14 replies to this topic

[thecooperman]

would the car run properly with a 1380cc? a cooper s engine and gearbox bored to 1293 cc with road rally cam and twin su's would it run properly with a bore to 1380cc as i would like to make it fast
kind regards

[Ollie180]

whats stopping it from running? lol

[thecooperman]

whats stopping it from running? lol

nothing mate but i was wondering if it would run smooth and still powerful with the bigger bore (sorry for the misunderstanding)

[The Matt]

Moved to the correct section.

There is no reason for it not to run better with a rebore. As long as the compression ration is correctly matched and the car is rolling road tuned to maximise the performance of the new engine capacity. Why go straight to maximum (1380) bore when you could go for a 1330 first and still have some life left in the engine for years to come???

[Sprocket]

If you work on 10 years for a well built engine to need a rebore, rebuilt at 5 years. Are you going to have it this long or will you be building another completely unique engine to replace it with. How much money will you be earning five years from now let alone ten. Its all relative. 1380 rebore, no reason not to if the only reason is that there is no more life left in the block, but then thats ten years away.

Consider this though. Search around for a standard bore block on its own in good useble condition. Do it, do it now while they are still cheep, grease it, box it up and put it into storage, that way when the bores are that worn (ten years from now) you can have your other block bored. Theres another ten years. So thats twenty years, two blocks, one set of pistons and four rebuilds. How old will you be then.

This all depends on good build practices, good maintenance and quality oils.

Reliability is not a problem. Only becomes a problem when you choose the wrong build spec. All out power is not what its all about. Its how it drives.

Thats my opinion. I say do it.

[fikus01]

the bigger cc would make it run sweeter if anything because big cc pulls a cam a lot easier! if its a little lumpy in a 1293, it'll be a little less lumpy in a 1380 or above if that makes sense!

[dayoungfella]

There's still another bore left in a 1380 block.

To achieve 1380cc the cylinders are bored to 73.5mm...74mm is the max and this would give 1400cc. Or you can stroke it to 1430, 1460, 1480 etc etc


I say definitely go for 1380 and get a decent head to go with it.

[neil_g]

providing its offset bored

[dayoungfella]

Well I woudn't even consider going 1380 unless it was offset bored...

[fikus01]

what about 74.7mm triumph pistons??

[Sprocket]

what about 74.7mm triumph pistons??

They provide their own sort of different problems though

Edited by Mini Sprocket, 23 January 2007 - 07:23 PM.

[Sprocket]

There's still another bore left in a 1380 block.

To achieve 1380cc the cylinders are bored to 73.5mm...74mm is the max and this would give 1400cc. Or you can stroke it to 1430, 1460, 1480 etc etc


I say definitely go for 1380 and get a decent head to go with it.

providing its offset bored

That is if you can find some 74mm pistons

Edited by Mini Sprocket, 23 January 2007 - 07:22 PM.

[dayoungfella]

Omega do them

[Sprocket]

Trust me they do not

That is unless you are talking about the small run of 10 sets of the expensive forged pistons that MED had specificaly made by Omega. At £450 its not going to be your first choice

[The Matt]

I am using modded fiesta 1100 crossflow pistons for mine, they come in at a nats whisker under 74mm, it's been tried before, by the likes of Keith Calver, problem is that they are a flat top piston, so you have to machine a dish into them, then even if you give the pistons the max. dish, you still have to have like 26cc chambers in yer head. :S And one day, I will finish building said engine!

Anyway, back to topic:

Nowt wrong with going for a 1380, I just think (somewhat hypocritically) that there is fun to be had with things like 1293s, 1330s etc. And a lot of people go straight for 1380, so it's nice to see the odd tuned up standard overbore.