Rotating assembly problem ...
#578142
01/10/10 01:09 AM
01/10/10 01:09 AM
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Joined: Nov 2003
Posts: 6,293 Rock Springs
Bob_Coomer
OP
master
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OP
master
Joined: Nov 2003
Posts: 6,293
Rock Springs
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Man... Number 1-2 pistons fell right in, good side clearance about .020-.025...Next Number 3 went right in felt good floated good on the rod. Each rod and piston I install, I have a habit of checking how easy the rods float in the crank, and I spin the motor over etc..Install number four..uh oh...I have no side clearance, well maybe .003-.005 if that. The rod doesnt float on the crank very well. I notice if I pull only the number 4 cap it has the side clearance it needs, this is with #3 still torqued etc. I So I pulled the piston and rod mic the width of the rest of the rods/caps..they are within a thousandth or so. I have some plasti gauge in the tool chest i throw a piece on and re check it..It looks like it has some taper. Its good toward the outer thrust, but toward the center of the rod journal it looses a good .001. Its not binding on the radius or fillet of the crank...I could turn the engine over with the both rods installed, and there was no binding, no mhar'n of the bearing..nothing. I take it back apart, swap bearings..look..look..and look some more... I dont know. I gave up for the evening, but Im going to have a go at it in the A.M...Any suggestions???? I thought about swapping out another piston like #6, or #8, they are all ready installed and have idea clearances/margins etc..I figure if this fixes the problem..It is in that rod, if its still there..its in the crank. This stuff was suppose to be checked out. I paid to have all rods check, and the crank checked, all bearings clearances set to my spec. This really is starting to @!@$ me off. Yes, some problems occur during a build..I feel this type of problem shouldnt have happened. This isnt some $500 small block Chevy that he hurried through the machine shop...Its been there for a year too. This really sucks.. Its going to be fixed what ever it takes. I can still knock out a few things as work goes. I can continue degree in the camshaft, clay the pistons, check valve to valve through the #4 bore. Figure out a length for Manton push rods.
[color:"red"]65 Hemi Belvedere coming soon [/color] [color:"#00FF00"]557" Indy engine 1.07 60ft 144mph in the 8th 2100 lbs package [/color]
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Re: Rotating assembly problem ...
[Re: jamesc]
#578144
01/10/10 01:24 AM
01/10/10 01:24 AM
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Joined: Aug 2009
Posts: 2,050 Mooresburg, Tn
'72CudaRacer
top fuel
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top fuel
Joined: Aug 2009
Posts: 2,050
Mooresburg, Tn
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Bob, I'm sure that you checked this, but make sure the rod cap wasn't installed backwards when it was machined. I agree that you should swap another assembly in to check. Brian
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Re: Rotating assembly problem ...
[Re: '72CudaRacer]
#578146
01/10/10 01:32 AM
01/10/10 01:32 AM
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Joined: Apr 2004
Posts: 1,981 SE Michigan
TS3303
top fuel
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top fuel
Joined: Apr 2004
Posts: 1,981
SE Michigan
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Quote:
Bob, I agree that you should swap another assembly in to check. Brian
I agree and if that cures it you may also want to put a different piston on the offending rod and check again.
could be a bad piston as Rowin4 is suggesting.
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Re: Rotating assembly problem ...
[Re: '72CudaRacer]
#578148
01/10/10 01:49 AM
01/10/10 01:49 AM
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Joined: Apr 2004
Posts: 1,981 SE Michigan
TS3303
top fuel
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top fuel
Joined: Apr 2004
Posts: 1,981
SE Michigan
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Quote:
Jim, Thats a cool head light you got in your hood scoop... Did it come with the Wayne County Speed Shop distributor gear? Brian
lol thanks, no wayne county parts on the car or NOS ever. just a cool fall night that we idled too long in the water. little back fire that they put out with compressed air, refired and went on and won the round. I have a larger version but this is Bob's thread.
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Re: Rotating assembly problem ...
[Re: Bob_Coomer]
#578152
01/10/10 10:37 AM
01/10/10 10:37 AM
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Joined: Jan 2003
Posts: 16,929 NC
440Jim
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,929
NC
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Quote:
This stuff was suppose to be checked out. I paid to have all rods check, and the crank checked, all bearings clearances set to my spec. This really is starting to @!@$ me off. Yes, some problems occur during a build..I feel this type of problem shouldnt have happened.
Sorry to hear of your assembly problem. Depending on what the cause turns out to be, the individual part checks will only find certain things, and the assembly checks are typically where other problems are found. I doubt they checked a new set of rods for straightness or width variation, etc. likely just the size and bearing clearances. Same with the crank rod journal, I doubt they measured the journal width, just the diameter and maybe for taper etc.
Quote:
I have no side clearance, well maybe .003-.005 if that.
This makes me think the bearing could be rubbing the crank radius. Since all the others had extra side clearance. What bearings and crank do you have?
Good thing you assembled it carefully and found it. Let us know the root cause.
As mentioned, swapping a piston/rod from another hole will tell you a lot. Piston pin bore, piston clearance to rod, bearing shells, rod cap, rod direction, rod width variation (spot), etc. See if the bearing locating tang in the rod is the same distance from the side as a "good" rod.
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Re: Rotating assembly problem ...
[Re: 1_WILD_RT]
#578153
01/10/10 10:41 AM
01/10/10 10:41 AM
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Joined: Aug 2008
Posts: 941 Texas, USA
ChrgrCuda
super stock
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super stock
Joined: Aug 2008
Posts: 941
Texas, USA
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I had this same problem, and had to find out the hard way about the bearing being upper and lower specific on my smallblock stroker. I felt like an idiot after pulling my hair out and finding this on my own.
68 Cuda Notchback [Email]10.86@120[/Email]
69 Charger R/T 440/505
2009 Challenger SRT8
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Re: Rotating assembly problem ...
[Re: rowin4]
#578154
01/10/10 11:04 AM
01/10/10 11:04 AM
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Joined: Dec 2009
Posts: 68 Detroit, MI
RawnDart
member
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member
Joined: Dec 2009
Posts: 68
Detroit, MI
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Quote:
You or the shop didn't put that rod on the piston backwards ? turning the rod around in the bore will make the straight side of the bearing to hit on the chamferd side of the crank ?
That was my first thought, as well. I recently made that mistake with my 390 when I was assembling it. I also remembered what a PITA spiro-locks are to remove without breaking anything.
I hope that it's something simple like that for you.
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Re: Rotating assembly problem ...
[Re: Bob_Coomer]
#578155
01/10/10 11:57 AM
01/10/10 11:57 AM
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Joined: Jul 2009
Posts: 413 Norway (old world)
Oyvind Mopar
mopar
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mopar
Joined: Jul 2009
Posts: 413
Norway (old world)
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I have been into similar problems where the rodcaps or the rod has been surfaced (as a part of reconditioning a rod, making the hole smaller before honing to size), and taken too much, and also not perpenticular to the sides. It all looks Ok untill you tighten the parts together, then the two halves are tilted when viewed from the side, and there will be no sideclearance. You can check this with some dye or marker on the whole sides of the rod and cap, then tighten, and turn the crank, pushing the rods to either side, and dismantle / check for the fit if even or not. Or, you can bolt the rod together outside the engine and put on a flat, and look for gap against the light, on either side. If it is inclined, I would demand a new rod from your machine shop; balanced to the same value as the others (if he got the records for them). Everytime such a job is done the rod gets shorter and you end up with a sheettt motor. The quick and dirty fix is to file it flat again on the sides. But the boltholes are no longer straight, and the bolt head surface or the threads will also be tilted and can fatigue the rodbolt in a shorter time.
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Re: Rotating assembly problem ...
[Re: Oyvind Mopar]
#578156
01/10/10 01:16 PM
01/10/10 01:16 PM
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Joined: Nov 2003
Posts: 6,293 Rock Springs
Bob_Coomer
OP
master
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OP
master
Joined: Nov 2003
Posts: 6,293
Rock Springs
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Thanks guys for the idea's....I wished it was as simple as the rod being installed backwards. These HXN bearings are super narrow, and the rod will touch the side of the crank well before the bearing does. When I plasti gauged this yesterday i made the piece long enough to extend from the radius to the center of the cap...Its not a radius problem. here is a bad picture, but you can see how narrow the bearing is and its location to the radius.
[color:"red"]65 Hemi Belvedere coming soon [/color] [color:"#00FF00"]557" Indy engine 1.07 60ft 144mph in the 8th 2100 lbs package [/color]
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Re: Rotating assembly problem ...
[Re: Bob_Coomer]
#578157
01/10/10 01:45 PM
01/10/10 01:45 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Bob, from looking at that pic it looks like the rod is over quite a bit on the wrist pin... is it hitting the piston .... hard to tell
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