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MG MGA - Air Filter and Bad Running

Seeing Steve’s name come up I thought I would add this one.

Steve has often mentioned engine problems caused by mounting air filters upside down. Well here is a variant on that theme. While driving round a large busy roundabout my engine went rough and lost power. I drove to a safe location and problem was obvious when I lifted bonnet. The rear air filter was hanging down at a funny angle as one bolt was missing and the other loose. I removed filter and all was fine for rest of run. By the way the cause of this was clearly an incompetent mechanic, i.e. me, not tightening it up last year when I had refitted it.

Clearly similar to Steve’s issue in that the bad running was caused by severely limited air flow into rear, oops.

Good full power running.

Paul


Paul Dean

Nice one!
Steve Gyles

I dont know if it's down to my big clumsy hands, but I have always found those air filter bolts a nightmare to remove and replace.
So much so that I purchased 4x M6 75mm furniture bolts. They have allen key slots in the head, so using a key, it's easy to hold them steady when tightening the end nuts.

I slid a small plastic tube onto the bolts so that they fit snugly into the apertures in the carb body, and centre everything nicely. And I slid a plastic straw through the air filters to protect the (unusued) threads in the filter bodies, so it can easily be re-instated to the original set up, if required.
The bolts runs through from the bolt holes in the carbs, then through the air filters, with a small nut on the end to hold it all in place. The float bowls do obstruct loading the outer bolts, but it's easy to remove the float bowl lids, which gives plenty of access.
It's now very easy to remover the air filters to play around with the carbs
Graham V

Graham,
I solved my problem of having both SU carbs and hands like shovels!

On my engine, I can see and get a spanner onto all of the carb fixing nuts and I can remove the carbs in less than 10 minutes.

I cheated and fitted a Weber 45 DCOE and I run it without an air filter!

I used to hate working on the carbs because I couldn't see anything and my big hands made it a real chore to reach around the heat shield.
But the Weber is just so easy to work on, but it also appears to have the advantage of never needing adjusting.
I have run with this carb for around 5 years now and I have never had to adjust the mixture.

Running without an air filter doesn't appear to have caused any cylinder wear problems even after around 25000 miles (I have had the head off twice over the last couple of years and the cylinder bores look perfect.

The only downside is that the Weber uses more fuel than a set of twin SUs H4s, and so the fuel consumption is probably worse by around 2 or 3 mpg.

But it certainly sounds great! :^)

Colyn







Colyn Firth

Colyn
Very nice. But my solution would have been much cheaper!😀
Graham V

This thread was discussed between 13/05/2022 and 14/05/2022

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