Topic: New Bolt Kit Mismatch

[BrickWoll]

Hey all,

I've purchased an allen bolt kit for my '77 550 K3.  Per the seller, not all bolt sizes match the OEM exactly.  No kidding.  It seems they have combined at least three slightly different lengths into a single length. 

My question is whether this is an issue.  For example, the kit's smallest bolts are much longer than the smallest valve cover JIS screws (4ea along the front edge).  The new bolts will show a lot of exposed thread where the OEM will not extend past the threads on the cylinder head.

Appreciate any advice.

[BenelliSEI]

You can shorten them with a hacksaw. The Rick is getting a nice, finished end. I have a small lathe that I can chuck up hardware and then finish the ends with a good file. You can also do this in a drill press, but be carefull!

[Don R]

 A bolt bottoming out in it's hole can cause a lot of different problems, we had a jr dragster engine with too long head bolts bottoming out, it distorted the cylinders and caused head leaks.  Just one example, or it could break through.

[Maltboy]

Thread a die (or a nut) onto the bolt to the length you want it to be.  Double nut (jam nut) is even better if you want to clamp it in a vise.  Saw off the unwanted part using the die/nut as a guide, being careful with the saw. Screw the die/nut down some more and chamfer the end of the bolt with a small file. Unscrew the die/nut. Have a beer and repeat as necessary.

Or just grind/file it off and chase it with a die. 

[Kevnz]

As a matter of interest (perhaps) and I assume you are not replacing these, but if you replace the 2 outer bolts that are under the cover at each end with ones that are too long, is there a risk of blocking the oil feed to the cam? Or does the thread stop short of allowing the bolt into the oil gallery? The upper threads on mine are stripped, so the standard length bolt won't grab, one slightly longer seems ok. Just don't want to block the oil flow.

[BrickWoll]

Thanks for the advice, everyone.  I will cut to shorten if necessary.  I should have clarified, on the front and corner holes in the valve cover, the bolt actually *pass through* the cylinder head, exposing them below the threads.  It is still possible to tighten them.

[HondaMan]

Don't forget to also use the washers on those fancy bolts. The hex-key heads are small and can distort the softer aluminum castings when tightened.

[BenelliSEI]

Don't forget to also use the washers on those fancy bolts. The hex-key heads are small and can distort the softer aluminum castings when tightened.

#1 and don’t over torque them! Use a 1/4” drive ratchet and be gentle.

[BrickWoll]

Don't forget to also use the washers on those fancy bolts. The hex-key heads are small and can distort the softer aluminum castings when tightened.

Yes - washers on all.  Thanks for the tip.

As a matter of interest (perhaps) and I assume you are not replacing these, but if you replace the 2 outer bolts that are under the cover at each end with ones that are too long, is there a risk of blocking the oil feed to the cam? Or does the thread stop short of allowing the bolt into the oil gallery? The upper threads on mine are stripped, so the standard length bolt won't grab, one slightly longer seems ok. Just don't want to block the oil flow.

I'm actually cutting to length based on the parts diagram (cmsnl.com), to make sure I'm not long on any bolt.  A little experimentation revealed going even slightly longer hits bottom on some.  Playing it safe.

Don't forget to also use the washers on those fancy bolts. The hex-key heads are small and can distort the softer aluminum castings when tightened.

#1 and don’t over torque them! Use a 1/4” drive ratchet and be gentle.

Good advice - thank you!