Tempered Posted December 16, 2009 Share Posted December 16, 2009 hello all, I am in the process of rebuilding an L6. I just installed the new main bearings and put the crank in. Now its sitting in there with the caps on but it's not bolted in. Now the crank spins freely but it takes a lot of force to move it. I have to use quite a bit of strength to get it to spin. Once its moving its smooth. Now I used Mell-lub pre assembly lube. Its a rather old bottle and the lube is a little thicker than it had been new. I've never rebuilt an L6 or any other engine for that matter but I feel as though it should spin a little easier, especially with no pistons attached. Any suggestions? Is this typical? Thanks. Quote Link to comment Share on other sites More sharing options...
Apex944 Posted December 16, 2009 Share Posted December 16, 2009 It does sound like something is wrong. The crank should move extremely easily without any extra's attached to it. As well as really easy when the main caps aren't torqued down yet either. Perhaps the old oil you used degraded into some kind of sticky or gritty like paste? How did you store the crank shaft, on one of it's ends or on it's side? Was the crank ever knocked over while you had it out of the engine? Correct bearings installed in the correct position? Have any dial calipers to check the main journals of the crank for roundness? I would start with cleaning all of the old oil out and trying some good new royal purple engine build oil or something similar and see if that helps. If not then the crank could be bent or a journal could have an issue. Even the block could be slightly warped, but according to the information i've found for the L6 it's not very common for a block to warp. Quote Link to comment Share on other sites More sharing options...
MAG58 Posted December 16, 2009 Share Posted December 16, 2009 1. What are your clearances? 2. Did you make sure none of the main caps are on backwards (it's happened before)? 3. Quantify "a lot of force" 4. Did you check to see if the crank is bent? I.e. put bearings on mains 1&7, put the thing in there and spin it with a dial gauge in the middle? Quote Link to comment Share on other sites More sharing options...
BluDestiny Posted December 16, 2009 Share Posted December 16, 2009 Correct bearings installed in the correct position? Are the bearings/journals in the right way? Would also help to check for clearences before you spin it. That may have causes mircoscratches in the crank Quote Link to comment Share on other sites More sharing options...
1 fast z Posted December 16, 2009 Share Posted December 16, 2009 What was the T.I.R. on the center main? Quote Link to comment Share on other sites More sharing options...
MAG58 Posted December 16, 2009 Share Posted December 16, 2009 Since you say you've never built an engine before, 1 fast Z is asking for Total Indicated Runout. Quote Link to comment Share on other sites More sharing options...
Tempered Posted December 17, 2009 Author Share Posted December 17, 2009 First, thanks for the help guys. Ok.. here goes. I bough the short block from the local pick n' pull. I did it because someone had taken the head and I was able to see all of the pistons appeared fine and the cylinders still had the hatch marks from a re-hone. It was an f54 block in an S30 which led me to believe someone had rebuilt it. once I got the block home the crank spun great, pretty easy even with the pistons in it. The bearings had some wear. I took the bearings to the machine shop and they measured them for the new set. At no time did I drop or bang the crank. I stored it on its side in my garage on some cardboard. My buddy ( a well rounded mechanic) inspected it and said it (the crank) looked great. I spoke to my local machinist who said the oil is fine and is probably thicker due to cold weather. He said my issue may be that i needed to torque all of the caps down and that would eliminate the issue. I just did that and it was still hard to spin. It takes about 70-80% strength with one hand (pulling or pushing) to move it a 1/4 rotation. Pulling all the caps off the crank spins freely when seated with lower bearings. The last two caps to take off were the main and the rear. With the rear off it spun easier. Could it have been I put the rear main seal in to soon and should have the crank torqued in first? (not sure if that matters). I took the crank back off and all the bearings were on correctly. Now.... what I did do when I first installed it was put the rear cap on first and then the rest. The second time around i'm gonna start with the main first and work outward, then tighten. Sooo... my buddy said try to use motor oil see if it aids the spinning. I bought new pre-assembly lube which is just as thick as the old stuff. So now I have to re-clean everything and will have results tomorrow, in lieu of new replies and maybe taking it to the machine shop for them to check. Also, Just to confirm correct bearing placement, the main bearings have the lips, the two widest sets bearings go on the front and rear and all of the rest in between. *Note, I can't find my Z shop manuals due to a recent move, I'm using the "how to modifiy your Z" as a reference book, not much but helps. Quote Link to comment Share on other sites More sharing options...
MAG58 Posted December 17, 2009 Share Posted December 17, 2009 You are putting the thrust bearing (the big wide one with the two big thick bronze lips in the middle bearing right? That would be main bearing 4. It's the only main cap that is threaded for a puller aside from the rear bearing. Quote Link to comment Share on other sites More sharing options...
Tempered Posted December 17, 2009 Author Share Posted December 17, 2009 yep, thats in the right spot. Quote Link to comment Share on other sites More sharing options...
FubarI33t Posted December 17, 2009 Share Posted December 17, 2009 At no time did I drop or bang the crank. I stored it on its side in my garage on some cardboard. Cranks like Cams need to be stored standing up or resting in there proper spot in the engine. Helps to have a spare head or block if your guna store for a long time. It might of warped Quote Link to comment Share on other sites More sharing options...
Tempered Posted December 17, 2009 Author Share Posted December 17, 2009 Cranks like Cams need to be stored standing up or resting in there proper spot in the engine. Helps to have a spare head or block if your guna store for a long time. It might of warped Thats good to know. I had the crank out of the engine for no more thank 3 weeks I believe. I hope that wasn't long enough to warp it. Quote Link to comment Share on other sites More sharing options...
Tempered Posted December 18, 2009 Author Share Posted December 18, 2009 Ok, well My mechanic guru came over and helped me put the crank on, very similar to the way I did it and the end result was the same. He said it was perfect and only harder to spin due to the thickness of the assembly lube. The cranks spins good and smooth. So I guess I made the mistake of thinking it should spin quite "freely". Thanks for the help gents. Quote Link to comment Share on other sites More sharing options...
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