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Old 01-20-2005, 07:50 AM   #1
Tattoo Collector
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Default Can I reuse block bolts/head bolts

I am rebuilding my motor and I was wondering if I could reuse the bolts that hold my block together and my head bolts, or are they torque to yield? I am assuming that the head bolts will have to be reused but I am not really sure on the bolts for the block.
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Old 01-20-2005, 08:02 AM   #2
quantum
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Unless things are really different between domestic and foregin parts you should be able the reuse them. I've used the same bolts on a chevy 350 5 or 6 times. Though, if you need added strength (holding the head on, or the block together for a nasty engine) a set of really nice bolts is never a bad idea.
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Old 01-20-2005, 08:38 AM   #3
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although it is recommended to replace them every time you remove them (as the threads will stretch slightly after they are torqued) most mechanics at dealerships don't even do it. if you are building an uber-nasty motor though, ARP head studs are the way to go. (around $250 a set)
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Old 01-20-2005, 08:49 AM   #4
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I haven't replaced them on the last two motors I have put together, with no problems to date. And there is a very specific torque sequence and series. I am just pulling this from memory, so be sure to look it up, but it is something like
1-6 (you will need a manual to see which bolt is which #) to 21lb
1-6 to 52lbs
back them off in order 180 degrees
back them off in order another 180 degress
tighten 1 and 2 to 27lb
tighten 3-6 to 22lb
tighten them all in sequence 90 degrees.
Tighten them all in sequence again 90 degrees.

Like I said, don't do it off my memory, which is poor, but you get the idea. If you don't do it this way you can warp your heads...
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Old 01-20-2005, 09:35 AM   #5
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Quote:
Originally Posted by Matt Monson
I haven't replaced them on the last two motors I have put together, with no problems to date. And there is a very specific torque sequence and series. I am just pulling this from memory, so be sure to look it up, but it is something like
1-6 (you will need a manual to see which bolt is which #) to 21lb
1-6 to 52lbs
back them off in order 180 degrees
back them off in order another 180 degress
tighten 1 and 2 to 27lb
tighten 3-6 to 22lb
tighten them all in sequence 90 degrees.
Tighten them all in sequence again 90 degrees.

Like I said, don't do it off my memory, which is poor, but you get the idea. If you don't do it this way you can warp your heads...
that's pretty much what TWE sent for directions for my heads... sounds right to me, but, like you said, i don't have the page in front of me, so i'm not positive.
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Old 01-20-2005, 03:42 PM   #6
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Default Thanks.

I have a subaru factory service manual, so I have all the torque specs. I was just wondering if you could use the headbolts or not.
As far as the guy with the chevy stuff, some bolts can be reused and some cannot. I just didn't know as to this specific application.
I am building a fairly serious motor, but as far as the head bolts go, I don't think I need the ARP headstuds. Not yet at least. The next motor, they will be a must have.
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Old 01-20-2005, 04:52 PM   #7
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I reused all the head bolts etc when I did my 4A-GE last year from the MR2 and I put 6k hard miles on it before I sold it with now problems, just make sure you torque them in the right order a little bit at a time
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Old 01-20-2005, 06:56 PM   #8
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Yes you can re-use them.
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Old 01-20-2005, 08:52 PM   #9
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You can but you are not suppose to. I am a mechanic and reusing headbolts is a no-no
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Old 01-20-2005, 09:12 PM   #10
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Quote:
Originally Posted by Russell Rogers
You can but you are not suppose to. I am a mechanic and reusing headbolts is a no-no
Ding Ding, torque to yeild not suppose to reuse them. Why do you think you torque them in sequence and in incriments. stretching etc.

Every Head Set I have ever gotten has included new head bolts.

Jay
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Old 01-20-2005, 09:44 PM   #11
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Default Head Bolt Replacement

Hey, I just happend to be searching and thought I'd chime in...

This is taken from our Cylinder Head Package installation instructions;

Caution: Cylinder Head Bolts are streched to yeild requiring that a new set of bolts is used each time the cylinder head is reinstalled.
Installation notes:
1) Install new cylinder head gasket and cylinder head onto cylinder block
2) Tighten cylinder head bolts following the numerical order that follows.
a) Tighten all bolts to 29 N***8729;m (3.0 Kg-m, 22 ft-lbs) in numerical sequence
b) Tighten all bolts to 69 N***8729;m (7.0 Kg-m, 51 ft-lbs) in numerical sequence
c) Back off all bolts by 180°
d) Back off all bolts by a further 180°
e) Tighten bolts 1 and 2 to 34 N***8729;m (3.5 Kg-m, 25 ft-lbs)
f) Tighten bolts 3 - 6 to 15 N***8729;m (1.5 Kg-m, 11 ft-lbs)
g) Tighten all bolts by 80 - 90° in numerical sequence
h) Further tighten all bolts by 80 - 90° in numerical sequence

Sorry I can't post the picture with the numerical sequence to illustrate this better. If you'd like to PM me I can forward you the file. We are working on a Tech Page for the website that will include all our installation instructions.

Thanks,

Keith
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Old 01-20-2005, 09:58 PM   #12
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Hi Keith. Thanks for the info. I just called there tonight and spoke to someone (i forgot his name; i'm terrible with names) and got some very good info. You guys are the best out there. I wish you were closer to me! Anyway, thanks again for the help and I'll get some dyno numbers for you on that header as soon as the car is running.
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Old 01-21-2005, 02:58 AM   #13
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Just my two cents worth, but when you back the bolts off the full 360 Deg, you will have a bit of space to squirt some more lube under the washers/bolt heads-eliminated alot of 'bolt-grab' for me....
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Old 01-21-2005, 03:04 AM   #14
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I have changed about 50 2.5 sohc head gaskets at a dealer and reused every single head bolt without one failure. If bolt replacement was required then subaru wouldn't pay the claims due to the bolts not being charged out on the repair order.
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Old 01-21-2005, 03:10 AM   #15
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I talked to ron at axis today because my arp head studs are a bit short for my sohc heads he told me I would be fine re using my headbolts as long as i use the proper tightening sequence etc.
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Old 01-21-2005, 06:56 AM   #16
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Quote:
Originally Posted by 00Maddog
I have changed about 50 2.5 sohc head gaskets at a dealer and reused every single head bolt without one failure. If bolt replacement was required then subaru wouldn't pay the claims due to the bolts not being charged out on the repair order.
Hey Bud,
IF it was the case....
If you read the 'Shop Manual carefully it will give you specs to check the bolts against, measure, tension and measure....time consuming, but cheaper than replacing bolts!!!!

Cheers,

(btw:did you know that the average load on any one head bolt/stud under normal operating conditions is between 1-1.5 tonnes, and when an engine detonates it can rise as high as 7 tonnes!! PER BOLT!! )

Sixpack Subaru
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Old 01-21-2005, 07:54 AM   #17
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Well, I would follow the directions if you have explecet ones that say change the head bolts. Maybe chevy's are different, or it could be that since I started with a nice set of arp bolts I got away with it. Anyway, like I said in my first post "A nice set of new bolts is never a bad idea."
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Old 01-21-2005, 09:20 AM   #18
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I believe 8complex has reused his like 6+ times If I remember reading correctly.
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Old 01-21-2005, 05:54 PM   #19
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I don't care who has or does reuse them. Never ever reuse headbolts. I know for a fact that Subaru does say to put new bolts in when removing head.
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Old 01-22-2005, 01:35 AM   #20
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As the "by-the-book" technician, you should replace headbolts. Especially those applied to TTY. Actual mechanics don't and usually reuse them just once or twice. Some TTY bolts such as those for mid to late 90s Volvos had their factory recommendations set to no more than 5 times of reuse.

Reuse or using new, it's a divided opinion among mechanics and technicians. I know plenty who've reused headbolts with no problems and those individuals have been Subaru mechanics/technicians for longer than I existed. Many here on NASIOC.

But, if one of them bolts snaps off as you torque it down, expect to have a very p00py day.

-paK +1
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