1950cc MGB way down on power!

1950cc MGB way down on power!

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Billy_Whizzzz

Original Poster:

2,008 posts

143 months

Friday 11th November 2022
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Got a ‘68 MGB that I bought with a 1950 Oselli engine that has been dry stored for a few years. I’m struggling to get it running well. It has been extensively recommissioned with a new stage 2 head, Weber, and 123 distributor. Sent it in to be set up on the rolling road and is way down on power - 65hp at flywheel and won’t rev beyond 4000. Compression is very good and I know engine is generally strong and in good condition. Carb has been rejetted. It was in the rolling road a few years back before it was put into storage and was showing 101hp at flywheel on twin SUs and standard head. We’ve been through most obvious things. Could for some reason the cam be a tooth out (can’t think how or why…). Anyone any other thoughts? No garage locally seems to be up for going through timing!

Geordie MGmike

134 posts

139 months

Thursday 24th November 2022
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It's virtually impossible to get the cam a tooth out and if you did, your compression would likely be down.
Sounds like a fuelling issue to me. I'd dump the Weber (for now), go back to simple SU's and start from there.



v8s4me

7,242 posts

219 months

Wednesday 30th November 2022
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Have you flushed out all the old petrol? if the car has been standing for a long time with old petrol then there's a good chance the whole of the fuel system is gummed up with crud.

Go back to basics. New plugs, air filter (if you have one, replace the fuel filter, replace the fuel pressure regulator (if you have one), fuel pump maybe? Personally I'd put the original mechanical distributor and new points in for this exercise so you can be sure this part of the ignition system is working. Once all that is sorted, set the timing up from scratch using a good quality timing light.

If the car was running well with the Webber before it was laid up then there's no reason why it shouldn't run well now. Strip, clean, make sure all the jets and galleries are clear, set the float height correctly and reassemble with new gaskets and seals. Refitting the SU's just introduces another set of variables and potential problems.

You might also want to make sure the cooling system is thoroughly cleaned out as well.