I was digging around in the Haynes manual and I came across something weird regarding the crancase ventilation (bottom of pg 71 in the 140 manual if anyone cares). I have a B20 engine (it is stamped B20 on the side), but it looks like the B18 picture, air filters and all.
Specifically, according to the book on a B20 engine,
-The hose from the crankcase breather connects to the big box air cleaner.
-The hose from the oil filler cap connects to the manifold.
Well, mine is connected backwards.
-The hose from the crankcase breather goes to my manifold.
-The hose from the oil filler goes to my round air cleaner.
On my 2 SU carbs I do have individual round air filters (like the picture of the B18) unlike the big box that fits over the pair. Is this type of air filter something that came standard or most likely aftermarket? Could it be carbs from a B18 that have been put on the engine?

Since I don't really know about this, would it cause any harm to switch the hoses and see how it runs? It seems it is all just air flow to/from the case, wouldn't it run fine without any hoses, much less swapped ones?

Thanks,
Phil

Hmmmm...... So you are saying your car runs best (runs at all) with the oil filler hose going to the filter box, and the crank vent hose going to the manifold? Whichever works best I suppose... but your initial post and subsequent responses got me curious, so I went out to have a look see at my 145.

It has the vent hose going to the cleaner box, and the oil cap hose to the manifold. And the hoses ain't the right lengths to set up the other way. My 145 ('71) is a very original, unmolested, low mileage original owner car...so I was certain it is original, but just to be sure, I looked in the owners manual pictures of the engine, and sure enough...mine does indeed appear to be correct...

That said though, my car doesn't idle very well either...and I've always thought it was a carb issue or vaccuum leak. Perhaps I'll try it backwards and see if it helps.

-Matt

My '71 145s

This response is to the best of my understanding/recollection, so YMMV.

The hose to the oil filler cap is an INTAKE. Air is taken in to replace the gasses expelled out the oil seperator/trap. As an intake, it needs clean intake air. Therefore, the filler cap should be connected to filtered air, i.e. after the air filter, before the carb.

The hose connected to the oil seperator is an EXHAUST. The trap catches the liquids, and the gasses are sent back to the intake to be re-burned. It should connect AFTER the carb(s) - i.e. into the intake manifold.

This is all emissions control stuff. Prior to 1968(?) the oil seperator vented to the outside air, and outside air was sucked into the engine.

I think you have the hoses backwards.

Boy, that sounds right to me!

Good points!
--
George Downs Bartlesville, Oklahoma

So if you think I have it backwards now, there shouldn't be any harm in switching them, right?
I'll try it out and let you guys know.
Thanks,
Phil

I've tried 'em every which way and they still blow oil!

No other harm, though.
--
George Downs Bartlesville, Oklahoma

Well, I tried it out and I think you said it best in another post, George. If it's not broke, don't fix it.
I swapped the hoses and it would barely run, much less idle. I thought I may have found something but that wasn't it.


I don't know if you remember a post I did a while ago about a problem where I thought the tranny was surging, but you suggested a vaccum leak somewhere. I think you were right because I was able to recreate the problem in several situations to rule out the tranny. I have changed out the hoses everywhere but still have the problem of the engine surging when I am at a constant speed (only bottom end, top end is strong and solid).

Thanks everybody for the info, I guess there is always more than one way to do something.
Phil

Surging at low speeds and not at high speeds definitely sounds like
either a vacuum problem or maybe a throttle butterfly problem (which
turns out to be a vacuum problem). Did you check to make sure that
your throttle butterflies are tight and closing right? Maybe your
throttle shafts are worn allowing air leakage, which screws things up
at idle but makes no diff at full throttle....
If you have secondary butterflies (cast arn dual manifold) you could
be having a problem with them also, a loose screw (we ALL have them!)
(Para los que hablan español, se nos aflojó un tornillo....)
or some such. I had a loose throttle butterfly in my 164 and it took
me MONTHS to figure it out!

If your engine wouldn't idle with the hoses hooked up backwards, you
know which way is backwards! You also know that you have the fitting
with the big hole rather than the metering jet fitting I have in my 164.
(which I have drilled out bigger on a couple of occasions but it is still
not big enough to pull in all the blowby!)
--
George Downs Bartlesville, Oklahoma

I could be wrong but that "hose routing for B20" applies only to Strombergs with the big air box and ALL vacuum hoses connected in the stock config... I think.

Does that mean you think I have it right? Since I don't have the stock "big box" and stromberg carbs?
Thanks for the input.
Phil