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Old 09-08-2005, 01:23 PM   #1
Mike1967
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Default Head Torquing

Torqued my resurfaced heads last night and was baffled by the torquing instructions in the FSM.

(1) Tighten all bolts in the specified order to 22 ft lb's
(2) Go back and Tighten all again in the same order to 55 ft lb's
(3) Back off all in the same order by 180 degrees
(4) Go back and back them all off in order again by 180 degrees
(5) Tighten the center bolts in order to 25 ft lbs
(6) Tighten the outer bolts in order to 11 ft lbs
(7) Tighten all bolts in order by 80 to 90 degrees (Do not go over 90 degrees)
(8) Again tighten all bolts in order by 80 to 90 degrees (Do not go over 90 degrees)

QUESTION: What is the purpose of step # 2 ?
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Old 09-08-2005, 01:31 PM   #2
n2xlr8n
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Quote:
Originally Posted by Mike1967
Torqued my resurfaced heads last night and was baffled by the torquing instructions in the FSM.

QUESTION: What is the purpose of step # 2 ?
To stretch the bolts and /or compress the HG.

The best advice I can give you on installing / assembling any engine is:

-Make sure your torque wrench is cal'd

-Carefully clean the threads and bolts / studs with a clean tap

-Use a recommended oil / lubricant on both the threads, the underside of the bolt head, and the washer, if applicable.

This may be too much info, but the technique has worked for me for 25 years.

S.
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Old 09-08-2005, 01:44 PM   #3
Mike1967
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Quote:
Originally Posted by n2xlr8n
To stretch the bolts and /or compress the HG.

The best advice I can give you on installing / assembling any engine is:

-Make sure your torque wrench is cal'd

-Carefully clean the threads and bolts / studs with a clean tap

-Use a recommended oil / lubricant on both the threads, the underside of the bolt head, and the washer, if applicable.

This may be too much info, but the technique has worked for me for 25 years.

S.
If I missed step #2 on the LH Head.......what are the odds that I have to tear it back down and start the torque process over ?

And if I do have to tear it back down....what are the odds that I need to get another new set of bolts to replace this new set of bolts ?

Please keep in mind that this is not a high compression setup.

Thanks for your help !!!!

Mike
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Old 09-08-2005, 02:05 PM   #4
n2xlr8n
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Quote:
Originally Posted by Mike1967
If I missed step #2 on the LH Head.......what are the odds that I have to tear it back down and start the torque process over ?
Wouldn't want to guess, but if it was my engine, I'd do whatever it took for piece of mind.


Quote:
Originally Posted by Mike1967
And if I do have to tear it back down....what are the odds that I need to get another new set of bolts to replace this new set of bolts ?
If the headbolts in your car are anything like the WRX (or the same), they are REALLY high quality bolts. I usually buy ARPs for everything I build, but I'm using the stock bolts in my build (>575whp EJ257).

Admittedly, I'm not a Subaru guru, but I've built an awful lot of engines. If you'd feel more comfortable, ask someone like Matt Monson.

S.
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Old 09-08-2005, 03:06 PM   #5
Storm
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I'm not a guru either, but I would think you'd be okay to just go back and redo the steps. Follow the loosening steps and then retorque everything. I torqued mine first using the loosening sequence before I realized what I was looking at and then went back and redid them the correct way. It didn't appear to harm anything, the motor has been fine for almost 12k miles now since the rebuild.

Jay Storm
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Old 09-08-2005, 03:29 PM   #6
Hayes
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Steps one & two are to compress the HG to an even thickness. These steps insures that at the starting point (step Three) the HG is the same flatness at all locations. Probably takes out small differences in the manufacturing process of 2 & 3 piece composite gaskets
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Old 09-08-2005, 03:41 PM   #7
Mike1967
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Quote:
Originally Posted by Hayes
Steps one & two are to compress the HG to an even thickness. These steps insures that at the starting point (step Three) the HG is the same flatness at all locations. Probably takes out small differences in the manufacturing process of 2 & 3 piece composite gaskets
This is what I was assuming that step was for.

So I am thinking it is limited risk since

(1) I already established an even torque on step 1
(2) The final torque on the bolts was per factory spec

At this point I think the risk of re-using the bolts is greater than the risk of resetting the torque on that head.

BTW: It was a 3 piece/layer gasket.
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Old 09-08-2005, 03:49 PM   #8
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There IS NO RISK in reusing the Subaru head bolts.....it's been done for years.

Jay Storm
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Old 09-08-2005, 04:11 PM   #9
Mike1967
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Quote:
Originally Posted by Storm
There IS NO RISK in reusing the Subaru head bolts.....it's been done for years.

Jay Storm



AAAAAAAAAAAAAAAAAAAAARRRRRRRRRRRRRRRRRRRGGGGGGGGGG GHHHHHHHHH

I just threw $ 150.00 down the drain !

Dealer told me yesterday that they had to be replaced. And everyone who weighed in here gave me the same advice.

I guess I will go pull those OEM bolts out of the trash and put them on Ebay :- (
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Old 09-08-2005, 06:27 PM   #10
Matt Monson
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Mike,
Guess I missed that thread. I would have told you the same as Storm...
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Old 09-08-2005, 06:38 PM   #11
Mike1967
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Quote:
Originally Posted by Matt Monson
Mike,
Guess I missed that thread. I would have told you the same as Storm...
Thanks Matt

I struggled with the decision on that one.

What is your professional opinion on the Torque issue ?
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Old 09-08-2005, 07:09 PM   #12
Tim Sanderson
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Is the engine in the car?
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Old 09-08-2005, 07:40 PM   #13
powerlabs
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Typically, in aluminum blocks the reason why the final torque specs are given in degrees as opposed to ft/lbs is because the bolts are torqued past their yield point and they elongate slightly in the process. I don't see how the Subaru engine would be any different.
As such, I would buy new bolts every time I replaced engine heads.
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Old 09-08-2005, 08:06 PM   #14
Hayes
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I disagree with the statement that the head bolts are stressed beyond the yield point. If that were the case then the torque value would drop dramaticly as you pass the yield point. I think you mean the bolts are torqued to a elongation dimention which has been common for years in high performance engines. New bolts should not be required but, are usually replaced as an additional safety measure just in case some have reached the yield point during service.
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Old 09-08-2005, 08:49 PM   #15
Mike1967
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Quote:
Originally Posted by Tim Sanderson
Is the engine in the car?
Not yet.

That is scheduled for Saturday
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Old 09-08-2005, 09:29 PM   #16
Tim Sanderson
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Re-torque them babies!
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Old 09-08-2005, 10:38 PM   #17
Mike1967
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Quote:
Originally Posted by Tim Sanderson
Re-torque them babies!
But..but...but...but...

I already

- installed the CAMS
- installed the rockers
- put a silicon seal on the cam cap
- torqued the 20 million bolts on the CAM Cap
- installed the rear oil seal and CAM seal
- installed the valve cover
- Installed the overhead manifold
- Installed the AC Compressor

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Old 09-08-2005, 11:52 PM   #18
Tim Sanderson
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Do you want to do it now while the engine is out? Or pull the engine later and do it then should you have a problem.

Leave the cams and the girdle alone. Loosen the rocker arm shafts and the intake manifold bolts.

Loosen the head bolts to hand tight but don't remove them. Then start your torque sequence over.

Retorque the rocker shafts and intake manifold bolts.

Make sure you set your valve lash now. Make sure your setting it while the rollers are on the base circles.

Put the valve covers back on.

That's how I'd do it and I think it should be safe.

When you installed the girdles you cleaned off the old sealant and used some good stuff correct?

You may also need to loosen the rightmost a/c bracket bolt but I don't think it goes into the head, I'm pretty sure it's on the block.

Good luck
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Old 09-09-2005, 04:48 PM   #19
Hayes
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What Tim said is exactly what I would do and you'll sleep well for many nights. Maybe overkill but a few hours now will give you peace of mind in the comming months. JMHO ed
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Old 09-10-2005, 09:55 AM   #20
kheff46
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mike- your 50/50 again with everyone on the head bolts like i said. i guess they aren't torque to yeild from what some others say, but your ahead of the game with arp's(you didn't waste $) anyway! like we talked about on the HG's you got equal torque to compress correctly, and your sequence didn't cause torque to bias toward any one location so your flat, and equally torqued to spec and your engine is almost built otherwise. your not building a race motor so you'll be fine. some get really anal with things like this, which i have before. but only on a race motors, or high comp builds. i've built dirt oval scatter motors just throwing nuts and bolts back at it in no order whatsoever, and have had it last longer than a "correctly built" motor of the same type. so there's no 100% garuntee on anything! those were iron block v8's so they don't require great engineering or much common sense to get them to work or run(kind of like briggs&stratton's)! sorry v8 fans if you actually reside here!
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Old 09-10-2005, 03:53 PM   #21
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I re-used the head bolts on my 2001 2.5 engine, and it's been over 10k on it, and no problems.
The only thing worse than missing a step in the tightening process, is to get it all tightened down, only to realize that in your haste, you put the HG on backwards....
Yeah, it happened...
It really doesn't take that much time to re-torque, it's worth it in peace of mind.
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Old 09-10-2005, 05:37 PM   #22
todnar
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Did you buy OEM bolts or ARP studs?
I ask because kheff46 mentioned ARP in his post.
If you bought ARP STUDS you might want to post that or start a new thread.
Check this out
http://forums.nasioc.com/forums/show...Arp+head+studs

If you bought OEM,please disregard this post.

Cheers,
Tod
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