WillieB's 1275 Engine Rebuild

[cstudep]

I know right, I was thinking he needs an apprentice or protégé or something.

[MiniDave]

Where would my business go if I taught everyone my secrets?   ;D

I might do that on a future build on one of my own engines, I'm not a good videographer or editor, and it's hard to get camera angles right while you're trying to do stuff - just ask Cole at Mini DIY!

[MiniDave]

Expecting parts over the next few days/week.....then I can get them delivered over to the machine shop.

Block has been honed, crank is polished, valves and seats have been cut to a nice 3 angle, now I need the pistons so they can swap them onto the rods (pressed in pins) then they can balance the assembly and I can pick stuff up for the build.

Once I get it back I will dry build to check clearances on the rods/mains/thrusts/ring gaps and clean everything one more time before final assembly.

[MiniDave]

Pistons came in today, so I ran them over to the machine shop. The head and crank are already done so I brought them home with me.

The block still needs to be honed to size, but we wanted to have the pistons before we did that -  and he'll also swap the pistons onto the rods for me - while the old pistons are off he'll double check the rods to make sure they're straight and the big ends are round.

He'll also match the weight of the new pistons to the old ones if they're close enough, otherwise I'll take the rotating assembly over and they'll balance the whole thing together....but they think just matching the pistons up will do it.

The block and pistons should be done by midweek......and I'll go pick it all up and get ready to build it up once the rest of the parts we've ordered come in.

[MiniDave]

What's the old Chinese curse? "May you live in interesting times"?

My machinist friend called me this morning to let me know he'll have the block done today, and that he was going back home cause he's had Covid for the last week and it's kicking his butt! Yet he's still going to work every day because he can't afford not to and the shop can't do without him as they're so backed up with work. I think the only reason our stuff got done so quickly is that it was fairly easy and he slid me in ahead of other work.

So, I'm going over tomorrow to pick it all up....I'll have plenty of hand sanitizer, latex gloves and mask on and just hope for the best. I dunno if I need to spray everything down with Lysol when I get it home or what? I sure can't afford to get it, what with my other health issues and upcoming surgery in early January! My daughter called and said both her oldest boy and she had it and the whole family is quarantined - fortunately they live on a small farm so they have room to get out of each other's hair so they all don't go nuts being cooped up together.

As for the block, he said it cleaned up with very little effort, he had to straighten and resize one of the rods slightly, and everything was close enough in spec that it took very little to balance it again. So, once it's all home  I can start the cleanup and measuring.....

New parts should be here both today and tomorrow, then I can get started in earnest. With any luck it will be home in time for Willie B to have it in the car by Xmas!

My health issues are kicking my butt too, and really limiting what time I can spend in the shop - some days I can't even get off the couch! I have yet another Dr. appt Monday, we'll see if he can get me over this crap.....I'm still convinced it's a meds issue.

Edit: My buddy is going to loan me his surface plate and burette so I can CC the head, and calculate the compression ratio...I'm sure it's fine but I want to document everything.

[BruceK]

Sorry to hear you're not at 100%.   

Good idea to go full hazmat suit when you pick it up!

Go for the high visibility orange.

[MiniDave]

Where do you suppose you would get a getup like that?   :-\

[gr8kornholio]

From China, by way of Amazon. 😁

[MiniDave]

So I went over to the plague infested shop today and picked up the block and pistons, I think I got out unscathed, they carried the stuff out and put it in the car for me, and they were wearing masks and latex gloves. I got it all in the shop but the block will need a lot of cleanup before it's ready to build....I wonder if safety solvent kills the 'Rona?  8.gif

The box with the belt drive came in and it's a really nice bit of kit - he got a great deal on it IMHO. The cover and back plate are a lot heavier than I expected, but the whole setup is nicely made with great little touches like the TDC mark on the cover.

Other projects will have to take precedence over the next few days, but I plan to get started on the build up phase early next week with the goal of shipping it by the end of the month or very early Dec.

[MiniDave]

Cam bearings installed using my custom cam bearing installer.

Next up check all the ring end gaps, then lay the crank in and check the clearance on all the bearings, with that all done I'll do one more final clean up of the block then I can start assembly.

[cstudep]

Cam bearing installer, just some length of all thread with properly sized washers and nuts as required? Do you use the same tool to uninstall?

[MiniDave]

Same tool to uninstall, it has some specially made bushings that fit inside the bearings and act as a guide on re-install.

I've put them in a lot of different ways in the past - I've tapped them in with a plastic mallet, knocked them in with a seal installer and so on, but using a properly sized bushing installer is the best way as you have to line up the front and middle bearings to the oil holes in the block.

[MiniDave]

This afternoon I worked on the cylinder head and rockers.....

First up was to clean it, then set the valves in, install the stem seals, then the new double springs, caps and keepers. I don't know why the gasket sets only come with 4 stem seals as I and every other engine builder I know puts them on all the valves. I keep extras on hand so I'll always have a full set available.

Next I run a tap in every threaded hole to make sure there's no crud in there that will keep the studs from setting properly. Lastly I'll run my flat block over the head surface with some 1200 wet or dry to make sure the head surface has a good "tooth", then I'll give it one last clean up.

I also assembled the rocker arm assembly with a new heavy duty shaft and new forged Cooper S rockers. There's nothing wrong with the sintered rockers on here as they tend to wear the shaft more than the rockers, but I've read that they're not exactly real accurate for geometry or ratio - these Cooper S rockers are an honest 1.13% and well made, so I prefer to use them with the cam we're using.

The shaft wear doesn't photograph well, but there was definitely some wear on it - they're considered a consumable and I always change them.

So that should do it for the cylinder head, valves done, new stem seals, new double springs, new rockers and rocker shaft.

Next up some more work on the block.

[Willie_B]

Have you got something like a piece of angle iron bolted to the head to hold it in the vise? Just wondering.

[MiniDave]

No, I put two studs in the head and I have some soft jaws in the vise to protect the studs - they're aluminum with hard rubber inserts in them.

[Willie_B]

That works too. Just thought you might be living on the edge having it just balance thete.

[MiniDave]

Ha! I'm not THAT good......   ::)

[MiniDave]

Got a little more done on WillieB's engine project today......I got the transmission cleaned out and all the old gaskets scraped off - I don't know what kind of gasket sealer he used before but it was some TOUGH stuff to scrape off!

I installed the rings on the pistons and but before I did I put the top ring in each respective bore and checked the ring gap. they were all in tolerance so I slid piston one into it's bore.

Then I installed the crank, and used plastigauge to check the clearance Clarance. Everything checked out fine. I also checked the crankshaft end play using my dial indicator.

With that all set I torqued the main caps and the cylinder one rod caps and checked to make sure it all turned smoothly, which it does.

Before I installed the front plate I put the oil gallery plugs in.

Next up I put the lifters and cam in, then filled the oil pump with oil and installed it to hold the cam in the right depth so I could do the front end.

Then it was time to figure out how to install that slick cam belt drive....I looked at it a while before I figured out I had it upside down - once turned around it fit perfectly!  :-[

I had to make some small modifications to the front plate - same as you do if you're going to run a dual chain - you have to chamfer the holes for the two bottom screws then you have to use allen head  screws instead of bolts. With that done and all the parts cleaned up it was ready to go together.

Lastly I had to clean off the end of the crankshaft, they tend to get a raised edge that keeps the lower pulley from sliding on easily. A little bit of work with a file and some 1200 cleaned it up . I also had to rework the woodruff key so the new pulley would slide on. It was interesting to find that the cam had a 3* offset key in it.

That's where I stopped for tonight, I'll install the cam drive and set the cam timing next....

[cstudep]

So when you are using the plastigauge to check clearances do you only check the main bearings and I assume you check them all?

I have never used it before but it looks pretty straight forward, I see they mention to check it in multiple places is that really necessary? Do you only need to check it on the cap side as well?

That timing set up looks great, it's almost a shame a guy will never get to see those pretty timing gears.

[MiniDave]

I check all the bearings, but I only check in one spot - I don't see the sense in checking all the way around the journal as I had the crank checked for size, taper and out of round. I'm merely confirming that the clearance is correct - it's probably overkill again as I've already had the crank and rods checked for size and true.

[BruceK]

Dave, that's a good photo of you working with the piston rings.  4.gif

[MiniDave]

Pictures with people in them are usually more interesting than those without, but they're difficult to set up and take time and I usually forget to even take them! Trying to make the thread more interesting and less dry....

Thanks Bruce.

[94touring]

Less dry.  Anyone?

[Jimini II]

Nice work Dave.
I had a belt drive set up on a pick up I owned and loved it and the lack of chain/gear noise was a bonus too.

[MiniDave]

Some more progress on this motor.

I installed the trick adjustable, belt driven cam drive kit and spent this afternoon getting the timing set right - 106* ATDC intake valve fully open. It took a while to get the set up right, then it's super easy to adjust the cam timing.

With that set I buttoned it up.

Next I'll go ahead and install the other pistons and torque everything up.

I also was lucky to find a couple gaskets for the center oil pickup in my spares stash. I don't think I'll be able to install the pick up unless I take the layshaft out first - with the screen on the end it's too long to bend around and fit in the opening with the layshaft installed.

With these things done the rest of the build will go much more quickly.....the head is done and ready to go on. with any luck by next weekend it will be headed back to Atlanta.