how often should you check engine valves ?

Post by **karl40** » 29 Jul 2011, 23:41

Have had a slight back fire for some time now(well more of a poping when breaking) i have changed all the breather pipes, new HT leads, cap, etc and retuned, But still have it. Could it be badly adjusted exhaust vales? I have never checked the valve clearenses in the two years i have had her. When excelerating up hill or under load there is a noticable beetle sounding clatter but no loss of power and the idle is smooth. Am i way off base and putting 2&2 together and getting 5.
Cheers Karl.

Post by **Hacksawbob** » 30 Jul 2011, 00:07

and the engine is? They are mostly hydralic valves unless changed for solid. If they are original they dont need adjusting, but if shagged then replace. popping? holed exhaust?

Post by **jimpainter** » 31 Jul 2011, 06:56

/\/\/\
WHS
Sounds like you may have a small hole somewhere in the exhaust.

Post by **BOXY** » 31 Jul 2011, 09:04

Popping on the over-run is normally caused by un-burnt petrol from a rich mixture flashing over when it gets into a hot exhaust. The "clatter" under load might be pinking this is caused by lean air/fuel mixture or timing being too advanced and sounds like ball bearings being shaken in a glass jar. If it is pinking it might be worth checking the timing to try to dial out the pinking because that will do more damage than the popping.

Post by **karl40** » 31 Jul 2011, 10:21

Sorry i should have said it was a 1.9 DF WBX with 102,000 on the clock. I followed the Haynes manual and adjusted the valves and replaced the rocker covers and gaskets. I have in the past adjusted the timing with the aid of a strobe gun and just twisted the distributor getting the notch on the fly wheel to line up, but that was as far as it ever went. As for adjusting the air fuel mixture i have never done that. Can someone give me an idiots guide on what i need to do as the popping is still there. I have inspected the exhaust and cant find any leaks and all the breather pipes were changed only months ago along with HT leads dizzy, plugs air filter, fuel filter etc. Cheers Karl.

Post by **kevtherev** » 31 Jul 2011, 10:40

Breather pipes?
Or do you mean vacuum hose?
Has the servo hose been tested for air leaks
Are all the manifold gaskets in good nick. Including the one on the head?
The mixture can only be set properly using a CO analyser or a gas analyiser.
With out ensuring that there are no leaks this mixture ajustment is futile

what carburettor is it?

Post by **karl40** » 31 Jul 2011, 12:34

Hello Kev
The break servo pipes, vac tubes were also changed only months ago. The carb is a PICT 3 single down draft i think, so it is an old style WBX 60bhp. The van runs very well other than when you put your foot right down when climbing hills ect and thats when you get the pronounced almost beetle sound from the exhaust.It might just be me being over fussy but when you ease off the throtle it subsides. The popping is most noticable when warm and coming downhill to a stop and thats when you get the odd pop but no backfire.I dont want to leave it and it might be damaging the engine, thats all.
The local garage near me has an old Vw trained mechanic there who normally gets the van when i take her in, so i might ask him to test the CO2 and set the mixture for me. My wife says i spend more time with the van than her..........she is a nice van though.

Post by **kevtherev** » 31 Jul 2011, 15:03

Popping is a leak
I'd hunt that down first... or your chasing dragons with emissions

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