Engine Rebuild

Post by **webbnuts** » Wed Aug 29, 2007 12:58 pm

Hi There,

I currently have my 1098CC engine completly stripped, so i can rebuild it starting from the block up, something i have always wanted to do.

I will be rebuilding it with a 12G940 head, the 1098 cam, MG Metro inlet, LCB exhaust, electronic ignition, HIF44 carb etc but i'm wondering if there are any other bits i should replace whilst its all stripped down, bearings pumps etc etc?

Any help would grately appreciated!

Many thanks,

Sam.

Post by **bmcecosse** » Wed Aug 29, 2007 1:12 pm

Well yes - the whole point of it being stripped is so you can measure up the bearing journals and the bores - and decide if they are fit for service. If so - then ceratinly new mains and big-end shells hsould be fitted, and you must decide if new piston rings and/or pistons are required. A new timing chain is a 'must' and a new oil pump is highly advisable. Your engine would be much better with an MGMetro camshaft if you can find one - but the standard 1098 cam is not too bad however later on Rover found better results when they timed that same basic cam forward by 4 degrees. And if you can lay hands on a crankshaft damper front pulley -that's worth fitting too.
I assume you do know about sinking the exhaust valves on that head by 40 thou ?

Post by **webbnuts** » Wed Aug 29, 2007 6:25 pm

Thanks for your help. I am aware of sinking the exhaust valves, but a friend has just said that this head wont fit my block because it has an extra hole for a stud near the rear of the engine. Is he right?

Post by **picky** » Wed Aug 29, 2007 6:31 pm

Your block is expecting a 9 stud head, some later heads were held down with 11 studs (an extra one at the back and one at the front). But the head should bolt on just fine, it will have two empty stud holes. You can drill out the extra two holes in the block if you want to hold it on with 11 studs, but it is not really needed.

While you have it stripped down, if you are into improving the performance then I would recommend fitting a centre main bearing cap, which helps stop the crankshaft from flexing as much. the crank damper is also a very good idea. Although neither of these mods will make it any faster, they will help it last longer.

Post by **bmcecosse** » Wed Aug 29, 2007 8:46 pm

The extra studs are not needed - but can be fitted if you wish - my engine does NOT have them. You will need a head gasket for a 1275 Mini engine. The centre main strap is quite complicated to do properly - and only necessary for very high output engines- don't bother with it!! Crankshaft damper is not essential - but good to have if you can find one at a fair price.

Post by **webbnuts** » Wed Aug 29, 2007 9:40 pm

thanks for all your advice, I am a bit new to this, but am thinking maybe 65 bhp ought to be acheivable?
Thanks again,
Sam.

Post by **wibble_puppy** » Wed Aug 29, 2007 9:44 pm

picky wrote:Your block is expecting a 9 stud head

beautifully put, picky

best of luck with your rebuild, webnuts

Post by **webbnuts** » Wed Aug 29, 2007 9:48 pm

Thanks! Im hoping to come to some shows soon so might start meeting you all!!

Post by **wibble_puppy** » Wed Aug 29, 2007 9:52 pm

hope so!!

Post by **bmcecosse** » Wed Aug 29, 2007 10:38 pm

65 if you get the MG Metro camshaft, and do a bit of work on the head - especially in the exhaust valve throats where it's v tight at the corner. Try pushing you finger through the gap!! You would also need a better exhaust system after the lcb - bigger bore and 'straight through'! Otherwise - more like 55/60.

Post by **webbnuts** » Thu Aug 30, 2007 5:52 pm

bmcecosse wrote:The centre main strap is quite complicated to do properly - and only necessary for very high output engines- don't bother with it!! Crankshaft damper is not essential - but good to have if you can find one at a fair price.

If i got a center strap and crankshaft damper, would that make the bottom end more willing to cope with a turbo at a later date? Or would i be better with the larger mains as found in a midget block?

Post by **bmcecosse** » Thu Aug 30, 2007 8:32 pm

Oh I would only 'turbo' a large main bearing engine - 1275 probably although last Spridgets had 2" main bearing 1098 engines. But supercharger seems to be the way these days - see Picky's threads!

Post by **picky** » Fri Aug 31, 2007 12:09 am

http://www.mmoc.org.uk/index.php?name=P ... ic&t=14832

yes centre main strap and crank damper help toughen it up - but I would personally only go turbo/supercharger on a 1275 as you have bigger bearings to take the strain.

Post by **bmcecosse** » Fri Aug 31, 2007 12:26 am

And - Picky had the crankshaft 'tuftrided' - an expensive extra, but worth it if very high power. The Metro turbo cranks are all tuftrided as standard.

Post by **webbnuts** » Fri Aug 31, 2007 7:53 am

Would a rebuilt 1098 not cope with a few PSI boost? I'm not talking 5 or 6 but maybe 2 psi? Just a little bit assist it's acceleration? If not then i might not spend anytime on the 1098 block, and start hunting for a 1275

Post by **bmcecosse** » Fri Aug 31, 2007 10:02 am

Of course it will - but it may not last long. If your long time ambition is for considerably great power then yes you should get hold of a 1275. But if you increase the power considerably - you must re-arrange the suspension/wheels/tyres and of course the BRAKES to cope !! It can all start to get a bit expensive.

Post by **picky** » Fri Aug 31, 2007 9:26 pm

I would recommend you go for the tuned 1098 setup for now - without any boost. You will learn alot from rebuilding the engine without it getting to complicated or expensive, and many people have gone before you, so posting on the MMOC board will solve any issues you have with the setup. I foolishly went for a very unusual setup.. which means I am on my own in terms of troubleshooting!!

I started off tuning a 1098, and it taught me alot. If you go for a too ambitous setup straight away then it is likely you will never finish it...

Picky

Post by **webbnuts** » Fri Aug 31, 2007 9:47 pm

Thanks for that Picky. My mate has said the same thing, learn with the 1098 and if i break the head porting and polishing it its not the end of the world, where as i would be gutted if it was a special unleaded one that had cost me and arm and a leg! I am hoping to learn a lot, and if i replace things like the oil pump etc as i go through it, then it will be a sound engine i can sell on ebay to fund another project engine another day!

Thanks for your advice. Btw, you morris looks amazing, wish i had half the talent you obviously do!

Keep up the good work!

Post by **bmcecosse** » Sat Sep 01, 2007 9:57 am

Don't go too mad on 'porting' the head - just the exhaust throats will do it and certainly no polishing! It does no good.

Post by **paul.kissick** » Sat Sep 01, 2007 11:33 am

just the exhaust throats will do it and certainly no polishing! It does no good.

Is this true for i thought that gettin a smooth flow of fuel air into and out of the engine was important? i have been doing the Mr vizard on my head. I would hate to think i have wasted my time.