Cowl vent question

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The gasket is the same thickness all the way around. The only way to adjust the height of the plate that holds the gasket would be to place washers under the plate. Even that is not a whole lot of adjustment.
 
Coolerman said:
The gasket is the same thickness all the way around.
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And on both sides of the vent, correct? In that case, I'll use the old carcass as the guide and make it the same thickness on both sides (the reverse side on my sample was disintegrated so I couldn't tell)

IMG_4776.webp
 
My vent still works and is fully operational after I took it apart and cleaned it up. I used some homegrown foam gasket to create the plate to tub seal. It's interesting that the OEM gasket is two sided, as there isn't a need to have the rubber on the top side of the plate. The only sealing that needs to be done is between the bottom plate and the tub itself. Maybe toyota made the gasket the same size on both directions in order to allow you to flip the gasket around and re-use the topside as the bottom side deteriorated? Otherwise it seems redundant. Off hand I'd say the plate moves up and down about an inch or so, maybe slightly more.
 
pavieSD said:
My vent still works and is fully operational after I took it apart and cleaned it up. I used some homegrown foam gasket to create the plate to tub seal. It's interesting that the OEM gasket is two sided, as there isn't a need to have the rubber on the top side of the plate. The only sealing that needs to be done is between the bottom plate and the tub itself. Maybe toyota made the gasket the same size on both directions in order to allow you to flip the gasket around and re-use the topside as the bottom side deteriorated? Otherwise it seems redundant. Off hand I'd say the plate moves up and down about an inch or so, maybe slightly more.
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That's amusing! I thought about that too, and came to the conclusion that the only purpose for the top half is so that the whole piece can be sandwiched onto the vent. Otherwise, you'd need to glue it on, which isn't reliable. Interestingly, on my sample vent, the top part gasket that's not used has completely disintegrated while the bottom part is mostly there (as seen in the photo above).
 
skully3 said:
The thin part goes twds the bottom stock 73.
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Wow, it's actually asymmetrical. That's quite a revelation. How come the notch is on the outside? Does it serve any purpose? I thought the notch is only on the inside to "grab" onto the vent. Can you please do the same measurement for the inside notch?

Amazing that you have such a well preserved gasket.
 
Racer65 said:
Your gasket looks a lot like the later 55881-90300 gasket. Are you sure your PO didn't replace it at some point?

The gasket on my sample looks like the one shown at the beginning of this thread. It doesn't appear to have a notch on the outside.
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Thats possible. I do have another set up for a 73. I will try and take a look tomorrow. Im pretty sure that its the same. If i had to guess the one in the pic was never replaced.
 
Racer65 said:
Thanks! Is the build date if these trucks actually in '73 or late '72?

My understanding is that '72 is the last year of functional vents.
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This thread has been a series of intriguing findings to me, to say the least. Just did a search, and found that some say the functional vent was deleted in '73 while others say '74. In any event, here's my hypothesis:

Throughout production, there has been 2 types of cowl vent gaskets made:
Early version ('69 to '78, according to ToyotaPartsZone): 55881-60010
Later version ('77 to '80, according to ToyotaPartsZone): 55881-90300

The early version was a simple wraparound gasket, while the later version has the inside/outside notches. Here are some representative pics of the two versions:

vent3-jpg.248766


img_6302-jpg.865754
 
Since I had gone down the road to reproduce the early version (55881-60010), I will proceed that way. At the end of the day it probably doesn't matter. I just wanted to make sure it doesn't restrict air flow, which would defeat the purpose of having a vent in the first place.
 
I had a '73 for parts from which I removed the cowl vent and put on my '78 about 16 yrs. ago :). It has the gasket with notches on both sides and I don't believe it was replaced before I got my hands on it. My dad also has a '73 w/functional vent, has never replaced his gasket and can verify later if it has notches on both sides.

The '66 FJ45LV parts wagon that I have I do remember it having the simple gasket with no notches.

I'm thinking the notch on the outside allows the gasket to have a slightly flexible lip for better sealing.:meh:
 
skully3 said:
Both examples are 9/72 (73). Full function vent. If you want a gasket to measure i can send it to you. Lmk
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I see. 9/72 is likely the last of the functional vent. Thanks so much for the offer, but since my mold is 99% complete, I will finish up based on the existing design, which is a single layer gasket.

With the help of your drawings and photos, I totally get how that gasket works. Essentially, the thick portion holds on to the vent, while the layer on the bottom provides padding to seal against the vent opening. How well did it work during use? Meaning, did it do a good job of sealing out the rain when closed and providing ample fresh air when open?
 
The full 73 model year had a functioning vent. It was the heater change in 74 with the vent on top for the vent being sealed. The 73 lever changed locations and I believe worked the opposite way. Pre 73 model pulled to close, pushed to open. I have 9/67 68 model and 3/73 model I can check but doubt there is any difference in what has already been posted. Would have to measure in the morning since it's already close to ninety degrees here.:bang:
 
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