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Discussion Starter · #1 ·
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
 

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jumbo2 said:
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.
 

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Discussion Starter · #3 ·
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
 

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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.
 

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jumbo2 said:
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.




Note dimple


PM rod on right.
Note how the profile around the bolt on the rod and cap is smooth. You can compare this to yours.


Side view, PM on right.


Other side.
 

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jumbo2 said:
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?
 

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Discussion Starter · #8 ·
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
 

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Discussion Starter · #9 ·
cobalt327 said:
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.




Note dimple


PM rod on right.
Note how the profile around the bolt on the rod and cap is smooth. You can compare this to yours.


Side view, PM on right.


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
 

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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.
 

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Discussion Starter · #12 ·
cobalt327 said:
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
 

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jumbo2 said:
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.
 

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Discussion Starter · #17 ·
well I fired it up for the 20 min cam break in and went from 1800 - 2400 for 20min , temp got up to 230deg so perfect no leaks no oil no smoke no nothing , valves were almost bang on , but had to advance the dizzy to start it and retard the timing to get a good idle 850 rpm , seems like the hyfire v1 box is blaying tricks on me ? its like I need start advance not retard unless im confused? I have to turn it clockwise about an inch to start or starter wont crank ? Its a powermaster mini but has been 100% up untill now
 

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well I fired it up for the 20 min cam break in and went from 1800 - 2400 for 20min , temp got up to 230deg so perfect no leaks no oil no smoke no nothing , valves were almost bang on , but had to advance the dizzy to start it and retard the timing to get a good idle 850 rpm , seems like the hyfire v1 box is blaying tricks on me ? its like I need start advance not retard unless im confused? I have to turn it clockwise about an inch to start or starter wont crank ? Its a powermaster mini but has been 100% up untill now
Turning the distributor CW retards a SBC, so that seems normal if you were using a healthy amount of initial timing.

All in all, good job.
 
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IMO get new bearings. its crazy to reuse them. some people might say go ahead but they aint got any ties to the damage that can and might occur.

first of all bearings are crush type and if you reuse them you can wind up with oil pressure issues and a spun bearing wrecks havoc on rods/crankshafts.
they are super cheap so get new ones.
if you cant catch your finger nail on the old bearings your rods should be fine and reuseable as is.
when i built my first SBC stroker in the 80s i made the mistake of assembling the engine and taking it apart a few times and not thinking of the crush on the bearings and it ended up with low oil pressure and eventually wound up spinning a bearing my machinist warned be about this but i thought they looked good and reused them. so please take it from me and get new bearings they are super cheap and great insurance as far as mains make sure they are the right ones as the discoloration you described may be due to undercut main journals.
 
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