Poppin' and misfiring

[ChesterThompson]

Hi
I've just done my first adjustment on the tappets of my newish car, in the end I didn't really change much because they all seemed in pretty good shape. But once reassembled the car is running terribly! It cannot idle to save its life and will only run vaguely well when a lot of throttle/choke is applied, before the adjustment it was running pretty perfect! (Why did i meddle?!?!).when trying to idle there are pops and the engine bay smells of petrol also a lot of vibration.

When i was adjusting i took out all the plugs and one of vacuum tubes, so maybe its not running on all cylinders?
Also when adjusting the tappets i turned the engine backwards a few times to try and get the valves in the right place, could this have slipped the timing gears? (Thought this only happened on belt and chain driven engines)

Anyway any insight would be great!

Thanks, Chester

[Volvo_133]

Hi,
A tappet over tightened may prevent a valve from fully closing, though your comments suggest minor adjustment only.

A loose plug?
Ht leads on wrong spark plug, re check firing order is 1342 anti clockwise rotation.

You cannot upset timing belt or chain as they are gear wheel driven.
If all car ran well and all was ok before your adjustments, there cannot be much wrong with it.

[ChesterThompson]

Alright I've done some more tinkering. Ive re-done the tappets, again very minor adjustments and the backfiring seems to have subsided a little though. I used the method of putting engine at tdc then setting valves 1,2,3,5 then rotating and setting valves 4,6,7,8.

If I add some throttle car seems to run okay, but just at idle it backfires then stops. Noticed the spark plugs have all got pretty black with carbon after this happened.

This is the first time I've adjusted tappets, is there something special i need to be doing?

Thanks for your help!

[amazon69]

It's quite easy to adjust the wrong tappet. Good advice here.

And, as suggested, check your plug wires. It'll be something simple. And it is worth doing, so once sorted, you'll be better off. Good luck.

[Noslho]

Hi Chester!

As mentioned, check the spark plug leads. I serviced a Morris Minor I had and experienced the same problems. Turns out I had been a numpty and put the leads on to the distributor to run in a clockwise firing order, not appreciating that the dizzy ran anti-clockwise. Swapping the leads round returned the smooth running.

Best of luck.

Cheers

Gary

[ChesterThompson]

All is well! Turns out i'd set up the dizzy for a clockwise firing order, as soon as i switched it back all was good! Tappets have got a little louder than they were before but after adjusting all of them about 5 times i dont think my back can handle any more tappets!

I suggest you don't remove the rocker cover to try and hear which is your noisy valve or you'll get a face full of oil splatters and your shiny engine will be covered in the black stuff. (Just a handy hint from what i've learnt today)

Also found out my carbs were pretty badly out of sync, I've try to adjust that with a piece of hose i think i got it pretty good! the engine now runs eerily smooth, it doesnt cover up all the other horrible shakes and jingles anymore....

Finally after trying to do a ghetto tune up without any of the proper equipment i've got it so that after a 10 min drive the plugs are a nice tan colour, does this mean this tune is all okay?

Thanks for all your help!

[arcturus]

Give it a really good hard drive and re check. As for dizzy dizy, we've all done it!

[niveketak]

I made a mess of replacing the leads on a mates Rover V8 engine Morgan. The car started and tickover was fine but misfired as soon as revs were applied. After much cursing, swearing, doubting of its parenthood I realised 2 and 3 were on the wrong plugs. As arcturus said, we have all done it at one (or more) time. Nice when it is something so simple in my opinion.

[volvogv]

Here's a good video on the topic:

https://www.youtube.com/watch?v=WwkEsDStWsM

Let Chantielle show you the way!