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Installed my cylinder head today. Thats where my problem lies. It feels as if its binding, well, not really binding because I can get it to turn over, its just a hell of a lot harder. It starts to get significantly harder about 20 degrees ATDC, which in my mind, is kinda weird. Pistons are well away from TDC and the valves that are open, are starting to close. So its definitely not piston to head, or piston to valve. What could this be? I was using a small crescent wrench since I didn't have the correct size socket, so it could even be that. The short block rotated perfectly fine and very smooth. Please run some suggestions my way.
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Just some data points for comparison, since I'm doing a nearly identical rebuild.
- With just the crank installed, I could rotate it easily with essentially no effort.
- With the crank, pistons (new rings, fresh hone), and cam installed I can turn everything over easily with a standard 1/2" ratchet and socket on the cam nut. The resistance is variable, but easy to overcome. Before putting the oil pan on, I could turn it over by pulling on the crankshaft counterweights . . . harder to get moving, but once I was past the static friction and was just sliding it wasn't so bad.
- Have not installed the head or valve train yet (awaiting a head gasket) but can certainly slap the torque wrench on there and let you know what it takes to turn over.
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Thats OK Tim, I've already figured it out. It was my rocker arm assembly. Valves weren't adjusted either. Right now I'm working on all the ancillary stuff. Rebuilding carbs, installing alternator, distributor, etc. Thank you though
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From your description, it sounds like gasket material is rubbing against a piston. You should have been able to turn the crank by hand, just spinning the fan. Or, you left a rag in one of the pistons...
Klaus
--
Did you do your Random Act of Kindness today?
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Definitely did not leave a rag in one of the cylinders. I'm not sure what you mean by "gasket material" either. If your talking about the head gasket i'm sure that isn't the case either because it gets harder to rotate 20-30 degrees ATDC. So number one/two piston is going down while two/three piston is on its way up. Could it be the ring end gap? THEY WERE ALL FILED WITHIN SPECS, but they were on the tighter side of the spectrum.
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You have perhaps limited experience with rebuilt engines. Piston speed ( from a standpoint of geometry) is greatest in the first 90 degrees after TDC. With new rings on a freshly honed cylinder, that's when friction will be highest too. I'm assuming the spark plugs are not installed.
So it sounds normal to me. As long as the rotation is smooth, without "sticky" areas, it will be fine. Certainly the engine will require greater and lesser torque to rotate through 360 degrees.
With a breaker bar on the crank pulley bolt you should be able to rotate the engine with two fingers and some effort.
If the ring gap was non-existent, you would never have been able to install the pistons.
Oil the cylinders and rotate the engine with a breaker bar a few times - you'll get a feel for what's happening quick enough.
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Tim;
I agree with all of Rhys' comments..the friction at the extremities of piston travel can be significant in a newly honed bore with virginal rings (particularly the Deves brand)...and moreso after the first few turns when much of the assembly oil is wiped away and things are a bit dry...but I always give a newly rebuilt block its first twenty or so turns by way of the crankbolt...without the rockers installed, so no camlobe to lifter friction either...and I swear I can feel the force required to turn be less by the twentieth turn (this is by feel and a WAG...I haven't measured this)...as long as you can turn the crank and there are no abrupt stoppage points suggesting an interference, keep trying and report back if you notice it getting easier to turn after twenty or so...only after that would I even think about installing the valvetrain, and adding its friction...besides, a 20" breakerbar applies double the torque of a ten inch adjustable/crescent wrench...could it be as simple as that?
Cheers
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It was more like a 6" crescent wrench lol. It ended up being the rocker assembly. I didn't adjust the valves either. Problem has already been fixed.
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I've built several engines in the past, all toyotas so the whole pushrod Volvo engines are new. The engine rotates, it's just a few degrees after each cylinders top dead center that I have to put my weight into it... Literally. Yet it could be that I was using a crescent wrench. And yes the spark plugs were out
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That's beginning to sound a bit odd then. Valvetrains don't make that much difference.
If you're using a 12 inch crescent wrench or so, the effort shouldn't increase too much - noticeable, but not excessive.
I know that some builders use beam type torque wrenches to measure the force, but I can't recall what values they aim for as maximum.
As a start you could remove the rocker shaft assembly and see if that changes anything.
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"That's beginning to sound a bit odd then. Valvetrains don't make that much difference."
It would if a rocker were far enough out of adjustment to put a valve spring in coil bind.
--
Gary L - 142E ITB race car, 73 1800ES
BlueBrick Racing Website
YouTube Racing Videos
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Mine can be turned over just using bare hands.
I'm thinking is it attached to a gearbox?
Maybe the 2nd rings are upside down?
--
Three 164's, Two 144's, One 142 & a partridge in a pear tree.
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Hello,
Are the valves adjusted correctly?
How easily will the crankshaft turn with the rocker shaft and spark plugs removed?
--
Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502
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I'll check on that today. To be honest, I didn't set the valves yet. They all seemed uniformed, as in how much the set screw was sticking out.
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O, and does the rocker shaft assembly have a specific torque value? I didn't find any in my Haynes manual.
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5/16"x18 fastener, use 15 to 18 ft/lb.
I have a digital readout torque wrench so I use 16.375 ft/lbs. Why 16.375? .... cuz I can!!
mike
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