Engine runs but no power in 41 tonner

[MDC]

I am looking for ideas about what my problems are. My Grandfather's 1941 one ton flathead truck sat for fifty years in the shed. I have the engine running and it sounds pretty good but I can barely get it to roll on its own power even revved up.

I have rebuilt the carburetor, Bubba rebuilt the distributor and set the timing, 3 valves were sticking open on one side so I took the head off and got them working. The brakes are not engaged so it should roll easily.

Compression testing shows each cylinder at 90 or better. Vacuum reading is only about 10.

I am no mechanic but I am trying to learn and I would like to do the restoration myself. Any ideas on where I should focus my attention now? It sounds good running but just no power.

Thanks for your help and suggestions.

[Capt Kirk]

MDC, you're vacuum reading is low...should be around 20 in. Timing can affect that but since Bubba did the distributor and you've got good compression, I'd look for a vacuum leak somewhere. If it sat for 50 years in a shed, gaskets and hoses can get pretty rotted. Intake/carb gasket? rotten vacuum hose(s). I've never tried it but have heard spraying some starter fluid (in a spark free environment) around hoses and gaskets to see if you get a change in rpm works...just be careful. Also, coming from Fairbanks AK, I know that (at 50 below) thick tranny and differential oils can really drag things down to the point it feels like the brakes are on. After 50 years, have you changed the fluids in these? You could jack the rear end up and let it idle in gear to re-introduce this truck back to life. The fluids in the trans and diff could be solidified after that amount of time.

[WestCoast]

check for plugged exhaust system, muffler, rats nests in exhaust pipe , put your hand over the back exhaust pipe and see how much exhaust pressure there is there, modern cars with catalitic converters that are plugged act like that

[Capt Kirk]

As an aside, I'm always amazed when I hear stories like this. Vehicle parked in the shed for 50 years and after a little dinking around with it, it runs and sounds good. You'd figure the thing was parked because something major was wrong with it and it just got hauled out back. For an engine to come back to life after sitting for 50 years is just amazing to me. Really a testament to these old flatheads.

[Capt Kirk]

Yeah, what WestCoast said! About 6 years ago I worked on getting my dad's old 67 IHC Travelall running again. It was parked in the barn in running/driving condition but the mice in the barn kinda ruled the roost for probably 15 years. I replaced what needed to be replaced on the engine to get it running...which it did...barely...then would die. After repeated attempts and some serious encouragement, crap started flying out of the exhaust like you would not believe! I would guess that it was close to a 5 gallon pail of dead mice, seat cotton from the 53 chevy wagon, mouse droppings...etc. Once she could breath out the pooper...things were all good!

[corvette8n]

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I've used WD40 instead of starting fluid to find vacuum leaks, a little safer.

[supereal]

Check the delivery of gas at the carb. You should have a steady stream into a receptacle as long as the engine is running. Check pressure of fuel will not tell you is the system not producing enough gas. Vehicles that sit for long time often have enough debris in the tank to affect delivery, as does a gas line that has rusted and/or filled with crud. Another common loss of power is a weak condenser. Substitution with another condenser will tell you if it is the reason. We are finding weak or open condensers being sold today.

[MDC]

Thank you all for the great replies! I jacked up the back today and put it in gear. The left rear tire turned great and the right rear only turned with help from me. I took out the plug in the differential and it was dry as far down as I could feel. I will get oil tomorrow and fill it. I am sure that is part of the problem. I will have to check to see if the right brake is dragging a little.

There are a number of holes in the exhaust system so I will have to do some probing to see if there are plugged parts. A mouse did crawl out of a radiator hose when I started working on it. ( The engine compartment was full of corn cobs, mouse and rat dirt when I started. )

I think Bubba checked the coil and condenser when he rebuilt the distributor but I will look into that. It is a new coil and condenser.

I took the gas tank out to clean it before I tried to start it and there was no rust in it as far as I could tell. I blew out the fuel line and installed a new fuel pump and line to the carb. The old pump fell apart when I took it off. I have a clear strainer in the line and the flow looks pretty good. I don't think it's a fuel issue. It revs up pretty good.

Thank you all for your help and I will look into all your suggestions.

[MDC]

Update: thanks again for all the great suggestions. I changed the grease in the differential and transmission. The brakes on each right side tire were dragging even though I thought I had fixed that before. I adjusted the brakes and packed the wheel bearings with new grease. I greased all the fittings in the drive train.

IT DRIVES!

After driving in big circles for only 10 minutes the engine runs really good (I thought it was good before but now better). The smoke is gone from the tailpipe! The vacuum reading is up to 14. It is amazing what running the engine under load can do to get the valves and rings working right.

Thanks again for the help.

[Capt Kirk]

Vacuum is still low. Check this out to see if it helps.
http://freeasestudyguides.com/engine-vacuum-test.html

[Capt Kirk]

Here's another one http://secondchancegarage.com/public/186.cfm

[mrmoose]

love this stuff!