23 replies to this topic

[stuart bowes]

Apologies if this is one of those done-to-death issues and I've a missed a sticky or something ..

 

in process of getting info together ahead of engine tuning and general cleanup / refurb

 

998cc engine in an '88 mayfair, have purchased a pair of 1+1/4" SU's, and just want to get it breathing a bit more than standard

 

prefer no rough idle or massively excessive consumption if possible.  ideally without having to do a lot of head work at least at the beginning, maybe later to get a little more out of it

 

just in terms of not having to pull the whole engine out again later on, I was thinking of just starting with a new cam

 

what would be a good choice for a fast road / weekend B road warrior spec, nothing outrageous just a bit of extra oomph

 

(I appreciate that thought will also have to go into the exhaust and manifold among other things but one thing at a time)

 

thanks

Edited by stuart bowes, 25 January 2022 - 08:49 PM.

[nicklouse]

What head will you be running?

[stuart bowes]

good question.. can I get away with the standard head to start with, and replace it / have it reworked later?

 

I actually don't know what 'standard' is in my case but it's outside I can go and have a look for a serial number or something I suppose

 

I have started picking at bits of the Vizard but obviously it's not just as simple as read the book and you'll understand everything straight away

Edited by stuart bowes, 25 January 2022 - 09:14 PM.

[nicklouse]

Changing the cam and keeping the same head will gain you nothing. Changing the head while keeping the same cam will give you increases. Fitting more carbs with out making changes will give you nothing.

 

you have bought new carbs. So you need to change the head along with the manifolds. That is the first thing. Then cam. Or do it all at the same time.

[stuart bowes]

that is the long term plan, but I'm talking about getting the engine in the car and not having to take it out again later..

 

so step one, build it with a suitable cam (no gain, fine)

step two put it in with the carbs (still no gain, not a problem)

chose a sensible exhaust and manifold because it makes sense to only buy that once (im guessing still no gains)

at some point in future, work on or replace the head, suddenly everything makes sense 

 

so I'm still in need of knowing what cam would be suitable

 

I say this because I assume a new head is going to be the expensive bit but I suppose we can always make a note of what head to change to anyway it wouldn't hurt

Edited by stuart bowes, 25 January 2022 - 10:18 PM.

[Daz1968]

I think the mini spares evolution001 cam is ideal in a 998,

don’t forget to have the distributor recurved when you have finished

 

i have a 998 cooper however I retained standard cooper cam, but I have a freeflow manifold, twin box rc40, large valve ported 12g295  complete with twin h4 1.1/2 su carbs and my 998 cooper distributor recurved to suit spec, it goes quite well,

[Minigman]

I ran a Kent 266 in a 998 with twin 1.25” SUs, a Calver 295 modified head and 3.76 final drive. It was a great little engine. As said above you won’t really gain much without improving the head but fitting the cam whilst the engine is out makes sense and won’t do any harm. It will run fine with a standard head but you won’t unlock the potential.

Edited by Minigman, 25 January 2022 - 11:50 PM.

[stuart bowes]

nice one thanks, a couple of options there then, sounds pretty much like what I'm aiming for

 

what would be a safe redline for the revs with that sort of setup and not changing anything else in the bottom end?

Edited by stuart bowes, 26 January 2022 - 01:40 AM.

[toppers3933]

Piper 255 will give you a good engine once you sort the head out. It’s a very underrated cam.
With regards your order of doing stuff, do cam if the engine is out. Makes sense to do that. You want to sort the exhaust when you sort the carbs. It’ll be a nightmare to set up on twin carbs and a standard drinking straw exhaust. You’ll at least give the other mods a fighting chance then. Rc40 or a maniflow would be perfect and neither are mega expensive.
You’ll be fine without changing the head but it will minimise the gains you’ll see from everything else. Once you have the funds then a decently modified 998 head or a 12g202 would give you a good boost. If you can find a decent 12g295 head then with the right modifications (usually skimming) you’ll see a decent gain too but good quality 295’s are very thin on the ground.

[stuart bowes]

Thanks again for the suggestions, I got a reply from Kent cams as well they say they recommend the MD246 for good torque from 2000 and revs to 5.6/6

I guess the decision will be made partly on cost, anything up to and around £200 is pretty feasible, more than that is probably excessive..

Thanks for additional pointers on the exhaust as well but for now as I said just to get the lump back in the cam will be job no 1 and as long as everything else looks OK I'll probably leave the bottom end alone, it's not high mileage or showing any signs of bore damage which is all I've really looked at so far

[stuart bowes]

Saying that new piston rings are probably on the cards, it would just seem silly not to.. and if the cranks coming out then new bearings or bushes or whatever they are I suppose

[mk1leg]

I fitted a 731 to my 998 back in the early 80s stage 3 head and a cooper exhaust manifold twin 1.25s SUs got 95 out of her on my first trip to the UK

[Spider]

The original 998 Cooper had circa 55 HP as opposed to the stock version of the time at 38 HP. These were a very street drivable engine. If you were to build an engine to these specifications, I doubt you'd be disappointed. Also, things like the Carb and Ignition requirements and set up are all there in the book, while not spot on these days, they will still be quite satisfactory.

The cams fitted to these was the same profile as fitted to the 1100 and standard 1275 engines + the MKI Cooper S. It's a fairly commonly factory fitted profile in the A Series.

[stuart bowes]

.. or a 12g202 would give you a good boost...

 

If you can find a decent 12g295 head then with the right modifications (usually skimming) you’ll see a decent gain too but good quality 295’s are very thin on the ground.

 

thanks for this, I've found some cheap 202's online, they seem fairly easy to get.. due to age though I'm assuming they will need unleaded valve seats, and a skim, and the inlet valves reseated while I'm at it, one quick price up with a place near me puts all that work at about £300  (+/-  some for valve guides if necessary) added to the £60 ish for the head which may or may not be good..

 

I'm wondering if it would be more cost effective in the short term just to keep my head which I know is ok for unleaded, get a very light skim if necessary (I dont think so) and maybe getting some porting done on it 

 

how far do we think I can go with my standard head or should I definitely be looking for a replacement, I suppose that does limit me on valve sizes though doesn't it

 

or would that literally just be a waste of time/effort/money 

Edited by stuart bowes, 27 January 2022 - 11:04 AM.

[johnv]

You’ll get a decent 12g295 for £300, run it unleaded with additive