940 spark plug preference on turbo? Standard or uprated?

[Clan]

Originally Posted by Laird Scooby

Once upon a time i would have agreed with you but as noted elsewhere in the thread, they're made by Bosch, albeit to (allegedly) better standards than the rest of what Bosch make.
I've noticed in general Bosch have been getting poorer in quality in recent times and in fact, i recently bought a NOS Bosch rotor arm (and dizzy cap) on ebay for my beast. I was astonished at the amount of flashing on the moulding, all of which needed cleaning off (came off easily enough, should have been done at the factory though) or it would have prevented the rotor arm mounting properly on the dizzy shaft. Someone else may not have noticed or worried about this and potentially had problems as a result. The point is, if there QC is letting things through with excess flashing, what else are they letting through?

In recent times (past 8-10 years) i've noticed a lot more misfiring Bosch plugs, even with correctly set gaps.

I've only found 4 misfiring NGK plugs and the gaps were ~1.3mm, representing 60-70k miles since they were last changed. Cleaned and regapped and the misfire was gone - they've since been renewed though.

I think they had every right to be misfiring a bit when they were that far past their useful life so even those 4 can't really be counted.

Also i later found an invoice from the plugs being supplied and fitted at ~60k miles (and 10 years!) previously which substantiated my theoretical 60-70k miles that they'd been in. As the receipt was from a relatively local Volvo "specialist" it would be nice to think they set the gaps correctly and didn't just leave them at the NGK factory-0.9mm gap.

Interesting to note though that an independent Volvo specialist was fitting NGKs in preference to Volvo plugs 15 years ago though.

I havent seen a New Volvo bosch distributor cap or rotor arm for a while , tell me , is the inside of the cap or surface of the rotor arm a matt finish or is it Lacquered ( shiny) ?

[classicswede]

Originally Posted by griston64

My nearest Volvo independent doesn't use any genuine Volvo parts

I think it's more down to price than quality though

With some things genuine parts are not far off aftermarket price. The key is knowing if the volvo part is good or not and if not what is the best aftermarket to use

[classicswede]

Originally Posted by Laird Scooby

In recent times (past 8-10 years) i've noticed a lot more misfiring Bosch plugs, even with correctly set gaps.

The problem with Bosch plugs has been there for at least 15 years. I have had problems with almost every set of Bosch plugs I have used but never and problems with Genuine Volvo Bosch made plugs or NGK's

The reason in part is down to QC
For the Volvo plugs 5 plugs are taken from each 100 produced. If any of the 5 fail the batch is rejected.
For Bosch 5 plugs are taken from every 1000, provided no more than 2 plugs fail the batch is ok and the 2 failed plugs are put back on the line to be sent out as the failure rate is in tolerance!

[Laird Scooby]

Originally Posted by Clan

I havent seen a New Volvo bosch distributor cap or rotor arm for a while , tell me , is the inside of the cap or surface of the rotor arm a matt finish or is it Lacquered ( shiny) ?

It's not lacquered, i don't know if Volvo still do that or not. I did consider lacquering it myself but was that disgusted at the poor quality of the rotor arm that i decided to save the lacquer and put what it would cost towards the next rotor arm and dizzy cap.

[john.wigley]

I have a set of 4 Bosch Super WR 6 DC plugs left over from my 740 / 940 days.

They are brand new and unused but must be now all of 15 - 20 years old, possibly more. Two of the boxes are still sealed, two have been opened, but the plugs still have on the little cardboard tubes to protect the threads.

If anyone can make use of these and would care to send me a stamped addressed Jiffy bag of appropriate size, they would be most welcome to them.

If interested, please indicate on here and then PM me for address. First come, first served, and I'll pop them in the post to you on receipt.

Regards, John.

[AllHailKingVolvo]

Originally Posted by Clan

I havent seen a New Volvo bosch distributor cap or rotor arm for a while , tell me , is the inside of the cap or surface of the rotor arm a matt finish or is it Lacquered ( shiny) ?

The Bosch dizzy cap I got from Volvo a couple of years ago for my petrol 940 (obviously!) was lacquered on the inside, as opposed to the Bosch one that came off the car which wasn’t, so as of 2019 the Volvo version was lacquered. Workmanship on it was superb, no issues whatsoever.

Plug wise I always use NGK BPR6ES, as I always have some around-I race go karts, and the engines I run use the same plugs which is a useful coincidence!

I’ll sling some genuine Volvo plugs in next time though as I’d like to compare the twain.

[ukvolvo]

Originally Posted by 360beast

Ngk bpr6es

Thanjs again,

So the general consensus is volvo or the basic Ngk's?

Gap size if anyone knows it ?

I personally dislike Bosch parts and saw the quality issues coming in years ago

Think i will go for some Ngk

Cheers
Mick

[griston64]

Originally Posted by ukvolvo

Thanjs again,

So the general consensus is volvo or the basic Ngk's?

Gap size if anyone knows it ?

I personally dislike Bosch parts and saw the quality issues coming in years ago

Think i will go for some Ngk

Cheers
Mick

For the B230FT and FK I'ts 0.7-0.8