not quite running properly

[hotrodder13]

finally got my clutch to work and the car sounds amazing but ive had the timing done and the carb set up but i think its too small as i have been told when i first put my foot doen there seems to be no power, then as speed piks up slowly it suddenly gets grip and flys could this be cause its not getting enough fuel, cant be head gasket as the water level is still up and oil is still on max

thanks tom

ps what should my oil gauge read when warm and ideling

[mike.perry]

Oil Pressure on a good engine + 60psi running and 30psi idle. My 1275 is still running with 30-40psi at 60mph so don't panic.
A small carb, HS4 or HIF38 should be adequate for bottom end performance and may be preferable to a larger carb which may give more performance at the top end. There are various air flow calculations to find te correct size carb. You may need to tweek your timing a bit to improve the performance.

[hotrodder13]

kk my psi is 25 at idle and around 70 when revving up a bit but it seems it just jumps a bit when i first put my foot down

[kittyfell]

What carb - and what needle in the carb? Also check the vacuum advance is connected, and working. Oil in the carb damper?

[MarkyB]

Try being a bit more progressive with the load pedal.
I get the feeling you are stamping on it and expecting the car to take off like a scalded cat.
Also who DID the timing? it may need to be tweaked a bit from what is says in the book.

[hotrodder13]

dont know what needle the carb is off a mini and the timing was done with a timing light will webber carb fit on an a series

[PSL184]

Forget a Webber. An HIF44 is more than adequate for your set up. Needle charts are available on line if you Google for them so it may just be a different needle that is required - However, a failed vac advance unit will give similar symptoms to those that you describe.....

[kittyfell]

Check the carb size - and find out what needle is in it. The timing can only be 'done' by trial and error - forget that timing light. You have no idea what to set it to. Advance it till you get some pinking and then retard it slightly from that point. You haven't confirmed if the vacuum unit is working. Yes a Weber will fit - forget it for a road car. Did you ever find out what cam is in the engine?

[hotrodder13]

well i tryed it by trial and error and it didnt work so its a lot better now i have tryed wth the light, and how would i check the vaccumm is working, no i asked the guy and he said it was an aftermarket road race cam shaft, aparently this engine was one of the last rebuild at leyland bmc and it was a special build with bigger valve and phropser brone valve guilds and boared out to 1310 not 1275.

and i think i need a new carb anyway because it has leaked a bit of petrol out of the choke bit and the choke dosent work on it

[PSL184]

Ahh, well with a "race" cam the engine may not pick up cleanly at low revs - Depending on the profile it could be designed to run at 6000rpm - not 600rpm

[hotrodder13]

it just seems like its holding back at the start then it just piks up so suddenly like its not getting fuel, if i drive normally it wornt do it as there is no accerlation just seems to jerk about a bit but if i put my foot down it goes like poo of a stick (cant i say that i know you cant sware)

[PSL184]

A rolling road set up (by someone who knows what they are doing) will solve your problem. Modified engines do not follow any rules for timing / fuel delivery etc and a session on the rollers is the only way to get it spot on. A decent place should charge around £70.00 for the session plus whatever parts are needed.....

[hotrodder13]

£70 !!!! ill have to have a look if i can find a place local thanks

[alex_holden]

Minisport in Padiham could probably do it:
http://www.minisport.com/mini-spare-par ... uning.html

[hotrodder13]

i emailed them and they said they can do it so i might book it in when i get a new carb

[MarkyB]

I suggest you ask them to tune it for drivability, rather than maximum power in a narrow band.
Unless you plan to race it of course.

[PSL184]

Good plan.

[hotrodder13]

might have to be driveability because its only taken 2 days to use half a tank and not done that many miles could be my driving though,

thanks tom

[bmcecosse]

If it has a 'road race' camshaft it will never be economical. Still waiting for carb size and needle spec ? Don't expect miracles from the RR session - they are mostly interested in producing print-outs of the power which are good for Pub Points........ apparently.

[hotrodder13]

carb size is 1 1/2 and i dont know what need all i know is it came off a mini