Slow crank

[crateracer16]

Just put my motor together and trying to get it fired up. Seems to be cranking over real slow. It will try to fire but just doesn't seem to have enough rpms to catch. i've tried 2 different batteries and 3 different starters. replaced ign switch and starter button. found some bad wiring and replaced it. Still no difference. It started to do this right at the end of the year last year with a different motor. What else could it be?

[parrot69777]

Bad ground? We had a problem similar to this once and we had to add a ground from the engine to the frame.

[fast_crew]

Does engine turn over ok with a ratchet on the crank? Maybe pull plugs and see how engine turns. May have a tight bearing or something along those lines, or what Parrot mentioned.

[Chaps46]

Had the exact same problem a few years ago. Turns out I had used WD40 on the cylinder walls (on the recommendation of an 'expert'). All it did was collect moisture and cause enough rust on the cylinder wall to seize the rings. Had to take the motor completely apart, clean it, and lube the walls with motor oil. No problem after that. Motor fired right up!!

I'll double check your ring gaps, piston clearance, and cylinder wall lube.

[joedoozer]

With no plugs in it, it should turn over with 40-50 lbs.ft. Put a torque wrench on the crank bolt and rule out the worst first. Also double check that the dizzy isn't 180*off.

Last season we chased a bad battery cable for a few days. Be thorough in testing, this is what we ended up doing.

After you rule out the engine being the problem.

1. Check battery ground
2. Check battery voltage during cranking right at the battery.(I would guess the voltage doesn't drop much during cranking); this shows you that there are no issues with it in its current position. If the voltage is dropping, put an ammeter on the battery cable running up to the solenoid. Not sure what the amp draw is with the gear reduction starters. Someone else might know.
3. Take your battery out and the work from the engine backwards
4. Hook the battery positive right to the starter. Use new cables for this (not jumper cables)
5. Hook to the starter side of the starting solenoid. (This tests the cable from the solenoid to the starter)
6. Hook to the battery side of the starter solenoid. (Using the start button like you would normally do); If the solenoid works then you can rule out the starter button. Test for a voltage drop across the solenoid. Check voltage to ground on both sides. DO NOT HOOK YOUR LEADS ACROSS THE SOLENOID DURING CRANKING
7. Last thing to check the the battery cable from the battery to the solenoid.

Step 7 is where we had our problem. Car would crank but not fast. I used brand new jumper cables to do these tests instead of a new short cable and got the same results; pointing me to the starter. The jumper cables weren't getting a good connection either and I was recreating the problem when testing. Don't assume something is good, that includes anything in the car and jumper cables. Oh and just because you find 1 problem doesn't mean it's the only problem.

We had a bad battery positive cable and the disc in the solenoid plunger on the starer was also bad. Both causing the same symptoms.

[dylchris]

Similar problem a few years back. the cylinder wall corroded and needed a good tear down and clean up.

[crateracer16]

Ok. Tried pulling the plugs out and cranking it. Took about 53lb to turn the motor over. I do not run a solenoid between the battery and starter. My positive cable goes from the battery to the master cut off, then from there straight to the solenoid on the starter. I have tried several different starters, all are good because i tried them on another motor, and no difference. I have found more hillbilly wire splices every where so it looks like I'm going to rip every piece of wire out of the car and start over. Is it still a good idea to put a ground strap from the frame to the motor? Thanks for the input. This is for a street stock motor not a crate. fyi.

[26-62 racing]

Check battery voltage 1st. A fully charged 12 volt battery in good condition will show 13.2 volts. Each individual cell put out 2.2 volts fully charged, which is how the voltage equals 13.2 volts. With the volt meter still connected to the battery when the engine is cranking over the voltage should stay at about 10.5 volts or better and stay there during cranking. A sudden or steady drop of voltage means a weak battery. Slow cranking could be a bad armiture in the starter. A good starter will draw 300 to 400 amps.

[joedoozer]

Ok. Tried pulling the plugs out and cranking it. Took about 53lb to turn the motor over. I do not run a solenoid between the battery and starter. My positive cable goes from the battery to the master cut off, then from there straight to the solenoid on the starter. I have tried several different starters, all are good because i tried them on another motor, and no difference. I have found more hillbilly wire splices every where so it looks like I'm going to rip every piece of wire out of the car and start over. Is it still a good idea to put a ground strap from the frame to the motor? Thanks for the input. This is for a street stock motor not a crate. fyi.

With 53 lbs I think you can safely rule out the motor. You don't need a ground strap on the motor unless you have rubber motor mounts. That being said, make sure you have good metal to metal contact. Take the paint off the mounts if you have to.

[26-62 racing]

When checking wiring connections, a hot connection to the touch means a bad connection. Even if the connection is tight. Connection could be corroded at the terminal and not be able to be seen. The crimped ends of battery connections could be corroded between the wire and copper connector, example, where it connects to the solenoid, causing a loss of voltage, high resistance, thus slow cranking. Electrical problems will drive you nuts. Everybody is giving you good ideas. When you figure it out it will probably be something small. Let us know so we call all learn another idea to look for when we have the same problem. Hope this helps.

[stock car driver]

With 53 lbs I think you can safely rule out the motor. You don't need a ground strap on the motor unless you have rubber motor mounts. That being said, make sure you have good metal to metal contact. Take the paint off the mounts if you have to.

Many big name engine builders want each head grounded and the block.... also the braided flat wire/cable is what your supposed to use for the ground electricity travels in the outer most wires only in round cables..

Also 0 is the size cable you should be running if over 8 feet.

[bushracing67]

the first thing i would do (and i am really suprised no one mentioned this yet, unless i missed it) try cranking the engine over with no power to the distributor, what you are describing sounds like an engine that is too far out of time to fire... and when you rewire the car install a ford starter relay, it cuts down power draw quite a bit

[crateracer16]

Sorry. Forgot to mention it rolls slow with and without the dist. plugged in. i'm going out now to check the grounds and other connections.

[Egoracing]

Many big name engine builders want each head grounded and the block.... also the braided flat wire/cable is what your supposed to use for the ground electricity travels in the outer most wires only in round cables..

Also 0 is the size cable you should be running if over 8 feet.

Agree 150%
I have seen heads grounded on the dyno be worth hp that was measurable. Over 7hp difference run to run just bolting a #10 fine strand ground from the block to the heads on an aluminum head 350hp motor. I do not agree with the above post that a ground strap not needed unless you run rubber mounts. I have corrected issues on late models by running a ground.
A GM style solenoid will pull 2-3 times the amount of power that a remote ford style unit uses. It has to due with the amount of power being pulled by the smaller wire and how the unit works as a whole. Try jumping from the small terminal to the battery wire and see if it spins faster. Then wire in the ford style unit in line and it will keep your battery lasting longer and will start easier when the engine and starter are hot.

[Werflus]

if your battery cables have got hot to the point of smoking they are bad. change the cables and that should corect the slow start.

[rick james]

do a voltage drop test hook a volt meter on the + side of battery then the other lead on positive cable at starter set to volts turn engine over if over .5 volts u have a bad connection or bad cable then repeat test at every connection untill u pinpoint bad component

[WheelchairWarrior]

We had the same problem this year when we put in the new engine. Turned out to be our master cut off switch. To check that just bolt the two cables together that go to the master switch. If it cranks good after doing that, replace your Master switch.

[ss86b]

always always always ground your motor to frame................. example we didnt ground the motor to the frame in my buddies camaro. the rules restricted us to stock distrib and module. after 5000rpm his motor popped and missfired. all i did was put an old ground strap we found in the trailor on a head to the frame. problem fixed. we took the ground off after races and made 2 laps popping and acting crazy came back. regrounded it and for the rest of the season no problems. i have never heard of grounding motor in 3 places but really what could it hurt. will have to play with grounds on next dyno run i will report if any differance when you ground all 3 both heads and block vs 1 ground vs letting motor mounts be the ground. i may put an old junker motor on the dyno in the morning just to see. courisity killed the cat thing.

[beer30]

i run a ground cable from the ground post on the battery to the back of the head. no problems ever

[crateracer16]

The master cutoff was bad along with some bad wiring. So after replacing all the wiring and it still cranked slow I by passed the master cutoff and it fired right up. Cranks fast as hell now. thanks for the help fellas.....