For those of us with a late 70's 280z folks with Fuel Injection there is a hidden part called the flame arrester.

 

My 77’ came from previous owners with various failed attempts at maintaining said Z.  Like mine, there is probably a chance that the Valve Cover Ventilation Hose has been replaced.  If so, check to make sure this part is in there and if you replace the hose be sure to remove and insert it into the new hose. It is part #5 from this page of the FSM.

Mine did not have this and since it is NLA I came up with this really inexpensive replacement.  It is a quick and easy part to substitute with very little effort behind it.

You will need :

(1) 20 gage bore brush (for cleaning shotgun barrels)

(2)  Needle nose pliers

(3)  and a bench vise or something to hold the bore brush firmly. 

20 gauge bore brush available from any retailer with a sporting good section. I paid less that $2 for this one. It fits snugly into a 5/8” valve cover hose.

Next, place it in a vise and Pluck out the bottom section of bristle.  The reason to remove some of the bristle is to allow air flow. The original part was less densely packed than this brush. I have no calculations to go by other that the picture of the original part. It’s only function is to stop any flame going through the tube, not to impede air flow. I think the finished bore cleaner resembles the original pretty well.

The bristle is held in place by the tension of the twisted wire. After the first few pulls the rest will come out very easily. It will leave a bunch of little wires 

 

Once you pull off about half of the bristles place the top of the bore brush in the vise. These will be loose so be careful. They want to make a mess. The aluminum base will come off easily with a twist leaving just the wire.  Now, just twist/retighten the wire with the remaining bristle. Make sure there are no loose wires. You don’t want those to get into the head!  Now trim it if you want with some wire cutters.  It’s ready to go!

 

Finished flame arrester. 

Here is where it will fit.

 

 

 

 

Place it in with some needle nose pliers. It just has to go in far enough to clear the nipple on the valve cover. 

 

Edited September 4, 20168 yr by gwri8

Groovy.  Looks familiar.  Yours seems a little bulky compared to the factory piece.  Is there nothing of lighter weight out there?

 

I've found those things from time to time inside the tip of the valve cover pipe outlet rather than in the hose.

I wonder if the brissle metal type has an effect on its flame retarding/extinguishing effectiveness. Maybe I'm just trying to justify an experiment that involves explosives. 

I have read that the org hose has grounding properties.

quoted from TonyD in a post on car.

 

Quote

When I put a pertronix flame thrower module on there, I learned the rubber for the valve cover vent hose was 'conductive' and would support a 4" long spark from the coil.

 

5 hours ago, Zed Head said:

Groovy.  Looks familiar.  Yours seems a little bulky compared to the factory piece.  Is there nothing of lighter weight out there?

Yep Zed, it should look a little familiar to you.  Bulky? I would rather say a little robust.  The wire gauge is certainly heavier and you can always pull out more bristle if that is more preferable.  I just finished a drive and had no problems with it, no flames either!  One could certainly make a lighter one with smaller gauge wire kinda like a Fly Fisherman would do,  but for under 2 bucks,  I'm gonna use my lazy gene on this one.

 

I didn't realize I was missing this until I was scanning through the FSM looking for the PCV. On old SOHC Volvos they use a "Flame Trap", between the air inlet and valve cover with a small vacuum draw that serves the same purpose, but that's it, they don't have a PCV in addition. 

Don't think I can make one of those work, so I guess I'm looking for the 20ga shotgun cleaning brush to mod 😄

I searched "flame trap" on the Google and some interesting things came up.

https://mossmotors.com/379-580-flame-trap

Another.

https://www.roversnorth.com/parts/603330_flame_trap_new_old_stock_3_5_3_9l_v_8_special_price_while_supply_lasts

I would use a Volvo part on my Datsun, however I would NEVER use a part designed for any British car. I used to have MGB's back in the late 70's early 80's. The quality of the factory parts was always less than stellar 😂

I'm sure you've heard the joke about why Brits drink warm beer? 

So, the flame arrester # 4159642 from 70'-80's Fiats is well constructed & fits perfectly inside the vent hose. EDIT: brand new, under $5

 

 

Edited April 25, 20231 yr by HusseinHolland
add info

I see 5 extra HP and 3 MPG.

That is a work of art.  I'd run a transparent hose with it so it can be admired.