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#1
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340 too tight upon reassembly
Need some help here. I have a 1969 340 block bored .040" over. Standard 340 rods that were resized and have ARP bolts. Forged crank is part # 2532457; Rods are part # 2699496.
All rods and main journals are cut .010". Upon reassembly, I have no side clearance on the rods. According to my 1971 factory manual, I should have .006-.014" of rod side play. My loose pair is maybe .003" and others seem to be binding. I can bearly turn the engine over with a 2' pipe wrench on the crank snout. When I put only one rod on a journal, I have free side play, this tells me that the rod bearings are NOT binding on the journal. All bearings were reassembled with special reassembly lube and I realize that everything is new/tight but..... Has anyone experienced this? All boring and resizing was done by a proffesional shop. I am measuring 1.830" at the front journal on the crankshaft. The two rods that I measured were .935" thick which equals 1.87" or binding big time. Is it possible that with resizing of the rods, demensions have changed?? |
#2
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hello, did you measure the rod bores before assembly? are the rods in the correct way? if rods are in backwards, they will bind on the cheek of the crank. If you have that much difference on the rods, how did you get them on? no way they would even fit down the crank. that's .040. I assume the rods have the numbers to the outside of motor?If you look at the rod ends, you will see that the bearings sit toward one side of bore. the open space is supposed to fit toward the crank cheek. this will also put the numbers on rod toward the outside. what kind of assembly lube did you use? some lubes are very sticky. best to use motor oil only. I had a customer assemble a ford 390 with a sticky lube, the motor was frozen tight. washed the sticky lube off, then motor would turn over. just food for thought.
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#3
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Thanks for the info. I will check the orientation of the rods/pistons. I used Sta-Lube engine assembly lube. The lube is in a tube and thick nearly like toothpaste.
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#4
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#5
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Take a good look at the radius on the crank compared to chamfer on the bearings to make sure they are not interfering. Same symptoms as putting in the rods or shells the wrong way.
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#6
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Quote:
wow we use synthetic engine oil, i believe it is royal purple or amsoil 50 wieght for assembly. toothpaste? that sounds too thick. dodgetkboy78's dad uses slick50 additive he has problems with it being stiff at first, but wont listen to us |
#7
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2' pipe wrench on the crank ???????????
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#8
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Quote:
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#9
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Of course. The wife had the 4' pipe wrench in use taking the batteries out of the flashlight. Silly You.
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#10
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ROFLMAO!!
torch |
#11
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Quote:
torch? whats wrong, you done that before? the engines my dad does are stiff enough to use a 2' wrench on |
#12
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Improper use of tools by the ol' lady!
torch |
#13
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Quote:
torch |
#14
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well............we are off topic now, thats for sure...............look in the poll's section please
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#15
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Thinking back........
I remember once of some bearing being miss sized. Take two rods off and press the bearings onto the crank and see if there is any interference. This and rod/piston installed on the wrong bank are most likely the problems.
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#16
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Quote:
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#17
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Bearings are round.........
although not perfect untill crushed in the rod. The idea is to check the side clearance to see if their is any interference. I have seen poorly made bearings that were the wrong width.
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#18
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Just a guess, but I suspect you may have put the rod caps on backwards?
This would explain no side clearance and binding on the crank. The bearing notches should be both on the same side of the rod. Another possability is the rod ends are on the wrong rods, or the bearing are the wrong size. |
#19
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Next time you assemble an engine spin the crank after torquing the mains and atleast a full revolution after torquing each rod.
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