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| | | | Joined: Oct 2009 Posts: 171 'Bolter | | 'Bolter Joined: Oct 2009 Posts: 171 | Hello,
How easily should a crankshaft rotate, which was re-used with the pistons?
Ask
Wolfgang | | | | | Joined: Jun 2011 Posts: 5,096 Crusing in the Passing Lane | | Crusing in the Passing Lane Joined: Jun 2011 Posts: 5,096 | New rings? New crank seals?
Ed
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
| | | | | Joined: Oct 2009 Posts: 171 'Bolter | | 'Bolter Joined: Oct 2009 Posts: 171 | Hello Ed,
no the pistons rings has running, the crank seals on the rear side are new.
wolfgang | | | | | Joined: Jun 2011 Posts: 5,096 Crusing in the Passing Lane | | Crusing in the Passing Lane Joined: Jun 2011 Posts: 5,096 | If you just added a new rear seal, it would be hard to measure the difference. Normally, when the crank is out, the main and rod bearings are measured and cleaned up with a piece of fine emery cloth if just need polishing, otherwise ground to the next undersize, rods are reconditioned, bore measured and if worn, bored to the next oversized which requires new pistons and rings. This is all normal and not overly expensive, at least in the 'states.
Measuring rotational drag is not a good measurement of engine health. I am sure there are machine shops in Germany that are familiar with this procedure. Good luck.
Ed
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
| | | | | Joined: Oct 2009 Posts: 171 'Bolter | | 'Bolter Joined: Oct 2009 Posts: 171 | Hello Ed,
the main bearings 40 undersize are new, the crankshaft is poished to '40 undersize.
Wolfgang | | | | | Joined: Apr 2005 Posts: 7,440 Bolter | | Bolter Joined: Apr 2005 Posts: 7,440 | Wolfgang, you should experience some drag with the spark plugs out. It should not spin easy but it shouldn't take too much force to turn. If your talking just the crank bolted into an empty block and torqued properly, there should be minimum resistance and no slop that you can feel. there will be some measurable end play. Check specifications in the shop manual. Good luck.
Martin
'62 Chevy C-10 Stepside Shortbed (Restomod in progress)
'47 Chevy 3100 5 Window (long term project)
‘65 Chevy Biscayne (Emily)
‘39 Dodge Business Coupe (Clarence)
“I fought the law and the law won" now I are a retired one!
Support those brave men/women who stand the "Thin Blue Line"! Hug a cop!
USAF 1965-1969 Weather Observation Tech (I got paid to look at the clouds)
| | | | | Joined: Mar 2010 Posts: 10,275 Renaissance Man | | Renaissance Man Joined: Mar 2010 Posts: 10,275 | You need to isolate where the drag is coming from. Are you able to check the rotation of the crankshaft without the connecting rods attached to the crankshaft?
Last edited by 52Carl; 06/02/2018 5:31 PM.
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
| | | | | Joined: Oct 2009 Posts: 171 'Bolter | | 'Bolter Joined: Oct 2009 Posts: 171 | Hello,
I took off the cranlshaft and the rods and shaw that two bearings were damaged. Why I don't know, I used a special grease for connecting different motor parts and there must be particles in it which damaged the bearings. And annother point could be that, there was no space or very small between the crankshaft and the mainbearing caps. So I have to look why.
Wolfgang | | | | | Joined: Apr 2005 Posts: 7,440 Bolter | | Bolter Joined: Apr 2005 Posts: 7,440 | Do not use grease on rod, main and cam bearings during installation. Only motor oil. Just my opinion.
Martin
'62 Chevy C-10 Stepside Shortbed (Restomod in progress)
'47 Chevy 3100 5 Window (long term project)
‘65 Chevy Biscayne (Emily)
‘39 Dodge Business Coupe (Clarence)
“I fought the law and the law won" now I are a retired one!
Support those brave men/women who stand the "Thin Blue Line"! Hug a cop!
USAF 1965-1969 Weather Observation Tech (I got paid to look at the clouds)
| | | | | Joined: Oct 2009 Posts: 171 'Bolter | | 'Bolter Joined: Oct 2009 Posts: 171 | Yes, I see it meanwhile also.
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