09-03-2020, 11:18 AM
Hi
Our engine suddenly started to run roughly and backfire through the SU carb part way through a trial this weekend. No 4 plug was very wet and the others dry so I suspected a problem on 4.
The engine turns over easily by hand and no apparent loss of compression on any cylinder on testing cold with the starter. However, the tappet on No 8 valve was loose (disconcerting) so I have reset this, checked the others and expected the fault to be cured - no such luck, no change to rough running or backfire.
I have now taken out and inspected all the valves. They are all straight, no damage I can see and they all slide smoothly in the guides.
I am not very familiar with the bottom end of 7 engines but could there be a timing gear problem?
At a recent rolling road exercise we fitted a short trumpet air filter instead of the previous pan one and got the distributor timing correctly set and the car has run very well since, no hint of a problem. I can't see a carb or fuel supply problem.
I have yet to test with another set of plugs. but have checked for a spark on each.
Any other ideas for me to try/check?
Cheers, Rod
Our engine suddenly started to run roughly and backfire through the SU carb part way through a trial this weekend. No 4 plug was very wet and the others dry so I suspected a problem on 4.
The engine turns over easily by hand and no apparent loss of compression on any cylinder on testing cold with the starter. However, the tappet on No 8 valve was loose (disconcerting) so I have reset this, checked the others and expected the fault to be cured - no such luck, no change to rough running or backfire.
I have now taken out and inspected all the valves. They are all straight, no damage I can see and they all slide smoothly in the guides.
I am not very familiar with the bottom end of 7 engines but could there be a timing gear problem?
At a recent rolling road exercise we fitted a short trumpet air filter instead of the previous pan one and got the distributor timing correctly set and the car has run very well since, no hint of a problem. I can't see a carb or fuel supply problem.
I have yet to test with another set of plugs. but have checked for a spark on each.
Any other ideas for me to try/check?
Cheers, Rod