Big end bearings weight dont match.

N

NitroInjected

Well-Known Member
So I put my piston's rods and pins together and weighed them with a dummy weight for the ring seeing as all the rings are zero to eachother and I managed to match everythig to zero in my scales resolution. I also bought a new certified lab grade scale. 1 problem. I didnt have my big end bearings in. Theres a weight difference of .3 grams total. one is .1 grams heavier one is .2 grams heavier... What should I do. They are all clean. I could try swapping rods around but everything is real close like .2 grams is my largest variance . am I chasing a ghost?
 
take a couple deep breaths, have a brandy, relax its almost a non-issue.
.3 grams is well inside a reasonable weight variation,
while I frequently have 2-3 sets so I can mix & match as required,
and
While I would try to match the weights,
I would not loose a seconds sleep,
over a .3 gram variation.
most shops only balance rotating assembly's to a .5 gram at best
 
Last edited:
I actually played with the rods as I know one of them has a .2 varience. Even my new scale looses resolution over 10 grams and only shows .5 grams. That being said I used both scales and got the total of the two sets to zero on my scales. the sets are still heavy. 1414.0 with everything. This is down from something like 24 or 2600 grams also the balance was off by three grams from the last rebuild. Each part is within .1 or .2 grams the bearing I measured was actually a little dirty and after breakkleen it showed .2 on the scale. I will be putting the three pistons in tomorrow. Still wishing it was a v8. :D Also thanks for the fast reply. I guess I did loose sleep over it and literally tore them all apart before bed. Kinda had that itch ya know.

MY WIFE IS GOING TO KILL ME. These piston rod assemblies are on a shelf by the bed with two lab scales next to them.... LOL. I also did my wire loom in here but she helped.
 
Got it all balanced. Granted the under side of the piston crowns look like I went at them with a pickaxe ( largest drill bit. ) but its all in the block . Used a hoseclamp to compress the rings... Cant get one out here in a reasonable time. no torque specs for the big ends so I looked around and the concensus is around 70-75 ftlbs for the 7/16 ARP rod bolts with their lube so I did 100NM Looks and feels good so I am getting ready to slap the sump on... Which is a pita. Had to get all of the silicone off and file the windage tray because some dink maybe even me bent it. Rings are gapped for turbo and nitro right out of the box. I am sure it was running lean and very hot on the top side in overboost so More pressure with a better air fuel ratio should run very well.
 
NitroInjected said:
Got it all balanced. Granted the under side of the piston crowns look like I went at them with a pickaxe ( largest drill bit. ) but its all in the block . Used a hoseclamp to compress the rings... Cant get one out here in a reasonable time. no torque specs for the big ends so I looked around and the concensus is around 70-75 ftlbs for the 7/16 ARP rod bolts with their lube so I did 100NM Looks and feels good so I am getting ready to slap the sump on... Which is a pita. Had to get all of the silicone off and file the windage tray because some dink maybe even me bent it. Rings are gapped for turbo and nitro right out of the box. I am sure it was running lean and very hot on the top side in overboost so More pressure with a better air fuel ratio should run very well.
Click to expand...
I have ran into that with those Mitsubishi EVO engines....No torque specs on the Rods.
Remember going to Carillo's website for torque specs.
One had L19 Rod Bolts.
Torqued them down to 100 ft/lbs with ARP Moly Lube.

Best to go by Rod Bolt stretch.
.008"- .009" typical stretch.
 
Maniacmechanic1 said:
I have ran into that with those Mitsubishi EVO engines....No torque specs on the Rods.
Remember going to Carillo's website for torque specs.
One had L19 Rod Bolts.
Torqued them down to 100 ft/lbs with ARP Moly Lube.

Best to go by Rod Bolt stretch.
.008"- .009" typical stretch.
Click to expand...

Just snug by hand each rod cap bolt.
Then 1 clean pull to torque spec desired or rod bolt stretch needed.
Do the other the same.
 
http://garage.grumpysperformance.co...ng-rod-bolt-stretch-preload.11050/#post-60457

ARP supplies bolt stretch charts
116_0609_rod06_z.jpg

116_0609_rod01_z.jpg



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bearingh8.jpg


bearingh10.jpg

bearingh12.jpg

bearingh13.jpg

1310.jpg

crnk1a.jpg

crnk3a.jpg

crnk4.jpg

crnk5.jpg

crnk6.jpg

bearingh11.jpg
 
Last edited:
Boys I do not have those tools. 75ftlb should be plenty. I cant see them sgoing over stretch nor can I see them coming loose. If I had the gauge I would use it. The sump is near on anyhow. Im taking a break from the slow process of installing the valves. I requested the head be washed in a solvent based wash along with all my valve parts.... Looks like someone wire brushed em... Theres still poop on everything..... So I am washing as I go. I still have to chip off the intake gasket... Just got word of a free mill and lathe. Looking for a flat enclosure to put em. Ill never send out parts to someone I don't know ever again.
16 valves and its 40* out...
 
NitroInjected said:
Boys I do not have those tools. 75ftlb should be plenty. I cant see them sgoing over stretch nor can I see them coming loose. If I had the gauge I would use it. The sump is near on anyhow. Im taking a break from the slow process of installing the valves. I requested the head be washed in a solvent based wash along with all my valve parts.... Looks like someone wire brushed em... Theres still poop on everything..... So I am washing as I go. I still have to chip off the intake gasket... Just got word of a free mill and lathe. Looking for a flat enclosure to put em. Ill never send out parts to someone I don't know ever again.
16 valves and its 40* out...
Click to expand...
There are not alot of good machinists left.

Use CRC Brake Cleaner to clean the valvestems and valveguides.
The Valve guides need to be spotless.
A 22 rifle bore brush will help clean the guides.
 
75 ft lbs is very likely to be too tight,
RULE#1 if your not sure about some aspect of engine assembly or clearancing,
STOP!.. do your research, ask questions and get info from a couple reliable sources before proceeding further
check your factory shop manual for torque specs or contact the connecting rod manufacturer,

https://racetoolsdirect.com/product...MI-cu3zOzv3gIVi4nICh1iVgDKEAQYASABEgJ2AvD_BwE
PFM66788-600x400.jpg

https://www.amazon.com/JEGS-80591-B...159417&sr=8-3&keywords=rod+bolt+stretch+gauge

(my choice in a rod bolt stretch gauge)
41Tgz5IYJ6L.jpg

https://www.summitracing.com/parts/pow-pow101300/overview/
POW-POW101300.jpg

http://www.eaglerod.com/mosmodule/bolt_torque.html

What Do I Torque the Bolts To?
The first step is to identify which bolts you have. Eagle rods are offered with a variety of different bolts. Each of which has a different torque requirement. Proper bolt torque is paramount to rod strength and life. Eagle does not use "off the shelf" ARP bolts. Eagle has ARP custom make bolts to our specifications. DO NOT use torque specs for off-the-shelf ARP bolts. Here is a diagram of some important bolt identifying features.
boltdiagram.jpg

The following chart shows the head of the bolt, the dimensions, and the proper torque spec. Be careful! the heads of some bolts look similar and some even have the same markings. DO NOT identify the bolt by the head alone. Verify dimensions also! If the head of your bolts do not match one of the pictures below - you do not have Eagle rods! Please consult the manufacturer of your rods for proper torque specs. Their torque spec is most likely different than ours! Always use ARP moly lube on the threads and under the head of the bolt when torquing!
871500head.jpg

material
socket
size
under
head
length
thread
size
torque
8740
7/16"
1.500"
3/8"
40 ftlbs
871600head.jpg

material
socket
size
under
head
length
thread
size
torque
8740
7/16"
1.600"
7/16"
63 ftlbs
871700head.jpg

material
socket
size
under
head
length
thread
size
torque
8740
7/16"
1.750"
7/16"
63 ftlbs
871800head.jpg

material
socket
size
under
head
length
thread
size
torque
8740
7/16"
1.800"
7/16"
63 ftlbs
201400head.jpg

material
socket
size
under
head
length
thread
size
torque
2000
3/8"
1.500"
5/16"
28 ftlbs
201500head.jpg

material
socket
size
under
head
length
thread
size
torque
2000
7/16"
1.500"
3/8"
43 ftlbs
201600head.jpg

material
socket
size
under
head
length
thread
size
torque
2000
7/16"
1.600"
7/16"
75 ftlbs
201800head.jpg

material
socket
size
under
head
length
thread
size
torque
2000
7/16"
1.800"
7/16"
75 ftlbs
191600head.jpg

material
socket
size
under
head
length
thread
size
torque
L-19
1/2"
1.600"
7/16"
79 ftlbs
191700head.jpg

material
socket
size
under
head
length
thread
size
torque
L-19
1/2"
1.750"
7/16"
79 ftlbs
ca1400head.jpg

material
socket
size
under
head
length
thread
size
torque
CA 625+
3/8"
1.500"
5/16"
32 ftlbs
 
Last edited:
Grumpy said:
75 ft lbs is very likely to be too tight,
RULE#1 if your not sure about some aspect of engine assembly or clearancing,
STOP!.. do your research, ask questions and get info from a couple reliable sources before proceeding further
check your factory shop manual for torque specs or contact the connecting rod manufacturer,

https://racetoolsdirect.com/product...MI-cu3zOzv3gIVi4nICh1iVgDKEAQYASABEgJ2AvD_BwE
PFM66788-600x400.jpg

https://www.amazon.com/JEGS-80591-B...159417&sr=8-3&keywords=rod+bolt+stretch+gauge

(my choice in a rod bolt stretch gauge)
41Tgz5IYJ6L.jpg

https://www.summitracing.com/parts/pow-pow101300/overview/
POW-POW101300.jpg

http://www.eaglerod.com/mosmodule/bolt_torque.html

What Do I Torque the Bolts To?
The first step is to identify which bolts you have. Eagle rods are offered with a variety of different bolts. Each of which has a different torque requirement. Proper bolt torque is paramount to rod strength and life. Eagle does not use "off the shelf" ARP bolts. Eagle has ARP custom make bolts to our specifications. DO NOT use torque specs for off-the-shelf ARP bolts. Here is a diagram of some important bolt identifying features.
boltdiagram.jpg

The following chart shows the head of the bolt, the dimensions, and the proper torque spec. Be careful! the heads of some bolts look similar and some even have the same markings. DO NOT identify the bolt by the head alone. Verify dimensions also! If the head of your bolts do not match one of the pictures below - you do not have Eagle rods! Please consult the manufacturer of your rods for proper torque specs. Their torque spec is most likely different than ours! Always use ARP moly lube on the threads and under the head of the bolt when torquing!
871500head.jpg

material
socket
size
under
head
length
thread
size
torque
8740
7/16"
1.500"
3/8"
40 ftlbs
871600head.jpg

material
socket
size
under
head
length
thread
size
torque
8740
7/16"
1.600"
7/16"
63 ftlbs
871700head.jpg

material
socket
size
under
head
length
thread
size
torque
8740
7/16"
1.750"
7/16"
63 ftlbs
871800head.jpg

material
socket
size
under
head
length
thread
size
torque
8740
7/16"
1.800"
7/16"
63 ftlbs
201400head.jpg

material
socket
size
under
head
length
thread
size
torque
2000
3/8"
1.500"
5/16"
28 ftlbs
201500head.jpg

material
socket
size
under
head
length
thread
size
torque
2000
7/16"
1.500"
3/8"
43 ftlbs
201600head.jpg

material
socket
size
under
head
length
thread
size
torque
2000
7/16"
1.600"
7/16"
75 ftlbs
201800head.jpg

material
socket
size
under
head
length
thread
size
torque
2000
7/16"
1.800"
7/16"
75 ftlbs
191600head.jpg

material
socket
size
under
head
length
thread
size
torque
L-19
1/2"
1.600"
7/16"
79 ftlbs
191700head.jpg

material
socket
size
under
head
length
thread
size
torque
L-19
1/2"
1.750"
7/16"
79 ftlbs
ca1400head.jpg

material
socket
size
under
head
length
thread
size
torque
CA 625+
3/8"
1.500"
5/16"
32 ftlbs
Click to expand...
 
Over torqued is bad....Big end of the connecting rod out of round & ruined.
Under torqued is not good either. Max clamping load is not reached or incorrect rod bolt stretch & will fail at max engine rpm.
 
NitroInjected said:
Boys I do not have those tools. 75ftlb should be plenty. I cant see them sgoing over stretch nor can I see them coming loose. If I had the gauge I would use it. The sump is near on anyhow. Im taking a break from the slow process of installing the valves. I requested the head be washed in a solvent based wash along with all my valve parts.... Looks like someone wire brushed em... Theres still poop on everything..... So I am washing as I go. I still have to chip off the intake gasket... Just got word of a free mill and lathe. Looking for a flat enclosure to put em. Ill never send out parts to someone I don't know ever again.
16 valves and its 40* out...
Click to expand...
When you get back this step is ULTRA CRITICAL!
THE EXACT TORQUE SPEC MUST BE USED OR A CONNECTING ROD BOLT STETCH GAUGE USED !
 
I bought the Crower Rod Bolt stretch gauge for my own 70TA 455 RAIV.
Have 1 set of custom made for a Pontiac V8 I bought New Crower Forged Sportsman connecting rods good for 1000 HP.
Another set of Crower Titanium Rods made for a Pontiac V8 with 11 drag strip passes on them.

Best way is to set by Rod Bolt stretch.
Chose Crower .
 
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