What would cause an A-series 1100 to fall flat at 4000RPM?

[Jim]

By not operating Iean instead of mechanical advance you may be getting mEchanical retard. Sorry still drunk here lol

[zooki]

How old is the fuel and has it had some lead replacement shit tipped in?
Mine 68 998 does this if the fuel is anymore than a month old, draining it and sticking fresh stuff in always fixes it, seems the additives go bad pretty quickly

[BMWTurbo]

Dave:- I'm aware of that method, but I'm too lazy to go through all that and risk an oil leak where there isn't one now. Everything that is looked at funily on a mini will create an oil leak as you know

Stock:- Mini's have this wonderful system where they have a flare on the exhaust that goes over a bulge in the manifold and it's clamped with a 2-parts 'U' style clamp that's a prick to get sealed. I would prefer to weld a bung in then mess with and create a leaking join

Batfink:- I had thought about that, but I can't see it being far out enough for that to identify a problem?

Jim:- Honda's spin the other way to most engines (mini's spin anti-clockwise also), but I have checked and double checked the dsitributor spins correctly. Confirmed with the timing marks moving in the advance direction on the FW.

Zooki:- Fuel is a few days old. I've been driving it around for a few weeks now and gone through a good few tanks in it. BP Ultimate with valve saver. The valve saver is older though.

[jmac]

I've had more minis that I care to admit, I'm bloody amazed it runs as well as it does with such a restrictive exhaust. Get a set of LCB extractors and a 2 inch system (the 1098 will do fine with a 2 inch exhaust).

If you are on a super tight budget, run a 1 1/2 SU with a red spring and a BQ needle (which I think was std combo for auto 1100s) - it's a reasonable match for that setup.

If you are chasing a set of extractors I've probably got a set or two you can have for fuck all plus postage if it's any help.

You'll probably also find there's a fair bit of blowby, and it's contaminating the intake charge as revs rise. The trick there is simple enough, plug the breather hose barb on the carb, and run the breather hose from the rocker cover down the back of the engine and cut it near the bottom of the sump, to 'outside air' like the old style 'road pipe' breathers on pre adr27 engines This might not prove enough, as there is often a lot of blowby, and it prevents oil satisfactorily returning to the sump from the rocker cover area (since that is typically the only outlet for blowby). The trick there is to add another breather, on the transfer case. there is provision for one on there, you just have to drill it and tap it and fit the breather (I can provide pics for this if you want. Of course that would ideally mean you have to pull the motor to do that work so as not to have alloy debris on the transfer gears.

And for gods sake don't keep revving the bloody thing past 6000. There's no way it'll make really useful power above there without a bigger cam, and the std flywheel is heavy, and in a prime position to turn you into a eunuch if it lets go.

Also - the honda dizzy - if it's the conversion i'm thinkning of - the weights etc 'work' because irrespective of whether the engines rotate the same way, the distributors happen to rotate the same way with both engines running.

[BMWTurbo]

Fuck... just lost my big reply, will start again...

Engine was rebuilt a few years back, by Mini Automotive in BNE. It's done maybe 3000klms in that time, so don't expect blow-by yo be an issue. It's interesting you mentioned that, when hunting through parts for a spare vacuum advance canistor I found my ole 1100 canistor breather for the crackcase the other week. I don't really want to strip it down and drill'n'tap the boss for this though and it 'shouldn't need it with the freshness of the engine.

It probably does sound like I'm ringing it conitinually, but I'm fairly easy on it, just bothered about it's non-willingness to rev, when it should easily push to 6000rpm if I kept in to it. The engine quiet literally does not want to go past 5000rpm, but it doesn't break up or vave bounce, or make any funny other noises when being asked to.

Does have std clutch and flywheel, on top of a rebuilt box with a 3.44 I think.

I made a few dizzy's a good 12-13 years ago now, from the 79-82 civics I think, needed to shorten the body, fit the mini drive cog, cut some O-ring grooves in the bosses and modify the adjustment plates to suit. They use the honda outboard ignitor also.

I'm keen for some cheapo extractors if you have a set lying around. I unfortunately got rid of my 3-1 set many years back when I got out of them after having an A/M lower arm break and send me into a gaurd rail. *EDIT* Might have a lead on a cheap set locally with system and muffler will be in touch if it's a dead end jmac.

I should be able to bang up a simple 1.75-2 inch system with a couple of mufflers for bugger all to match it. I'll just seperate the 1.5inch cast manifold to retain the inlet side. SS cut off wheel should make short work of that.

[da9jeff]

you can drill the flywheel housing breather hole without striping (i assume thats the one your all talking about) the mounting bolts obviously dont go in the whole way, the actual breather hole you use, say a 10mm bit and just take a poofteenth out at a time, and when its a few (3-5mm) through, start trying to pierce with a certre punch. Take your time and you can get a 2-3mm hole without striping the side case off the engine.

Its not ideal, just a backyard solution that works.

[Dave75]

Also ,if you have the block with the tappet coverplates on the back behind the exhaust, you should already have provision for a sump breather unless your motor has 2 LH cover plates [the RH cover normally has a 90* X 1/2" copper pipe braised to it] I have 3 breathers on my engine... flywheel,sump as above & tappet cover plumbed into a catch tank vented to atmo.Carby fitting is sealed.

[F|sh]

what air filter is on it btw?

[BMWTurbo]

The Std mini 10inch? Round air filter.

I have tried it without this also and no difference, so althought it could probably go a change, it's not the cause.

[F|sh]

i was thinking if it was a foam filter. bin it. they deteriorate and clog shit.

[jmac]

If it's any consolation I just lost an entire post too!

Shorter version.

Of the minis I've had a 1098 recod, with std head and cam and twin 1 1/4s and lcb ran ok, but it really woke up with the change to a 12g295 head (998 cooper - same port, similar chambers to a 1275 head, but chambers positioned to suit the 850/998/1098 bore spacing) which I got from an early mg specialist then had to spend dollars fixing their so called re-co work (live and learn) Anyway, with M needles, blue springs and non std air filters (M needles would be too rich with std air filter and that combo) it woke it up. Revved to around 6000 usefully, and higher if you had to, just not as effective to do so.

I would be my left nut that even on a std 1098 you'd make more power with a 2 inch vs 1 3/4 inch system. I don't know why, but the larger mini engines really seem to love 2 inches even in mild states of tune.

One last thing - a lot of people end up leaving hte intake too thin where it used to join with the cast exhaust, in an attempt to clear the extractors properly, often opening it up completely by accident. Very easy alternative is to simply get a second manifold gasket, and cut out the two pieces where the intake goes, so it's double thickness there. Attach with a little smear of grease around each sealing edge, and they'll stay put whilst tightening the manifold bolts. Then you instantly space it back that extra 2-3mm and avoid all the head fucks. The other alternative I've seen people do is to belt the centre pipe with a hammer to dent it inward, thus affecting exhaust flow of #2 and #3 cylinders. Fuck that for a joke.

[BMWTurbo]

Cheers Jmac.

I got hold of a fairly basic 3-1 set of extractors and a sedan system made from 1.75inch OD pipe.. The ID seems to be about 42mm in the round, but it's press bent so looses some of this in the bends.

Should be okay though once I fit and extend it to suit the van. Possibly get onto it this afternoon weather permitting.

[BMWTurbo]

All fitted and running.

The engine wants a shit load more fuel now though. It's a slug when you put your foot down at any speed it will hold back and slowly accelerate away.

If I pull the choke FULL on so the seat drops 15mm + further down then it's normal position the engine pulls away cleanly and has a bunch more poke.

I'll dig out the details on the 'ADF' needle and see if I can work out how much needs to be honed from the needle and where to provide the additional fuel in the mid-high range. I may as well mod the current needle then spend $15 on another guess, as it's no good currently and will only need to get smaller anyways to provide more fuel.

The engine also seems much more willing to rev, I hit 5500RPM for the first time ever tonight and it would have kept barreling on I think, but it was pointless as it was nosing over in power...

[da9jeff]

so did you solve the original issue? was it just the tiny exhaust?

what needle is it now? if you have a couple spare just wet and dry it down to the next richest needle, if you search ausmini.com there is a link somewhere to a simple database that gives you all the diameters at each needle station for whatever needle. I'll try and find the link.

edit: fuck im good :D

http://www.morrismini.com/suneedlesv2.aspx

[BMWTurbo]

I think it's gone a long way to resolving the issue. The previous exhaust had a 28mm ID the new one has a 42mm ID and has 3-1 extractors.

Current needle is the 'ADF' I found a program called 'WinSU' that has all the needles listed and sizes etc. so if I look at the ADF cross-section and then work out how much smaller it is 15mm down the needle I should get an indication of how much i need to tweak it back.