Just a couple of questions....
Turbo Mini Forums

Right, my latest engine is up and running. Just a couple of simple questions.....

I run a low compression MED fully worked head, 1.5 rollers, 10cc dished pistons, MED T3 cam, standard bottom end/transmission.

Thats my rough specs.

My timing gear is all standard non adjustable, should i really be looking to fully adjustable stuf for this cam shatf??

The engine will not lean out, drives fine but allways runs rich. I never had this prob on the last engine, and up until it blew it was spot on fuel wise. The carb WILL NOT lean out, im sure it doesnt wear out over night, can anyone explain the sudden rich-ness?

The carb needs a rebuild - just wanted some ideas really and no the choke is not on/stuck!

Ideas??? (sorry post is a bit long)

FAO Turbo Dave.

I seem to rember you saying something about the bio metalic Jet holder in the float chamber not being 100% suitable for use in the confined space of the Mini engine bay, as the temperature drastically affects it, any info on this would be great please!!

Ideas on the carb... if its been sat maybe the choke o-rings have gone hard? (makes it run nice and rich )

I wondered that, but it seems to have occured in the 4 months my car has been off the road, really think they have perised in that time of non use?

Could have done, anythings possible!

Sounds like a strip down of the carb is in order, atleast its not too big a job

Carbs have a bad habit creating all kinds of problems when sitting idle. The fuel evaporates and leaves deposits, crap whatever. One thing to check is the needle valve. It is possible that it leaks and creates a rich situation. SU is such a simple pece that there are practically no other reason for over fuelling it it ran OK last time. OK; HIF choke might be another but those carbs I have taken apart had o-rings in good shape.

Jukka

As jukka says, stagnant fuel is a reall rotter.
I suspect the main jet is seized in the carb body, hence it won't raise and lower... I've had this on two carbs that had a lack of use.


Replacing the bi-met strip is a good idea, but admittedly many 'appear' to work fine without the mod...

There is a whole section on this in the FAQ!

Edited by turbodave16v on 19th Feb, 2004.

Theres no such thing as non-adjustable valve gear on a mini Just measure your current cam timing... and then to change it to the desired figure use an off-set woodruff key!

Alex

AlexF

I have had lots of problems with carbs arter they have been sitting for awhile. Last time i couldnt get the car to fire. I stripped the carb a number of times but i couldnt find anything. I solved it by putting the fuel line in on the anti run on valve out pipe ( if that makes sense) this did the job and the car fired first time

Can someone please explain to me what an"offset woodruff key is" how to use it etc, It is something i have never done before...

Any ideas what i should be running? (my rough spec is on the first post) + the head has 30.5 cc chambers and i use a standard metro turbo head gasket, standard bore 1275, 10cc central dish pistons, 1.5 roller rockers, MED t3 cam, standard metty turbo dissy mk2,)

And dave, why when talking about the bi-metalic jet holders do you say " many "appear" to work properly "

What do you mean by appear??

Offset woodruffs have a 'step' in the cross section, such that the area protruding from the camshaft is 'offset' hence meaning the cam wheel moves round slightly.

By 'appear' i mean that not many people have actually done this modification to the jet holder, and claim to have no problems. You can't deny however, that the device is great on carbs that aren't subject to external heat sources (on a crossflow head for example). It is just too compromised with a hot turbo only inches away from it - especially if the vehicle is left idling and heat soak is carried into the float chamber...


Try it on a rolling road - get the vehicle up to full temperature, with lots of heat soak by letting it idle, then do a power run immediately.
Now repeat by 'driving' on the rollers for at least 30 seconds at light throttle to get a good airflow through the carb (to cool it).

It does make a difference!!!

D