New build tightness

[Econoline]

Not sure if I have a problem or not. What I have is that if the motor sit's for a while like a day or 2, when I go to turn it over, by hand, it takes a fair bit of effort. I have to use a 1/2" breaker bar wedged between 2 flywheel bolts threaded into the crank. I'd guestimate ~100lbs of pressure maybe more. Then once it's turned at all I can turn it with the balancer bolt no problem, I measured the effort @ around 35lbs with my torque wrench. But if it sit's for 5-10 minutes it goes back up to around 75-80lbs to budge it again then back to 35lbs. I can't feel or notice any point in it's rotation that is tighter or looser when spun around steady by hand. I used assembly lube on all bearings, plastigaged all bearings and they were right on the low end of spec. Threads all give a light coat of light weight oil. The cylinders have a light coat of 30wt and the pistons with rings were dipped in 30wt before they were installed The head is off the short block is complete, motor is still on the stand. It's been sitting for a while, few months and I've notice a fair bit of assembly lube drip out of it. Also, I re-torqued the rod nuts and dbl checked the main bolts before I installed the oil pump and oil pan. I had to re-torque the rod caps or properly torque them b/c my torque wrench was at work when I installed the pistons so I was careful to lightly torque them until I got my wrench home.

Am I being paranoid or should I pull the pan and dbl check the rod caps? Also, 25lbs of tq on the rod caps doesn't really seem like the bolt is getting much stretch, but that's the spec right? I torqued to 25lbs then 1/8-1/4 turn more.

 

[wsa111]

This could be caused by no spacer between the timing gear & the camshaft. Remove the timing gear & see if that's your problem.
If that's not the problem loosen the main bearing bolts & see if that helps. No rod bearing clearance could cause a binding condition.
Best of luck.

 

[Econoline]

By spacer do you mean the 'wedding ring' type ring? I've got the ring -> dowel pin -> thrust plate -> cam gear -> washer -> bolt

And while it was somewhat stiff before when I degree'd the cam, I didn't notice it being like it is now until I closed up the bottom end.

 

[wsa111]

I hate to say it, but you better dissemble the whole deal to find the problem.
Did you end gap the rings for proper gap???
Bite the bullet, find the problem before you attempt to crank it up. Bill

 

[Econoline]

Yeah, I hear that, you're feeding my fears lol I did measure the ring gaps and there was just a .0005 or less under on a cylinder or 2. Everything has spec'd out on the tight end but pretty much on the money. I've been as careful as a novice can be. Crank was ground under 10/10, using nos clevite 77 -.010 bearings, plastigaged. I've helped build a few motors and always fixed my own, but this is the first one I've built from the ground up on my own in my garage. I'm leaning towards closing her up, flicking the switch and damned the torpedoes, let her run. But there is this nagging on my shoulder saying 'damn that's a bit stiff'

 

[CNC-Dude]

I'm going to bet that you will be pulling it back out and tearing it down regardless, so you might as well do it before wasting the time and effort to put in the vehicle, and then redoing all that in reverse again. I say damn the torpedoes and pull the pan back off and find out the problem.

 

[Econoline]

Alright, thanks for the help guy's. I'll let you know what I find.

 

[MustangSix]

30-35 lb/ft is about right for a new rotating assembly in my experience. It's possible that you have some "sticktion" going on with the pistons against cylinder walls.

Oil the piston skirts and cylinders really well and see if that eliminates the problem. If not, I'd start pulling one thing at a time to see if I could find the sticky piece. Pull the cam, then one piston at a time to see how big a difference it makes. If do end up pulling all the pistons and rods, you can then see if the crank rotates freely. It should spin with little or no effort.

 

[my way]

Yeah, I hear that, you're feeding my fears lol I did measure the ring gaps and there was just a .0005 or less under on a cylinder or 2. Everything has spec'd out on the tight end but pretty much on the money. I've been as careful as a novice can be. Crank was ground under 10/10, using nos clevite 77 -.010 bearings, plastigaged. I've helped build a few motors and always fixed my own, but this is the first one I've built from the ground up on my own in my garage. I'm leaning towards closing her up, flicking the switch and damned the torpedoes, let her run. But there is this nagging on my shoulder saying 'damn that's a bit stiff'

.0005 ring gap??? Way too tight-Old school for me is .004 per inch of bore with regular top ring placement. Pistons like the old Keith Black hyperutectic with thin top land where the ring would run hotter needed more. There's more current experience here than mine, but .0005 for sure won't work.
My way

 

[MustangSix]

Dang. Missed the ring gap. That is way too tight. Even if you had too many zeros, .005 is to tight.

.004 per inch is right, or about .015" for this engine. Thx, myway.

 

[Econoline]

No no no there was one that was a smidge less than the others, the ring gap wasn't .0005 I'm sure the ring gaps are fine. I'm sure the crank is fine. Tonight I'll pull the damned pan off and loosen one rod cap at a time and try and find the problem if there is one.

 

[Econoline]

Ok, I've found the problem, when I did the final install on the pistons I mixed up the #5 and #6 pistons. But I put the caps on in the proper order.

So the question now is do I just swap the caps and have the #5 and #6 pistons swapped or do I pull the pistons and swap them so the #'s are right? The crank has been freshly ground 10/10 and polished.

 

[bubba22349]

congrats it's an easy fix then to get the right cap installed on the right rod and your done! but if it was me I know I would just have to go ahead and pull them both out to then put them into the right holes too. :rolflmao: Good luck

 

[CNC-Dude]

You may have some bearing interference issues because the caps and rods are specific to one another and not interchangeable to other rods/caps, so look at the bearings and see where they are shiny, you could have damaged them. But yes, put the caps on the right rods.

 

[Econoline]

Bubba your a man after my own heart, lol. I'll probably swap the pistons/rods to the 'proper' holes just b/c. I'm going to check out the bearings to CNC-Dude. I figure if they look off at all I might as well replace them. Thanks for the help and nudging

 

[Econoline]

I've pulled the caps and examined them now and found the bearing in the #6 hole was pretty much fine, the other bearing got a bit reamed. The journals are fine, so I'm going to go ahead and just get couple new TM77 bearings and replace them. It doesn't make sense not to for the $7 it's going to cost.

 

[CNC-Dude]

Aren't you glad you checked into it now instead of later?

 

[Econoline]

You bet I am

 

[bubba22349]

That's great not so bad on costs, and it's for sure far less time as well as cheaper to fix it right now. Good luck