Crap To Cream, MGB engine still a bit rough at idle, finally figured it out, wasn't what I expected.
Вставка
- Опубліковано 25 тра 2024
- Since finishing the rebuild of Millie my MGB has been running a bit rough more so on idle than any other time, also a bit of back firing happening,
I posted about this before and got suggestions of things to check, the majority of which I have done with no success. So I finally gave up blaming the HIF carburettors as being the fault after many happy hours trying to set them up right.
The issue seemed to be around number 3 and 4 cylinder which seemed to have no power and also had little impact on how the engine ran at idle when the plug leads were disconnected.
I ditched the HIF carburettors blaming them for the problem and I fitted the Weber 32/ 36, only to find out a day and a half later that the carburettors weren't the fault.
So let the fun begin, I've now figured it out, the story is in the video. Enjoy more than I did trying to find the problem..........
Thank you to all my subscribers and followers, comments are much appreciated, loving the encouragement to do more............. Hope you enjoy this one. - Авто та транспорт
I remember being shown that if you start the engine with your foot on the brake pedal, you should notice it drop a little if the servo is working correctly.
Hi Julian, now you mention it I seem to remember something similar, at the time I was in a different head space. My brakes have been pretty crap since the rebuild, still got air in the system somewhere, I have to bleed the brakes properly when I’ve replaced the servo. I got there in the end. I’ll be interested to see what the inside of the servo looks like when I get that apart. Again thank you👍👍
Stepped washers - had to do the same on mine. A good solution
I have had 3 MGBs and friends with another 2. All of the cars had been replaced with webers, but I had always heard from purists on the fourms how horrible Webers were, and 'perfect' the SUs are, mostly about so much more power. Ended up coming across a forum post last year where someone swapped out carbs on their B and dyno'd them all. Turns out very little difference between them (even the zenith) in terms of power delivery--under 5 HP if I recall.
Thanks for the comments John, what you say doesn’t surprise me. The Weber 32/36 does claim better efficiency which I have found myself, however better efficiency in the same engine means using less fuel which in turn does mean. Less power, you’re not burning or using the fuel. Power is nice but I enjoy my B for the driving pleasure and experience on the open road, I’m not what you would call a “speed demon”. Again thanks for the comments.
Hi Marty, Great diagnosis. I'm guessing if your servo has failed, the brake pedal must have been really heavy?
Thanks Carsten, the brakes, that’s a whole other video, had a lot trouble bleeding the brakes in the first place, hopefully easier when I replace the servo unit.
No offense but I prefer the SUs. Balancing is simple and rarely needs re adjusting. Performance and economy are about equal to the Weber
No offence taken at all. All credit to the SU's they hid the issue with the servo diaphragm leaking better than the Weber did. Had I not had the Weber option I could well still be in a place with the rough idle and leaking servo. On closer inspection I found the SU on cylinders 3 and 4 had been adjusted (by me) to compensate for the additional air flow from the leaking servo. Whilst the engine ran better it was by no means perfect hence the reason I went down the track I did. Thank you for the comment, appreciated your perspective.