998 build
Turbo Mini Forums

As said in the introduce yourself section, I have purchased Dan_W's project and am currently rebuilding the engine.

Totally a novice when it comes to this but I'm a hands on so going to give it a go.

Rather than taking the easier route and sending the engine off to get built, I've decided to take on the challenge myself with a local mechanic.

Currently stripped the gearbox to replace the bearings and seals. Also, after reading a lot about upgrading the diff, I thought whilst the engine/gearbox is split I would take the opportunity to purchase and fit the minispares cross pin diff. And from what I understand, everything else should be fine for a reasonable amount of power.

I do have a few questions, if you would be able to possibly help...

I wanted to replace the piston rings as a precaution, all I know is that the pistons are Powermax +30 offset pin pistons (quoting from previous owners description.) I've attached a photo. On the tops it says: B.030 - H and underneath RP 54.

Wondering if anyone could help me locate any rings?

Thanks.

Attachments:

914.96kb

Edited by smit360 on 19th Mar, 2013.

998 t2 ongoing project.

Anyone know anywhere? Tried a few companies but no luck.

Got my basic spec for the engine, if you could let me know what you think..

-t2 turbo on mirage manifolds
-HIF 44 carb with turbo rebuild kit
-Block +30 with powermax pistons as above
-wedged and drilled crank
-12g940 head as blocks already pocketed
-standard gearbox rebuilt with fresh bearings with cross pin diff and centre oil pick up
-verto clutch

Questions regarding a few other bits:

- Should I ideally upgrade the oil pump I have read a few people have used the 1275 with an adapter plate. Would something like this be ok.. http://www.swiftune.com/Product/406/oil-pumps.aspx

- Cam wise i've read the standard metro n/a cam is good for a reasonable amount of power. Would this be the 998 cam or?

- Rebuilding the gearbox at the moment and ordering a load of parts. Minispares are out of stock of the genuine gasket set is the £9.00 one (AJM804B) alright to use?
Also replacing the baulk rings and the same situation for them, they only have 22G2033MS those ones. Would these be fine to use or?

- Finally would you use a center main strap with this setup? or is it not really needed.

998 t2 ongoing project.

Save some money on the crank and buy some new pistons. Calver ST do a good range. Standard crank balanced will be fine.

You mean the MG Metro cam not the standard n/a cam. There are other options available.

Have a look at some of the other builds in this section.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Hiya i personally wouldn't worry too much about a centre main strap as i feel they are only really required on engines that rev high and with most turbo engines there is no need to rev that high. as for gaskets i have used the cheaper sets the only trouble it they tend to be thinner so shimming etc can be effected ie with drop gears. With the 998 turbo engine the can most used it the MG metro n/a cam this is a slightly longer duration than the standard metro cam. Hope you find the rest of the info you need here.

My small bore turbo project http://www.turbominis.co.uk/forums/index.php?p=vt&tid=473901

Have a look at this:

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=448833

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Cheers guys.

Paul S - the crank came with the build already like that. Would you suggest changing pistons rather than trying to source rings?

I havent worked out the cr ratio yet, would it be too high with flat top pistons and a 12g940?

998 t2 ongoing project.

Yes, doubt you'll find +0.030" rings.

Your CR will be too high with flap tops and 12G940 unless you open the chambers up about 7cc.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Cheers paul, having no real luck at all getting the rings so may have to just get a new set of pistons.

Would the oil pump I linked to be fine to use?
And in regards to the baulk rings, would you use the non-genuine or source some genuine from else where?

998 t2 ongoing project.

you could always get some rings made at someone like total seal. But that will probably be over half the cost of a new set of pistons.

My small bore turbo project http://www.turbominis.co.uk/forums/index.php?p=vt&tid=473901

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Here you go:

http://www.ebay.co.uk/itm/Austin-Piston-Se...=item3a73436119

Far from being a performance piston, these have been proved in a race engine on 15psi boost.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

I think I will just get some new pistons as you said paul. Got to send some measurements to one company and if they haven't got them then i'll go down the route of buying some dished ones.

The rods are interference fit, does this limit piston choice? And block is +30

I only need two according to the guy whose helping me build. I can get genuines from a website so may get those..

998 t2 ongoing project.

The rods are 12g124. These are standard 998 rods I believe.

Im unsure about the whole piston thing - was told they were powermax offset pin pistons... whats that mean?

998 t2 ongoing project.

All 998s have offset pins (well all the ones I have).

I would say that the +30 will limit choice more than fitment.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

www.twin-turbo.co.uk

I just had a google and read up on it, the piston pin hole is slighty off centered.

Yeah, I've just been looking at the 20773's that Paul S recommended, but they dont come in a +30.

998 t2 ongoing project.

You'll need to rebore to fit either +0.040" or 0.060" 20773s.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Yep forget about +30 you are going to need to rebore.

May be worth going straight to +60 as there is no guarantee that if the bore is worn/marked that another +10 will clean it up.

If something is worth doing, it's worth doing half of.

overbore by 30 inches John?

Those pistons are most likely Powermax 20950s and would be better then the 20773s in a boosted application.

You could get some +0.040" rings to fit, but it depends on the slot depth. Vizard lists the 20950 as having a 0.157" oil control ring, but the latest equivalent in my parts bin has a 0.125" oil slot.

Have a measure of the slots.

However, if you use the flat tops you still have the CR problem.

Edited by Paul S on 24th Apr, 2012.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

I remember someone making a much bigger error.

On 8th Dec, 2008 apbellamy said:
Under Bonnet - Originaly I was going to put a 1360 pre -A plus lump in and be happy, but then I realised I needed Forced Induction in my life . So the spec is/will be:

MG Metro 1275 Engine with +20,000 over bore.

If something is worth doing, it's worth doing half of.

Get .40 rings. Should be easy....

[X] nail here for new monitor

998 t2 ongoing project.

Top and second ring slots should be 1.6mm at most.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Oh that throws a spanner in the works. I think im going to run these pistons and rings and get them machined to get the CR needed.

The block is one of morspeeds, but i suppose now there is no way of finding out the spec from the number..

998 t2 ongoing project.