Valve seal questions (1 Viewer)

[daniel.watters]

A couple months have passed since my 40 started puffing smoke. It puffs around the exhaust side in the number 6 cylinder and tail pipe. I removed the head, springs w/ keepers, and valves. I also received new seals from Rockauto after reading through a thread on mud. I’m certain I got the part number right. But look at the difference in size. Both in height and the diameter of the hole. Do I go forward and in stall these?

 

[Steamer]

I bought the same Fel-Pro seals from them for my 74 and they look the same. I would say you have the right seals. I did not use them though, instead I got the positive seals Toyota 90913-02033 which came along a few years later. They push onto the valve guide and stay there versus the umbrella type you have that stay with the valve and go up and down with it. I believe the positive seal style came along with improved rubber compound technology.

 

[daniel.watters]

So I replaced the seals with the ones that I purchased above. Before I restabbed dizzy, I thought that I had tdc from visually getting the #1 piston to the top of its stroke. Did that and place head back in and touched everything back down. Now I’m getting back pressure through the carb. Even before it fires. The back pressure of air it’s blowing / misting fuel up and out. Thoughts on what my issue might be?

 

[B y r o n]

Was it 180 degrees off?

 

[daniel.watters]

I guess it could be…. I forgot to mention that I did restab dizzy after bumping starter over until pressure on my finger. Got the same back pressure.
I know now an exact method. Just was trying to rule out timing as issue.

 

[middlecalf]

Compression stroke on #1 required at TDC so both valves need to be closed. #1’s intake & exhaust rockers will have a little wiggle otherwise you have #6 on its compression stroke, aka 180-deg out as suggested.

 

[daniel.watters]

Compression stroke on #1 required at TDC so both valves need to be closed. #1’s intake & exhaust rockers will have a little wiggle otherwise you have #6 on its compression stroke, aka 180-deg out as suggested.

Right. My finger being blown out on #1 suggests that both intake and exhaust valves were closed on one for that to happen. No?

 

[middlecalf]

Seems like that’s good. I’ve always had the valve cover off when mucking with the dizzy (to check valve lash) so jiggling the rockers is my easy button.

 

[aztoyman]

If it's the exhaust stroke instead of compression stroke, you will still feel some pressure because the piston is coming up pushing exhaust out the exhaust valve.

Also, how were the valve guides? The umbrella seals help keep oil from running down the guides but have their limits. Worn guides with new seals "might" still leak if the guides are bad enough. I hope that you're go to go though.

 

[whitey45]

I have never felt compression on the exhaust stroke in 35 years as a professional mechanic?

 

[aztoyman]

I didn't say compression. I said he " may" feel air since the piston is moving up. I have seen plenty of people think they were on compression stroke because of it. Didn't say it was definite, just a possibility. I wasn't trying to insult anyone or be a smart a$$. Just saying it's worth confirming it's not 180 out. Sorry if I came across that way.