intake valve seals??

D

durk

Junior Member
Hi,

I bought a flathead engine for my 35 Ford. According to the previous owner, the engine is perfect.

The engine is running. But smokes when I let go of the gas. Idle is good and when I accelerate it is also good but when I let go of the throttle it smokes a little bit.

In a modern engine I would say, 100% the valve seal.
But in flathead I am not sure. hard for oil to run uphill

20210503-135913.jpg
 
On an engine with similar symptoms the cure was to add a can of any 'no-smoke' product and run normally. (Rislone, etc. ) (don't over-think it)
 
Have you run it up to temp to be sure your not seeing water vapor? Is it spitting water?

Do a compression check at operating temp throttle wide open.

I didnt see any blowby in the second video.
 
Thank you!

I'm not worried about it....
but prefer not to have the engine smoke. even if I want to sell the car. and the engine is not in the car yet so if it is easy to fix, I prefer to do this.
 
no it is not an easy fix, lot of work to do that job. run compression, check for vacuum flutter indicating bad or stuck valves
 
It is a lot of work as you'd have to pull the heads, pull out all the valve assemblies, switch them over to the later 49-53 guides, valves, retainers, etc - and do a complete valve job for the whole new valve train. Then you can put seals into the later solid guides. :rolleyes:
 
If it has good compression, run the crap out of it. Any motor continually run on a stand without load, will carbon up. Till it's in a car running down the road it's a guessing game.


Flatheads will leak a little oil. They were built in the 30s, They are meant to run, don't over think it.
 
thanks for your comments.
I also try not to overthink it :) but I have 3 flatheads and all 3 of them don't smoke.
So it would be nice if this one doesn't smoke either.

I checked the valves. These all go up and down ...

below the compression test.
But if the engine needed a ring job then the engine suffered more from blowby right?

20210504-091307.jpg

Looks like the split guides are still there indeed.

Screenshot-20210504-091600-Gallery.jpg


is this amount of oil normal here?

20210503-155130.jpg
 
Those compression numbers are pretty low and the valley area looks like it was not recently rebuilt (based on sludge), so my guess is that the engine is a bit tired and the rings are worn. If it was mine and I had the time/money, I'd probably go through it.
 
Are those honest numbers,,,,?
This engine will be a real dog with compression like that .
I would seriously consider a rebuild,,,,,,at least clean,,,ring,,,,and valve job .
29 psi is non existent almost .
The engine looks good from the outside,,,,,,but it needs attention on the inside for you to be happy with it .

Tommy
 
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