The NGK's will be gapped to the correct gap out the box.

I use Denso KPRU20s straight out of the box. I do check the gap every time though - a .7mm feeler will go through but a .8 feeler won't..

If the engine feels jerky at low revs and you've checked/renewed everything electrical then re-checking the plug gap, closing it gently to .7mm is worth a try I guess. But Classicswede's advice is professional based on many cars, I've only experience of just the one!

The other thing to check is the condition of the throttle cable. The plastic coating degrades and then the cable rusts, making it jerky in operation.

Might be worth having a look at that too!

Cheers

Jack

Thanks guys, what would we do without your accumulated experience and wisdom? :)

LPG Volvo S40 T4
 

Hello.
I have read all the posts in this thread with great interest.
I recently became the new owner of a 1998 Volvo S40 T4, which I adore apart from one thing... it is very thirsty. A bit of a shock after running a diesel Mercedes 190 for many years!
So I figure I have 2 choices... I trade it for something less beautiful but more economical :broken_heart:, or I go the way of the LPG.
So my inevitable question is .. is my B4194 engine going to be OK with a conversion? And, if it won't have valve seat problems, what's the best manufacturer to go for?
Many thanks!

what kind of MPG are you getting? This engine is the ,most economical petrol engine in the S40 range except the GDI . you should get over 30 mpg and upper 30's on a run , but if you buy a T4 you use the performance i guess .

Hello Clan.
Thanks for your interest!
The point really is that my Merc did 40 imp. mpg (7 litres per 100km), and with diesel at 1.5 euros a litre here in Portugal, that worked out to be around 10 euros per 100km.
The Volvo, at an optimistic average of 32 mpg, let's say, (8.5 litres per 100km) runs best on '98, at +- 1.76 euros per litre, that works out to be close to 15 euros per 100km!
So, my point is not that I am disappointed with the Volvo, or that it is economic relative to other Volvos in the range, but that it is costing 50% more than my previous car to take out of the drive!

It's a great car with just 112,000 km clocked, and full service history from Volvo. So I would like to hang on to it, hence my interest in LPG conversions.

:car-smiley-003:

maybe you got the wrong car , the diesel S40 will do 55 mpg easily on a run ...

Ha! Quite possibly you are right Clan! At the time I bought the lovely S40, I wasn't looking for another diesel, and just maybe my expectations are too high?... But this is Portugal, where annual wages are dictated by a measly 460 euros a month minimum.... so fuel efficiency really matters :) Maybe I'll just go out less often!

People are staying home more often in england due to the price of fuel , it is going up to over £1.50 a litre in the new year ..

So, the best way to go is with a good hefty old diesel engine and a generous amount of chip fat then? :)