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fiberbug Samba Member
Joined: July 23, 2006 Posts: 38
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Posted: Wed Dec 06, 2006 9:05 pm Post subject: engine rebuild // hard to rotate crank pulley |
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rebuilding my 1500. I have brand new cylinders, pistons and rings installed.
I then installed heads and rocker assembly. When I rotate pulley to set valve timing. There's a bit of resistance when turning engine over. (I've got a crescent wrench on the crank pulley.)
This is my first rebuild. Is this resistance normal? |
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fiberbug Samba Member
Joined: July 23, 2006 Posts: 38
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Posted: Wed Dec 06, 2006 9:19 pm Post subject: |
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Also... The new pistons shipped fitted into their cylinders. I noticed these were very tight when pulling them out. I'm guessing that this is where the resistance is occuring.
Thanks in advance for any help |
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Max Welton Samba Member
Joined: May 19, 2003 Posts: 10697 Location: Black Forest, CO
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fiberbug Samba Member
Joined: July 23, 2006 Posts: 38
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Posted: Wed Dec 06, 2006 9:58 pm Post subject: |
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The crank was spinning fine before I put the cylinders/pistons on.
Since the rings came already installed on the pistons, I didn't check any gaps. It was a complete set. Pistons, cylinders, rings.
I made sure I flooded the cylinders with plenty of oil before installing. It just seems really tight as I turn the pulley over. |
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Towel Rail Horizontally Opposed
Joined: April 15, 2005 Posts: 4622 Location: SE CR IA US NA PE
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Posted: Wed Dec 06, 2006 10:09 pm Post subject: |
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Try leaving the plugs out until you're ready to start the engine.
When I rebuilt my 1600, I almost thought something was wrong, but nope, new pistons are tight in their cylinders. _________________ 1974 Thing -- under the knife
1967 Beetle -- spring/summer/fall driver
1996 Subaru OBW (EJ22, 5-speed, AWD) -- winter car, 3-seasons "don't feel like biking today" car
049 > 070 > 053 > 009 |
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Mr. Loaf Samba Member
Joined: March 30, 2005 Posts: 2098 Location: Okra, Oklahoma
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Posted: Thu Dec 07, 2006 6:55 am Post subject: Wrench |
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Get rid of the crescent wrench.................. _________________ Never drive faster than your Angel can fly
$24,100 was too hard to resist................. |
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Max Welton Samba Member
Joined: May 19, 2003 Posts: 10697 Location: Black Forest, CO
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Posted: Thu Dec 07, 2006 5:24 pm Post subject: |
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fiberbug wrote: |
The crank was spinning fine before I put the cylinders/pistons on. |
Good. That rules out the crank and case.
fiberbug wrote: |
Since the rings came already installed on the pistons, I didn't check any gaps. It was a complete set. Pistons, cylinders, rings. |
IMO, that is a mistake. You did take the rings off and clean the pistons and rings right? There is typically all sorts of very abrasive grit in there.
Max _________________ 1967 Type-3 Fastback
Under the Knife https://shoptalkforums.com/viewtopic.php?f=24&t=151582
Home Stretch https://www.thesamba.com/vw/forum/viewtopic.php?t=767836 |
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DrDarby Samba Member
Joined: May 12, 2004 Posts: 6531 Location: Northern Illinois
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Posted: Fri Dec 08, 2006 6:02 am Post subject: |
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Also I hope you set the ring gaps per spec. _________________ Midwest Autosavers, Inc. Woodstock, IL |
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airic Samba Member
Joined: December 11, 2005 Posts: 170 Location: Wisconsin
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Posted: Fri Dec 08, 2006 9:19 pm Post subject: |
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Take the pistons back out, check for broken rings, clean them, align them, check gaps.....
Or just put it back together, and fire it up and hope it was all right.,
your choice |
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vintageorbust Samba Member
Joined: November 07, 2006 Posts: 217 Location: Ridgecrest, CA
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Posted: Fri Dec 08, 2006 9:32 pm Post subject: |
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Make sure you're placing the gaps of the rings away from each other. i.e. the ring openings should be in a Y shape. Make sure the rings are right side up. Did you put some motor oil in the cylinder before you stuck the pistons in? It's important. It'll help things move easier. _________________ Meredith Phillips
Silly riceboys... useless wings are for penguins!
Chicks that can work on their own cars?! Yeah I know we're hot =) |
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Rome Samba Member
Joined: June 02, 2004 Posts: 9603 Location: Pearl River, NY
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Posted: Sat Dec 09, 2006 11:46 am Post subject: |
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Try leaving the plugs out
Yep. If you have the spark plugs firmly tightened, but do not yet have the rocker arms+pushrods installed, you are compressing 375cc of air into about 55cc for each cylinder (7:1 compression ratio). The air has no where to go except slowly past the fresh new piston rings, since the valves are not yet opening to let the air pressure escape. This is why you experience so much resistance to turning. Take the plugs out before you do anything, then see how "easy" the engine turns. |
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Busin Samba Member
Joined: June 20, 2007 Posts: 205
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Posted: Wed Jul 01, 2009 8:02 pm Post subject: |
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with new pistons and cylinders you should ALWAYS take them apart before installing them to check the alignment of the rings, as the factory doesn't do that before they ship them out. |
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connella08 Samba Member
Joined: February 28, 2009 Posts: 833 Location: south central mass
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Posted: Wed Jul 01, 2009 9:01 pm Post subject: |
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mine were the same way when i bought them. they came with the pistons inside of the cylinders. i pulled them out and cleaned them, then lubed the side walls with 10W30 and slid them back in. i bet thats where he made the mistake. i wonder if maybe he didnt oil the pistons before he put it together.
after about an hour of running time, my engine turns nice and smooth. |
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