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Engine Covers Bolt Question

4K views 16 replies 8 participants last post by  berserker 
#1 ·
What I'm refering to is the cam, primary and tranny top and side cover bolts.

They are all stock and today I noticed that they look like the might be corroding. They looks dull and they might be affecting the chrome around them.

My main concern is that they'll freeze up or corrode apart.

Anyway, I know there are web sites where I can get sets but my local hardware store has a pretty good selection of grade 8(possibly grade 5) SS bolts.

Obviously I'm talking about replacing them but can I just remove one at a time and put a new one in? I realize it could cause a leak but will doing it this way warp any of the covers?

If I can do this I'm only going to do the ones I can get to with the exhaust on for now and finish up this winter.

I'd like to start with the cam cover. Are all those bolts the same length? And if I can't get grade 8 will 5 do?

Thanks.
 
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#3 ·
hdmarsh77 said:
What I'm refering to is the cam, primary and tranny top and side cover bolts.

They are all stock and today I noticed that they look like the might be corroding. They looks dull and they might be affecting the chrome around them.

My main concern is that they'll freeze up or corrode apart.

Anyway, I know there are web sites where I can get sets but my local hardware store has a pretty good selection of grade 8(possibly grade 5) SS bolts.

Obviously I'm talking about replacing them but can I just remove one at a time and put a new one in? I realize it could cause a leak but will doing it this way warp any of the covers?
I did mine one at a time and torqued them. No leaks.


hdmarsh77 said:
If I can do this I'm only going to do the ones I can get to with the exhaust on for now and finish up this winter.

I'd like to start with the cam cover. Are all those bolts the same length? And if I can't get grade 8 will 5 do?

Thanks.
The primary cover has some different sizes. The cam cover might can't remember for sure. The timing cover they are all the same size (make sure these are no less than grade 8).

I did mine in www.alloyboltz.com polished stainless 12 point grade 8 on the primary, derby, chain adjustment, and cam covers. For the timing cover I had to use HD chromed bolts . Alloyboltz didn't have grade 8 for the timing cover and the head stripped out real easy.
 
#4 ·
Use an anti-sieze.
 
#5 ·
Thanks all. The reason I'm not going with a kit is because it's just too much for me to spend on bolts right now. I was at the hardware store today and go some smaller SS bolts and only cost arounf $.50 each. Sinse I'm not doing it all at once it will cost less this time around. Might cost less all together too because some bolts don't seem to be corroding at all.

Already did the timing cover when I replaced the stock cover so that one is done with HD bolts.

Would grade 5 be ok for everything else? If not, I might have to go with one of the web site kits after all if the store doesn't have 8.

Paul, antiseize, really? Not locker?

Just thought about the manual. Have to check if bolt sizes are in it. That would help a lot.
 
#6 ·
hdmarsh77 said:
Thanks all. The reason I'm not going with a kit is because it's just too much for me to spend on bolts right now. I was at the hardware store today and go some smaller SS bolts and only cost arounf $.50 each. Sinse I'm not doing it all at once it will cost less this time around. Might cost less all together too because some bolts don't seem to be corroding at all.

Already did the timing cover when I replaced the stock cover so that one is done with HD bolts.

Would grade 5 be ok for everything else? If not, I might have to go with one of the web site kits after all if the store doesn't have 8.

Paul, antiseize, really? Not locker?

Just thought about the manual. Have to check if bolt sizes are in it. That would help a lot.
The manual will tell you what to use...locktite, anti etc.
 
#7 ·
vafatboy said:
The manual will tell you what to use...locktite, anti etc.
Manual does not cover SS.

Anti-seize and differant tq values. I was thinking about this when my engine was apart and primary off last year. Eventually got to be to much to think about and put stock back in.

I agree kits are expensive.

I have had 3 derby bolts strip, so was thinking about 12 pnt. I started using anti seize on my derby and inspection. Can't remember if I did on the outer primary, doubt it.
 
#8 ·
I wondered about that too. But how much difference could there be between steel and SS and such small bolts at a light torque?

I used a tiny dab of locktight and torqued them to manual specs. They have been at temps from 30* to full operating temps and no drips yet. I rechecked torque and all seem to be holding fine but time will tell.

I got them from my local hardware store and they average $.70 each so I'm only up to a few dollars. I ran them over the buffer quick and they turned out almost like chrome.
 
#9 ·
I think you want to use antiseize cause, ss will gall.
As for the question about one at time, I would not have been afraid to, especially on the primary. No big deal.

I wanted to py head bolts and rocker covers, when I had it apart. But I wanted rocker cover bolts that have 3/16 allen hole. Not sure the aftermarkets have that.
 
#11 ·
I now antiseize my derby, I have had 3 bolts strip. Not sure if I am not pushing hard enough or what. two of them were in same hole, not sure about third. So maybe bad hole. Dunno. So far antiseize and fine.
 
#12 ·
The problem is that there is a chemical reaction between SS and aluminum. SS corrodes the aluminum part... so, regardless of torque, over time, your threads in the aluminum part can weaken and rot. Anti-seize prevents this by being a barrier between the two. To some degree, Lock-Tite will do the same thing, but the anti-seize seems to spread better.

I learned this the hard way years ago. Had a Corvette with a stuck thermostat. Removed the therm housing bolts and the threads came out with the bolts. The intake manifold was aluminum. The bolts were SS. Trust me, there is nothing more nerve wracking than having to tear down the entire fuel inj sys in a Vette on a 20 degree day, just so you can drill and tap the aluminum manifold for heli-coils. It should have been a 5-min job and ended up taking all day. Whoever had assembled the car didn't use anything on the threads.

Since then, I use anti-seize or lock-tite on anything aluminum. Went with SS allen heads on my primary, used anti-seize and haven't had a problem.
 
#13 ·
Thanks, Jamie. What do they do to make steel into SS and why does it react with aluminium, I wonder?

Good to know and I think I'll antisieze them sooner rather than later.
 
#14 ·
hdmarsh77 said:
Thanks, Jamie. What do they do to make steel into SS and why does it react with aluminium, I wonder?

Good to know and I think I'll antisieze them sooner rather than later.
I'm not sure what they do to make steel into stainless steel. It should also be said that the problem can happen with regular steel bolts too and not just stainless steel. Anytime you have a threaded aluminum part and steel or SS bolts, you need to use something on the threads or you risk corrosion.
 
#15 ·
hdmarsh77 said:
What do they do to make steel into SS and why does it react with aluminium, I wonder?
Stainless Steel is composed of an entirely different group of elements than regular (carbon) steel. The element(s) that make Stainless Steel corrosion resistant are Chromium and (sometimes) Nickel. Informative article here: http://en.wikipedia.org/wiki/Stainless_steel

The Chromium in Stainless Steel forms a very thin layer of Chromium Dioxide upon exosure to oxygen in the air. Aluminum similarly forms a layer of Aluminum Oxide upon it's surface. These oxide layers do a damn nice job of preventing corrosion in a perfect environment.

The cheap ass moco hardware is zinc plated carbon steel, which doesn't resist corrosion nearly as well. Zinc plating is not a homogenous coating, there are tiny pores in it. These pores allow oxygen to get at the underlying carbon steel, causing corrosion (rust). The pores also allow the zinc to corrode from underneath, forming zinc oxide (that white powdery lookin' stuff that you see)

The main culprit that causes corrosion on our bikes is salt, or any compound with clorine - like most of our tap water. The clorine (cloride ions, actually) get in there and eat away the protective oxide layers - especially on aluminum and zinc plated stuff. The effect is 100 times worse in areas that can't dry quickly or are hard to rinse. These areas include the inside of a tapped hole, between the little grooves on the outside of moco bolts, inside of an allen head, in between cylinder fins, under head bolt covers, etc etc.

That all said, you're going to eventually get corrosion inside all your bolt holes for your outside covers. The effect will be much less severe if you use Stainless Steel bolts, but you should still use antiseize, if the fastener will hold it's torque. The antisieze provides an additional coating to both the male and female threads to form an additional barrier to corrosion. Only if the fastener won't hold torque (keeps coming loose) should you use loctite. Loctite cures in the absence of air, which is the ideal environment for the types of corrosion we see when we pull a dry moco cover bolt off our bikes.

For what it's worth, most hardware such as nuts and bolts are made in cold heading machines from coils of wire. We're talking rather large diameter wire, like 1/4" or more. The machines smash and form the wire into the finished product. The steel alloys used gain hardness and toughness from the cold working process. Grade 3 hardware is cheap ass (read Chinese) steel. Grade 8 hardware is highly alloyed high quality steel. By it's very nature, Stainless Steel hardware is grade 8 (most of the time).

T. Mealer
Flowerfield, IL
 
#16 ·
Excellent friggin post. I never knew that they made bolts by smashing wire like that.

I asked at the store what grade SS was and the guy wasn't sure but knew it was high.

Thanks a ton for the info.
 
#17 ·
As for identify grade of SS, I think if you look in the front of auto repair book they will cover it under the common knowledge stuff. How many marks on it.

As for making SS. I have work in steel mills, and foundry. Did not make SS, but probably jsut a matter of chemistry. Certain jobs dump differant sacks in.

!st you make iron, then you make the iron into steel. A foundry just pours the iron into whatever they are making. When they turn it to steel is cool, alot more volitile then iron.
 
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