The Stovebolt Site Forums The Shop Area Engine Shop 46 216 cranking slow and no power

Maybe some one can steer me in the right direction, last week I took my 46 PU out of storage to exercise it. 216 3 speed 12 Volt. Drove a few miles then it seemed like the engine could not get enough power, like the brakes were on and I had to pull over. I got it restarted but it died when I tried to let the clutch out, it just seemed like there was no power under load, so I had to tow it back to it's parking spot.
I went and started it today and the starter seemed like it was dragging but then was OK and it started and seemed fine. Then I turned it off and tried to start it and the starter was dragging again.
I don't have the heat riser flapper on the exhaust and it is just frozen in the open position. Would this have any effects after the truck has warmed up? I will be checking the charge on the battery and possibly changing the starter. I have a 12v system. How do I check if this is a main problem?

1) charge battery, check battery
2) clean all battery cable ends and contact points ( be sure cable size is big enough, even 12 volt system benefit from large diameter cable )
3) get generator cleaned and/or checked ( if it has an alternator, go to next step )
4) clean all generator or alternator wire contact points
5) clean, check voltage regulator wires ( disregard if it has an alternator )
6) with it running, check voltage at battery

A) if it won't start, or turns slow, pull starter off for a cleaning and check
B) if it won't start, clean and file points and clean spark plugs ( don't mess with timing )
C) jack up each corner, check for brake drag ( you cold have faulty wheel cylinders or brake hoses from setting )
D) clean carburetor and change or clean fuel filter last if everything above is OK

You could just have bad gas, so add fresh to it or drain and refill with fresh. Water in fuel makes for really bad running engines.

When it does start and run, get it up to road speed and drive it a while, the miles will help it.
Heat flap in the exhaust manifold won't do what you are having trouble with. The heat helps fuel stay vaporized, on hot days it likely not needed, on humid days you could get a little stumble every now and then.

Try a compression check and some engine cleaner like sea-foam.

Any plug voltage problem will instantly get worse with open throttle, and "recover" when you roll off.

It sounds like you have two problems. A cranking problem with the starter and a running problem once it's started. I've had both with my 49' that drove me nuts. The starter dragging were worn brushes. The loss of power, hard starting, and dying when you let the clutch out was a bad condenser that burned my points out. I got a mile down the road to take it to a car show and I barely made it back home. Also you took it out of storage, Any chance critters built a nest blocking your exhaust choking out the engine with back pressure? Just food for thought.....

Wow, a lot of really good suggestions. I will start with the battery and visual, cables, then work towards the starter and then jack it up & spin the wheels. Then look in the distributor. I will skip the heat flap as I am in Cali. and it's warm out.What am I looking for on the compression?

Uniformity of compression pressure between cylinders is far more important than the actual pressure number. I've seen pressure figures on the same cylinder tested with four different gauges show as much as a 15 PSI difference in readings. All the cylinders should test within 10% or less of each other- - - - -5% is better. If you've got a minimum reading of 80-90 PSI, that's plenty of compression for smooth running and adequate power. I've seen engine that ran smoothly and had acceptable power with compression pressures as low as 65-70 PSI, but gauge accuracy becomes more of a factor with the lower readings. Plugging a compression gauge into a shop air line with a known pressure reading is a good way to spot-check the gauge for accuracy.
Jerry

You mention that, "the heat riser flapper on the exhaust and it is just frozen in the open position". Does that mean that there is always hot exhaust in contact with the bottom of the intake? That will cause poor performance once the engine reaches operating temperature.

Yes, it is just frozen in the open position. You hit on one of my questions. After I check some of the other basic issues ie battery, starter, and connections, I think I need to find another exhaust manifold or try to free-up the flapper.

Kroil, a little heat from a Propane torch, a SMALL ball peen hammer, and a little patience will probably get the one you have working. Soak/heat/tap- - - - -repeat as required!

www.kanolabs.com

Jerry

cool beans, went be today, the starter is working ok, but I will need a battery. It was hard starting, backfiring from the carb, then was ok running for a while but the intake manifold heats up fast. This is a canadian truck and my casting numbers are tough to read. I will bring a crayon by next time and try to highlight them. the stamping above the dipstick only says T41, the GM cating number on the block looks like 3835125 but I will need to highlight it to be sure.I have had this truck now since 2014 and only know a little of it's history. Bought from from a producer in Ventura Ca. that got it from a movie lot.
I will put some new fuel and a battery in it and then see what it does, also start soaking the heat flapper.