Engine lower rotating assembly installed. Quick question
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Engine lower rotating assembly installed. Quick question Just finished installing my rods and pistons on my 2002 6.0L LQ4. First V8...I know what your thinking.
I have built engines before, but was in the 4 cylinder realm. So now we are past that, I noticed something, which maybe normal. For every piston I installed, it became more and more difficult to rotate. I checked all the rod bearings with plastiguage and the rod to crank clearance is fine. It seems to be dragging hard on the rings and when I rotate the engine, some of the pistons are chattering in the bore. Also, everything is installed with brake in lubricate and oil. If I can give a rough estimate on the amount of torque I would say I dropping about 120 to 140 ft pounds to rotate it. Am I just freaking out for no reason.
-Fresh block 10 over and deck paralleled.
-Rotating assembly balanced.
-Dimond pistons and TSP rods.
I have built engines before, but was in the 4 cylinder realm. So now we are past that, I noticed something, which maybe normal. For every piston I installed, it became more and more difficult to rotate. I checked all the rod bearings with plastiguage and the rod to crank clearance is fine. It seems to be dragging hard on the rings and when I rotate the engine, some of the pistons are chattering in the bore. Also, everything is installed with brake in lubricate and oil. If I can give a rough estimate on the amount of torque I would say I dropping about 120 to 140 ft pounds to rotate it. Am I just freaking out for no reason.
-Fresh block 10 over and deck paralleled.
-Rotating assembly balanced.
-Dimond pistons and TSP rods.
Sounds like you’re talking just the short block right? No heads yet? That kind of effort sounds extremely high for a short block to me. Crank with torqued mains should be smooth to turn by hand. It will get progressively tighter with each piston but I wouldn’t expect as right as you’re seeing. Once the heads and valvetrain go on thing do get extremely tight especially with aftermarket valve springs. Are you sure the rods are orientated correctly on the rod journals? Do you know what you piston/cylinder clearance was machined to?
I've been down this same road with my lq4 408 stroker build. As I put all the pistons in it did the same thing yours did. I checked the mains and rod bearings and all were installed right and clearance were great. No scoring on the wall no nothing. So I went ahead and installed every thing and now it's in the engine bay. Hard as hell to move with a torque bar but the starter moves it just fine. And after cycling the engine several times to get oil flowing it got a little easier to move by hand. I changed the oil and used a magnet and found no metal once so ever in my oil. Im sure if something was wrong their would be something in the oil. So Idk what my issue was it was the same as yours but every thing seems ok.
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Did you mic all the pistons to the bores? did you check all the ring end gaps in the bores? 140lbft to rotate doesn't sound right to me, maybe 20lbft to break free but once turning it should feel fairly easy to turn in my world. Make video of this and pistons chattering.
Thread Starter
Teching In
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I've been down this same road with my lq4 408 stroker build. As I put all the pistons in it did the same thing yours did. I checked the mains and rod bearings and all were installed right and clearance were great. No scoring on the wall no nothing. So I went ahead and installed every thing and now it's in the engine bay. Hard as hell to move with a torque bar but the starter moves it just fine. And after cycling the engine several times to get oil flowing it got a little easier to move by hand. I changed the oil and used a magnet and found no metal once so ever in my oil. Im sure if something was wrong their would be something in the oil. So Idk what my issue was it was the same as yours but every thing seems ok.
Did you mic all the pistons to the bores? did you check all the ring end gaps in the bores? 140lbft to rotate doesn't sound right to me, maybe 20lbft to break free but once turning it should feel fairly easy to turn in my world. Make video of this and pistons chattering.
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Verdad Gallardo TECH Addict
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well I did find the issue..."over confident me assumed when I had given all the parts to the shop and they pre-assembled and rotated the block and make sure everything fit that they also had filed my piston rings. I removed one of the Pistons and tested upper and lower ring in the bore and found that it actually had a positive overlap on the rings. This was a juvenile move and I should have took my time and not assume that the shop had taken care of me. Lesson learned the hard way.
I was just wondering how setting end gap could have been overlooked by a machine shop, or at least communicated to the engine assembler (customer) that it hadn’t been done yet. I could almost understand if they were advertised as drop-in (requiring no file fitting), but even then it would be worth a quick verification. Glad the OP caught it. It would have meant a catastrophic failure otherwise.
Are you sure you are using the correct rings ? I've never assembled an engine where the rings were butted against themselves. There is always a slight gap that usually needs a little filing for the correct ring gap for your particular application
Hey you’re absolutely right! I never had any intention of having the machine shop build this engine for ME lol. However, when the OP mentioned the machine shop pre-assembled the engine, you would think they would have caught this (maybe they did) and offered to gap the rings for a small fee. But yeah, I agree that the person doing the final assembly should catch and correct these issues (which luckily he did!)
It’s common with forged pistons. I’ve used Wiseco pretty often and will usually get “file fit” rings, which are generally about .005” over the bore size. Right out of the box, they’ll overlap like that. You have to check them all too, even the oil rails as I’ve encountered those on a few occasion to overlap as well.
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It’s common with forged pistons. I’ve used Wiseco pretty often and will usually get “file fit” rings, which are generally about .005” over the bore size. Right out of the box, they’ll overlap like that. You have to check them all too, even the oil rails as I’ve encountered those on a few occasion to overlap as well.
they fit in the ring grooves in the piston?