Couple questions about rebuilding a DI motor

[sagent]

I will soon begin my top & bottom end rebuild on my 951 Di motor and have a couple questions for the guys that have done it

Do you apply the sealant to both halves of the crankcase ?
Should I buy new cylinder bolts ( ones with blue coating under the heads ) or reuse old ones ?

I think manual says you can reuse the bolts but coating must be removed and blue loctite applied in its place ?

Thanks in advance

 

[mikidymac]

You apply a thin layer to both sides of the crankcase halves. Use either ThreeBond 1211, 1194 or hondabond 4.
You can reuse all the bolts but clean them up and a wire wheel on a bench grinder is the easiest. Also make sure you chase all the threads in the cases. Check the manual for sealant and thread lock on the bolts. Some get grease some get sealant and some get thread lock.

 

[Sportster-2001-951C-Stock]

I have to disagree with using a wire wheel, seems to round-over the threads throwing off the torque settings. Wire wheel will damage the protective plating on steel zinc phosphate bolts.

A die to clean the threads in a vat of solvent bath parts washer are my preference if possible. Many times just washing them is good enough.

I will use a wire wheel in extreme cases when the bolts are already kaput and it doesn't count (like for an old mailbox of fence rail) and I have no spare but that's acceptable I think.

 

[sagent]

Thanks for above, I ordered the three bond 1211. What is the best way to apply it ? With a rubber roller like the manual states ? Also don't understand what good loctite on the underside of bolt head will do ? Would rtv sealant work better ?

 

[ski-d00]

3bond 1211 is the best stuff, you only need to put it on 1 side just using your finger to spread a thin gooey layer is fine, the side w/o the crank in it and you should work quickly depending on temp. 1211 will skin over which is what you don't want, so cooler is better and should be assembled within 5 minutes of applying and then start torqueing. some say to put a bead down but I don't although this may help keep it from skinning but you just can't judge how much to put down and your relying on it to travel quite a bit when squished. ultimately, 1211 is good stuff and just seals really well.

I know the manual says to remove the blue coating on the head bolts but I don't if it is in good shape, meaning not torn or cut or chewed up. Then I apply blue Loctite as well. Probably done a hundred this way and never had problem, also have removed it and just used Loctite which also worked but I like the end result to look identical to stock.

The Loctite under the bolt heads will lubricate for torqueing and help seal microscopic voids. necessary? probably not but I do it. thicker sealants will take up space and may not do well with the heat cycles over time.

I clean bolt threads lightly with a brass wire brush, doesn't normally take much but I don't deal with saltwater motors much.

 

[mikidymac]

I have to disagree with using a wire wheel, seems to round-over the threads throwing off the torque settings. Wire wheel will damage the protective plating on steel zinc phosphate bolts.

A die to clean the threads in a vat of solvent bath parts washer are my preference if possible. Many times just washing them is good enough.

I will use a wire wheel in extreme cases when the bolts are already kaput and it doesn't count (like for an old mailbox of fence rail) and I have no spare but that's acceptable I think.

I have always used a brass wire wheel on a bench grinder without a single issue and it works great for removing the factory threadlock. Also all the bolts on these engines are stainless so there is no plating to worry about. In the end just do it whatever way works for you. I also never use 1211 on cases as I like 1194 better and it is what all other brands use on cases and is more oil and gas resistant than 1211. I use a thin coat of 1211 on all gaskets and o-rings though. I have never had an engine fail leakdown. You are testing all engines to hold pressure after a rebuild correct?