Can I reuse head bolts? 225.

Hey Guys....I was planning to start reassembling my motors/heads tomorrow, but then I realized the new head bolts that I ordered aren't here. According to tracking, the box was left in our mailbox while we were gone, and apparently someone raided it. No box, no headbolts. Argghh!!

That's $140 down the drain, and it'll be double if I have to reorder. I've heard both ways.....yes, you can reuse the old ones, and no, not a good idea because they're stretch bolts.

Any suggestions?

Edit: the shop manual clearly states not reuse the oil passage o-ring or the head gasket (obviously). But it says nothing about the listed head bolts. It would seem that if they weren't reusable the manual would have stated it. How to figure?

Ihave reused them many times,clean the threads really well on a wire wheel

Should not be a problem, I'm going thru 2nd round of slapping on my heads again. Seems like you and I are on the same page..lol

You can easily tell if the factory would advise using new bolts by looking at the torque specs for reassembly. If the directions for tightening the bolts have you tightening with a torque wrench and then going back and additionally tightening a given angle, then that is more likely than not a "torque to fail" process and the bolts should always be renewed.
For example:
"Tighten each bolt to 85 lb.ft. and make a second pass rotating the bolt an additional 90 degrees".
That is a typical torque to fail instruction.

This process puts the bolts so deep into what is called the "elastic limit zone" of the fastener, it would not be wise, nor is it recommended, to reuse the bolts.

jgmo said:

You can easily tell if the factory would advise using new bolts by looking at the torque specs for reassembly. If the directions for tightening the bolts have you tightening with a torque wrench and then going back and additionally tightening a given angle, then that is more likely than not a "torque to fail" process and the bolts should always be renewed.
For example:
"Tighten each bolt to 85 lb.ft. and make a second pass rotating the bolt an additional 90 degrees".
That is a typical torque to fail instruction.

This process puts the bolts so deep into what is called the "elastic limit zone" of the fastener, it would not be wise, nor is it recommended, to reuse the bolts.

Click to expand...

Rats!! I was afraid you'd say that. Sure enough, the torque values in the manual call for an additional angle value of 103 degrees. Now, is this a tool that I can rent? I'll ask my mechanic about it as well, and maybe even borrow his.

Sorry to be the bearer of bad news. As the other guys indicated, many, if not most, of these bolts "survive" the procedure and are used again by many people. But it is a crap shoot since the idea, from an engineering standpoint, is to take them right up to the edge of failure. The ONLY way you could reuse bolts that have been torqued this way with absolute confidence that they are still good would be to very precisely measure each one's length when new and then again before reusing. If the bolt's length is exactly the same, then it is ok. But if the bolt is slightly longer the bolt has "stretched" and has failed elasticly.

A bolt can be looked at as being a spring of sorts. If you had measured it before torqueing you would find that it gets longer the more you tighten it. Up to a point. If you stop tightening it within this lengthening zone it will remain in elastic tension and will resist loosening due to shock and vibration. Then, when loosened it will contract, much like a spring does, back to it's original length. But if it doesn't "spring back" it is said to have gone "plastic" and has lost all tensile properties that it once had.

The tool you refer to is a simple protractor called an anglemeter for measuring angles. There is a "professional" model that fits to a breaker bar or on a torque wrench but I have done this type of work, in a pinch, using the plastic protractors that kids use in school. You torque the bolt to spec and then lay out your angle and mark the bolt head and a target point on the head. Then, simply rotate the head mark to meet your target point.

The hard thing about not having the anglemeter is seeing the marks. If you have the tool you simply tighten the bolt in one sweep. Without it you will need to be cautious about going too far because you can't easily see your marks. In which case you have to keep stopping and checking.

Harbor freight has one that is magnetic and fits on ratchet.

Just be careful of the scale on the HF stuff. I found out the hard way that a "Chinese inch" can be about 3/64" shorter than an American inch.

Not sure about degrees but...

Just sayin'.

OK, I'm ordering the new bolts. And while I'm at it, I'm trying to order the oil path orifice o-rings that the manual calls for on page 9-25. But none of the diagrams even show the "oil path orifice", let alone the o-ring, so I don't have a part number.

I have found what appears to be the same thing: Nippon Reinz Seal Ring W0133-1808317, but I'm not 100% sure.

Can anyone locate the correct part number for the o-ring.....and tell me where you found it?

Does anyone have the correct length of the head bolts? They have them as 12x163mm. I measured mine not including washer and 162mm

1mm shouldn't make much difference but to be safe, measure the depth of the hole in the block and add that to the depth of the hole in the head to ensure plenty of clearance. If the hole has room go ahead and use the longer bolt.

I guess what Im trying to find out is the amount my bolts are stretched..They have been torqued down twice and wondering if i could use them a third time. Thats why i measured them. I have my heads back and dont want to wait another 1.5 weeks if I can safely use them. Engines have less that 800 hrs

btravlin2 said:

I'm trying to order the oil path orifice o-rings that the manual calls for on page 9-25. But none of the diagrams even show the "oil path orifice", let alone the o-ring, so I don't have a part number.

I have found what appears to be the same thing: Nippon Reinz Seal Ring W0133-1808317, but I'm not 100% sure.

Can anyone locate the correct part number for the o-ring.....and tell me where you found it?

Click to expand...

I'm answering my own question: I had to look closely on the cylinder block diagram to find the orifice and o-ring. There appears to be only one set per head. Strangely enough.....I didn't see this part during disassembly?!

The stretch I'm referring to would be measured with a micrometer with a 0.0001 scale. Or in other words, ten thousandths of an inch and is done as the bolt is in tension. I have no idea how long they would "grow" if they failed.

A more reliable way to see if a bolt has "gone plastic" is to look for "necking down" of the major diameter just under the bolt's head. But no matter how you look at it, you have to take into consideration the cost of a set of bolts vs. what an engine replacement might be.

In my opinion, using old bolts is just playing with fire. It is done all the time but with no guarantees.