Here is what I've got going on. Last week I replaced the gas tank on my truck, while I was at it I fixed a issue of a air/vacuum leak at the base of the carb. I drove it for a few days and it ran great. Two nights ago on the way home while after a sustained cruise on decel I had a loud pop I assumed it was a back fire. Got home let it cool down and went to look for the offending exhaust leak that would cause the backfire. The truck would not start and was very slow cranking. While looking for the root of the problem I left the key on and discovered that the because a piece of trash was in the carb, the float did not close properly and the electric fuel pump fed about two gallons into the manifold. I cleaned the carb, drained the oil, left all plugs out and left it for a day. Tonight I placed a little oil down each cylinder replaced the plugs, and tried to start it. It cranked very slow, still.... I have checked the compression on all cylinders 35 with a slow cranking 6v battery. (90 with a 12v battery.) The distributor is tight and I have a strong spark at each wire. I have tried it with a 6v battery and 12 volt jumper and with the plugs in both turn very slowly. I. Fact there is very little difference. Without the plugs it spins freely and there is a noticable differnce between 6 and 12v The slow turn condition has no change if the coil is on or if it is just turning the engine over. If my timing some how jumped off wouldn't it turn easier when the coil is off because I wouldn't be fighting the ignition. The engine spins very fast when all plugs are removed. If you install any of the plugs it will slow down greatly when that cylinder hits. The starter was rebuilt by a shop recently, but could that be the villain? What could be going on? I have spark, compression and fuel. ... Sent from my SM-G920V using The H.A.M.B. mobile app
I'd check your battery ground and starter connections. See if anything is loose or corrode. Make sure your cables are for a 6 volt system. 12 volt battery cables are not heavy enough to carry enough current for a 6 volt starter. Lastly make sure it's still getting fuel. All of these can lead to very slow cranking in a 6 volt system.
I would suspect a fault in the starter motor Your symptoms suggest to me that there is a short in it causing it to crank slowly. It's not cranking fast enough to whirl the engine over and the short will take all the electrical energy
Installed the rebuilt starter tonight , installed a fully charged battery and no luck. Still cranked very slow with the plugs in. Next I rechecked the timing. It is set at 4btdc. So it is where it was prior to this all starting. New plugs and I am getting spark. I have fuel and it is visible when the accelerator pump is pressed. I installed the known good working carb off of the running 53. No difference.... Switched out the coil with a known good one. No difference. Removed all plugs , left them connected to the spark plugs and cranked it over with the key on. All 6 arced and 2 ignited the fuel/air mix exiting the spark plug hole. I removed the lead to the starter and used jumper cables straight to a 12v battery to eliminate all bettery cables options. It turned over faster but did not fire. The exhaust is removed to eliminate the chance of blockage on that side, heck I even removed the belt thinking perhaps the water pump or generator had started to seize and was slowing cranking. The entire time tonight when ever the plugs were in I never had one false start, a backfire, it never even seemed like it was trying to catch. I am stumped. What should I try next? Sent from my SM-G920V using The H.A.M.B. mobile app
Pull the timing cover, check the chain, it might have jumped a tooth...you've isolated everything else..
...a chain has to be pretty sloppy to jump but it does happen. So, to the OP, how many miles on the chain? You might also ask the guys over at www.p15-d24.com .
Yep. Happened to me years ago. Timing chain jumped with a bang. Got it running after a much needed rebuild .
If the timing chain jumped it would have affected the ignition timing. This one has me beat. Based on the information given there is no reason it won't turn over properly if it did before. There must be something the OP is not telling us, something he may not know himself. I keep coming back to the flooding situation but there is nothing there that would make an engine turn over normally with the plugs out but not with the plugs in. The only difference there, is the resistance of compression. For that to slow things down excessively, suggests weak battery, starter, too small cables or bad connection. But all those things were working perfectly a few days ago.
The truck was parked in 68. There are 64,000 mile on it but this is not the original engine. It is stamped as a 48 dodge 230 and had a paper rebuild tag from 67(We think) On it from the look of the gaskets and oil pan it was never run after the install. Sent from my SM-G920V using The H.A.M.B. mobile app
If the chain jumped a tooth or two would the distributor match the piston tdc? I am also thinking about removing the flywheel cover to see if something is in a bind on that side. I will plan bypass the ignition also and wire the coil direct. other options pull the battery cables and possibly starter out of the 53 and test the on the 40.... I am also considering pulling the plugs on the 53 and counting the revolutions in a set time vs the same condition in the 40 and see if it truly is turning over at the same speed? I'm also thinking about pushing it down a hill and see if I can push start it. Sent from my SM-G920V using The H.A.M.B. mobile app
Have you checked the compressions?? You have everything else, fuel,spark,air,timing, all that's left out of the equation is compression.
If you havent already, mark the distributor at its current location for reference. Loosen it a bit so you can turn it and while cranking, slowly retard it and see if it cranks faster. If no difference do the same but advance it. If no change just put it back to your referencemark. Point being, even though you think the timing is statically set correctly it may not be for whatever reason. This will help eliminate a timing issue. I'd also recheck for loose/corroded cables especially the grounds. Sent from my SM-G900V using The H.A.M.B. mobile app
any chance your clutch is dragging? Put the rear on jack stands so the rears are off the ground and give it a spin. if there was that much fuel in the crankcase, you ay have dilluted the oil so much that is quit lubricating. Might want to pull the pan and check rods and mains.
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