Planning on re-using Main Bolts.... question...
04-11-2005, 09:56 AM
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Planning on re-using Main Bolts.... question... Yes, I've done the searching. Came up with some good info on whether or not to re-use main bolts.
I'm pulling my shortblock apart to replace the cam bearings, and putting the stock crank, rods, pistons back in it afterwards. Only 20k on the engine so no machine work. The plan is to re-use the stock main bolts.
My question is, are the top main bolts TTY (torque-to-yeild) or not? From my reading alot of people said that NO they are NOT TTY bolts, only the side bolts are. And most people reply with you must use ARP's blah blah blah failing to realize that the stockers are not TTY stretchable bolts.
I just want to confirm that they are not TTY bolts, right?
And even if I get new GM main bolts, it won't thow the mains out of round and be in need of an allign hone correct? That's only with studs, correct?
I'm pulling my shortblock apart to replace the cam bearings, and putting the stock crank, rods, pistons back in it afterwards. Only 20k on the engine so no machine work. The plan is to re-use the stock main bolts.
My question is, are the top main bolts TTY (torque-to-yeild) or not? From my reading alot of people said that NO they are NOT TTY bolts, only the side bolts are. And most people reply with you must use ARP's blah blah blah failing to realize that the stockers are not TTY stretchable bolts.
I just want to confirm that they are not TTY bolts, right?
And even if I get new GM main bolts, it won't thow the mains out of round and be in need of an allign hone correct? That's only with studs, correct?
04-11-2005, 12:56 PM
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The four main bolts are tty and need replacing. The side ones can be reused. Spend the money and get a new set for 30 bucks. For the amount of effort that it takes to pull and reinstall a motor saving a couple bucks on bolts is rediculous. Buy some arp bolts for the stock rods while your at.
04-11-2005, 01:06 PM
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Originally Posted by strokedls1
The four main bolts are tty and need replacing. The side ones can be reused. Spend the money and get a new set for 30 bucks. For the amount of effort that it takes to pull and reinstall a motor saving a couple bucks on bolts is rediculous. Buy some arp bolts for the stock rods while your at.
04-11-2005, 02:45 PM
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Originally Posted by jswhite
How do you line bore the mains if you have to replace the bolts every time they're torqued?
04-12-2005, 07:51 AM
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From another thread:
Ok, now I am more confused. It seems like main bolts are torqued differently than other fasteners within the engine, but the bolt is still being streched, right?
I'll spend the $30 on new GM bolts, but not ARP's. I dont want to have more money in fasteners than I paid for the shortblock altogether (and its getting there).
I just don't want to worry about screwing up the crank allignment withing the block!
Originally Posted by 4mulaJoe
HELL YES
I did this as well as many other people. The actual main cap bolts are not even torque to yield. The small ones in the side are but they are ok as long as you use a little lock-tite on them like they do from the factory.
Guys like the above will have you thinking your crank is gonna fall out, but it will be just fine even spinning over 7k.
I did this as well as many other people. The actual main cap bolts are not even torque to yield. The small ones in the side are but they are ok as long as you use a little lock-tite on them like they do from the factory.
Guys like the above will have you thinking your crank is gonna fall out, but it will be just fine even spinning over 7k.
Originally Posted by JS
I agree with Joe..
Mains are not TTY...
I re-used mine for my budget 346 shortblock.
Mains are not TTY...
I re-used mine for my budget 346 shortblock.
Originally Posted by Shinobi'sZ
I have use mine in 2 different motors...bearings have always looked brand new...not worried about it at all.
Originally Posted by Brian@AP-Engineering
The correct way to measure any fastener is to measure bolt stretch. The main bolts are tourque to angle, but not TTY. In my opinion , it seems a little silly to try and pinch pennys on a bottom end.
Ok, now I am more confused. It seems like main bolts are torqued differently than other fasteners within the engine, but the bolt is still being streched, right?
I'll spend the $30 on new GM bolts, but not ARP's. I dont want to have more money in fasteners than I paid for the shortblock altogether (and its getting there).
I just don't want to worry about screwing up the crank allignment withing the block!
04-12-2005, 09:32 AM
#7
FWIW , Jeff Creech @ CAM will re-use your stock main bolts if you dont specifically ask for them to be changed . He says there is nothing wrong in reusing them and has never had a motor come back as a result of a failed main bolt that was reused .
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04-13-2005, 07:38 PM
#8
cut and paste from GM Service Information for 2003 Corvette -
To prevent engine block oil leakage, install NEW M8 crankshaft bearing cap side bolts. The crankshaft bearing cap M8 side bolts have a sealant patch applied to the bolt flange
Notice
To maintain proper crankshaft end play, use extreme care during crankshaft installation. Avoid scoring or damaging the thrust bearing.
Install the crankshaft.
Important
The bearing caps must be installed in the proper location and direction.
Install the crankshaft bearing caps, with bearings, into the engine block.
Start the M10 bolts and bolt/studs.
Tap the bearing caps into place with a plastic-faced hammer.
Start the NEW M8 bearing cap side bolts. -ONLY MENTION OF NEW BOLTS IN THE PROCEDURE
Notice
Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
Tighten the inner M10 bearing cap bolts first pass in sequence to 20 N·m (15 lb ft).
Important
To properly align the crankshaft thrust bearings, the final thrust of the crankshaft MUST be in the forward direction.
Using a plastic faced hammer, tap the crankshaft rearward then forward to align the thrust bearings.
Tighten the inner M10 bolts final pass in sequence 80 degrees using the J 36660-A .
Tighten the outer M10 bolts/studs first pass in sequence to 20 N·m (15 lb ft).
Tighten the outer M10 bolts/studs final pass in sequence 53 degrees using the J 36660-A .
Tighten the bearing cap side M8 bolts to 25 N·m (18 lb ft). Tighten the bolt on one side of the bearing cap and then tighten the bolt on the opposite side of the same bearing cap.
Install the crankshaft position sensor.
Inspect the crankshaft position sensor O-ring seal. If the O-ring seal is not cut or damaged, it may be used.
Coat the O-ring seal with clean engine oil.
Install the sensor. Align the notch in the sensor retaining bracket with the bolt hole in the block.
Install the sensor bolt. Tighten
Tighten the crankshaft position sensor bolt to 25 N·m (18 lb ft).
Measure the crankshaft end play.
Thrust the crankshaft forward or rearward.
Insert a feeler gage between the center crankshaft bearing and the bearing surface of the crankshaft and measure the bearing clearance. The proper crankshaft end play clearance is 0.04-0.2 mm (0.0015-0.0078 in).
If the bearing clearance is not within specifications, inspect the thrust surfaces for nicks, gouges or raised metal. Minor imperfections may be removed with a fine stone.
To prevent engine block oil leakage, install NEW M8 crankshaft bearing cap side bolts. The crankshaft bearing cap M8 side bolts have a sealant patch applied to the bolt flange
Notice
To maintain proper crankshaft end play, use extreme care during crankshaft installation. Avoid scoring or damaging the thrust bearing.
Install the crankshaft.
Important
The bearing caps must be installed in the proper location and direction.
Install the crankshaft bearing caps, with bearings, into the engine block.
Start the M10 bolts and bolt/studs.
Tap the bearing caps into place with a plastic-faced hammer.
Start the NEW M8 bearing cap side bolts. -ONLY MENTION OF NEW BOLTS IN THE PROCEDURE
Notice
Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
Tighten the inner M10 bearing cap bolts first pass in sequence to 20 N·m (15 lb ft).
Important
To properly align the crankshaft thrust bearings, the final thrust of the crankshaft MUST be in the forward direction.
Using a plastic faced hammer, tap the crankshaft rearward then forward to align the thrust bearings.
Tighten the inner M10 bolts final pass in sequence 80 degrees using the J 36660-A .
Tighten the outer M10 bolts/studs first pass in sequence to 20 N·m (15 lb ft).
Tighten the outer M10 bolts/studs final pass in sequence 53 degrees using the J 36660-A .
Tighten the bearing cap side M8 bolts to 25 N·m (18 lb ft). Tighten the bolt on one side of the bearing cap and then tighten the bolt on the opposite side of the same bearing cap.
Install the crankshaft position sensor.
Inspect the crankshaft position sensor O-ring seal. If the O-ring seal is not cut or damaged, it may be used.
Coat the O-ring seal with clean engine oil.
Install the sensor. Align the notch in the sensor retaining bracket with the bolt hole in the block.
Install the sensor bolt. Tighten
Tighten the crankshaft position sensor bolt to 25 N·m (18 lb ft).
Measure the crankshaft end play.
Thrust the crankshaft forward or rearward.
Insert a feeler gage between the center crankshaft bearing and the bearing surface of the crankshaft and measure the bearing clearance. The proper crankshaft end play clearance is 0.04-0.2 mm (0.0015-0.0078 in).
If the bearing clearance is not within specifications, inspect the thrust surfaces for nicks, gouges or raised metal. Minor imperfections may be removed with a fine stone.
