Evo head torque

[BluHarley]

Well, finally got my bottom end back from the shop.  Put the heads back on, but one thing about the bokks method of torquing them, when I take them off the next time, all the head bolts have different stresses.  So the books method of torquing to 18 foot pounds and then turning them 90 degrees just doesn't work.  What is the correct torque?  After finding a few head bolts were at about 60 foot pounds after turning 90 degrees, I just set the all at 60 whether they were 90 degrees or not.  Is 60 about right?  Thanks.

[BB]

The torque plus 90 is the correct way . 60 ft pounds is to much you could pull the studs out of the cases.

[BluHarley]

Well, at 60, some didn't go 90.  So I figure I'm light on some if anything.

[BluHarley]

What do they sound like when they go, "BOING"?

[hawwk]

What do they sound like when they go, "BOING"?

It is a sound you never forget

It's been a while since I did mine but it was around 45 lbs

[choseneasy]

You won't get any reading worth considering by using a torque wrench to take them off(if i am reading your post correctly). The book method is good as is the info from various gasket manufacturers. ie 45 ft lbs.
 

[BluHarley]

Well, I torqued the front head, put it all together, kicked the back wheel, and I thought, "what was that?"  I put on the rear haed and stuff, kicked the rear wheel, and another boing.  It didn't sound good, but I watch the torque as I was trying to reach 90 degrees.  For the most part, I landed on 60 when I went 90.  One time on the front I wasn't near 90 when I hit 75 foot pounds.  I was trying to get a match.  I'm using an old needle torque wrench, because the "clicker" I got from Harbor Freight didn't click and broke a bolt on my primary.  I don't think I over torqued, but now I'm paranoid.  I'll back them off tomorrow and see if I messed anything up.

[BluHarley]

If I run it and have a pulled stud, what will be the indications and the consequences?  I'm thinking if that was the case, a short 10 mile ride would not do a lot of harm and maybe show up in leaking heads or something.

[choseneasy]

A pulled stud or a headbolt that isn't torqued to spec will blow the head gasket.
Symptoms will be a "chirp" when the engine is cold and started up. You may even feel a little blast of air near the head or see evidence of failure at the gasket.
Hopefully your wrench is reading poorly and you have nothing to worry about--with the torque-turn method it is hard to overtorque it that much.

[BluHarley]

I'm thinking a pushrod (taper-lite quick install, was sittin on the edge os a lifter and when I kicked the wheel, it adjusted.  I did that once with a stock pushron, and it went "TING" and bent.  I was watching the 90 degree thing closely.  I started it and warmed it up, and it sounded great!  After listening to a crank pin chewing up for the last year, it just sounded really nice.  I don't think I over torqued it, but I'll be paying close attention.

[Lumpy8]

I always use this theory of tightening bolts, "Strip it, then back it off a thread" 

I could never understand why some mechanics think they know better than the manufacture/engineers that design the machine!

[BluHarley]

I have read the book!  What I was trying to say was that every time I pull the heads ( a lot in the last year), the head bolts are at varied tightness, this last time one on the front was almost loose.  I've taken great care to do it by the bokk, so why are they not the same tightness when I open it up after a couple hundred miles?

[bigtone]

The problem with torquing bolts is the friction of the threads, bottom of the bolthead, etc. The higher the torque value, the more potential friction. Oiling the bolt threads helps overcome some of this. Torquing by squish (degrees) is actually more accurate. You torque to a certain low value to ensure a good starting point, then the number of degrees give you a pretty much guaranteed amount of compression (squish). Gasket compression is what sealing is all about. I work in the Nuclear Industry, and torquing by squish is an accepted practice in many fields.

[attachment removed after 60 days by system]

[BluHarley]

"Torquing by squish" at a Nuclear facility?  Interesting, makes me wonder why we have torque wrenches at all.  The bike is running great, a little oil at the front head, but I'm not sure yet if it's new oil or just spillage from putting it together.  It's too damn windy and cold here in Florida to do any serious riding, better weather ahead.

[Norton Commando]

bigtone is right; small amounts of friction result in huge changes in stud preload when torquing a fastener. Preload is how much load/stretch you've put into the bolt by torquing it; the torque value is irrelevant, accurate preload is what you're after. The torque-turn method prescribed in the shop manual is some 15% more accurate in generating proper bolt preload than torque alone - use it.

[harleytoprock]

bigtone is right; small amounts of friction result in huge changes in stud preload when torquing a fastener. Preload is how much load/stretch you've put into the bolt by torquing it; the torque value is irrelevant, accurate preload is what you're after. The torque-turn method prescribed in the shop manual is some 15% more accurate in generating proper bolt preload than torque alone - use it.

I'm not trying to stir the pot but how come Cometic recommends using only the torque method over the torque-turn oem method?

[bigtone]

You'll have to ask Cometic, but all I was saying is that Harley isnt the only one saying to tighten by gasket crush, it is common in other industries. If you think about it, it does make sense.

[Buddy WMC]

You'll have to ask Cometic, but all I was saying is that Harley isnt the only one saying to tighten by gasket crush, it is common in other industries. If you think about it, it does make sense.

As I only use Cometic head gaskets due to my larger bore cylinders, I follow Cometics instructions. The studs are always cleaned and lightly oiled before the torquing process. My wrenches have been calibrated and are accurate. If time allows after the final step I'll let the engine sit overnight and then check the final torque again in the morning. It has never changed and we've done many EVO and TC engines without a head gasket failure. Last thing you need is a comeback or problem later on down the road. We also never reuse headbolts as Harley recommends. New ones are always installed, so perhaps reusing the headbolts contrary to the instructions could be causing some of these problems? My thinking is that the bolts itself takes more of the preload than the stud does or should.

[bigtone]

"Torquing by squish" at a Nuclear facility?  Interesting, makes me wonder why we have torque wrenches at all.  The bike is running great, a little oil at the front head, but I'm not sure yet if it's new oil or just spillage from putting it together.  It's too damn windy and cold here in Florida to do any serious riding, better weather ahead.

Not to scare anyone, but many bolts do get torqued at Nuclear Power Plants, but in many situations where a gasket is involved, the gasket manufacturer states a desired crush and the torquing is performed to attain the specified crush. The only difference is that usually the actual crush is measured, not just converted from the number of degrees times the actual threads per inch.

[ridemyEVO]

"Torquing by squish" at a Nuclear facility?  Interesting, makes me wonder why we have torque wrenches at all.  The bike is running great, a little oil at the front head, but I'm not sure yet if it's new oil or just spillage from putting it together.  It's too damn windy and cold here in Florida to do any serious riding, better weather ahead.

Ahhhhhh poor baby, you want some of my -15 celcius? Just kidding.

[BluHarley]

Um, no thanks!    Monday will be in the mid 60's  

[FXRocket]

James MLS Gaskets also spec out a set value and not the 90 degree bit, so I went that route this time.