Jaybird's official 2.7 rebuild thread

[jaybird840]

Yes, I had Dennis at precision engine service do it locally. He had about the best reputation of what was available. Unfortunately, I have no way to verify if the work he did was good or not. Looks professional, tho. Fortunately for me, I attacked my 901 prior to doing the engine. When I finally get this beast to fire off, it should be good to go down the road with no grinding or tranny leaks. Onward thru the fog!!!!

[jaybird840]

Ok gang, it's underway! I followed Wayne's advice, and spent an hour cleaning up the shop and bench before test-fitting the rods. I had forgotten what the top of the bench looked like......



I followed Wayne's instructions, and fit the new bearings into the rods and then onto the crank. I used plastigauge, and got some confounding results. The book says the spec for bearing clearance is .030-.080mm for the rod bearings. I got .025mm on five out of the six rods, with the sixth showing to be in the .035mm clearance range. I'd love to hear what the wise motor builders in the group would say??? I had the crank polished, so it should have lost a touch of material on the journals.... I can't imagine that they'd be that tight. I double checked the rod bearing box, and it shows standard sized bearings, as does the invoice. I had the big ends of the rods checked by two machinists (can't be too careful) and they both measured them to be within spec (no rebuild done on the big ends). I suppose I could have smeared the plastigauge, but it would be hard to repeat that five times in a row. For the torquing procedure, I tightened to 14.7 lb/ft, then went another 1/4 turn (90 deg.) Is that right?

[cgarr]

So the range is .00118 to .00314 and your at .00098 Your 2/10th of a thousands tight? Do you have the crank and rod measurements? I never had good luck reading plastigauge down that close.

[jaybird840]

After more eyeballing, worrying, cleaning, thinking, and repeating... It was time to reassemble the crank. OK, re-read the chapter in Wayne's book another 14 times. Lather, rinse, repeat.... I felt like Jack Nicholson in "As Good as it Gets." So, I assemble the first rod... line it up.... apply the thread locker....torque it down.... and "whew"! Let's give her a little spin to see how buttery smooth it feels. Uh oh.... doesn't feel that smooth In my obsession, I forgot to make sure the rod halves were mated correctly!!!

Well, %&$!!!! Nothing like making an error with rod bolts that can only be torqued once. Oh well, it's only money, right? I managed to assemble the rest of the rods without incident. They all spin smoothly with about the same amount of drag. I'm thinking about calling the local stealership to see if they stock the rod bolts/nuts. I guess this is God's way of telling me that I need to spend more time cleaning the case! Here's the assembled crank (minus one rod)


Onward through the fog!!!!

[kenikh]

This is a fun read. Good luck!

[jaybird840]

Well, while I wait patiently for a pair of rod bolts to arrive I thought I'd spend some time prepping the case for assembly. I had it cleaned at the machine shop and did some scrubbing before. I sent it to CGarr for machine work, and it came back cleaner than I had sent it. I scrubbed it in hot soapy water again, and then went after it with brake cleaner. It's starting to meet assembly standards.



Next, I broke out my trusty second amendment cleaning kit... All of the main oil passages can be done with a .45 cal brush and jag. It looks like a couple of the outer ones might need a .40 or 9mm.



See what good tools do for you!!! This is what the Kimwipes + brake cleaner looked like as they came out of the oil passages..... No shavings or chunks, but still a good bit of gunk.



More tomorrow!!!

[jaybird840]

Alrighty then.... Finally got the new rod bolts and got the crank completed. I got some time today to finally start the case reassembly I installed the intermediate shaft bearings, and test fit it to the case....



Everthing is snug, and turns freely with no binding. Next I installed the seal in the number eight nose bearing. I applied Curil-T like Wayne's book said to. The Curil-T seemed to make the seal want to squirt out. I basically held it in and flush with a wood clamp until it "set" enough to stay in. Next for the flywheel seal. Is this installed correctly? Both arrows on the seals are pointing the same direction. I can't remember how the seal looked on disassembly....




Next, I dropped the crank into the case. All appears snug and it spins freely....



I guess I'll wait to hear from someone on the flywheel seal orientation before I continue. Thanks all!!!

[Dick Shift]

Flat side out tward the flywheel. Reverse of what is shown in the picture.
Set seal deep into the grove provided in case with only lite oil on all contact areas.

[jaybird840]

I guess I should consider myself lucky..... I had my first real "unexpected" problem with my rebuild this morning. You gotta love magnesium cases. I thought I might actually get to seal my long block today. No chance. I dropped the oil pump/intermediate shaft in and started to torque the nuts to the required 25n/m. Much to my chagrin, the third nut kept spinning...and spinning....and spinning. Even an idiot like me knows what that means Yep. Pulled the stud right out of the case.







OK, so somebody get me on the right track here. My guess is that a helicoil would do the trick. The stud doesn't take much load it doesn't seem to me--just holds the oil pump firm in the case. If so, where can I pick the correct one up? CGarr, I'd love your input here!

Thanks all!!!

[cgarr]

Yea, Mag cases are great for this, you usually only get one shot before the threads are shot in these old cases thus the casesavers! I would not use a helicoil, I have some threaded inserts, they are casesavers for the 8mm studs, the OD is 10mm just tap out the hole and insert and you should be good. PM me your address and I will send you a few of them. I will check the case I have here and machine the insert for the correct depth.


Craig

[jaybird840]

Thanks Craig... You Da Man!!!! (for the thousandth time...) PM on the way.

[jaybird840]

Found an interesting thread where bobboloo used a flex hone to deglaze and prep his 2.7 Nikasils for his build. I contacted Bobboloo, and he agreed to rent me his hone. Here it is in comparison to a flex hone that I use to polish shotgun chambers.


I used WD40 as a honing medium as he did. It only took a few strokes on the lowest setting of the drill to get them all nice and clean--my cylinders weren't bad at all. Here's the before and afters....
Before



....and after







Unfortunately, my WD-40 can ran dry after the first cylinder. Off to the store tomorrow!!!!

[Bobboloo]

Looks good Jay.

Just to let people know. The flex-hone medium is aluminum-oxide which is designed to go easy on Nikasil unlike the silicon-carbide hones out there that can actually damage Nikasil cross hatches.

[jaybird840]

Well,
After a couple of months of real life kicking me in the pants, I finally got back to my project Sealing up the case has been the scariest part of this whole thing so far (I'm not to cam timing yet, tho). Once the case is sealed, it is really expensive and time-consuming to correct errors. I would have taken pictures of the case going together, but I was so paranoid of the Loctite setting up before I got everything together that I figured I had better focus on that over pictures. It seemed to go pretty smooth with the exception of a lost perimeter bolt. It's the one at the bottom corner that isn't a stud--I looked everywhere for it, or something similar to bind it together until I could find a replacement. Hope it doesn't mean an automatic oil leak later Here are the pics..... Onward towards a longblock!

[David Borden]

Nice progress...

If that hole that lost bolt goes into goes all the way through the case, just find a longer/ smaller diameter bolt/nut to hold the case together until you find the proper hardware.

David

[jaybird840]

OK, thanks for forcing me to go finish it right. You may have saved me an oil leak down the road. I finally was able to locate a bolt from another project.... Thanks!

[David Borden]

BTW, I really appreciate threads like yours... I have a 74S that I am slowly restoring, so its a great help to have people like you document your experience!

It gives someone like me great information/tips to be sucessful in tackling the same project

David

[Dick Shift]

BTW; I was taught and always practiced a @ 45 deg. cross hatch when honing cly's.
With many successful rerung 2.7's, 3.0's, 3.2's with Nik's and no more than .003 taper I might ad.
Can't see yours crosshatch but just thought I'ed ad my 2 cents.
Aloha

[frankc]

Jaybird,

Did you find the 12pt-12mm tool for the flywheel bolts locally? If so, where? I need to pick one up to remove mine.

thanks,
Frank

[jaybird840]

Yes, I believe that they are sold as a brake tool. They come in a pack of four, and you can pick 'em up at O'Reillys, Autozone, etc. I'll see if I can find the package for a picture.