Saving an old 2.7 case

[304065]

Very clever replica of the old plug! "Modern" plugs have a hex head so you don't have to get out the P74!

[cgarr]

While waiting for my shell reamer to cut the lay shaft bearings I made a jig to cut oil grooves in the main and rod bearings. This is just an old test set. Yes I'm bored..

[TimT]

made a jig to cut oil grooves in the main and rod bearings

Nice work!

I have a similar jig we made to cut the bearings.





Dont think there is a need to modify the rod bearings though, you want them to be as robust as possible. We have more than a few engines running with the crank crossdrilled and the main bearing modified, not the rods.

On a 9000 rpm engine we built we reground the rod journals, had the radii modified, etc. and used Clevite Nascar rod bearings

[HawgRyder]

You can get Clevite bearings already cut if you ask.
Also...Clevite has a special type of cut they do to make the oil groove area look sort of like a leaf (veins) to allow the oil to migrate to the outer edges.
I have used these in high HP race engines and find they do reduce the oil pressure slightly, but the longevity is amazing.
Also...Clevites have embedability (?) properties that will save the crank instead of galling it.
Bob

[Nitrometano]

this is the first time I heard that. Do you have pictures of how that bearings looks? Also what is the purpose of that modification in the engines, better lubrication at high speeds?

[HawgRyder]

No pix I'm afraid, but the overall look of the grooves are like those in a leaf of a tree.
The main groove goes along the bearing and the shallower diagonal grooves lead off of that main groove.
Let me stress the importance of the smaller veins going in the correct direction....with the rotation of the crank...and they are very shallow...almost like lines drawn on the bearing.
I haven't used them in some years, so I cannot state that they still carry them.
The idea was to allow full width hydraulic lift on the bearing.
You know that in operation, the bearing does not touch the crank, only the oil "wedge" supports the crank.
If evrything is correct, the worst thing you can do is "start" the engine, because every time you do, the oil has to build up pressure to "lift" the crank.
The best possibility is to never shut the beast off.
This is why big diesel rigs last so long, they rarely ever get shut off.
Bob

[Nitrometano]

thanks, I understand now.

[cgarr]

Got the layshaft case bore cut, 26.5mm and 27.5mm on the money, piston oilers are out, next is the case savers, then a good cleaning.

[cgarr]

Wanted to check the crank in the case before I go any further. I got .002 on the mains, .0015 on the flywheel and .001 on the layshaft.

[dion914-6]

Craig, great job so far. I'm enjoying watching this progress. How did you get your case looking like an Aluminum case? Man, that thing looks clean for a one-time basket case.
Dion

[76911]

A speical G2 formula that is in testing stages right now

[dion914-6]

So, are the tests done, and can I get some?

Dion

[turboteener]

Are you not using a dial bore gauge to measure the bearing clearances and ovality of your case? I am concerned the accuracy of plastigauge is not accurate enough for this. It won't show an egg shape in your main bearing bores (although I doubt there is any).

Did you use a fly cutter or a face mill for your case surfacing? Also how do you account for the taper in the bed/ways of your mill?

[cgarr]

The case was surfaced on a surface plate not a mill. The bearing bores were cut with a shell reamer then checked with a bore gauge. The plastigauge was only used to check crank bearing clearances not to check bearing bores.

[Walko]

Craig

do you do this for a living or a hobby.

I have a couple of 2.7 cases that need saving.

Michael

[cgarr]

Right now its just a personal challenge, but if you have a case that is headed for the trash anyhow, then we have nothing to loose. I would like to get 2 or 3 more done before I will call it just luck on this first one..

[84toy]

Has anyone tried machining the case halves and using an automotive line hone instead of boring? I can't picture that a few thousands would be enough to require the main seal to be re-bored. I have a mill to machine the halves and access to a line hone........Don't know how to do the intermediate shaft bore. Got the daughter project engine to do.

[HawgRyder]

Very difficult to hone a hole into round.
Boring to make it round...then honing to size (slightly) is preferred.
The hone is a spring loaded tool and as such will "bounce" in and out as it hits harder spots in the parent metal.
This will end up making an out of round hole.
And dont forget...after machining the case halves....the seal hole will be oblong to start with.
Bob

[84toy]

Originally Posted by HawgRyder

Very difficult to hone a hole into round.
Boring to make it round...then honing to size (slightly) is preferred.
The hone is a spring loaded tool and as such will "bounce" in and out as it hits harder spots in the parent metal.
This will end up making an out of round hole.
And dont forget...after machining the case halves....the seal hole will be oblong to start with.
Bob

Bob, the Sunnen automotive line hones are rigid and not spring loaded. They are about 4 feet long. On V-8's you cut the main caps, bolt it together and line hone all the mains at the same time. It does a great job. I can't see any reason why this wouldn't work for a split case after machining the case halves. The problem is going to be the intermediate shaft. Anyone tried it?

I have a 2.7 engine coming apart and I'm sure it's gonna need a repair.

[dweymer]

Craig,

I now have 2 cases to work on(as projects to learn and practice on) and wanted to know how you checked the case half mating surfaces to arrive at the .001 off?

I was planning on mounting the case level, and using a dial indicator on an arm go over the surfaces. Any suggestions?

D