Pinto Poping and back firing !

[Chris R]

Hi Guys,

I'm in the middle of a long winter refurbishment. However I am running the engine at least once every three weeks just to keep this moving etc.

I know leaving engines on tick over for long periods will cause more harm than good due to the acedic build up in the oil etc. So I let the engine idle for about five minutes with short periods at about 1500 rpm until the temp shows normal. I then run the engine at about 2000 -2500 for about 3 - 5 minutes and the turn off.

This should ensure the thermostat has opened and coolant has flowed round the system.

The engine is a 2.1 Pinto with a stage 3 head, fast road cam (not sure which number) and twin 45 DCOE Webbers. The exhaust has a newish repackable silencer.

My problem is that the exhaust is back firing and poping through out this period.

Is this normal ? (I haven't had the car long and only managed to drive it on two very cold weekends before starting the strip down.)

I'd appreciate any guidance you can offer.

Thanks

Chris

[Thrustyjust]

With the fact that the car isn't moving and you are revving it stationary,might mean that the exhaust is hotter than when moving,you will probably be pushing fuel into the exhaust because the cam overlap that you will get on modded cams.This is then igniting in the manifold and causing the popping.One guess.

[Blatman]

Yup. And/or you have a loose/leaky collector...

Plus, revving it to 2500 for a few minutes isn't giving you the "protection" you imagine, and as Thrusty says, you're probably just running neat fuel into and out of the bores. It'll clean the oil off pretty effectively...

If you aren't going to drive it, just leave it. It'll be fine, honest. I leave my Cossie from October to June (usually, and for the last two years, it's been left outside) without starting it. It normally starts first go. Biggest grief is the siezed clutch which takes bravery and an empty bypass to unstick

I haven't started my Vx for 4 or 5 months (has it really been that long? ). I'm not worried that it won't start, and it isn't coming to any harm just sitting there. It'll need another coat of WD40 soon though...

[Chris R]

Okay, thanks guys.

Chris

[Man On The Clapham Omnibus]

Biggest grief is the siezed clutch which takes bravery and an empty bypass to unstick

My late father-in-law's old K reg 1.3 Marina sat in his garage for the last few months of his life some twenty-odd years ago. Eventually the time came to sell it and it fell to me to get it out and clean it up. The clutch was totally stuck to the flywheel and it took a lot of pretty brutal treatment trying to stop the car against the brakes with the clutch depressed to free it. When it went, it went with a damned great bang - very satisfying.  

[bultacobarry]

My 2.1 pinto does the same if I have to idle for too long, nothing to worry about, i think

As an aside, are you sure it has an unleaded head in it ? Many big valve pinto heads do not have hardened valve seats.

Barry  

[Chris R]

Hi Barry,

Yes the valve seats were changed to suit unleaded, it was uprated at the same time to gas flow the ports, match the manifolds and three angle work on the valve seats.

I've read different ideas regarding the twin webber carbs, how often do the carbs setting up ? and how will I know they need setting up ?

Thanks

Chris