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Discussion Starter #1
I did a search on this and didn't get an obvious answer. I did get some hits, but none that directly answered this question.....

I know it's necessary to replace the head bolts when re-assembling because they are a torque to yield design, but what about the main cap bolts and the rod cap bolts. The torque specs say to tighten to a specific value, then 85-95 degrees more. From what I understand, this is usually the process for fasteners that stretch during assembly and can't be reused. Would somebody confirm that I can or can't re-use the main bearing cap bolts and the rod cap bolts. I would certainly appreciate it. I'd hate to re-use them and have the engine catastropically fail!
 

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I cant answer your question about the reuse of the bolts. However If I were rebuilding an engine, Iwould use new bolts. I am replacing a blown head gasket now and I have the new (required) bolts. I think I paid 56 for each set.
 

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Discussion Starter #4
281 Tuner,

I'm going to call Max tomorrow...but is that $56 price for the main AND rod cap bolts? Since I paid that much for each of my head bolt sets...if I can get them for that price I'll jump on it. It is a bit steep, but I really can't trust the used ones. I would always wonder when they are going to stretch beyond yield and blow my engine. Good luck on yours....I've got two pistons installed in mine and when I was doublechecking the torque values...I saw the note about angle/torque and started to wonder. I've already got about $1200 in the rebuild...sure hate to blow it all because I was too cheap to spend another $60, but at the same time...it's killing me to do it.

Nick-H,

I know I need new head bolts...got two sets at about $45 per set. They sure think alot of them...eh? I was specifically wondering about main and rod cap bolt replacement. Nobody seems to know for sure.

If someone has a Helms manual or CD...would you please look this up for me? All I've got are the crappy and sometimes ambiguous Haynes and Chiltons. No flames please. I know I should have a Helms.

Thanks!
 

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Here's the advice the Car Quest parts guy gave me. The also operate a machine shop out of this location and this guy is the machine shop manager. I don't know if he's full of it but when I called to get a price on new bolts, he told me this:

"If you replace the rod cap bolt and/or the main cap bolts, you must align bore all the main journals and re-bore you rod ends."

He recommended against replacing the rod cap bolts and the main cap bolts. Does anybody know anything about this?

Please...HELP!
 

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rustyul said:
Here's the advice the Car Quest parts guy gave me. The also operate a machine shop out of this location and this guy is the machine shop manager. I don't know if he's full of it but when I called to get a price on new bolts, he told me this:

"If you replace the rod cap bolt and/or the main cap bolts, you must align bore all the main journals and re-bore you rod ends."

He recommended against replacing the rod cap bolts and the main cap bolts. Does anybody know anything about this?

Please...HELP!
He's an idiot and I raise the BS flag on his statement. :bs:

One, the rod ends on a 4.6L can not be resized/re-bored since they are of the sheered cap design.

Two, I have NEVER heard of having to align bore due to a bolt change. Now a re-bore for a cap change, yes. But I’ve never heard for bolts and the many ARP studs and bolts I’ve used in engines have never called for an align bore.

When I built my 4.6L, I went under the assumption that if the spec called for a torque to a number and then an additional amount of degrees, I would replace that bolt. On the 4.6L I replaced the head bolts, main bolts, and rod bolts. But I reused the side bolts. (But I'm not done yet, so it may grenade when I start it up :D)

Just my opinions. :thumbsup:

p.s. Don’t you just love torque to yield bolts…. :D
 

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Here is what it says on the ford repair cd in the engine disassembly instructions.

I put the previous step in for the heck of it...

31. Remove the connecting rod cap and lower connecting rod bearing. Keep cap and lower connecting rod bearing together. Push the piston, connecting rod and upper connecting rod bearing through the top of the cylinder bore. Use care to prevent damage to the bearing and cylinder bore surfaces. Keep upper connecting rod bearing and connecting rod together.

32. CAUTION: Care should be taken not to damage the fractured rod and cap joint face surfaces or damage to the engine may occur.

NOTE: Connecting rod bolts are retained in the connecting rod cap with a light press fit. The connecting rod bolts have been torqued to yield at least twice and must be discarded. Use a hammer and punch to drive connecting rod bolts from connecting rod caps

And as for the Man Cap bolts... Here is what it says...

6. NOTE: No. 5 main bearing cap must be seated until the main bearing cap bolts are fully tightened as outlined below. With crankshaft pushed forward, install pry bars or similar tools to push both RH and LH front edges of No. 5 main bearing cap rearward and position the lower crankshaft thrust main bearing rear face properly against the thrust face of the crankshaft.


7. CAUTION: Main bearing bolts must be replaced with new bolts. They are torque-to-yield designed and cannot be reused.

Tighten new main bearing cap bolts in two steps as follows:

a. Tighten bolts in sequence to 30-35 N-m (22-25 lb-ft).

b. Rotate bolts in sequence 85-95 degrees.


There you go... hope that helps

Willum
 
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