21 replies to this topic

[Tupers]

I was really looking to bore a 998 to a 1180 is it? Or get a 1275 and bore it to a 1308, and to a 1380cc later.

You're not going to make a powerful engine just by boring it out. There are two main sections you need to address first, one being the cylinder head and the other being the camshaft+valve train.

You would be much better served to get ahold of a lightly ported 2nd hand head for a 1275 engine and a Kent 266 or Swifttune SW5-07 camashaft with new cam followers and oil pump. This is of course assuming that the 998 engine that you're starting with isn't in need of a full rebuild already.

[SteveeR]

@oltonlad
How much would it be for that engine and parts?
Cheers for the help guys

[oltonlad]

@oltonlad
How much would it be for that engine and parts?
Cheers for the help guys

my 1098 cost around £800 including buying the engine

[AVV IT]

The cheapest way of getting reliable power would probably be to source a decent 1275 MG metro engine, particularly on a £500 budget. The popularity of MG metro engine transplants means that donor engines are much rarer these days than they used to be, but you can often still pick one up for around the £350-£450 mark.

[coopdog]

well my spec im building atm is
12G295 head stage 3 £250
998cc engine +60 so its 1046cc
+60 pistons cost £220
Mg metro cam £80 (brand new)
28/36 weber and manifold £50

all the bits gaskets and that sort of thing £200 ish
machine work £250

so it isnt cheap!!

[_mini1000_]

If I kept the 998, I would only want to bore it to a 1100-1200.
I meant changing the engine to a 1275, then boring that to 1380.

to get close to 1100 out of a 998 using just pistons you need a set of+120 pistons which will give you about 1095cc
you can run the standard 998 pistons with a 1098 crank which has a longer stroke to give you 1098cc
or a +0.1 overbore with a 1098 crank to give 1186cc.

[oltonlad]

If I kept the 998, I would only want to bore it to a 1100-1200.
I meant changing the engine to a 1275, then boring that to 1380.

to get close to 1100 out of a 998 using just pistons you need a set of+120 pistons which will give you about 1095cc
you can run the standard 998 pistons with a 1098 crank which has a longer stroke to give you 1098cc
or a +0.1 overbore with a 1098 crank to give 1186cc.

you have to use 1098 pistons with a 1098 crank.