Topic: Sandcast #97 restoration

[Old Scrambler]

Mark.........start-up is an event a lot of us would like to see......and hear ........but removing the cover and showing the bike to the public is an event and should be done on your time...............no time lines are needed on a quality build.

Nick........ROCKERBOX is at Road America.......June 6-8.  I was just contacted regarding setting up ride-routs and coordinating the types of ride-events....breakfast; dinner; big-bikes; little bikes; scooters; all pavement; some gravel; .............all will depend on how may riders have interest. Take a look at http://www.rockerbox.us/

[markb]

I know I’ve been gone for a while but my summer is over and I’m slowly getting going again.  The hardest part is trying to remember where I left off.  One of the last things I was working on the engine was torqueing the head nuts.  It was about that time that I saw some posts about the copper washers on the outside rear head nuts to help prevent oil leaks.  They're circled in the picture.

I’m ready to retorque them and in the interest of keeping things “original” I’m wondering if I can get by with using a thread sealer on the washer and threads.  I looked it over and I guess I’m not sure where it will prevent the oil from going to.  Any thoughts?

[ekpent]

Welcome back--Did you get many big fish this summer ??  Good luck on the rest of the bike.  Eric
PS-My Sandie friend we have talked about in the past is living next door to me now 

[HondaMan]

I know I’ve been gone for a while but my summer is over and I’m slowly getting going again.  The hardest part is trying to remember where I left off.  One of the last things I was working on the engine was torqueing the head nuts.  It was about that time that I saw some posts about the copper washers on the outside rear head nuts to help prevent oil leaks.  They're circled in the picture.

I’m ready to retorque them and in the interest of keeping things “original” I’m wondering if I can get by with using a thread sealer on the washer and threads.  I looked it over and I guess I’m not sure where it will prevent the oil from going to.  Any thoughts?

The oil leaks were at the base gasket on the K0. It was thought to be coming down the studs from the top end, as that area is usually submerged in oil. It then weeped out the base gasket and showed up along the front of the engine.

The outer front "corners" of these engines have so much 'fin area' that it runs far cooler there. This caused the head gasket to not always seal well there, even with Honda's wonderful goo-impregnated gasket (I wish I had a dozen of those today...). This would, after some time, also let this filled-up stud hole(s) leak out out at the head joint, too, when the hot-cold cycles would make the goo let go in those areas of the head gasket.

It's interesting to note they did this again on the F2/3 engines (and some K8) as well. They also added O-rings on the base of the studs to try to hold it in: they knew the extra-hot temps of those black engines would make them leak.

[markb]

Welcome back--Did you get many big fish this summer ?? 

Thanks Eric.  Overall it was a great summer.  Lots of fish.  The two biggest were 20 pound lake trout.  Here’s a pic of one of them.

[markb]

Thanks Mark for excellent explanation on the copper washers.  Makes sense to me.  For what I'm doing I think the thread sealer will be more than adequate.

[Slinky]

damn that's a big fish!!

[oasis]

beautiful work!!

[tango911]

Thanks for all the detailed pics, im sure I will need this thread for my #658 build.   Great work!!

[markb]

Thanks for the compliments. 

I went ahead and retorqued the head.  I used thread sealer on the nuts and under the washers.  I’m satisfied.

I want to continue to assemble the motor but it won’t be long and I’ll need the cam chain adjuster and the breather cap which aren’t painted yet so I want to get that done.  But after looking over the adjuster I found that the seal is bad.  I want to save the sandcast housing so I needed to figure out a way to repair it.  After thinking about it for a while I made myself a little puller.


Here’s how it fits into the housing.  I had to put the fingers in first and then screw them to the holder.


Then I put it in the arbor press with a rod through the housing and the seal cup came right out!


There it is.


Here’s the housing without the cup and seal.


I have a donor that looks good.  I don’t think there is any pressure on the seal so I figured this simple leak test would be good enough.


And here is the housing with the replacement seal and all cleaned up and ready to paint.


As long as I had it apart I figured I should identify the seal in case I do need to replace one someday.  It is an 8mm x 18mm x 5mm.  Honda part number 91209-MB0-003 looks to be an exact replacement. Note: I have learned that this number may not be the correct one. I am trying to verify so proceed with caution until I can confirm.

[markb]

I need to decide what colors to use on my breather cover and cam chain adjuster.  After discussions on the SOOC site I agree with the consensus that the breather cover and cam chain adjuster are a darker shade than the cases and that the cover has some gloss.  (By the way, I also observed that the breather covers on later VINs are even darker than E100’s).

I’ve had good luck with the Duplicolor high temp engine paints so I picked up cans of what was close to compare.  It’s difficult to get the colors right in the photo but the three samples in the top row aren’t close.  In the second row the E100 cover is on the left and the adjuster on the right.  In the center is a sample of the DE1650.  I used the DE1636 clear on the left half for some gloss.  For comparison the sample on the bottom is the DE1615 that I use on the cases.  I think this is pretty close and have decided this is what I am going use.

[HondaMan]

Thanks for the compliments. 

I went ahead and retorqued the head.  I used thread sealer on the nuts and under the washers.  I’m satisfied.

I want to continue to assemble the motor but it won’t be long and I’ll need the cam chain adjuster and the breather cap which aren’t painted yet so I want to get that done.  But after looking over the adjuster I found that the seal is bad.  I want to save the sandcast housing so I needed to figure out a way to repair it.  After thinking about it for a while I made myself a little puller.


Here’s how it fits into the housing.  I had to put the fingers in first and then screw them to the holder.


Then I put it in the arbor press with a rod through the housing and the seal cup came right out!


There it is.


Here’s the housing without the cup and seal.


I have a donor that looks good.  I don’t think there is any pressure on the seal so I figured this simple leak test would be good enough.


And here is the housing with the replacement seal and all cleaned up and ready to paint.


As long as I had it apart I figured I should identify the seal in case I do need to replace one someday.  It is an 8mm x 18mm x 5mm.  Honda part number 91209-MB0-003 looks to be an exact replacement.

Hey, Mark!
Can I rent that puller from you? I forgot to change the seal on my K2 last summer, and it has weeped for years. Thanks for reminding me! It has completely prevented rust on my starter cover by giving it an oil film every time I make a 3-digit speed run.

[markb]

I would be happy to let you borrow it.  But there is an easier way for you.  I had to do it this way to save the sandcast housing for E100.  There are plenty of tensioners available on eBay for $10-15.  If you don't want original or "correct" that would be a lot easier.  Let me know if you still want to do it and I can send it to you.

[jprochnow]

Great work on the build!

[HondaMan]

I would be happy to let you borrow it.  But there is an easier way for you.  I had to do it this way to save the sandcast housing for E100.  There are plenty of tensioners available on eBay for $10-15.  If you don't want original or "correct" that would be a lot easier.  Let me know if you still want to do it and I can send it to you.

On my own engine, I am trying for that "original" thing, too, as it is a fairly rare one (K1 engine in a K2 bike, factory-built that way). The later K2-and-later tensioners are slightly different (stronger, really), although I would be hard-pressed to describe the changes. Side-by-side with a K4, for instance, the differences are apparent, although the parts fit up OK. It's just the OCD thing with me and my 750...

[markb]

Mark, I know where you're coming from.  I will send you the puller.

[markb]

I’m jumping around a bit here but I guess that’s what happens when you have so many things that need to be done.  I decided this weekend to try to finish the top end of the engine: cam holders, camshaft, rocker arms, valve cover, etc.  First order of business – clean up the cam holders.  That’s when things came to a screeching halt.  Remember the crankshaft earlier in the thread?  And all the hardened gunk that was in the oil passages?  I don’t know why it didn’t dawn on me that I would have the same issues with the oil passages in the cam holders.  So no problem, I figure I’ll just run drills in the passages to clean them all out.  Here’s a pic of what came out of one of the holes to the cam journals. 


Then I look at these holes.  Plugged too.  Luckily I happen to have a 1mm drill that fits that hole.  But wait, here’s the problem.  The junk I removed from the holes is now trapped in a hole that runs the width of the holders but that hole is plugged.


Here’s the plug.  I really had no choice.  The holes had to be cleaned out and that was the only way to do it.  So here I am again where I really want to save the original parts if I can.  They are unique to the early engines.  So I need to remove the plugs.  The first thing I did was drill and tap a #6-32 hole in the center of the plugs.  Then I used a small drill and drilled out the dimples on the outside of the plug.


Then I adapted a #6 screw to the end of my puller.  I call it a slide hammer but I think it’s for pulling dents.


Here’s my setup.


About 4 or 5 medium taps and they came out.  So the hard part is done.  I’m going to pick up a long drill to clean out that hole.  Then just for good measure I’m going to have the holders ultrasonically cleaned to make sure everything inside is clean.  Then make up some new plugs and good as new.  But so much for finishing the top end this weekend.

[HondaMan]

Nice save!

Most of the early sandcast cam towers have the oil restrictor built into the cam tower, in the hole where the oil feeds in from the head. That was a precision-drilled hole, too. The later oil jets that replaced then have hole sizes of .035", .037" (actually .0365"), and .038" (F2-3 heads the latter), for reference. I don't know what hole size was used inside those early towers? They were asymmetric, only being installed as LEFT or RIGHT types, which Honda changed before the sandcasts were even done, to become symmetric with oil jets in the head, instead. This was when they added those big jets with the strainers on the back side, which became the smaller ones somewhere in the K2 series. Thus, the sandcasts had no debris strainers, so sometimes the gasket fibers or other construction 'dust' found their way up top and plugged the oil holes, usually the squirters to the cam lobes.

[ekpent]

I wished you lived next door to me   

[markb]

Nice save!

Thanks.  For a while I wasn't sure what I was going to do.  Thanks for the additional info too.  Very interesting.

I wished you lived next door to me   

I think there is a house for sale down the block. 

[markb]

I bought a long drill so I could clean out the long oil galleries.  Then I had the towers ultrasonically cleaned.  I’m convinced there is nothing left in the holes.


Here’s the new plugs.  They’re pretty small to make but they turned out nice.


And here’s the repaired towers.  I even re-punched them for authenticity even though they went it hard enough that I know they won’t fall out.


If you pick them up and look close you can tell it’s not original but if you just look at them lying on the bench you would never know.


By the way, if you’ve read this entire thread you may remember that one of the towers had a crack in it.


I had that repaired some time ago.  After welding I ran a 20mm reamer through from the opposite end to make sure it lined up and it’s good as new.  Now they’re ready to put on the engine.

[Old Scrambler]

Nice detail............So when you start the motor and have the carbs dialed-in.........I'm expecting the 'balanced nickle' demonstration of how smoooooooth the motor is. If you did it RIGHT..........the nickle won't fall over until about 5000 rpms.

[markb]

  I will try that.  To be honest though, I will be happy to have it run good and continue running.  Then I'll know I caught every problem.

[markb]

I wanted to get the cam and rockers in today and made good progress.  I took a shot of the head for proof that I had all pins, o-rings and plugs in place before proceeding.


Same for the cam position…..


….and crank position just in case I want to check later that I did it right.  The original advancer is in pretty rough shape so I temporarily used another one for now just to get it together.  More on the advancer later.


Fortunately the original R1 cam was good enough to use.


I initially had a little trouble with the new cam chain (not much extra slack) but it's all done including the tappets meticulously adjusted.  It sure is nice to adjust them when they’re in the open.


By the way, there is an interesting feature about the sandcast heads (maybe early diecast too).  They don't have the separate oil orifice.


They just have a small angled hole drilled over to the vertical gallery that comes up the back of the cylinders and head.

[markb]

Here’s a follow up on the puller I made for the cam chain tensioner.  I was looking on the Yamiya site and stumbled across this.  They have one although it is different than mine.  It is another way to do it.  Unfortunately they can only sell it in Japan (why is that?).  I thought it was interesting that someone else had already done it.