Cold starting issues - new build rover 3.5v8

[atkinsal]

Hi all

 

Wonder if anyone can help.

 

I have a series 2a landy which I recently fitted with a rebuild rover 3.5 v8 from a Rangie classic (been wanting to do it for years!!). As part of the rebuild I also replaced the igntioin electrics with a kit from powerspark so it has new distributor, 8mm leads, plugs, coil etc. 

We also rebuilt the carbs (strombergs CD175) with new gaskets and it also runs on lpg.

 

So the problem is that it starts and runs well when it's warm but is an absolute bugger to start when the outside air temp is cold. In the summer it was ok, I could get it to start but now it is getting cold it is an ordeal to get going. I usually crank and crank and then smell petrol in the exhaust so give up. When I come back in a few hours (and often with jump leads) it will eventually fire but again, after cranking and cranking. Once it fires just once it will then restarts straight way, even if I turn it off as soon as it starts the first time.

 

Also I’ve never been able to start it on lpg when the engine is cold, even in the summer. Again, it'll start on lpg after the engine has been fired up the first time.

 

So, anybody have any ideas that might help. I've never owned a rover v8 so am at a bit of a loss where to start troubleshooting.

 

Is there a technique to starting these v8s when the air temp is cold?

 

I thought I might be over choking but have tried without and, a little and a lot, still doesn't seem to help.

I did think perhaps I'm not getting a really strong spark?

Any pointers on how to diagnose the problem would be great.

 

Thanks. Alex

 

Specs:

Rebuilt (with Rimmer kit) 3.5 v8 from late 70s / early 80s range rover

Carbs - strombergs CD175

Complete 35DLM8 Electronic distributor

Genuine Lucas ignition module

Genuine Lucas DLB198 Coil

POWERSPARK™ 8 Cylinder Red Powercor HT Leads 8mm

[Bowie69]

Does sound like your spark is weak, I used to start my LPG Rangie in all weathers without issue.

What voltage have you got to the coil, and what voltage is the coil? Some are 6V coils, which get supplied with 12V when cranking, and then revert to 6V when running, this is a ballasted system. Others, just use 12V all the time.

I just checked your coil, and it is unballasted, so needs 12V all the time. I don't know what your wiring is like so can't comment further, but it will need this (or close to) during cranking as well as running.

Check the spark with a screwdriver in the coil lead and allowing it to spark to the block, if thin and blue, rather than a nice fat spark, then something is wrong.

Have you checked your timing? If a long way out it will affect cold start, then once the plugs are fouled you have no hope.

 

 

 

 

[Jon White]

You have got the choke connected up and are using it?

[lo-fi]

Is it easier to start if you squirt a little fuel into the intakes when cold? If so, you have a fueling problem, if not, you've likely got a spark problem. Have you balanced and tuned the carbs when you have had it running? 

One other thing I'd ask is when you rebuilt the carbs, are you sure you got all the bits of the choke mechanism on the right way? If I recall correctly, you can get one of the plates or linkage on 180 degrees out, so the holes don't line up. Also that the tiny little passages were clear of buildup. Mine weren't when I rebuilt them, and took some clearing. If it's too lean due to lack of working choke enrichment, it will be a pig to start, but still smell of unburned petrol - it's just too lean to burn. Obviously not a problem when hot. 

My 3.9 on rebuilt similar vintage Strombergs, a Bosch coil, Powerspark electronic points and standard leads starts hot or cold with the merest ticket of the starter, no special technique required other than setting the choke. Right out if it's really below freezing; less depending how cold. A tiny smidge for first start on hot summer days, and nothing if the engine is even the least bit warm. 

Could be weak spark as Bowie says, the Lucas stuff isn't always what it used to be even if it's brand new out if the box - that's why I've got a Bosch coil... 

Pop a squirt of fuel down the throat of each carb on the next cold start and see how it goes.