theiceman

as others have pointed out .. it is good insurance if you think you need it ...

scottrx7tt

*This is not a trick question! In the engine compartment, the airbox (black plastic) has a flat side directly below the fuel distributor that faces to the right of the car. On that flat surface does your car have a rectangular blue sticker (about 1" x 1.5"), or glue residue from a sticker?

(ice: Correct, the original airbox on all '82 models came with the internal diffuser).[/QUOTE]

I will have to look, ive already had the engine out, to fix some oil leaks, i took the whole intake/airbox off and replaced the rubber couplers and such. So i assume if the airbox is original, it has the diffuser, and i guess thats the reason why i have not had any airbox mishaps.

Peter Zimmermann

I will have to look, ive already had the engine out, to fix some oil leaks, i took the whole intake/airbox off and replaced the rubber couplers and such. So i assume if the airbox is original, it has the diffuser, and i guess thats the reason why i have not had any airbox mishaps.[/QUOTE]

If it has the blue sticker it's the original box. I drive an '82 also (now at 203K +), and the original box lasted 192,000 miles. It did not blow at that point - I had the engine out for camshaft replacement and noticed some pretty bad fractures in the epoxy that holds the box together. I replaced the box at that time, but it might have made it to 200K - maybe.

Oldtee

A quick way to check for a leaking flapper valve is to spray water on it while the car is running. If you hear a woosh with quickly disappearing water, you have a leak.

theiceman

i am not sure i would want to be injesting water into my engine. but perhaps some thing else that would cause the idle to pick up ..

race911

Good ol' carb cleaner does the trick too.......idle will smooth out (to a certain point). And there's some LubroMoly, etc. product that is actually a vacuum leak detector that does the opposite--tries to kill the engine.

Back to Pete and his anti-pop off valve stance, he weaned me off of using those 20+ years ago when I had my shop. Unless a customer absolutely demanded it, it would only be on a new install. I was loathe to put them on used boxes. The cold start manifold they finally put inside sure did seem to do the trick, didn't it? (Can't believe it's probably been 15 years now since I've worked on a CIS car!)

theiceman

My new airbox I put in in my 78 had the diffuser inside and I did NOT install the valve ... starts and runs as sweet as ever.

Oldtee

Water injested at idle thru a leak in the pop-off valve won't hurt your engine. Engines injest water all the time. What do you think goes into an aircraft engine when flying in rain,

Peter Zimmermann

I don't know squat about aircraft engines, but I'm not buyin' your method of diagnosis. The risk of hydraulic lock is way too high, and if your "test" is done on a cool engine the chance of rust/corrosion is extreme.

theiceman

Well i imagine ram jets don't have pistons and piston engines draw air in from a rear facing scoop. Nevertheless I think I might survive a snake bite, doesn't mean I am gonna let one bite me. Point is there is just better things you can use than water..

Peter Zimmermann

It's just shy of 10 years since I sold Red Line to Marc (11/99), man does the time fly or what?

theiceman

on a somewhat non related note .... i went to replace my air filter today . i replaced my airbox last May. It had been 11 months and I twll you the inside of that box was like BRAND NEW still. I couldn't belive it , no dust , no dirt , no oily residue .. nothing ..i don't know what i expected but certainly not that ... Guess things must be performing pretty good.

itisaniceday

i just bought my car, it has almost 166k on it, and no pop off valve, if it has not blown up by now, it probably wont.

theiceman

..read back from post 8 ......

HarryD

*This is not a trick question! In the engine compartment, the airbox (black plastic) has a flat side directly below the fuel distributor that faces to the right of the car. On that flat surface does your car have a rectangular blue sticker (about 1" x 1.5"), or glue residue from a sticker?

(ice: Correct, the original airbox on all '82 models came with the internal diffuser).[/QUOTE]

Pete,

So I am correct to assume that the internal diffuser (which is not not present in my '73.5) has much to do with avoiding the need for a pop-off vavle?