Ace L6 head bolts...maybe?

[m4xwellmurd3r]

the higher in power you go, the more of a no-brainer it becomes. You could get twice the factory rated output on most engines with OEM head bolts, but why take the chance if you spend the money to get there?

 

A few things to remember are

 

1) torque in steps. 2 to 4 steps, Ideally. 3 if you like odd numbers. 5 if you have the time to do so (make time).

 

2) ALWAYS use proper 10W-30 or 30W weight oil, or even better, the provided assembly lube. dry threads have create more friction, thus more resistance, thus making the torque wrench FEEL like it's working against more fastening torque than it actually is. If you don't use the provided assembly lube, you better be good at calculating what the resistance and final torque rating must be in comparison to the fastener's provided instructions (or... dont even try to and just do it the proper way), as they're read with proper assembly lube. You can buy the assembly lube in 25ml and 50ml bottles direct from your ARP distributor, which is better than the small sample-pack that they supply you with. Mostly because engine assembly can take several tries. Don't lube once and never again. Always put enough to cover all threads.

 

3) Re-torque once the engine is run in for a while, or after the break in period. Metal needs to go through heat cycles to relax itself. If you have to take the cam off to do so... so what? it's part of engine building. Either do it before a head gasket problem occurs, or do it when the head gasket problem occurs anyway... I'd rest knowing I've done the former.

 

4) make sure your torque wrench is within proper spec. Don't go by the supplied spec sheet, there are various ways to calibrate your device. and make sure you always relieve the spring tension in the torque wrench when it's not being used. they will settle and provide inaccurate readings if they are tightened all the time (that's how torque wrenches work, they use an internal spring, and they settle over time if always taught).

 

ummmm, anyone have anything else to add? or should we move this to another thread or something?I guess it sorta does coincide with not using cheap bolts from the hardware store too... right?

 

thanks for all the tips. I'll keep them in mind/write them in my work book i use for my Z (i have the hot/cold valve adjustment settings in it, and various checklists for things that need work)

if i can find space to rebuild the engine i'm going to do it thoroughly, and correctly (i don't care if it takes me a month) this WILL be the first engine i've built 100% on my own (i have put VW engines together, but not 100%) what do you mean about the torque wrench spring? mines a simple bar style. Anyways, the reason i want to put in studs instead of bolts is well...i trust studs more than bolts. I'm probably going to overbuild this engine when i overhaul it (all new hardware, especially con-rod bolts, etc)

 

anyways, on topic.

I wouldn't trust hardware store bolts. even if they are rated correctly, i doubt that they were produced with holding engines together in mind. Even if they are rated for it, i'd rather go with a set of bolts that are specifically for engines.

[Tony D]

as for using ACE hardware bolts, forget the grading scale. ALL internally wrenching fasteners are grade 5 minumum, if they are of any account. Grade 8 internally wrenching fasteners are *MOST LIKELY* going to be fine for a mild L-series. ARP headstuds are not required for a good engine, but like others here have said, if you're going to be working on it a lot, go for it. You'll like the extra insurance. In OTM's situation, the ACE hardware store bolts will probably be fine, as long as he keeps an eye on them.

 

Those are some very dangerous assumptions to be making for such a critical component.

 

If the head of the bolts only had an '8' on the head, then by the industry standard, it would be a manufacturer's identification and nothing more! When they say it should say '8.9' that is what it will say. The markings for bolts are very specific! Lacking of a specific rating marking denotes the minimum quality standard for the class of fastener.

 

For the costs involved, I would not be 'cheaping out' on head bolts, studs, connecting rod bolts, main cap hardware, etc...

 

Japanese manufactured automobiles, just in the way they interacted within the supplier network and the integrated governmental oversight they had usually had supplier relationships that allowed them to have much higher standards for hardware in many applications than would normally be supplied to general industry. Head bolts/studs would be a prime location for this kind of 'cooperative relationship' where the supplier gave them a beyond industry standard bolt or stud, thereby cementing a supplier relationship longterm, and insuring there would only be ONE source for the bolts. Everyone made the maximum profit.

 

American engines at the same time were really a 'low bidder' application, where each engineering decision was MBA'd and Accounting Department/Purchasing Department lowballed. Consequently they engineered to industry standard fasteners to keep construction costs as low as possible.

 

There's advantages in each way to engineer the package, but on German and Japanese vehicles, I would be VERY wary of exchanging ANY engine hardware in critical locations for run-of-the-mill industry standard hardware. On a SBC...sure, I can see lots of stuff that has Gr5 in it and a possible cheap upgrade to a Gr8 fastener would work fine.

 

But on the 'ungraded' application specific hardware like a Nissan Head Bolt...

 

Not for me! Stick with OEM or BETTER quality.

[Careless]

Wow...What a threadjack...

 

Anyway the ACE bolts have "8" stamped on them. Not "8.8" so I guess that means the're the equivalent of a 10.9 on the US system.

 

really sorry bout that OTM. was a little sauced, bored at my parent's place, and really didn't feel that hardware store bolts were well enough to use to fasten a head down onto an engine.

 

But i think it would be cool if you tried it and checked to see how long it would last.

 

I myself am just out of college and pay my own rent and buy my own things. Haven't received a dime from my parents since before I moved out, so I can appreciate the cost savings associated with running these hardware store bolts. Especially since the engine is going to be replaced.

 

However, if it were a long term build, I'd just fore go the guinea-pig setup and go with race tested products.

[WizardBlack]

Just as a semi-relevant 'cost effective' solution... I have heard of old timer mechanics (on old-timer cars) use a flattened-out cardboard cereal box for a replacement head gasket.

[Guest TeamNissan]

There is the can of soup exhaust patch method too lol. Ahhhh the good ol' days......

[ktm]

Just a quick correction. Metric Grade 10.9 is equivalent to SAE Grade 8; Metric Grade 8.8 is equivalent to SAE Grade 5.

[Tony D]

KTM is correct, which is why I'm pointing out that '8' on the bolt head means nothing, and may well mean SUBGRADE fasteners.

 

Was it John Coffee that used the 'batch built in china crap' to desribe the bolts? Pretty apt.

 

if it doesn't say '8.8' then it's not grade 8.8 and it's a dangerous assumption to think so!

 

The only headbolts I would consider would be as KTM points out, 10.9 or 12.9.

 

8.8 is at least a GRADE of fastener. When you deal with a lot of hardware like I do, you realize ANY GRADE of fastener is better than an UNGRADED fastener. Which it sounds like the local ACE is stocking, and ungraded fastener, which likely is SUB GRADE 5 in American Parlance (Grade 3 Hardware or worse)....

 

I am very leery of using hardware that do not meet some objective grading criterion.

[OlderThanMe]

Ok...Now I know.

Thanks guys!

This may help others later on that find the same thing.

It was an interesting idea.

 

OTM

[rejracer]

Just a note...

 

Grade 8.8 does not exist. Grade 8 does. Class 8.8 does too, but it's not the same as Grade 8.

 

Please don't get the terms class and grade mixed up. If you are referring to a metric fastener then it's strength is measured by the Class system. Now if you wanted to say that a Class 10.9 fastener is the same strength as a Grade 8 fastener then that's a true statement, except for the fact that the fasteners are not the same size. However... I am rambling on..

 

now on to the meat and potatoes of why I am posting...

 

The hardware store variety of fasteners should not be used on any critical component, especially one that is exposed to coolant. Lower grade bolts have less corrosion resistance. When the lower grade bolts start to corrode they do so at an alarming rate as compared to a Class 10.9 or even a class 8.8. When they go chances are they will damage the block threads too, as the threads are most likely whats going to fail on them.

 

 

Yes the strength is a factor, but not the biggest in my mind for the given application. Now to give you an idea of the strength differences. A Class 10.9 bolt is rated at 130,000 psi yield strength. No markings (as in a valid class) have a rating of about 57,000. That's less than half. To give you an better idea, Aluminum alloy bolts (used in aviation) have a rating of 62,000. Or think of it another way: Put in some timeserts and get 6mm class 10.9 bolts instead. it would be about the same strength. Do not underestimate the importance of base materials. Strength ratings do not tell you the whole story either. For example the weaker materials may stretch much more before reaching their proof load, or yield ratings. In other words it may be a "springy" material which is the worst thing for a head bolt.

 

If your trying to save a buck I would just get some used stockers. I know you could pick those up on the cheap. It's nice to save a buck, but honestly I would save it by going used oem rather than a hardware store time bomb. At the very least find out from ACE what these things are so at least you know the risk. If you have to use them be sure and run distilled water and 70% coolant to prevent the corrosion of the bolts.

 

Hope that helps, and happy wrenching.

[Tony D]

Very good point, I should have said "Class" he is correct on the terminology for sure!

 

The points on type of fastener and corrosion are also well taken.

 

I remember both the Bowman and Lawson Hardware Reps trying to sell me on their 'Ultra-Grade' Hardware which was 'better than Grade 8'---and they always trotted out tensile strength. Which is fine if you need that. It can also mean they are brittle, as rejr alludes to in his post. As you can see the "No Marking" can have a drastically lower strength rating. And that is why I was cautioning about misinterpretation of the bolt head marking---being a manufacturer's mark, as if it was 'Class 8.9' it would not simply say '8', it would be '8.9'.

 

Beware.

 

Aluminum fasteners. Love that timesert example! I have a story about aluminum fasteners, and how someone thought they were 'too heavy', but that's for another time...LOL

[ktm]

You learn something new every day. I did not know about the metric Class rating. Thank you.