6 replies to this topic

[Gr4h4m]

Hi I have a 998 Mk2 which I wnat a bit more power for fun at the weekend. I have a low C/R engine with a 295 and twin 1.25 + free flow but only gives 46hp and I wanted a bit more fun at the weekends........

It has a remote change box, can I fit a different short engine to it if so what will fit ?
I was thinking about getting a small bore, balanced bottom end and better cam but I was told that swaping the box for a rod change would be a bit of a change + I would need pot joint drive shafts so I didn't know if I could use a different short engine and bolt it onto my box????

Any idea's

[dklawson]

Guessworks will know for sure, but I believe that since you're talking about putting a 998 where a 998 was before... you should be OK. I know that on some of the early 3-synchro boxes it was necessary to add relief to the gearbox casing if you put a large bore block on a gearbox originally installed under a small bore engine.

[The Matt]

Dunno how interested you'd be, but I've got a good 1275 on a remote change box sat in my garage. Infact, I've got all of the necessary bits that you'd need to convert either way. You could go for large bore A series on remote box, small bore A+ on rod box or small bore A+ on your original remote box.

Did you have a specific short engine in mind? I mean, have you found a decent A+ unit or are you just toying with the idea at the moment? If you are just toying with the idea, then I'd go for a low mileage 998 A+ and get it modded. Not sure what sort of output you're after, but to be honest the output you're getting from your current engine isn't too bad for a small bore. You need to retain some reliability, so it's all about whether you want to go for a 998 screamer and just build an engine that can rev and rev and rev! As for fitting a different 998 on it, yeah, you can. You could go for a 998 A+, but I believe that the idler gear is different from A to A+. I believe the A+ has a bigger shaft. All that means is that you'd have to use the idler gear from your exsisting gearbox AFAIK.

Or, you could go for a rod change and have a 4 synchro box, it's a shame to go away from remote in terms of modding the shell. To be honest, I am doing that though, going from a remote change box to a rod change, but I am having the gear change unit fitted internally, rather than in the exhaust tunnel.

I guess the other alternative is to get your block pocketed and put a 12G940 head on your existing engine (you'd probably need to fiddle with the CR to do that too). A lot of people seem to be doing that these days.

Hmmm, I don't seem to have helped there!

Ummm, in short, if you want to keep small bore, I believe you can use an A+ 998 with relative ease!

[Gr4h4m]

Dunno how interested you'd be, but I've got a good 1275 on a remote change box sat in my garage. Infact, I've got all of the necessary bits that you'd need to convert either way. You could go for large bore A series on remote box, small bore A+ on rod box or small bore A+ on your original remote box.

Did you have a specific short engine in mind? I mean, have you found a decent A+ unit or are you just toying with the idea at the moment? If you are just toying with the idea, then I'd go for a low mileage 998 A+ and get it modded. Not sure what sort of output you're after, but to be honest the output you're getting from your current engine isn't too bad for a small bore. You need to retain some reliability, so it's all about whether you want to go for a 998 screamer and just build an engine that can rev and rev and rev! As for fitting a different 998 on it, yeah, you can. You could go for a 998 A+, but I believe that the idler gear is different from A to A+. I believe the A+ has a bigger shaft. All that means is that you'd have to use the idler gear from your exsisting gearbox AFAIK.

Or, you could go for a rod change and have a 4 synchro box, it's a shame to go away from remote in terms of modding the shell. To be honest, I am doing that though, going from a remote change box to a rod change, but I am having the gear change unit fitted internally, rather than in the exhaust tunnel.

I guess the other alternative is to get your block pocketed and put a 12G940 head on your existing engine (you'd probably need to fiddle with the CR to do that too). A lot of people seem to be doing that these days.

Hmmm, I don't seem to have helped there!

Ummm, in short, if you want to keep small bore, I believe you can use an A+ 998 with relative ease!

I mate I don't think we are far from each other as I live in Chester. I would be interested in the 1275. I can't send you a PM for some reason?? but if you PM me with a price.

Oh as for answering your question. I'm looking for more power with very little mods to the body... so either a 998 that I can cam, pocket and 940 so as not to change my original engine or a 1275 which seems to be the better option as its quicker out of the box... but the main thing is not to change the body. I would rather get a box with it so I can just swap it out and have mine as a complete spare engine and box.... but I don't know how much is involved in swapping for a 1275 so I need to start the research....

Edited by Gr4h4m, 30 May 2007 - 07:19 AM.

[The Matt]

Well, I'm about 25 minutes from Chester (A41 to Whitchurch, then head for Oswestry/Ellesmere).

I've sent you a PM about price etc.

In some ways though, it'd be nice to see another beefed up 998. So many people go straight for a 1275, but I guess that's for obvious reasons of reliability and cost per hp (above a certain point).

[Gr4h4m]

Well, I'm about 25 minutes from Chester (A41 to Whitchurch, then head for Oswestry/Ellesmere).

I've sent you a PM about price etc.

In some ways though, it'd be nice to see another beefed up 998. So many people go straight for a 1275, but I guess that's for obvious reasons of reliability and cost per hp (above a certain point).

Thanks... It is down to cost v power but I don't want to do anything to the shell as its so original. The reliability is a factor but I only do about 3k a year in in on club runs etc so even if it lasted 15K I would still 5 years out of it.... I like the idea of a 998 but I don't think the other half would want to sit in a car that you rev hard it would be very noisy... either way I think I would be best looking for a remote change and getting a decent engine that has been cam'd.. I could then look into a any engine work and hopefully get away with small amount of work to keep the costs down.. like a re-hone rather than a re-bore and new pistons... + get the bottom end balanced. The top end stuff I can then bolt-on after. Should get a good amount of power and a big upgrade on my 998 without spending too many ££££

[The Matt]

I like the idea of a 998 but I don't think the other half would want to sit in a car that you rev hard it would be very noisy...

My other half won't even go in my mini!!!