
i would but i here bad things about them. i just want something reliable for my 79 which has a bit of power when needed.

[Beej123]

I've never heard or read of any problems with a 1330, no more than any other

[Shane.spears.91]

so why would mine, shatter a piston? with no signs on the sleeve?

[Beej123]

Sub standard assembly or faulty parts would be my guess. If 1330 is the choice of engine for Cooperman then the chances are it's the best choice haha

[Shane.spears.91]

it had a stage 3 head on it. and ive also been told the piston may have been a issue. but it suvived 34k befor killing its self lol

[Shane.spears.91]

mine are dished pistons. they good? or shall i get some flats?

[Pauly]

Depends what compression ratio you want, flat tops will up the compression ratio, do you know what your current C/R is? I personally would go dished for a road engine, flat tops are generally for high comp units. 10/10.5:1 would be fine C/R wise for a road engine in a weekend car.

The piston damage could more than likely be due to pinking/pre-igntion. That could be down to ignition timing/fuel/Compression ratio.

Are the bores un-touched? If so just get it re-honed, new rings and piston and your good to go. If there is bore damage you may aswell get it off-set bored to 73.5mm as its the next size up anyway. In terms of bore size you wont see major inprovments between sizes IMO, unless you go from 1275 to 1380, it is nice to have a 'square' engine though. Other factors contribute to power, such as head flow, valve lift and flow, iginition and fueling.

The more basic the motor the more reliable it is, power and relability dont go together .

Edited by Pauly, 02 January 2012 - 07:55 PM.

[Cooperman]

For a road car the dished P21253 pistons are great. I built an Endurance rally car a while back and the max overbore allowed was +0.060" and the engine had to be standard (!). With those pistons I used up to 7000 rpm and used high revs a lot. The car is now owned by my friend in our village who still uses it for competition and has never touched the bores or pistons. It still uses virtually no oil and has never blown a head gasket or had any other problems. BHP on the rollers with MG Metro cam and some slight tweaks (all within the regs, of course!) gave 84 bhp.
The big engines are best with the 8.4 cc dish pistons. Set the comp ratio to about 10.5:1 with the 35.6 mm inlet & 30.5 mm exhaust valves as on the MG Metro. Gas-flow the head a bit and with an HIF44 carb and good exhaust it'll go really well and be reliable.