Newly assembled Flatty cranking force??
 

Help me just validate my assumption here... :cool:

I've got an assembled flathead that hasn't been run yet. I can turn it over with a breaker bar (plugs in), and cranked it with the plugs out with the starter to make sure the oil was flowing, etc...
But with the plugs in, the starter don't move it and the wires start smoking. I've tried both 6v starters.

So I'm assuming it's just the starters are tired and I've killed them both. Sound logical?

There's no chance the motor is too tight for the stock starter, if I can crank it by hand (breaker bar), right?

It's a Merc with Navarro standard heads, and I didn't relieve it. So the compression is high, but not crazy.

Re: Newly assembled Flatty cranking force??
 

Use a torque wrench to measure the force. You could also measure the compression pressure of the cylinders. I had one that measured 160 lbs on the stand. You might also use 12 v I alway do, doesn't seem to hurt the starters.

Re: Newly assembled Flatty cranking force??
 

Thanks Ron. I should have been more clear on the starters... 12v neg ground, New 12v solenoid, 6v unrestored starters.

I'll try the torque wrench but I'd guess it's around 40-50 lbs at the most. Maybe less.
If you had 160lbs and it was fine, I guess i won't worry. I just was a little concerned with the seeming jump in resistance across 2 different starters and the fact that I thought a 6v starter on 12v would spin it over at a decent pace. Even with the plugs out it wasn't spinning it much faster than a good 6v system.

I started to worry that maybe something wasn't right inside.

Re: Newly assembled Flatty cranking force??
 

check the wires that are smoking sounds like bad terminals on the ends of the cables.

Re: Newly assembled Flatty cranking force??
 

I think 49/59 lbs is fine on a fresh engine, the rings and seaks account for most, The 160 was the compression pressure .

Re: Newly assembled Flatty cranking force??
 

When I first tried to crank my motor the wires got hot. Replaced them with new and still got hot. Moved the ground wire down from ceramic coated header to one of the starter bolts and that solved the problem.

Re: Newly assembled Flatty cranking force??
 

An assembled V8 engine should not take excessive force to turn over with the spark plugs removed. If it is HARD to turn over, look for the reason. As Ron said, seals and rings are the main culprit on a new engine... but if it is truly hard to turn over, start looking for interference or bad machine work. Crack one main cap loose, and try again. Re-tighten, and crack another loose... and finally the third. Go through this same scenario with the rods. If cracking anything loose frees the assembly up, then you've found the root of the issue.

Cracking any of those fasteners loose should have ZERO affect on how hard it is to turn the engine over. There is bearing CLEARANCE. Bearings should be touching nothing but a film of oil. Sometimes, bearing clearance can be zero or less with bad machine work or the wrong bearings.

Was there issue installing the pistons/rings? Remember back, and see if you can recall any issues upon installing any of the pistons/rings. Look for scratches/marks in the cylinder that would indicate a mis-installed oil ring, etc.

Point is, there should NOT be excessive drag when turning an engine over without spark plugs. If there is, find it now.

Good Luck

Re: Newly assembled Flatty cranking force??
 

I had one that was hard to turn over. It had the wrong main caps. luckily, with some other "wrong" caps fitted it was able to turn. You might have a cap on the wrong way round.
Pistons, rings, rope seals lifters, valve springs all create drag, but only a finite amount. If it is really heavy to turn, you need to look at the bearings.
When I was assembling one recently I checked it was still turning ok after every step.

Mart.

Re: Newly assembled Flatty cranking force??
 

I learned a long time ago to give the crankshaft a complete rotation each time I torque a bearing cap (including rod caps) just to be sure that nothing is binding. Saves having to backtrack to find a problem.

Re: Newly assembled Flatty cranking force??
 

Well, I'm getting about 46 on the torque wrench after the initial 180 degrees or so to free it up from sitting over night. (It was up around 60lbs for that).

Higher than I thought but I'm going to assume that's OK.

The machining was done by an old 4 banger and v8 flathead guy who was known for keeping things on the tight side.

I guess I'm gack to looking at the starter and wiring.

Re: Newly assembled Flatty cranking force??
 

I did that. I think it was in the Tex Smith book or one of those... :cool:

Re: Newly assembled Flatty cranking force??
 

No issue with the rings. The gaps were all right on and they slid right in with no problem. If anything, it kind of freaked me out how smooth it all went. So I double checked everything.

After I installed the crank, it spun on the assembly lube with minimal resistance.

After hearing Ron's numbers, I think I'm OK at 46 lbs with the spark plugs installed.

Re: Newly assembled Flatty cranking force??
 

This is something to think about actually. I'm going to take a closer look at the wires now and see if that may be part of the problem.

Re: Newly assembled Flatty cranking force??
 

Rope seals front & rear I’m guessing. Oil has them swollen. Once it has run you will be fine.

Re: Newly assembled Flatty cranking force??
 

I noticed I have the wrong numbers on the torque readings. I have a new pomputer keybord on order. This one has some letters an numbers covered wit ford grease si I don't see them very well. I check for the red line from miss spelled words, but I might be color bling\d as well. Sorry about that. Take care
Gramps

Re: Newly assembled Flatty cranking force??
 

Using plastigage to confirm crank and rod clearances always gives peace of mind on a newly assembled engine

Re: Newly assembled Flatty cranking force??
 

Definitely. Did that too. And clayed the valve and piston clearance.