10 replies to this topic

[minilee94]

The reason why I'm asking is I'm building / built a 1380 running 11.1 and me reading up on the net about the rebuilds you Gota do after a certain amount if miles etc has worried me abit now and is making me not want to keep the engine as I don't fancey laying loads of money out every few years or so

So what's people's views is it really worth pulling lump out and spending the money

[Midas Mk1]

Just get it in and running, drive it and stop worrying! :)

[Oldskoolcool]

You shouldn't have any problems running 11.1 compression ratio.
Just make sure you use super plus unleaded , and I would use a lead replacement additive if you haven't got hardened valve seats in the head already.

All tuned engines will need more mantinance than a standard one, engine life has more to do with the quality of the build ,components used and owner abuse!

[Cooperman]

It depends more on what cam you run than the C.R. If you runs a cam like, say, a 276 or a 286, where the power is at 6100 and 6400 rpm respectively, the engine will be revving to get the power and engine life will be short. If you fit either of those cams and don't rev it to those revs a lot of the time, then you have 'over-cammed' it.

With a 1380 you need to use a softer cam, like a 266, and rev it to only about 5800 rpm when using the power, but the torque will make it excellent at lower revs.

Remember, re-boring a 1380 is not cheap and may not work, requiring sleeving back when the bore is worn.

AS above, the quality of the parts used and the accuracy of the build will help.

At 11:1 use 97/98 octane petrol and add some Castrol Valvemaster-Plus each time you refuel.

If you have built a 1380 presumably it is to get maximum power, otherwise you would have kept it to 1275/1330, so you'll be using it and must expect more frequent re-builds than with a standard-ish engine. Modified classic cars of any type require frequent (in modern terms) re-builds.

[jaydee]

What shorts engine life is revs, remember the A series has only three mains..

[Cooperman]

The other thing with higher performance engines is that a heavier clutch is needed. Then, if you start the engine with the clutch pushed down the crankshaft thrust bearings are heavily end-loaded whilst the engine starts and they suffer from poor lubrication until the oil pressure builds up. Never start a Mini with a heavy clutch with the clutch pedal pushed down and don't sit with the pedal pushed down at traffic lights for more than a few seconds - always take it out of gear and let the pedal up.

[welshdan]

I ran around 12:1on my old 1360 mpi engine.it was very quick for what it was. No issues here, covered big miles in it also

[Ethel]

Dynamic compression ratio is the term to google. In short, compression only really starts when the inlet valve closes.

[ACDodd]

If you don't use it all the time it'll be fine. Most 286 cam builds have about 10K miles in the before a rebuild is required.

The life span is down to you, how fast can you afford to go?

AC

[Pigeonto]

My experience of running at 11:1 ( static) CR is that it's fine if you don't use a distributor. I ran that CR quite happily on a Megajolt system and set as much  advance as poss with no pinking then subtracted a little advance to be sure. Had no issues. Then someone else had it  using  a dizzy and damaged pistons after a while. Distributors just cant be set for all conditions the engine will encounter. I would use 11:1 again with my Megajolt 

[minilee94]

Right okay thank you everyone

And cooper man I'm using a piper 285 cam

And for the fuel yeah il use good fuel for mine and I can't have unleaded seats as my valves are to big

Thanks for all the help