O.K i feel stupid to ask this but I am confused. Is the housing of the flame resistor the flame trap? The reson I ask is my oil cap is leaking so I figuered it was the gasket but it wasnt. When I removed the cap the was a good bit of the gas that is to go though the flame trap, but if the flame trap is what I think it is then the PCV system is clog somewhere else but where. I check to see if the was any gases comeing though the flame resistor and there was very little if any. Someone help me please.

Thanks,
Ace
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88 240DL a.k.a the Blue Tank

The flame trap on our 81's takes a 5/8 ID hose. If you buy a couple feet of 5/8 ID PCV hose, it can be used in conjunction with a piece of 5/8 OD copper pipe and a new piece of the smaller hose to relocate the flame trap to a more convenient location. This worked great on our 81 K-Jets.
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Thanks everyone for all the information and advice, Doug C. 81 242 Brick Off Blocks, stock, B21F (non-Turbo), M46; 86 244, B230, 140k , auto.

Yes, the "flame trap" includes the housing that the actual flame trap (plastic or metal with many holes in it) sits in. If you disconnected the hoses to the flame trap then you probably wouldn't see much gas since you effectively removed the vacuum source which is pulling the gases out of the crankcase...

The PCV system consists of the following (starting from the engine block):
"Breather Box/Oil Separator" - big black box under the intake manifold.
This box collects whatever oil vapors that may be in the crankcase and turns the vapors back into a liquid oil. This separated oil flows down a long tube that ends in the oil pan.

"Flame Trap" - This is the housing that we are talking about, inside is the plastic disc with all the holes in it. Has one inlet and two outlets. Inlet attaches to the breather box. Two outlets: Small one connects to a nipple on the intake manifold, the other (larger) outlet connects to the Air intake hose (I believe) just before the throttle body.

IPD has a great picture:
http://www.ipdusa.com/images/Categories/RearWheelDrive/flametrapdiagram3%20copy.gif

The breather box may be plugged with oil residue which will prevent the system from breathing properly. The test to see if your crankcase ventilation system (PCV) is working is to loosen the cap while the engine is running. If the cap dances/jiggles while its loose then you have a plugged PCV system, if it stays put then the system is doing its job. Did you change the gasket on your oil cap?

Check the 700/900 FAQ for details about this test and for solutions to your problem.


Good luck,
Bean
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'80 242GT 93k, '94 945T 139k, '89 765T 68k (new '94 B230FT)

Yes I did change the gasket that was what I thought to be causing oil to leak out, but with the new gasket it still leaks. I clean the flame trap and all of the hoses and the inlet in the man. last weeked and they all are still clog free with a little oil on them. The "jiggle test" only works on matel caps, I have the plastic one. Would a piece of graden hose be to big/small to do the test said by Art, I dont have any other hose that may fit.

Thanks,
Ace
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88 240DL a.k.a the Blue Tank

Off the top of my head, a garden hose should fit. Pull off the hose between the breather box and the flame trap and compare it to the hose you have. If your garden hose is too large (you want to get a good seal) then go to any hardware store and they should have a diameter which will suit you.

Didn't realize the jiggle test only works for metal caps...I wonder why?

Good luck,
Bean
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'80 242GT 93k, '94 945T 139k, '89 765T 68k (new '94 B230FT)

The gases have to pass through a labyrinth in a box, called the oil separator, or oil trap, bolted low on the block above the starter. The top of this has an outlet tube that connects to that three-way flame trap holder. One way out is the small hose to a restricted port of full manifold vacuum. The other way, for when the throttle is open, is through a large hose to the throttle, connected into the airflow sensor-to-throttle hose.

The smallest place is in that manifold nipple where the small hose connects. It is usually clogged solid and sometimes the small hose is too, when the blowby doesn't get sucked up at idle. But the oil separator can get clogged too. If you stick a hose on its outlet port, say a 5/8 or 3/4" ID hose, you can blow through to see if it is clogged. New separators are not that expensive, I think less than US$30, but a job to change.

If you grab the "features" pulldown selection from the brickboard menu, look for 700/900 FAQs. There's a good section in there about the PCV system, kinda unique to Volvo.

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Art Benstein near Baltimore