compression

[majic1400]

Hello, i've had a problem setting up a webber carb on my mgb with fuel being spat out the bell mouths sometime even flames,i've just done a compression check and have 180 psi, (it is a newly rebuilt engine) could that have anything to do with the problem, any help will be appreciated,also is there anyone in the poole area who does this sort of work.

[MGJohn]

majic1400 said:

Hello, i've had a problem setting up a webber carb on my mgb with fuel being spat out the bell mouths sometime even flames,i've just done a compression check and have 180 psi, (it is a newly rebuilt engine) could that have anything to do with the problem, any help will be appreciated,also is there anyone in the poole area who does this sort of work.

Post something similar over on the MG BBS here. Far more MGB types who've been there done that there :~

MGB TECHNICAL :~

http://www2.mgcars.org.uk/cgi-bin/gen5?runprog=mgb...

[wildoliver]

The usual cause for the spitting back is timing, either cam timing if the engines freshly assembled or ignition timing. Being a tooth out on the cam does cause this problem.

You don't say what the car is being used for, if it isn't racing then I'd suggest abandoning the weber, it will not improve your ownership experience one jot.

[pikeyboy]

Doubt its a race engine with 180psi compression readings. If it is it wont be very competetive.

[benters]

can the ignitionbe 180. out ?
on an A series its not always easy to identify the dizzy drive as being round the right way . . .i think its a question of the wider part being uppermost, but its a good while back that i made the error of having it round the wrong way. . .i know this is B series, but just a thought

[wildoliver]

180psi sounds pretty good to me on a B-Series.

[pikeyboy]

wildoliver said:

180psi sounds pretty good to me on a B-Series.

It is for a road engine.

From memory mr burgess says 220 ish for a race engine with a decked block burretted chambers to the correct cc etc. Prepared to stand corrected though.

[majic1400]

Thanks for all your replies, the engine is being built as a fast road engine not out and out race, although i do want to do some hillclimbing in it, it has a peter burgess fast road head, lcb exhaust,and a 285 cam, it has been bored 60 thou over with the bottom end balanced

[pikeyboy]

majic1400 said:

Thanks for all your replies, the engine is being built as a fast road engine not out and out race, although i do want to do some hillclimbing in it, it has a peter burgess fast road head, lcb exhaust,and a 285 cam, it has been bored 60 thou over with the bottom end balanced

If your still having problems speak with the maestro, he's forgotten more than most know about these engines. I've always found him very helpful and make sure you let him set it up on his rolling road to iron out any bugs. Has he sold you a 123 dizzy yet? he was raving about them when he first started doing them when i last saw him. Also ask him about whether a dcoe is good idea twin su's as wild oliver says will be a nicer ownership experience and almost flow the same cfm.