1936 Ford flathead advice needed..Part 2

A

akino

Junior Member
Hi guys, My 36 coupe, (with 37 flathead) seems to be running OK on an engine stand. I am trying to clean the cooling jacket with vinegar/water mix, and a lot of rust is still coming out. I see a rusty crust inside so I will keep going on cleaning. I was trying to get some metrics on general health of this engine by doing a compression test. Results are as follows:


Cylinder #1 98
Cylinder #2 (not sure as it seems to get to about 80, but falls off quickly) 50 or 60 final?
Cylinder #3 90
Cylinder #4 80
Cylinder #5 89
Cylinder #6 93
Cylinder #7 93
Cylinder #8 90


I did the test engine warm Throttle Wide Open (no plugs installed)
Not sure how I can determine how to troubleshoot Cylinder #2. I can watch the pressure build to about 80, but then falls off considerably when it gets to max almost immediately.
I took the head off and removed the valves in that #2 Cylinder and lapped them in for good measure, and verified valve lash, but still get same result.


I can try to post a short video of compression test if it would help. Let me know.


Any Ideas or path forward would be greatly appreciated.
Thank You,
Andrew
 
akino said:
Hi guys, My 36 coupe, (with 37 flathead) seems to be running OK on an engine stand. I am trying to clean the cooling jacket with vinegar/water mix, and a lot of rust is still coming out. I see a rusty crust inside so I will keep going on cleaning. I was trying to get some metrics on general health of this engine by doing a compression test. Results are as follows:


Cylinder #1 98
Cylinder #2 (not sure as it seems to get to about 80, but falls off quickly) 50 or 60 final?
Cylinder #3 90
Cylinder #4 80
Cylinder #5 89
Cylinder #6 93
Cylinder #7 93
Cylinder #8 90


I did the test engine warm Throttle Wide Open (no plugs installed)
Not sure how I can determine how to troubleshoot Cylinder #2. I can watch the pressure build to about 80, but then falls off considerably when it gets to max almost immediately.
I took the head off and removed the valves in that #2 Cylinder and lapped them in for good measure, and verified valve lash, but still get same result.


I can try to post a short video of compression test if it would help. Let me know.


Any Ideas or path forward would be greatly appreciated.
Thank You,
Andrew
Click to expand...
you can try a leak down test.
 
Try a wet compression test. Just squirt a spoon full of motor oil in spark plug hole before doing test. This will temporally seal piston rings that may be the problem.
 
Thank You,
I tried to squirt oil into combustion chamber. This brought the compression up about 10 lbs., (I could see gauge read about 100lbs before dropping off to about half that) but did nothing to stop the compression loss. I'm wondering if the crack near the stud in the center of block is causing the issue. I also did a straightedge and feeler gauge test across the head and block. Not much deviation on block (I could not get a .002 feeler gauge under straightedge) but on the head, the straightedge test allowed a .007 feeler gauge near the #2 cylinder. Question is whether or not torquing the head down is enough to eliminate the .007 difference... Thoughts?
Thank You
Andy
 
If its been sitting a while, get it running and give it a good hour of run time with mmo in the fuel . Longer run would be better . How much of a ridge ?
 
If you want to see where the compression is going , have both valves closed , block the crank from rotating, inject air into the cylinder and listen , exhaust, intake or block ( oil valley )
 
unless you choose to do a valve job and get some rings, i'd run it as is and see how it goes. it may clean up a bit depending on how long its been sitting idle.
 
Thanks guys,
This engine has been rebuilt supposedly, but it was done back in 1968. I have had the car for about 10 years and finally decided to start the restore after I retired. It was frozen when I started. I let it soak in Kroil for a week, then it broke loose. It used to belong to my cousin who lost interest in the restore and it basically sat in garage since 1968. If the rebuild was done, it was either not a complete rebuild, or the car was driven before being put on blocks. I found a lot of carbon and **** in the cooling jacket. It seems to run well and maintains a 180 temp idling for 1/2 hour on a 85 degree day. I will try mmo in the gas and run it some more.
Cheers,
Andy


PS if interested, I have an earlier post with same title with pics of inside...
 
Another technique:

- get engine running and up to temp
- Raise the RPM
- Put some water in a spray bottle and spray a fine mist directly into the carb while working the throttle by hand

This will steam clean the heads, valves and top rings
 
Thanks again for all the advice. I will pressure test the #2 cylinder and get a better idea when my pressure loss is occurring. Will also run it with MMO this weekend. I am thinking of running it as is because it starts right up and runs pretty smooth. Am also musing about next step...Transmission. I show SN #18-2460313 and from what I can ascertain, it is from 1936. However, upon inspection, I see some teeth have been crunched a bit. Attaching a pic to determine if a simple cleaning will do, or if I should rip it down and replace the bad gear. TIA for any advice on this...
Cheers! TrannyIMG_6696.jpg
 
If it were me, I would go through the transmission from stem to stern and clean out the case and replace any gears or bearings that look questionable. A lot easier to make the repairs while it is out.
 
akino said:
Thanks again for all the advice. I will pressure test the #2 cylinder and get a better idea when my pressure loss is occurring. Will also run it with MMO this weekend. I am thinking of running it as is because it starts right up and runs pretty smooth. Am also musing about next step...Transmission. I show SN #18-2460313 and from what I can ascertain, it is from 1936. However, upon inspection, I see some teeth have been crunched a bit. Attaching a pic to determine if a simple cleaning will do, or if I should rip it down and replace the bad gear. TIA for any advice on this...
Cheers!View attachment 592303
Click to expand...
592303
 
akino said:
Am also musing about next step...Transmission. I show SN #18-2460313 and from what I can ascertain, it is from 1936. However, upon inspection, I see some teeth have been crunched a bit. Attaching a pic to determine if a simple cleaning will do, or if I should rip it down and replace the bad gear. TIA for any advice on this...
Cheers!View attachment 592303
Click to expand...

I'd rebuild it with '39 parts. The syncros are a modern design and used by Ford for many years after.
 
For comparison, I just went through the '39 trans with the later improved synchro hub in my '34. Here is what the improved (1946 to 1954) synchro hub looks like.
 

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