Carb problems!!

[Mark1Ant]

Hey guys long time no speak!!!!

been busy putting my escort back together over summer.

basically the car was running a slightly tuned crossflow on twin 40's and through about six months of abuse i think it bore washed and ended up doing the piston rings.

so since april ive been building a new engine and went a lil bit mad!!!

the cam for starters wasnt exactly ideal for the road but down the strip will hopefully make a huge difference. cam i went for then was a KC262, then had the bottom end all lightened and balanced having gone mad with everything else, apart from a steel crank due to the fact that they cost millions!!!!

the head is stage 3 with roller rockers etc....but the car was only running twin 40's. it made good power on the rollers at 135bhp n still spinning but was dropping off a top end and generally felt lacking if you know what i mean.

so i went straight down to southern carbs and purchased a brand new set of twin 45's!!

now they are all bolted on and the car is running better than before however, without being rolling roaded! but it has a missfire at 5000rpm and beyond. ive asked posse what he reckons it could be and he thinks it may be an air leak in the inlet manifold?

Any suggestions chaps? other than the routine stuff ive done, i.e ive changed the dizzy cap, plugs, and got a new set of magnecor leads. Please help!!! Cheers guys

[Cookie]

Not much help i,m afraid as twin carbs i'v had very little experience of

 

But to rule out an air leak on inlet i do know if you keep engine running and spray some wd40 (or similar) around all gaskets and joins etc, if the engine revs up then you have found the problem! if not then back to square one

[Gareth]

It could be an airleak, but I thought that'd be evident at idle

I'm not overly sure as I've no twin carb experience.

 

U sure the timng or fuelling's not a little off

 

That can cause a misfire at high revs.

[Fiesta Steve]

Check your fuel pressure

[Fiesta Steve]

Check your fuel pressure

[erick]

Fuel starvation at high rpm would cause misfiring, what fuel pump, regulator are you using?

 

Also what jet sizes are you using.

[Capri_Steve]

Check jets are correct and your O-Rings are not leaking.

[Mark1Ant]

i asked they to sort out the jets for the cam before i bought the carbs so they should be jetted correctly however you never know! but i do have the right set of jets in the 40s which may be worth a quick swap just to see wat happens!

as for the fuel pump im using a facet silver top.

[Fiesta Steve]

Is it Silver top road (upto 150 bhp) or Silver top race (upto 200bhp)

[Guest jimbo]

Sounds like its not getting enough fuel at higher revs, try going down one size on the air jets and see if that has any effect

[jayson2.3pinto]

check fuel pressure m8 check points are ok ,or fit lumenition /also check leads plug s dizzy cap southern said carbs are jetted correct ? theres no way some one can judge your carbs m8 unless engine is there in front of them ie rolling roads you could take car to rolling road peter sanspeed he is at bexly heath

[Mark1Ant]

im pretty sure its a silver top race as the fuel pump came out of a starlet hotrod. didnt actually know that they made different spec silver tops.

ive changed the leads for magnecors and got a new dizzy cap but its a weird screw in side entry. supposed to be off a mini. its all lumintion on it so im guna have the car all set up on the rollers now and see wats wat.

jus wana get the car sound before i tuck it away for winter.

thanks for the help guys ill keep you all updated. i would a put a few pics of the car up but it wont let me!

[faster]

Check your fuel pressure

 

So good he had to say it twice