hard cranking after warm

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coreyg

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I have a 71 scamp with a 318. I have the fitech fuel injection, 360 heads I'm assuming the stock 360 cam not 100% sure though. I'm going through and setting up the fitech for cold starts which is now doing a lot better, but after the engine warms up to temp and I try to restart the car the engine has a hard time cranking over like my battery is almost dead. If I let it cool back down it starts up fine and turns over fine. Any thoughts?
 
Does this have stock 318 pistons? If so, then high compression is not the problem.

Battery up front? Cables and connections are suspects. Clena all connections to a bright clean, including the battery cable direct to the block. It appears that you have eliminated the problem of a dragging starter with the new unit.

Check the battery voltage with a known accurate voltmeter when the car is at a fast idle. It should be around 14.0 V + or -. This will say if you charging system is up to snuff.
 
Charging voltage won't tell you in this case. You need to measure STARTER voltage WHILE CRANKING. Check connections and grounding, inspect cables. Then "rig" your meter with clip leads right to the starter post and to the engine block. Absolute minimum in my book "while cranking" is 10V, and should be more

If you have that and it drags, pull the coil wire. Might be kicking back?

If that has no effect, it's either the starter or you have an engine problem, tight bearings, spun bearing, or something wrong in piston/ ring fit

Your "new?" (rebuilt) starter does not mean "good." It could be defective
 
Check grounding. I always like running a ground strap from engine to body & frame just to eliminate potential problems.
 
Not sure if its stock pistons or not, I would assume so. I don't think its the battery cause after it cools down it spins over just fine, its only when the engine is hot it turns over really slow.
 
Besides an electrical problem with the starter/battery you might have a tad too much initial timing...
 
it was set a 10.5 backed it down to 8 same problem
 
coreyg said:
Not sure if its stock pistons or not, I would assume so. I don't think its the battery cause after it cools down it spins over just fine, its only when the engine is hot it turns over really slow.
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This is a wrong assumption.
It may even be that the battery is just too small.Or the cables are too small. Or the effective cross section in the battery clamps is too small. I mean you can only suck so much water thru a straw; and so it goes with electrons.
I tend to allow a 9.5 volt minimum cranking volts on a low-perf carbed engine.
67Dart273 gives great advice.
 
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coreyg said:
I have a 71 scamp with a 318. I have the fitech fuel injection, 360 heads I'm assuming the stock 360 cam not 100% sure though. I'm going through and setting up the fitech for cold starts which is now doing a lot better, but after the engine warms up to temp and I try to restart the car the engine has a hard time cranking over like my battery is almost dead. If I let it cool back down it starts up fine and turns over fine. Any thoughts?
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From what i know that system takes a while to calibrate itself, ,within reason, that will go on a while till it learns. Reason being you don't somehow have the timing at 50 initial
 
67Dart273 said:
Charging voltage won't tell you in this case.
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The point in checking the charging voltage is to see if the battery is being properly charged. If it is charging at, say, 12.8 volts (like with several bad diodes), then the battery will not be adequately charged and the starter may drag.

OP, how are you measuring your ignition timing? I know this sounds like a dumb question, but you gave a number of 10.5, and tenths of a degree is an unusually fine resolution for a timing number. That makes me wonder if this is a number being set in the FiTech and not read from a timing light, and that begs the question of how is the FiTech's timing actually sync'd to the engine's actual piston timing?
 
nm9stheham said:
The point in checking the charging voltage is to see if the battery is being properly charged. If it is charging at, say, 12.8 volts (like with several bad diodes), then the battery will not be adequately charged and the starter may drag.

OP, how are you measuring your ignition timing? I know this sounds like a dumb question, but you gave a number of 10.5, and tenths of a degree is an unusually fine resolution for a timing number. That makes me wonder if this is a number being set in the FiTech and not read from a timing light, and that begs the question of how is the FiTech's timing actually sync'd to the engine's actual piston timing?
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With the fitech, you rev the engine to around 2000rpm then look at the fitech handheld unit and see what the timing is reading, grab your timing light and turn the distributor until your timing matches with what the fitech is saying.
 
coreyg said:
With the fitech, you rev the engine to around 2000rpm then look at the fitech handheld unit and see what the timing is reading, grab your timing light and turn the distributor until your timing matches with what the fitech is saying.
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OK, I get it. (I think, LOL) Just be aware that the timing light only shows the damper mark against the timing mark on the timing cover. That counts on the damper and its mark being properly aligned with the engine's crankshaft. Old damper rings have been known to slip and no longer be properly aligned with the crank; the crank position is what you want your ignition timing to be truly aligned to. (And a 1970 and later damper and a pre-1970 timing cover will be waaay off.....)

That may not be any issue for this hard-hot-crank problem but IMHO you would be wise to check the damper and its mark's alignment to #1/#6 piston TDC so that you have a known good timing baseline as you tune this thing up.
 
nm9stheham said:
OK, I get it. (I think, LOL) Just be aware that the timing light only shows the damper mark against the timing mark on the timing cover. That counts on the damper and its mark being properly aligned with the engine's crankshaft. Old damper rings have been known to slip and no longer be properly aligned with the crank; the crank position is what you want your ignition timing to be truly aligned to. (And a 1970 and later damper and a pre-1970 timing cover will be waaay off.....)

That may not be any issue for this hard-hot-crank problem but IMHO you would be wise to check the damper and its mark's alignment to #1/#6 piston TDC so that you have a known good timing baseline as you tune this thing up.
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Yeah my old was like that, put a new one on from summit.
 
I agree with pulling the coils wire and see what happens.
Old and new starter have the same problem......probably not the starter.
The ground is the best place to start. To make it simple, Get a set of jumper cable and add a ground by putting the Negative(-) jumper from the (-) of the battery and the eng block.
only take a minute and you didn't have to take anything apart.
But my money's on the positive cable' that goes from the battery to the starter. if you have headers, it tends to get cooked at the starter. that one is probably vary old and need replacing anyway.
How ever if you want to test it. Set the voltmeter to 12 volt and tested at the starter and a good ground, is a good test for that. report back how low the voltage drops. then do the same thing right on the battery itself.
 
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