5.3l Vortec 3 pistons risk collision with counterweights
08-22-2018, 01:03 AM
#1
5.3l Vortec 3 pistons risk collision with counterweights
Doing a DOD delete and 3 piston skirts on right bank are 0.030 away from hitting counterweights at BDC. Two of those same three pistons have edge of piston rod at piston pin within 0.010 of edge of counterweight. Pistons go flush to top of block. Building up engine with a different block and crank because same 3 pistons with clearance problems now had busted skirts after 100,000 mi. Anyone have a 5.3 apart now to check if this is common clearance problem inherent to this motor? I could get the recommended 0.060 clearance by putting a deeper side radius on counterweight to clear ends of 2 rods and shave 0.030 off of 3 counterweights to get skirt clearance. Area to be shaved would be 2 1/2" long. Rods are not being used again and ones in use have been trued magnufluxed and checked for straightness.
08-23-2018, 06:57 AM
#2
What block are you using? What crank and rod setup are you using?
Example: 6.0 block with 4.8 crank and 5.3 rods
I advise against doing some “home clearancing”, unless you work at a machine shop. Either way if you mod the crank it will need to get rebalanced
Example: 6.0 block with 4.8 crank and 5.3 rods
I advise against doing some “home clearancing”, unless you work at a machine shop. Either way if you mod the crank it will need to get rebalanced
08-23-2018, 07:05 PM
#3
Well I laid the patient on her side wrapped it with Saran wrap 3/4 of the way around taped Saran drape to counterweight and started filing.Talked to my machine shop guy and he agreed the small amount I removed would not make a noticeable difference especially on generic stock build. I magnetized the files and the malleable metal mostly stuck to them. A gentle rap of file on engine stand leg and metal dust fell to floor. A light wipe with rag on Saran drape a gentle suck from shop vac and wipe down of exposed counter weight and 1 of 3 needed clearances was done. Ripped the Saran drape off and went on to do 2nd and 3rd counter weight the same way. While I was in there doing the clearance work I noticed the #1, #2, #4 and #5, main caps were not centered between the counter weights. The #3 thrust main was set by percussing the crank rearward then forward then final torqued.The thrust bearing clearance was 0.005 This did little to position the other 4 main caps to where I liked them. So I loosened (caution on proper technique so as to not warp crank) and was able to move main caps to a more pleasing position between counter weights. This whole rework was easier than I thought it would be, metal was soft and malleable and very easy to work with. Maybe the motor with the larger room for wear will make it well past 100,000 mi mark this time.
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