motor won't turn over

hotrodt

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Nov 30, 2006

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Jul 13, 2008

#1

• Jul 13, 2008

• #1

Brand new motor new bearings,rings etc,etc I cannot get this motor to turn over. I tryed putting two bolts in the pully holes on the dampner and used a 6' crow bar and it still won't turn over just bent the bolts. Checked the torque numbers on the rod and mains, rods checked right under 45lbs. the mains checked at about 105lbs. no obstructions, I don't understand is a new motor supposed to be that tight? And if not then wtf is going on here. these are all matched parts from the machine shop.Oh by the way this is without the heads on so no compression whatsoever.

 

hotrodt

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Jul 13, 2008

#2

• Jul 13, 2008

• #2

need help

 

jrichker

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Jul 13, 2008

#3

• Jul 13, 2008

• #3

Did you put the main bearing caps and rod caps back on the same main and rod that they came off of? If not, that is your problem.

 

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347HO

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Jul 13, 2008

#4

• Jul 13, 2008

• #4

I assume you were able to rotate the engine when you installed the camshaft?
You would have to have set TDC for this.
If the engine turned over with a small wrengh back then... it's very possible you installed the camshaft incorrectly and you are binding the crap out of a valve to piston.

 

hotrodt

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Jul 13, 2008

#5

• Jul 13, 2008

• #5

no I did not, what do I do now, short of trashing it?

 

hotrodt

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Jul 13, 2008

#6

• Jul 13, 2008

• #6

I just got through checking p tp v clearence with modeling clay .113 exhaust and right around .083 on the intake.

 

hotrodt

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Jul 13, 2008

#7

• Jul 13, 2008

• #7

Sounds like I have an " i am not an engine builder " issue. Smarts definately don't match experience here! What do I do from here guys?

 

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347HO

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Jul 13, 2008

#8

• Jul 13, 2008

• #8

hotrodt said:

no I did not, what do I do now, short of trashing it?

Click to expand...

So, your answer is that you could not rotate the engine after installing all rods and mains?

hotrodt said:

I just got through checking p tp v clearence with modeling clay .113 exhaust and right around .083 on the intake.

Click to expand...

Your PTV is absolutely good... IF it was accomplished after TDC and camshaft indexing properly.

hotrodt said:

Sounds like I have an " i am not an engine builder " issue. Smarts definately don't match experience here! What do I do from here guys?

Click to expand...

Let's back up a few steps here.
Who assembled the engine?
What were the bearing clearances on your mains?
What were the bearing clearances on your rods?
What was the bearing clearance on your thrust?
Did you accomplish a rotational torque check on your assembly after full assembly of the shortblock?

 

hotrodt

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Jul 13, 2008

#9

• Jul 13, 2008

• #9

Checked p to v right at the overlap of the intake and exhaust valve. Jrichter hit it dead on, I can torque the mains to spec no problem spins great but the second I torque the rods down then oh f#$@ it wont spin. I did not label the rods per the cylinder like a dumb A$$ so now I don't now whether the only option is a machine shop or what.

 

hotrodt

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#10

• Jul 13, 2008

• #10

The parts were a basket case from my local sellers paper and were according to the seller "a match set of machined parts". So I guess now the problem is my lack of engine building skills and his lack of honesty. Or maybe my stupidity for trusting the human race. He saw me coming.

 

jrichker

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#11

• Jul 13, 2008

• #11

Time for a trip to the auto machine shop. They can match and machine the rod big ends and mark them for you.

 

capri debris

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May 5, 2007

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Jul 13, 2008

#12

• Jul 13, 2008

• #12

The rods are labeled for you from the factory... they have a number stamped on each of them so you can't get them mixed up unless you don't look at the numbers. Do you have the correct size rod bearings for the crank journal diameter? Also, there is a chamferred edge on the big hole of the rods that must face away from each other... two rods share a single journal on the crank. And BTW, plastigauge is your friend... an engine should never be built without using some of it to make sure things are right.

 

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347HO

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#13

• Jul 13, 2008

• #13

capri debris said:

Also, there is a chamferred edge on the big hole of the rods that must face away from each other... two rods share a single journal on the crank.

Click to expand...

This is MOST likely the problem.
Go back and check each rod for the chamfer is toward the crank journal radius and not towards each other.
Don't forget... it's possible to have installed the rods on the pistons backwards. When you have the rods installed on the crank correctly, the pistons must also face the correct directions too!

 

hotrodt

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#14

• Jul 13, 2008

• #14

where are the numbers ? I can't find anything but casting numbers on the rod length. When I assembled the motor I turned the notch in the piston towards the front of the motor i have never seen factory pistons put in any other way, with the exception of some old mopar men who believe turning the notch backwards is good for 5 or so horsepower.

 

hotrodt

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Jul 13, 2008

#15

• Jul 13, 2008

• #15

Capri debri is right as rain the rods have each cylinder number stamped on them albeit very small you can see them if you know to look. Now moving on, let's say I tear this thing back apart yet again switch the slugs to the proper holes, check clearences and chamfer's and retorque everything do I still need to expect problems because of the first wrong assembly? I did not use excessive force trying to get this thing to turn so i know i did not damage anything, and the bearings are the correct bearings as far the size. thanks you guys you have been a life saver and have deverted a disaster.

 

capri debris

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#16

• Jul 13, 2008

• #16

Rods and caps are matched sets. They are put together and then the big hole is machined. They can not be mixed up. Each rod has a cap that goes with it and only it. The numbers are stamped where I put arrows in the pic below. Each rod, cap and piston assembly must must go in the proper cylinder with the notch or dot on the top of the piston facing the front of the engine. You should have done some more homework before trying to build this engine. I wish you luck, but who knows what else you may mess up before it's all done.

 

hotrodt

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Jul 15, 2008

#17

• Jul 15, 2008

• #17

This is how as human beings we learn, by hands on experience and with the help of fine folks such as yourself capri debri. Im sure those that are willing and have the required knowledge will step me through this engine build and the results will be just fine. As for the motor I tore it back down tonight and plastigaged the mains. All 5 mains measured .002 in. and .051mm I am to tired to check the rods tonight but tomorrow night I will check the clearence on those, and yes I'll put the slugs in the right holes. I really do appreciate your help and patience capri debri. How about those clearence numbers? To tight, good, bad, what?

 

hotrodt

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Jul 19, 2008

#18

• Jul 19, 2008

• #18

lets try this again