164 Flame trap

[woolfie1948]

I checked the valve clearances on the 164 B30A this afternoon.
While the rocker cover was off I noticed in the top there is a mesh flame trap inside a connector for an air hose that goes to the air filter.
It appears to be clear and clean but somewhere in the back of my mind I seem to remember reading that it should be removed and not replaced.
Please can someone let me know - should it stay or should it go - or does it matter either way?
Thanks
Jonathan.

[Audrey Old]

Hi Jon

Somewhere deep in the old grey matter I recall reading that they should be left out of the B18/B20 engines - possibly to avoid a blockage. As the B30 is just a big B20 that logic should prevail.

I also recall the rigid outlet pipe on the Amazon can get blocked thus pressurising the innards so that either the rockerbox cover gasket or the filler cap leak oil. On the B30 I've found it very difficult to prevent seepage around these gaskets, but haven't tried it with a new cork gasket yet. That will happen when I do my tappets (after I do a dizzie swap due worn bushes and clacking balance-weights).

Perhaps others can comment.

Paul

[john h]

I have read the same. I'd remove it.

John

[woolfie1948]

Thanks Paul and John.
Good to have confirmed it is not just in my head!
The question that however does spring to mind is - why did Volvo want to trap a flame and so put this in the pipe?
Paul, I also found I needed a new rocker cover gasket yesterday, not having the forethought to buy one, I put a little red Hermatite on it that I found in the box of bits that may come in useful oneday, must have been there for more years than I care to think about. Hope that will do it till next time it has to come off.
You have reminded me now there should be a spare oil cap sealing washer in that box too!
Jonathan

[guitarman]

The wee piece of gauze in the top of the flame trap is an odd one-mine was totally blocked when I bought the car so I chucked it and have never replaced it.What its purpose is remains a mystery!

[john h]

I think it was intended as protection in the event of a huge backfire... to stop any flame in the inlet manifold igniting the oil vapour in the block.

I've never known such a thing to happen on a Volvo. Or heard anyone else that has.

So, I'd say remove it and don't loose any sleep over it!

John