New big block 451 Swap cranking issues

-
Razorfish451

Razorfish451

Member
Joined
Aug 12, 2016
Messages
6
Reaction score
1
Location
Amarillo
I am having a hell of a time trying to get my new motor to crank over
10:1 compression motor had already been broken in properly with no issues
But now it struggling to turn over
Things i checked -Ground from battery to starter -power from battery to starter
grounds from block to frame
New stock mini starter-nothing special
New optima battery - charged
check trans to insure nothing binding up-Took fly wheel bolts and trans spun freely
Even with a charger pushing 200amp to help start it turns over slow
Making my Main power wire to get hot - they are 1 gauge
My only other thought is i need a mini race starter-
when cranking is sucks the juice to where my power probe would even die
 
Can you turn it over by hand? If not then pull the plugs and try again. If you can't turn it over with a wrench without the plugs in it then something is very wrong. Most likely used long bolts in the flex plate or something like that.
 
AndyF said:
Can you turn it over by hand? If not then pull the plugs and try again. If you can't turn it over with a wrench without the plugs in it then something is very wrong. Most likely used long bolts in the flex plate or something like that.
Click to expand...
Its super hard to turn with plugs out in but with plugs in its crazy hard-but will turn over when crank but like i have a low battery
I pulled the fly wheel bolts they seem to be fine
When im cranking it does not have a knock or clunking sounds like its toast- but did find my plugs had fuel from my carb that was leaking
I dumped all of the oil out and cranked with the plugs out to blow any out of the chamber
 
Razorfish451 said:
Its super hard to turn with plugs out in but with plugs in its crazy hard-but will turn over when crank but like i have a low battery
I pulled the fly wheel bolts they seem to be fine
When im cranking it does not have a knock or clunking sounds like its toast- but did find my plugs had fuel from my carb that was leaking
I dumped all of the oil out and cranked with the plugs out to blow any out of the chamber
Click to expand...
Im going to pull my crank pulley and see if the bolts are to long and maybe binding it up
Also my timing was at 30 degrees just for break in
 
Last edited:
With the plugs out it shouldn't take more than about 25 ft-lbs of torque to spin over. If it takes more than that then you have something wrong. Could be bolts rubbing or a bad main bearing. Maybe the thrust bearing is super tight? You should be able to check the thrust even in the car. Hook up a dial indicator and then pry the crank back and forth. If you don't have any thrust clearance then you found your problem. If it isn't a bolt hanging up then it is probably a bearing problem. In that case you should be able to see it in the oil or in the filter. Maybe cut the filter open first before pulling the pan.
 
AndyF said:
With the plugs out it shouldn't take more than about 25 ft-lbs of torque to spin over. If it takes more than that then you have something wrong. Could be bolts rubbing or a bad main bearing. Maybe the thrust bearing is super tight? You should be able to check the thrust even in the car. Hook up a dial indicator and then pry the crank back and forth. If you don't have any thrust clearance then you found your problem. If it isn't a bolt hanging up then it is probably a bearing problem. In that case you should be able to see it in the oil or in the filter. Maybe cut the filter open first before pulling the pan.
Click to expand...
Oil was perfect after draining it
I will try I'm praying bolts! Thanks again I will try that
 
bOb shingler said:
buy a new starter
Click to expand...
This is what I just installed

image.png
 
What's the history after break in? Transmission install 'issues' have lead to killed thrust bearings, which lead to things like this.

If you can't turn the thing over by hand, it's not a starter issue. Don't try to force it, the engine "clearancing itself" will be a metric buttload more expensive than fixing the real problem now. S/F....Ken M
 
Razorfish451 said:
I am having a hell of a time trying to get my new motor to crank over
10:1 compression motor had already been broken in properly with no issues
But now it struggling to turn over
Things i checked -Ground from battery to starter -power from battery to starter
grounds from block to frame
New stock mini starter-nothing special
New optima battery - charged
check trans to insure nothing binding up-Took fly wheel bolts and trans spun freely
Even with a charger pushing 200amp to help start it turns over slow
Making my Main power wire to get hot - they are 1 gauge
My only other thought is i need a mini race starter-
when cranking is sucks the juice to where my power probe would even die
Click to expand...
Razorfish451 said:
I am having a hell of a time trying to get my new motor to crank over
10:1 compression motor had already been broken in properly with no issues
But now it struggling to turn over
Things i checked -Ground from battery to starter -power from battery to starter
grounds from block to frame
New stock mini starter-nothing special
New optima battery - charged
check trans to insure nothing binding up-Took fly wheel bolts and trans spun freely
Even with a charger pushing 200amp to help start it turns over slow
Making my Main power wire to get hot - they are 1 gauge
My only other thought is i need a mini race starter-
when cranking is sucks the juice to where my power probe would even die
Click to expand...
PROBLEM SOLVED!!!!
I Guess it was the fuel in the oil that was causing it not to move freely
Changed out the oil and we are back in business-
 
68Fastback402 said:
PROBLEM SOLVED!!!!
I Guess it was the fuel in the oil that was causing it not to move freely
Changed out the oil and we are back in business-
Click to expand...

If you think that was the problem YOU HAD BETTER PULL THE ENGINE DOWN AND INSPECT IT!!!!!!
 
I built a 408 and got it all together, could barely turn the crank with a breaker bar...WTH? tore it down one rod cap at a time..bingo. I had flopped 2 rod caps and about locked up the crank. Guess which ones? 3 and 8. Stampings were light on both and looked identical I didnt think they were swapped until I torqued one on the other rod and it turned smoothly. I looked at bearings and they looked OK plenty of assembly lube still on them and were not deformed.
 
You must log in or register to reply here.
-

Back
Top