Air cleaner question 65 HT

[Alan H. Tast]

I have a question on my air cleaner in the 65 tbird (I’m a little new to the tbird restoration). There is this plastic breather pipe going from where the oil cap would be - it is running into the air cleaner. It is very loose. I would like to get one of these oil cap breathers vs the breather tube. Would i need to switch out the whole air cleaner as well to get that set up?? Can I just switch to a breather cap. Any help would be awesome

It would be most helpful if you could post another photo showing what the overall engine bay looks like and the full valve cover. I can't tell from the photo you posted if it's a '65-'66 style cover or the "Powered by Ford" '67-later cover.

You wouldn't need to switch out the air cleaner, provided you get the right oil filler cap with a straight spout/hose nipple and use a straight length of hose to connect the two. The fitting in the air cleaner shown in your photo is not correct for '65-'66 air cleaners - it's an aftermarket add-on to allow for installing a closed breather cap with a hose. The original closed emission air cleaner has a metal tube that was welded to the wall of the air cleaner at the 6-o'clock position when looking at the air cleaner from the top with the breather/snorkle at the 7-8 o'clock position.

With closed emissions systems that have the air cleaner connected to the oil filler cap, the '65-'66 rocker arm cover required an oil filler cap, C4TZ 6466-B, that has a couple of tangs at the bottom to allow it to turn and lock into the cover, along with a straight spout/hose nipple. A molded hose, C6AZ 6A664-A, was used between the air cleaner's straight hose nipple and the straight spout/nipple on the oil filler cap; the original-style hose has a 90-degree bend at the air cleaner spout/nipple. The hoses were held in place to the hose nipples with spring-style "Corbin" hose clamps. Thankfully, these cap-hose combinations were used on more than T-birds, including full-size Fords, Fairlanes and Mustangs.

The caps, hoses and clamps can be sourced from T-bird, Mustang, full-size Ford and Fairlane parts vendors; just be aware that the oil filler caps can be fund with a straight (typically used on T-birds) or bent hose nipple (see the attached chart for part numbers/applications), so make sure you select the right one.

This is a list of hoses used for both the air cleaner-oil filler breather and for connecting the PCV valve in the opposite side air cleaner to the intake manifold.

Hose - Oil Filer Cap-Air Cleaner - Closed Emission

The closed-emission caps are listed below. The C4TZ 6766-B cap is shown for use on the '65-'66 T-bird.

Oil Filler Caps - Rocker Arm Cover - Closed Emission

For comparison, here's a listing of the open-element oil filler caps typically found on T-birds and others. The '65-'67 T-bird used C5AZ 6766-B

Oil Filler Caps - Rocker Arm Cover - Open Emission

[ScooterJazz]

So Allan thank you for the time you put into your reply.

Yes I have seen that exact cap breather. I would prefer to switch out the air cleaner and the oil cap. Could I use a breather cap with out the nipple and then switch out the air cleaner with open sided co create the airflow needed??

https://a.co/d/8HzP4fC

https://a.co/d/1vwS1gz

Thank you for the info on the rocker cover and the part numbers.

[Alan H. Tast]

THIS is why I wanted to see a fuller photo of your engine bay - YOU DON'T HAVE A '65 STYLE AIR CLEANER to begin with! What you have appears to be a '68 or '69 version (a look at the air intake/snorkle confirms that for me), which makes me suspect the original engine was replaced with a 390 out of a later ('68 or '69) Ford product.

And I'll wager, though I can't see it very well, that you have the '68 or '69 valve covers as well. Both the valve covers and the air cleaner can be swapped out for the correct parts. As for the oil filler cap connection to the air cleaner, if you get the much-more-common air cleaner assembly without the hose nipple, and get the oil filler cap without the hose nipple, you'll be just fine.

Replacing the air cleaner assembly with an open-element version would be OK, too, but for heaven's sakes please don't use one of those gawd-awful cast aluminum ones that does nothing more than have advertising for the manufacturer on it (hint - starts with 'Ed' and ends with 'ock'). There are period-correct reproductions available of Ford's open-element air cleaners used on hipo Mustangs and Fairlanes with a chromed lid that will look much nicer, especially once you get your engine bay cleaned up and detailed.