53 F100 continued driveability issue

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Aug 13, 2018 | 07:26 AM

lakeboater

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53 F100 continued driveability issue

I posted a few weeks ago about this and just had a chance to do further testing. To recap, my engine is a 6 cyl 215, it bucks and stalls when hot under a load (going up a hill). The engine idles perfectly and runs well otherwise. Over the weekend I ran a compression test and found compression ranging from 70 to 90. I wet tested the cylinder that was 70 it went up to 85 with oil. I tested a 2nd cylinder that was at 80 and it went up to 90 with oil. The plugs are burning black and slightly wet but not all sooted up.
My theory is that when hot and under load I am getting oil blow by past the rings causing it to foul and stall. Seems like bad news and at least a ring job ahead.
Looking for opinions or further tests before I pull this motor apart.

Thanks!

Aug 13, 2018 | 08:35 AM

52 USCG Panel

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From: Deerbrook, WI

Welcome! I have the same engine, and it was probably in similar condition to yours. My compression readings ranged between a high of 88 and a low of 62. I was having some drivability issues, but not specifically like what you describe. You can read all about my issues and their resolution in my 1904 Holley Carb thread. I ended up re-building my engine last spring for about $2300. At the time, I didn't want to spend the money (or more correctly my wife didn't), but looking back, I'm glade I did.

With the engine rebuilt, I can cruise easily at 60 mph, and I was even able to make an epic 1400 mile journey to Kentucky last fall. Having a dependable engine is a great thing. There are enough other things that can go wrong on these old trucks.

Good luck!

Jim

Aug 13, 2018 | 08:39 AM

mechmagcn

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From: Moro Bay, AR

Is the engine smoking blue and using oil? If not then oil is not your problem. Black, sooty plugs could be either a too rich mixture or a weak ignition. With the problem you have described I would lean toward weak ignition, points, condenser, coil, plugs or wires.

Aug 13, 2018 | 09:28 AM

firstrider

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From: Pt.St.Lucie , Fla.

Check and or replace the condensor . Make sure it has an operating range of .21- .25 microfarads . Good luck and report back .

Aug 13, 2018 | 10:14 AM

lakeboater

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So the compression results are not the smoking gun I thought it was based on the feed back? I do not have heavy blue smoke, It does use some oil, but has a rear main leak which contributes to the loss. A couple more notes: A replaced the fuel pump for a gas leak recently. (before the driveability issue) I also put in a coil as it was my 1st instinct as to the cause. I replaced the plugs at the same time and did a visual on the points and cap which seem ok. Maybe I should give it points, condenser and cap as a hopeful try? The carb is pretty new, but who knows, maybe changing the fuel pump dislodged some dirt?

Aug 13, 2018 | 11:04 PM

52 Merc

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From: Burbank, WA

You might also check the distributor to make sure the advance mechanism is working properly. If your timing is off in relation to load, that can cause problems too.

Aug 14, 2018 | 11:23 AM

ALBUQ F-1

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Joined: Jul 2004

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From: NM

The fuel lines accumulate rust particles from the gas tank, it can get to where flow is severely restricted. Very hard to get it out, it sets up like concrete. I ended up just replacing them with coated steel lines, no issues since.