I really need help on an aluminum BB assembly question
#1784475
03/20/15 05:35 PM
03/20/15 05:35 PM
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Joined: May 2014
Posts: 503 Idaho
1320Dart
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mopar
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mopar
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I have a tall deck KB block. The cam is standard location. But it has been machined for the 54mm cam by KB. I have a 4.675 crank with 2.2 diameter rod journals. I know that my 7.1 aluminum rods will not clear the cam. Does anyone know if steel rods will clear without having to modify them? I don't have steel rods to do any mocking up with. I'm hoping that other people have ran into this situation before. Any info is helpful.
Greg ----------------------------------------------------------------- Cost is irrelevant, making memories is far more valuable!
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Re: I really need help on an aluminum BB assembly question
[Re: avenger572]
#1784477
03/20/15 06:55 PM
03/20/15 06:55 PM
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Joined: May 2014
Posts: 503 Idaho
1320Dart
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Quote:
Im using oliver steel rods with 4.75 stroke callies crank in a kb block standard cam location. . I had remove a small bit off rods for clearance to the cam .
Are you running the 54mm cam as well?
Greg ----------------------------------------------------------------- Cost is irrelevant, making memories is far more valuable!
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Re: I really need help on an aluminum BB assembly question
[Re: avenger572]
#1784479
03/20/15 07:09 PM
03/20/15 07:09 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
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Master
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Quote:
Standard cam bearing , and cam base circle is 1.012 " . Cam lobe size will affect clearance .
The cam journals will effect the clearance.. the lift is ground down into the base to increase lift from the journal diameter... if he doesnt get crazy with lift he can cut the OD of the cam and cut farther into the base just as long as it doesnt flex with high spring pressures
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Re: I really need help on an aluminum BB assembly question
[Re: MR_P_BODY]
#1784480
03/20/15 07:21 PM
03/20/15 07:21 PM
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Joined: May 2014
Posts: 503 Idaho
1320Dart
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the lift at the lobe will be about .490/.495
Greg ----------------------------------------------------------------- Cost is irrelevant, making memories is far more valuable!
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Re: I really need help on an aluminum BB assembly question
[Re: 1320Dart]
#1784481
03/20/15 07:28 PM
03/20/15 07:28 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
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Quote:
the lift at the lobe will be about .490/.495
Thats not bad at all... and with a 54mm that would be easier to grind the OD of the lobe and cut into the base to get the lift and get you some clearance.. the big 54mm starts with a taller lobe.. once you get a rod to mock up then you can see if you need to grind much off the OD
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Re: I really need help on an aluminum BB assembly question
[Re: MR_P_BODY]
#1784482
03/20/15 07:36 PM
03/20/15 07:36 PM
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Joined: May 2014
Posts: 503 Idaho
1320Dart
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I don't want to go much farther with this setup if there is going to be a ton of issues. I may have to abort this big crank and stay with my 4.375 crank instead.
Greg ----------------------------------------------------------------- Cost is irrelevant, making memories is far more valuable!
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Re: I really need help on an aluminum BB assembly question
[Re: 1320Dart]
#1784483
03/20/15 07:47 PM
03/20/15 07:47 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
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Quote:
I don't want to go much farther with this setup if there is going to be a ton of issues. I may have to abort this big crank and stay with my 4.375 crank instead.
With the 54mm lobe your taller than the smaller lobe so your gonna have to cut the OD of the lobe as the starting point then cut the lift into it on the base.. but the 54mm gives you more meat to start with.. I dont know how much you would have to cut off the OD since you dont have a rod... this is a test and see UNLESS the cam grinder has a bit of knowledge of this set up... might be time to call a grinder and this is assuming you would use a chevy rod(more clearance)
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Re: I really need help on an aluminum BB assembly question
[Re: MR_P_BODY]
#1784484
03/20/15 07:51 PM
03/20/15 07:51 PM
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Joined: May 2014
Posts: 503 Idaho
1320Dart
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yes it's a 2.2 rod journal
Greg ----------------------------------------------------------------- Cost is irrelevant, making memories is far more valuable!
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Re: I really need help on an aluminum BB assembly question
[Re: avenger572]
#1784486
03/20/15 10:08 PM
03/20/15 10:08 PM
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Joined: May 2014
Posts: 503 Idaho
1320Dart
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Quote:
You stated above that the 54 mm is the bearing journal not the lobe right
Correct
Greg ----------------------------------------------------------------- Cost is irrelevant, making memories is far more valuable!
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Re: I really need help on an aluminum BB assembly question
[Re: 1320Dart]
#1784488
03/21/15 08:09 AM
03/21/15 08:09 AM
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Joined: Jan 2003
Posts: 2,902 A shed in England
Tig
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Quote:
I have a tall deck KB block. The cam is standard location. But it has been machined for the 54mm cam by KB. I have a 4.675 crank with 2.2 diameter rod journals. I know that my 7.1 aluminum rods will not clear the cam. Does anyone know if steel rods will clear without having to modify them? I don't have steel rods to do any mocking up with. I'm hoping that other people have ran into this situation before. Any info is helpful.
Wedge or Hemi head?, you will be able to run more lobe lift with a Hemi, Hemi cams clear the rods better with a 4.75 crank.
'74 Challenger..9.46 @ 145.9 1/4, 6.001 @ 118 1/8 so far. 4023lb !!! # N/A, Marsh performance 655ci, Indy Maxx, T/R, Indy 600-13 X's, Street legal, pump gas, full interior, Cal-Tracs, mufflers, 3:73's and real 10.5 radials. 9.51 @ 142.4 1/4, 6.003 @ 114 1/8 with our old mule KB, 572-13, 580 wedge. RHD '68 Barracuda Fastback 323ci street/strip. Best ET 13.88 @ 99.03
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Re: I really need help on an aluminum BB assembly question
[Re: Tig]
#1784489
03/21/15 09:12 AM
03/21/15 09:12 AM
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Joined: May 2014
Posts: 503 Idaho
1320Dart
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Wedge KB block 4.500 bore. Standard cam location. Has the larger 54mm cam option. K1 crank 4.675 with 2.2 rod journals B1-MC's with Jesel, 1.7 ratio, paired shaft rockers. CNC ported. Flows 445 on the In. and 300 on the Ex. Will be running carburated alcohol. Scott over at Koffel's recommends this cam grind; 285 @ .05 In. 300 @ .05 Ex. with a 115 lobe separation. .490 lobe lift In. .485 lobe lift Ex. I also wanted to run the dual swap firing order. 1 8 7 2 6 5 4 3 I dont know if any of this helps
Greg ----------------------------------------------------------------- Cost is irrelevant, making memories is far more valuable!
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Re: I really need help on an aluminum BB assembly question
[Re: 1320Dart]
#1784490
03/21/15 10:22 AM
03/21/15 10:22 AM
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Joined: Mar 2006
Posts: 9,791 MI, usa
dvw
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master
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Quote:
I have a tall deck KB block. The cam is standard location. But it has been machined for the 54mm cam by KB. I have a 4.675 crank with 2.2 diameter rod journals. I know that my 7.1 aluminum rods will not clear the cam. Does anyone know if steel rods will clear without having to modify them? I don't have steel rods to do any mocking up with. I'm hoping that other people have ran into this situation before. Any info is helpful.
Which aluminum rods? A BME 396 forging has a smaller outer configuration than a 426 forging. Doug
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Re: I really need help on an aluminum BB assembly question
[Re: 1320Dart]
#1784491
03/21/15 11:38 AM
03/21/15 11:38 AM
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Joined: Mar 2012
Posts: 220
Jerry Kathe
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I’m guessing that your crank is 4.625? As a first step, I wouldn't advise cutting the cam BC below or into the cam core, money and effort spent on the 54mm is lost, unless its absolutely a minor amount. Restoring the radius’s to prevent stress risers adjacent to the journals and lobes and the column profile isn't as easy as it sounds. If conditions allow minor lobe reductions, then OK, but avoid getting into the nominal core diameter.
There are so many variables with these combinations that mocking is the only answer, unless….someone has built the same exact combo right down to every last characteristic such as exact cam grind/core, rod profile, journal diameter, rod length and so on – Take a spent rod and start the clearance process until you get there and then evaluate the practicality of the end result. Personally, I would want to see for myself and have the end result in my hand over taking a forum reply for granted anyway….
Finding a spent 2.2 / 7.100 aluminum rod shouldn't be too difficult – brand won’t matter for mock up, your only looking for dimensional criteria.
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Re: I really need help on an aluminum BB assembly question
[Re: dvw]
#1784492
03/21/15 12:08 PM
03/21/15 12:08 PM
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Joined: May 2014
Posts: 503 Idaho
1320Dart
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R&R billet Pro-Mod rods.
And no. The crank is in fact a 4.675
Greg ----------------------------------------------------------------- Cost is irrelevant, making memories is far more valuable!
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Re: I really need help on an aluminum BB assembly question
[Re: TS3303]
#1784494
03/21/15 12:43 PM
03/21/15 12:43 PM
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Joined: May 2014
Posts: 503 Idaho
1320Dart
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That's refreshing news! I have no problem getting steel rods, if it will gain the extra clearance. It looks like me getting greedy on cubic inch and finding this 4.675 crank has caused me heart burn
Greg ----------------------------------------------------------------- Cost is irrelevant, making memories is far more valuable!
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