Technical Slow Cranking 318 Poly

I'm helping out on a '63 Plymouth Sport Fury. The car is unrestored, killer patina and very clean. It's destined for greater things, but for now the goal is to get it driving with original equipment, a 2 bbl 318 poly and a T-10...yes, that's how it came off the line. The original owner was a Mopar engineer involved in one of the 1960s racing programs. The 318 is not original to the car, but year correct.

I' don't know much about this engine, so I have no comparison. The issue is that it cranks very slow...and won't fire. Tried 2 different starters, checked wiring etc. Got it to pop a couple times, but not enough to give it any chance of starting. This particular 318 was sitting for a long time, so that doesn't help. Compression is below what it should be, but I suspect most of the rings are sticky, they may loosen up once/if it ever fires. We had 6 of 8 plugs out and cranked it. I thought it would spin much faster, it didn't...same rpm. So with that, one might conclude that the starter drive gear is really tight on the flywheel gear, but these starters don't use shims...really a head scratcher.

We spun the dist'r 180 degrees more than once, re-cleaned plugs (which they needed due to all the Mystery Oil dumped in the cylinders), checked for spark continuously, used ether, checked points gap and we just couldn't get it to fire. Even advanced the timing incrementally while cranking with a light to help out. At one point we got a backfire through the little 2 bbl Stromberg. Still not sure if the distributor is 180 off, it cranks so slow it's hard to tell.

Even though this old 318 Poly is a temporary engine, and doesn't have to have peak performance, it's important to get it going. Any ideas pass them along.

 

Why only 6 of the 8 plugs ?

how tight is it rolling over with no plugs?
How long has it been sitting ?
Do you have good spark at the plugs ?
Fuel at the carb ?
Is the carb working correctly ?
Distributor clean and working?
Confessor , coil , ballast resistor ok ?
What is the compression ?

have you removed the valve covers to look at the valves if they are stuck ?

good battery ?
Battery charger ?
Grounds good?
Powers good?

I got a good hunk of brisket in the slow cooker covered in onions and garlic!

 

I was going to ask about the ground also. From the battery to the frame to the engine needs to be good.
Have you seen oil pressure yet while cranking? The engine could be very dry on the main bearings along
with the lower ends of the cylinder walls. Just a thought.

 

Have you squirted lube down the cylinder bores??
How long has it been sitting for?
Reason I ask, I bought a 350 Chev powered vehicle that had been sitting for a while, wouldn't even try to turn over (even tho it was a runner when parked).
I pulled the engine, and stripped same, found most of the wrist pins were semi seized in the pistons..
Possibly the same problem as yours..

 

Maybe check the starter itself? Is it producing enough speed and torque?

 

Well your compression sucks .

and with no plugs and it still rolls over that tight it ain’t gonna run .

what and how long have you been soaking the cylinders ?

might have to tear the engine down a bit and free it all up, pull the valve covers and take a look.

and a compression test is only 1/2 the story a leak down test will tell you the rest.

Ive had engines with decent compression have burnt valves , worn rings etc .

50 psi ain’t getting you no where .

and you need all plugs out and throttle plate open with a good battery amd crank the engine over equal times on each cylinder when doing a comp test.
Did you do it dry and wet ?

 

If I were there I wouldn't take anything for granted. It seems you or someone has messed with everything. To start with, how hard is the engine to turn over by hand, with the spark plugs out, using a wrench on the crankshaft or by hand turning the fan? If you want to get icky it should be no more than about 20 ft lbs.
If the engine is not seized I would check the battery cables, make sure they are clean and tight and not frayed at the ends, and the engine has a good ground to battery and to body. Then put in a known good battery if I have to borrow one from my daily driver and see how fast the engine turns over. If still real slow may be time for a new starter.
With the engine turning over I would next give my attention to the ignition. Make sure you are getting a good spark and timing is set right. Spark plugs should be clean, if they are oily or gummed up they could be grounding out and not sparking, the only way to clean them is by sandblasting. A little $12 spot blaster will do the trick. Then set the gap.
With the engine turning over and a good spark on all cylinders next comes the carburetor. If you have not messed with it, it may be ok but don't trust old gas, disconnect the fuel pump and connect to a small gas can. Pour a little gas down the carburetor and see if it will fire. You may need to do this a few times to get it pumping gas to the carb, check by working the throttle and looking down the carb for a squirt from the acceleration pump. If the carb won't cooperate it may need to be taken apart and cleaned or rebuilt.
That is how I would approach it, in outline. There are other details to diagnosing and fixing ignition and carburetor. If you have a problem come back with a specific question and I will see if I can help.
If I was there I would have it running in a couple of hours or know the reason why.

 

You said the compression was low, but no figures. Did you actually do a compression test? If you can't get at least 120 psi on 5 or 6 cylinders, it isn't going to run.

Since you have point ignition setting the ignition timing is quite easy. Pull out #1 plug and crank the engine until you just feel compression. Now slowly rotate the engine until the timing mark comes up and align it with the correct mark. A 63 318 calls for 5 degrees BTDC with a stick and 10 degrees BTDC with an automatic (anywhere between the two will get it to run). Now check to see if the rotor aligns with #1 plug location on the distributor cap. If it does you can set the distributor. If not, you have to remove the distributor and use a screw driver to turn the oil pump drive gear until you can drop the distributor in and get the rotor alignment correct.

With the distributor in the proper place and the rotor aligned with #1 cylinder position, slowly rotate the distributor body counter clockwise until the points just open (the rotor must still be roughly aligned with #1 cylinder position). You want to determine the place where they just begin to open. You can use a test light to determine this point. Some people used to use a very thin piece of paper between the points. When you can just pull it out, the points are just beginning to open. Paper doesn't work well if the points are pitted. Tighten the distributor hold down, the engine is now properly timed. It will start if you have compression, spark and fuel.

 

All the cylinders were checked. Varied from 50 to 90 psi, but it was cranking so slow, I think it skewed the readings to the low side by a lot.

I didn't think about it until later. The compression tester needle will bump at the same time the #1 plug wire fire, more or less. Just by grounding the plug on something while turning it over.

I'm a GM guy, so this MOPAR stuff is new to me. My understanding was that the dist'r gear was fixed to the cam and couldn't be adjusted. It goes in 1 of 2 ways. Right or 180 degrees off. I haven't looked at any 318 diagrams yet, I'll open up the Motors Manual and review.

We'll revisit and use your directions.

 

GM guy or mopar guy they are all the same. Don't let that freak you out. Lippy

 

Sounds like a battery issue. Lippy

 

Time to check for voltage drops Check the ground side first Put the + lead on the starter and the - lead on the ground terminal of the battery Hit the starter and you should zero or next to it reading then + lead in the + battery post and the- on the battery cable post of the starter hit starter same zero reading. A good battery should have at least 10V cranking.

 

The difference between GM and Mopar dist'r/oil pump setup is that one has the gear on the dist'r, the other on the oil pump drive shaft, which can be easily lifted out on the Mopar and/or misaligned if not careful. The other item that could be weakening the spark is the ballast resistor, be worth checking.

We'll recheck for proper rotor clocking at #1 compression TDC...I have a feeling it's about 90 degrees out, that would explain absolutely no firing whatsoever when there's both spark and fuel present.

 

If you're not used to working on Mopars of this vintage, keep in mind that these engines used a gear reduction starter. These starters made a lot more torque than GM's and Ford's starters but they only turned at something like 1/2 or 1/3 of the cranking speed.

 

What Rusty said! I would probably start with NEW ,heavy battery cables. If the starter did not turn it then , out comes the starter.

Ben

 

If you have checked all the regular problems....loose connections, dirty connections, bad battery then it may be so advanced that its cranking slow.Mark the dist. in relation to the block so you know where you started. Loosen the dist hold down,and turn it as someone else cranks it over.If the rpm picks up as it turns over then it was too advanced.

 

Even easier, just disable the ignition by grounding the coil wire, and see if it cranks or turns over faster.

 

is it parked on a hill for a bump start? or maybe (and its not overly recommended) the good old tow start. If its tight forget both suggestions it might nor end well.

 

It sounds like maybe these older points ignition systems aren't exactly your area of expertise. Before you start throwing good money after bad, this link may help to clear things up for you.

https://www.jalopyjournal.com/forum/threads/hot-rod-technical-library-basic-ignition-systems.983424/

 

With the compression numbers you have I don't see it ever starting ! you could go old school, pull the heads ring it put some rod bearings in it and do it in the car. I have done more than one that way.

 

Just to remind you when you do a Comp. Test take ALL the Plugs
Out & then you do the Test.!
I had a 318 mopar that I had a problem it Broke down & would not Start
after checking everything I found the Culprit.
The Positive Battery Cable between the Batt. the Starter Corroded eternally
just my 3.5 cents

Live Learn & Die a Fool

 

The gear is part of the oil pump drive. You can move it by inserting a screw driver in the slot and turning it clockwise. It will lift and jump one tooth at a time.

 

A lot of great suggestions. I am merely helping out with this so I didn’t do any of the prep. I do know my way around vintage engines but this one appears to have numerous issues so it’s a process of elimination.

According to the owners, no significant changes were made to the engine proper. New parts: ignition set, plugs and wires, battery, rebuilt alt, rebuilt carb.

Compression was checked. It was poor. 50-90 psi but it was cranking so slow I don’t know if the readings were true.

I would like to know the torque required to crank by breaker bar. I have no idea. Will ask the owner. It would help determine if the starter is the culprit. 2 different used starters were bench tested and tried on the car. Both performed the same way. I was told shims aren’t used on these starters, I guess but it wouldn’t hurt to add a pair of thin washers to see if that eliminates any binding between the gears.

It has spark, fuel, but low compression and a very slow crank over rpm. Im afraid this thing won’t start no matter what.

Another thing to do that I don’t think was done, spin the oil pump. It’s worth a try. Owner didn’t say he did that, he should’ve. If several bearings are on the dry side the cumulative resistance would require more draw on the starter. No doubt.

Won’t attempt anything until next week so to be continued.

 

You can't spin a mopar oil pump like a chevy. The distributor has a drive tang engaged with the top end of a shaft that drives the pump, but that shaft is geared to the cam.
I prefer a preoil using a fitting into the oil passages and a pressurized source. A Hot Shot sprayer can be adapted, or even a normal garden sprayer. Spinning the engine with the starter while pressuring the oil in will get it on all bearing surfaces.
Over the years I've encountered a lot of engines with 60psi compression that started and ran. Not well or smoke free but ran. and you can't really tell the actual pressures on one that has sat for a long time until it has been run for a while. Rings stick, rust forms etc that cause poor seating.
I think I'd hit the starter with two 12v batteries in series for a short burst to see if it will spin. Atf is my lube of choice in cases like this.

Wish I had a good poly to work on. Would look good in my 56 pickup

 

The oil pump shaft does pull out. Why can't you remove that and engage the oil pump directly with something that would mate up in a similar fashion? Maybe it's difficult to remove the shaft and replace...I don't know just asking.

 

You can, but you have to time the gear also. It has been a long time but I believe the poly motor you want the slot in line with the crank on the compression stroke. And if it was a LA motor you line the slot up with the drivers side front intake bolt on the compression stroke, that is with the gear fully seated.

 

Yes. The gear would have to be re-timed to point the rotor at #1 on the cap on the compression TDC. Not sure how to extract it though. Maybe a really strong magnetic screwdriver? Looking for what tool and process before attempting it.

 

it is a challenge with the intake on, you will have to take a piece of round stock and make a hook and pull it and turn it at the same time. I would not spend the energy. I would get it back in time and go from there.

 

Even if a motor is running and you are not familiar with it's history it is a good idea to verify where they have number one timed at on the cap before pulling things apart. You can put number one anywhere and then wire the cap accordingly.