2.7 Rebuild – To bore or not to bore and other questions

[Rosco_NZ]

I thought LN used JE pistons ..

[PeteKz]

Usually, but they don't have to.

[Molton]

Those pistons are still attached to the rods in the pic. That’s how they were installed and it looks like it was able to run like that, too.

[rgofast]

My 2.7 is a short stroke. We fabricated steel sleeved 93mm cylinders, and are using Cosworth racing pistons. If you want to rev that engine, make sure your cams have a range high enough so they don’t top out early. We used a crane Modified S grind, Aase racing springs with titanium retainers. We rev to 7300, but probably could go higher. Don’t need to as the car is in the mid 1800 lb range. I would also get the distributor re curved for your application. I had Jerry Woods do mine, after giving him all of my build specs. That and custom hearing makes a huge difference.

[STYZ993911]

Thanks for sharing.

[draw]

When I'm in the mood to clean parts, which isn't very often, I clean parts. And in no particular order...

It's no joke when people say to clean until you think things are clean, then clean again...I cleaned the rocker shafts twice and then decided to clean them again. On the last pass, something that looks like Loctite 574 appeared...



Some ham-fisted person mangled the swivel foot adjusters by over-tightening them during a valve adjustment, so I had to buy all new ones. Also ran a forming tap through to clean up the threads. Rocker arms were refinished by John Dougherty.



All of the rocker shaft bolts had Loctite 574 on the threads, too. So I ran them through an M7 die.

[draw]

Originally Posted by Rosco_NZ

I thought LN used JE pistons ..

They have quite a few options now...

Originally Posted by rgofast

My 2.7 is a short stroke. We fabricated steel sleeved 93mm cylinders, and are using Cosworth racing pistons. If you want to rev that engine, make sure your cams have a range high enough so they don’t top out early. We used a crane Modified S grind, Aase racing springs with titanium retainers. We rev to 7300, but probably could go higher. Don’t need to as the car is in the mid 1800 lb range. I would also get the distributor re curved for your application. I had Jerry Woods do mine, after giving him all of my build specs. That and custom hearing makes a huge difference.

Thanks for the advice, I appreciate the feedback. The DC43x-102 cams I'm using are good for 7200+ and I had Aasco springs and Ti retainers installed when I had the heads rebuilt. So the valvetrain should be good to 7500+. I plan to have the engine dyno'd and I'll see how that turns out before "setting" the redline. I'm also planning to use the twin plug distributor from Patrick Motorsports.

[draw]

As part of the case prep, I pulled all of the studs to clean out all the gunk (oil, RTV, 574, etc.) that had collected around them over the years. And, before I bolted everything up, I also wanted to assess the health of the threads in the mag case.

All looked pretty good except for two where the threads basically disintegrated when I removed the studs. Looks like I "get" to learn how to install Time-serts!



Drilled out for the Time-sert and installed (tapping the hole and installing the insert with blue Loctite not pictured)...

[draw]

On to prepping the crankshaft...

I took the crankshaft to Marine Crankshaft for all the good stuff.



$800 later...



The crank was covered in machine shop gunk, so I put on Metallica's Master of Puppets and went to town cleaning the crank in my parts washer. Cleaned all the oil passage ways with brake cleaner and a nylon brush. Looking clean and shiny!



Threaded oil galley plugs...



Installed the plugs with some blue Loctite...



I got myself a "gear and bearing heater" toaster oven at the local thrift store for $10.



Heated the gears and spacer to 220F and dropped them on to the crank...



All ready to be put in the case with the intermediate shaft to measure backlash, etc...

[Walt Fricke]

Neat microwave trick - happy spouse. Did you use an IR gun to read the temperature of the parts?
Conventional wisdom has been, for the kitchen, not to put anything metal in there. Obviously you didn't explode your garage. How'd you get to the temperature of the pieces you wanted?

[targa72e]

Hi Walt,
Its a small toaster oven not a microwave. I have a similar set up in my garage as well.

john

[draw]

Originally Posted by Walt Fricke

Neat microwave trick - happy spouse. Did you use an IR gun to read the temperature of the parts?
Conventional wisdom has been, for the kitchen, not to put anything metal in there. Obviously you didn't explode your garage. How'd you get to the temperature of the pieces you wanted?

Originally Posted by targa72e

Hi Walt,
Its a small toaster oven not a microwave. I have a similar set up in my garage as well.

john

Sorry to disappoint, but John is correct, it's a toaster oven. I have seen people on youtube successfully use an old microwave, and I did think about it, but decided to go with the oven because I felt like I'd have more control over the temp. I do use an IR laser gun and a spray bottle with water in it to judge the temp. Works a treat!

[draw]

Intermediate shaft teardown, inspect, and rebuild, part A...

My original plan was to clean the intermediate shaft, measure backlash, and move on with the rebuild. But after seeing these witness marks on the case, of what I assume was from a loose chain caused by a failed tensioner, I decided to tear everything apart and replace the chain gears.



Everything torn down...
(Oh, and I'd just like to say that the Knipex snap ring pliers are one of the best tool purchases I've ever made.)



Comparison of new gear beside old gears. Definitely some minor wear on the gears, which I could probably reuse, but the slippery slope of "while you're in there" continues...





Cleaned intermediate shaft. Amazing how much gunk came out of the oil passages...





"0" gear looks ok...



I need to finish prepping the case so I can put the bearings in and measure shaft runout and end play. That will come someday soon, hopefully...

[draw]

More minutia...

I started to wrap up work on the case by applying the Hysol epoxy to the case plugs. I know it's probably overkill to seal them all, but better to be safe than sorry...

[draw]

And I took care of Technical Service Bulletin 8911...

[draw]

And, a milestone! 37 months after the motor came off the stand, the case is back on...

[draw]

One of the reasons this rebuild is moving at the pace of a glacier is that I enjoy researching the various parts and techniques that go into engine building. My latest tangent involved what to do about hardware. Buy new? Send it out for zinc plating? Zinc plate it myself? What about black oxide?

For this batch of hardware, I finally settled on using a black oxide kit from EPI because it includes a sealer/corrosion inhibitor.

I first ran the hardware through an ultrasonic cleaner with degreaser, then made another pass using evapo-rust.



Came out clean as a whistle...



The four part process. Clean, prep, blacken, sealer...



The final product...



Very pleased with how these turned out!

[Uwon]

Amazing work.
Cheers,
Johan

[RobertDurff]

Those look great! Which kit from EPI did you end up going with?

[iq207]

Originally Posted by draw

On to prepping the crankshaft...

I took the crankshaft to Marine Crankshaft for all the good stuff.



$800 later...

The crank was covered in machine shop gunk, so I put on Metallica's Master of Puppets and went to town cleaning the crank in my parts washer. Cleaned all the oil passage ways with brake cleaner and a nylon brush. Looking clean and shiny!

Threaded oil galley plugs...

Installed the plugs with some blue Loctite..

I got myself a "gear and bearing heater" toaster oven at the local thrift store for $10.

Heated the gears and spacer to 220F and dropped them on to the crank...

All ready to be put in the case with the intermediate shaft to measure backlash, etc...

I had not heard of grooving / cross drilling the #4 main journal before. I assume this is to help oil supply to #2 and #5 cyl rod bearings. I have a crank at Marine right now (1 month, no word yet...) from a spun #5 rod bearing so this might be a very good mod for me. It is not in Wayne's book, not in Anderson's book, not much in a google search. Found a few threads here on it with some different search words. Henry at Supertec says he does it on all his cranks. That is gold for me. Gonna do it.

This is a great thread. Thanks.