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-   -   Crankshaft worry , now unsure of what to do with rod caps ?? (http://www.hotrodders.com/forum/crankshaft-worry-now-unsure-what-do-rod-caps-220441.html)

jumbo2 06-11-2012 11:11 PM

Crankshaft worry , now unsure of what to do with rod caps ??
 
3 Attachment(s)
Bought a used engine , guy said 383 bla bla bla so I took a gamble and when I got home tore it apart , everything was looking 100% until I dropped the pan and saw some color on the crank , so i pulled the rod cap to make sure it was fine and bearings and crank grind look perfect no wear or color , looks like at one time it spun a bearing so they ground the crank and re used it , crank is an eagle , pistons are probe flat top's and rods are unknown , I don't know what to do now ? Loosen all rods are re torque ? seen 45lbs with oil and 50lbs with lock tight ? bolts are 3/8 24 fine I believe

S10 Racer 06-11-2012 11:33 PM

Quote:

Originally Posted by jumbo2
Bought a used engine , guy said 383 bla bla bla so I took a gamble and when I got home tore it apart , everything was looking 100% until I dropped the pan and saw some color on the crank , so i pulled the rod cap to make sure it was fine and bearings and crank grind look perfect no wear or color , looks like at one time it spun a bearing so they ground the crank and re used it , crank is an eagle , pistons are probe flat top's and rods are unknown , I don't know what to do now ? Loosen all rods are re torque ? seen 45lbs with oil and 50lbs with lock tight ? bolts are 3/8 24 fine I believe

If the crank has been reground, it should be designated on a counterweight. The main & rod bearings will also be designated on the back side. Because you don't know the history of the motor, if you are going to keep it, I would take the crank to a machine shop and have them mic the journals unless you can do it yourself. If the journals spec out ok, just have the machine shop polish it, then install new bearings. The discoloration is really no concern as long as everything checks out. The rods should be removed, checked and manicured as well. It makes no sense to have a perfectly round crank if the rods aren't.

jumbo2 06-11-2012 11:54 PM

Because everything looks so good I was going to re torque the rods and run it , there is no way the crank would be colored and the bearings and rods be fine , im just unsure of what to do ? back all caps off and re torque all of them to ? ft lbs

engineczar 06-12-2012 06:10 AM

Can you tell if the rod bolts are aftermarket? You might need a mirror to see the head side of the bolt. If we can determine what the bolts are then we can figure out a torque spec.

cobalt327 06-12-2012 09:09 AM

Quote:

Originally Posted by jumbo2
I don't know what to do now ? Loosen all rods are re torque ? seen 45lbs with oil and 50lbs with lock tight ?

Rods look like OEM powdered metal and the bolts look stock, judging by the details that can be seen, including no balancing pad on the cap, and similarities to the photos below.

IF you choose to reuse the rods as-is, I would retorque to stock specs. The reason is the bolts are knurled (not Waveloc), and the visible end does not have a dimple used to locate a stretch gauge. There are still knurled aftermarket rod bolts, and there may be knurled aftermarket rod bolts w/o a dimple for a stretch gauge, but my guess is those are stock.

But if it was me, I would have to give some hard thought to pulling the rods and having ARP bolts installed, unless the cam/redline/ how the engine will be used is such that the stock rods and bolts are deemed to be enough.

http://www.hotrodders.com/gallery/data/500/rod_bolt.jpg

https://deezperformance.com/media/ca...64_2_1_1_1.jpg
Note dimple

http://www.hotrodders.com/gallery/da...piston_004.jpg
PM rod on right.
Note how the profile around the bolt on the rod and cap is smooth. You can compare this to yours.

http://www.hotrodders.com/gallery/da...n_005.jpg?3631
Side view, PM on right.

http://i.ebayimg.com/t/Chevy-Corvett...9+TKoQ~~_3.JPG
Other side.

jumbo2 06-12-2012 02:31 PM

Rod bolts have what looks like a capital I on the head , it's the out line of the I

cobalt327 06-12-2012 11:26 PM

Quote:

Originally Posted by jumbo2
Rod bolts have what looks like a capital I on the head , it's the out line of the I

'96- up Vortec type OEM rods and bolts. I have an identical set out of a '97 5.7L Vortec L31 engine out in my shop.

Are you sure the pistons are forged? Are they stamped w/a part number and/or an oversize ID on the tops?

jumbo2 06-13-2012 11:59 PM

so Yes they are 98 vortec rods , motor was a vortec and has had probe flat tops and eagle crank installed , only thing I could find was 15ft lbs then 70 deg on the rod bolts ?

Talked to eagle crank is fine to run

jumbo2 06-14-2012 12:01 AM

Quote:

Originally Posted by cobalt327
Rods look like OEM powdered metal and the bolts look stock, judging by the details that can be seen, including no balancing pad on the cap, and similarities to the photos below.

IF you choose to reuse the rods as-is, I would retorque to stock specs. The reason is the bolts are knurled (not Waveloc), and the visible end does not have a dimple used to locate a stretch gauge. There are still knurled aftermarket rod bolts, and there may be knurled aftermarket rod bolts w/o a dimple for a stretch gauge, but my guess is those are stock.

But if it was me, I would have to give some hard thought to pulling the rods and having ARP bolts installed, unless the cam/redline/ how the engine will be used is such that the stock rods and bolts are deemed to be enough.

http://www.hotrodders.com/gallery/data/500/rod_bolt.jpg

https://deezperformance.com/media/ca...64_2_1_1_1.jpg
Note dimple

http://www.hotrodders.com/gallery/da...piston_004.jpg
PM rod on right.
Note how the profile around the bolt on the rod and cap is smooth. You can compare this to yours.

http://www.hotrodders.com/gallery/da...n_005.jpg?3631
Side view, PM on right.

http://i.ebayimg.com/t/Chevy-Corvett...9+TKoQ~~_3.JPG
Other side.

those are the rods on the right midle picture , block was a 98 cortec so it makes sense , cant find details on the torque specs

cobalt327 06-14-2012 07:25 AM

Engines I've done w/those same rods and bolts got 45 ft/lbs. Just like any other SBC w/stock 3/8" rod bolts.

You can use the 15 ft/lbs plus 70 degrees if you have access to the tool that shows degrees, I got mine at NAPA. It is kind of bulky so you may need an extension so it clears everything. The final choice is yours as to which method you use.

GRIdLOCK 06-14-2012 10:13 PM

+1 on the ARP Bolts

jumbo2 06-19-2012 12:55 AM

Quote:

Originally Posted by cobalt327
Engines I've done w/those same rods and bolts got 45 ft/lbs. Just like any other SBC w/stock 3/8" rod bolts.

You can use the 15 ft/lbs plus 70 degrees if you have access to the tool that shows degrees, I got mine at NAPA. It is kind of bulky so you may need an extension so it clears everything. The final choice is yours as to which method you use.

so I just loosen all rod bolts , then retorque all 8 to 45 ft lbs in any order and make sure there is lots of oil or just wet ? I need to do this and get motor back togther asap

cobalt327 06-19-2012 01:17 AM

Quote:

Originally Posted by jumbo2
so I just loosen all rod bolts , then retorque all 8 to 45 ft lbs in any order and make sure there is lots of oil or just wet ? I need to do this and get motor back togther asap

Motor oil on the rod bolt threads and bearing assembly lube on the bearings and journals (or motor oil).Tighten the rods in at least two steps and rotate the crank after each cap is torqued to assure there is nothing binding.

I don't know how much you wanted to inspect and measure, but you can plastigage the rod and mains for oil clearance as well as check the crank end float and rod side play before the pan goes on.

jumbo2 06-19-2012 11:12 AM

It was a running motor so I don't think I need to worry too much , thanks for all your help :-)

cobalt327 06-19-2012 03:38 PM

Quote:

Originally Posted by jumbo2
It was a running motor so I don't think I need to worry too much , thanks for all your help :-)

Any time, jumbo2. Keeping us posted is thanks enough.http://www.chevelles.com/forums/imag...s/thumbsup.gif


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