87 replies to this topic

[callyspoy]

Hello folks, hope you can give me some pointers.
I saw on ebay a 1098 engine that had been bored out with standard size Imp pistons. The seller was told the engine was capable of 7000/8000 revs, and that it had been centre strapped. He told me that he had no reason to disbelieve the person that it was not the case.

Now, i bought it with no head (it had a 295 that was with it) as i am planning on putting a 940 head on it. The bores look excellent. I was told the engine had only been run for a few thousand miles.
I bought the engine for £150 as i took some of the things he said with a pinch of salt as i didn't really think that a 1098 would really be worth speccing to the extent explained, but i figured the pisons alone would be worth the money and it was very local.
Having taken the chain cover off, i have discovered that the cam is Kent MD286. My understanding of this, is that this is a seen as a race cam on a 1275, let alone a 1098! It has a duplex fitted and the clutch/flywheel looks to have been drilled (i assume for balancing).

Really what i'm after is some advice/thoughts on what this engine could be like? I get the feeling it will be a complete pig to drive on a daily car? I don't do much driving as i live next door to where i work, but it is my daily driver (more social/pleasure if you will!)

By all accounts, and i should find out later on today, the bottom end would seem to have been balanced up. So my question really is, is it worth me trying it as is? Or, should i put a milder cam in it? The block has been decked (i am not sure if that is standard for a 1098?) along with the 940 head and one of three choices for carbs (i have twin hs2, twin hs4 and Hif 44 at my disposal) would it be a useable engine? I am fine with piutting high octane fuel in, because as stated, i don't do enough miles for the extra cost to be a concern. So if the compression is high, it's not a problem.

I have waffled on a bit, but i am undecided what to do!
Thoughts my friends...

[callyspoy]

Anyone? (

[Sam Walters]

If the spec is as said, keep the head. Chances are its been modified.

Although i would hardly call any engine with a 286 a race engine. Its luke warm at best. Even the 296 in a 1293 I would consider to be tame.

With the use of mappable ignition, good setup and decent gearing there is no reason why these cars should be an issue to drive.

[whitecliffsmini]

When you over bore an 1098 with imp pistons you take around 11mm from the top of the block we used to use these for racing donkies years ago with 649 cams in etc they do tend to work much better with a 940 head on though

[bmcecosse]

Calyspot! We meet again!!! There is no way a Mini 1098 engine crank can be revved to the numbers you suggest - but this could be a 998 engine bored to take the Imp pistons and coming out to ~ 1098 cc - is that possible? The 286 cam will be excellent - and yes - fit a 940 head, big valve version if you can get it. Stick an HIF 44 on it and it will go very well indeed......

[callyspoy]

Hi, thanks for the replies folks, i am feeling more comfortable with it now!
I was told it is a1098, and i am pretty sure i heard that only the 1098 could be bored with the Imp piston, but i am probably wrong!
Yes, it was sold as a 1215, so i'll take his word for it!
I have a big valve 940 already Roy, so should be plenty of laughs! I didn't take the 295 head, so i can't use that anyway.
So, with a bit of pocketing, it should be alright. I have a Maniflow inlet manifold, so i am tempted to "borrow" my old mans Hif and go with that. But i do already have the 2 sets of twin carbs also! Decisions decisions.
I saw the Kent 286 powerband is 2000 to 7500, will that mean it's a pig below 2000 or just not "on power"?

[hazpalmer14]

the 998 and 1098 blocks are the same, its only the 1098 crank and rods that are different.

[bmcecosse]

It's going to be a bit of a revy engine - but I was always happy with my 544 cam - these 286 cams are supposedly 'improved' versions of the 544. Stick with a big single HIF 44. If the block has been machined down - there may not be much meat left for pocketing, so check carefully. Probably better (and certainly easier) to sink the exhaust valves into the head.

[Tupers]

the 998 and 1098 blocks are the same, its only the 1098 crank and rods that are different.

I think it's crank and pistons that are different actually.

[callyspoy]

Ha, well twins are still going for good money, so i could always move both sets on and put the money towards a good filter, stub stack.

I was under the impression that the Imp pistons could only be fitted to 1098's, but like i said, probablt wrong.

Roy, i had a look on a chart i have about cams, and my cam with standard rockers should give exhaust valve lift of .405, so i assume i just measure if/how far the valve comes out of the head and find out from that how much i need sink the valves?

[Guess-Works.com]

A 998 with std Imp pistons would be 1105cc, a 1098 with same size imp pistons would be 1214cc

First thing I'd be doing is measuring the bore.... bore for imp pistons is 2.675"

[jaydee]

I dont know if that crank will accept long duration cams, you shouldnt rev it above 6k rpm..
I'm afraid if you cant pocket the block for the 940, you wont have enough clearance to accept a 286 in terms of valve lift.
In that case you can try the 544 which has less lift at the exhausts, or an MG metro cam (tame camshaft with standard lift) or even a 'happyer' and expensive SW10.

[callyspoy]

Ok, so some conflicting advice here...
I will measure the bore tomorrow, i'm doing a double at work today. I'll measure the stroke also, just for good measure (see what i did there?!)

Jaydee, why would the lift affect whether i can pocket the block? Is my thinking correct in my last post about how to measure valve clearance? I take on board BMC's thoughts on whether there is enough meat in the block to allow, is this the same thing you are suggesting?

[jaydee]

The kent 286 has a very high exhaust lift.
I'm saying that if you cant pocket the block because it was decked, then you have to choose a cam with standard lift (or slightly more) on the exhausts or the valves will hit the block, even when recessed. You can sink valves as per Roy's advice, but i'm afraid it wont be enough for a 286.

Edited by jaydee, 07 December 2011 - 04:20 PM.

[callyspoy]

Hi Jaydee, thanks for that. I will measure it all up hopefully tomorrow, see what is and isn't viable.
I am willing to change the cam if neccessary, but obviously would rather not if not needed as the cost of it would be the cost of the engine again!
I still need clarification on the lift though...the book figure lift for the Kent 286 states that using 1.25 rockers (standard) then exhaust valve lift is .405 of an inch. So can someone tell me if this is the full lift, ie; the amount the valve actually opens? That is what i am assuming, but i don't want to get it wrong!
Cheers!