Saving an old 2.7 case

[cgarr]

What did I have to loose? So far so good, also added supports to mains: and took about 4 thou off the case halves: Reposted from GruppeB, you know, GruppeB those cheap Bas**rds


Well, Just got done center boring the case back to standard, This worked out so much better than I thought it ever would, I guess all that measuring and testing paid off. Here are some pics of the process. I then cleaned up the old bearings, set the crank and bolted it up to see if I was even close. This thing turns soooooo nice, I was surprised to tell you the truth. i dont know what the clearance is yet because I did not plastigauge it but the center main bores are within .0002 of standard. I guess all those nights setting up and resetting the reamer paid off.

Cutting the mains



Checking the finished bores



Setting the crank

[J P Stein]

Nice!

[cgarr]

Oil bypass mod done!

[304065]

Craig,

What's the history of this project, was this a line bore to standard following surfacing of the case, or to oversize with the case the way it was? On one hand, the bearing webs look like they have been surfaced, but on the other I see some red dye at the upper right and the right half has an M10 and two M8 studs installed, which makes it hard to surface

[cgarr]

The plan was to bring the mains back to standard, the mains were oval shaped as many are in these cases, I took the case down as far as I dare, (all studs removed) the only area which is about a thou off is where the red dye is but that is not a critical area and it still bolts up well, next I used my jig to ream the main webs for the insert guides, then installed the necessary studs to bolt the case back together and bored the mains, next will be to cut the lay shaft bearings and the flywheel seal area. I didn't want to take off so much as to alter the chain boxes. I still have the casesavers to install but didn't want to do that until I knew I could bore it back to standard. Remember I really never thought this would work, it was a junk case and really only started as a personal challenge, I was running out of things to do! I'm almost 50 and been married for 20 years if you know what I mean!

[Steve@Rennsport]

Nicely done, Sir.

IMHO, this should SOP for ALL mag cases, nowadays.

[cgarr]

After whipping out a home made cutter on the lathe I cut the rear main seal in the case.

[Nitrometano]

thats a great jobs. I like to do a lot of stuff by my self because I consider it a challenge.
Craig, I think that you have do a lot of machine shop works, do you have a special procedures to remove the rusty cylinder heads exhaust studs? Mines are no broken yet, but in very very bad shape that I would like to replace all with a new ones.

[TVRLOTUSTR3]

I was running out of things to do! I'm almost 50 and been married for 20 years if you know what I mean!

If you really want more time in the shop, I have a few cases you can do.

[cgarr]

Repaired the badly corroded oil relief tube with an aluminum sleeve, reamed to oversize and made a sleeve, only thing to do is re drill the ports.

[76911]

That will be a good motor to test in the 74 when the body is completed

[304065]

Craig, did you use an interference fit on the oil tube?

[cgarr]

Originally Posted by john_cramer

Craig, did you use an interference fit on the oil tube?

It was just a light press/slip in fit, and I bonded it in. The problem was I finished bored the center for the piston first and if I had to press it in then the bore would have been changed. If I was to do it again I would have pressed it in leaving the inside a tad smaller then reamed the bore to 15mm

[cgarr]

Originally Posted by 76911

That will be a good motor to test in the 74 when the body is completed

Yea but its going to be a long time with only one sponsor so far, there is plenty of body panels for others!!!

[gigem75]

man, if I lived near you I'd be camped outside your shop until you taught me what you know.

[76911]

Originally Posted by gigem75

man, if I lived near you I'd be camped outside your shop until you taught me what you know.

We actually have two shops......one for the clean work and the other for the rest

[gigem75]

I'm about to build one (shop) for my stuff. Looking for a spare 2.4 or 2.7 to build. The 2.2 I built has over 1500 miles on it and is running better each time I drive it so I'm fairly confident she'll hold together. The 2.4 or whatever I get will take what I learned from that a couple of steps further. Nice looking machine work your doing there.

[HawgRyder]

Sleeving the bore was a good idea, but did you consider using Bronze or Stainless for the sleeve?
I have R&O'd a bunch of piston-in-bore apps using Bronze, and I find the long term results are better with the harder material.
Also...when cutting the side openings in the newly sleeved tube, you might want to back cut the edges to prevent early galling of the piston.
Good job
Bob

[cgarr]

Originally Posted by 76911

We actually have two shops......one for the clean work and the other for the rest

Here is the other shop and the ENZYTE sponsored project


[IMG][/IMG]

[cgarr]

Had to make a new plug since the reamer took out the original case threads. New threads are 3/4-20