LY5 engine tight spot
03-16-2009, 07:25 AM
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LY5 engine tight spot Hello all
I am a long time viewer, first time poster. I am looking at a swap and got a 5.3L LY5 out of a 08 roll over Silverado. I took the plugs out and rotated the engine via the front pulley to find there is a spot in each rotation where it gets tight and needs a lot of pressure to turn. If I turn it quickly it goes through smoothly but when turned slowly when the timing dot is at the 11 o’clock position it gets stuck and requires a lot more pressure to get past. It happens at the same spot on each rotation so I was thinking it may be in the rotating assembly. As a rollover could something have damaged the bottom end?
Thanks
I am a long time viewer, first time poster. I am looking at a swap and got a 5.3L LY5 out of a 08 roll over Silverado. I took the plugs out and rotated the engine via the front pulley to find there is a spot in each rotation where it gets tight and needs a lot of pressure to turn. If I turn it quickly it goes through smoothly but when turned slowly when the timing dot is at the 11 o’clock position it gets stuck and requires a lot more pressure to get past. It happens at the same spot on each rotation so I was thinking it may be in the rotating assembly. As a rollover could something have damaged the bottom end?
Thanks
03-16-2009, 02:15 PM
#2
If the motor has been sitting, without the manifolds, or in a garage where the floor sweats, It will surface rust up the tops of the cylinders pretty quick, and cause it to be sticky rolling it over. I have had 3 that were like this either when I got them, or have gotten like this from my garage. Might pour a little trans fluid in the spark plug holes and let it sit. All of them ran like a champ, no smoke or anything when they finally got installed, but if you don't oil them down from the get go, it is pretty easy for it to happen. That would be my guess moreso than the bottom end.
03-16-2009, 02:36 PM
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Thanks, not sure how long it sat, but the truck just hit the bone yard and was delivered within a week. It is very strange that if rotated quickly it does not get hung, but when rotated slowly it takes a good hard push to get past the spot. I'll try the trans fluid trick and see if it loosens up. Any other guesses?
06-27-2009, 12:54 PM
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If the motor has been sitting, without the manifolds, or in a garage where the floor sweats, It will surface rust up the tops of the cylinders pretty quick, and cause it to be sticky rolling it over. I have had 3 that were like this either when I got them, or have gotten like this from my garage. Might pour a little trans fluid in the spark plug holes and let it sit. All of them ran like a champ, no smoke or anything when they finally got installed, but if you don't oil them down from the get go, it is pretty easy for it to happen. That would be my guess moreso than the bottom end.
07-03-2009, 05:52 PM
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Ok, so we tried to lube up and sit then turn over without plugs for a min or so. The tight spot remains. Now for the strange part, if you are turning it with a ratchet and can get some momentum before the tight spot it will glide past it, but if you turn it slowly it takes a fair bit of force to get past this spot. When I say a fair bit of force, the starter cannot start spinning the motor if it lands on the tight spot without the plugs in (when being powered with a booster/charger). I am worried to take it apart as the yard may not take it back, but if it could be something simple I got a great price for the combo and it very low miles. Any ideas?
