drilling main bearings

[kenpo2]

I am trying to get the crank cross-drilled (1974 2000 GTV ). My mechanic has done it on many other engines (1600..etc) but the 2000 he has had trouble. he tried a couple of machine shop in the area and they could not drill it's too hard!!!. He said the 2000 crank is "nitrided".

Can anyone recommend or know in the Pennsylvania/NJ/NY area where to go. Could not even tap the holes for the plugs to replace the aluminum plugs with threaded plugs (breaking taps and bits).

My concern is that during this rebuild, I plan to install a modified oil pump higher volume/pressure from Spruell. Will the pressure delivered by these modified pumps cause the std aluminum plugs to fall out resulting in low pressure?. How high is this pressure?

Is there a way to seal these plugs other than the standard way form the factory. I plan to use the engine for street and time trials.
your suggestions and knowhow are greatly appreciated!.

74gtv,76 spider. Phila

[alfalfa GT]

hello alfistas!
At mikevalant.com I've found a lot of useful information about this and other questions during the restoration of my GTJ. Photos step by step and tech explanations.

[alfalfa GT]

hello alfistas!
At mikevalant.com I've found a lot of useful information about this and other questions during the restoration of my GTJ. Photos step by step and tech explanations.

[Wil Painter]

Hi Kenpo2:
There's no "cross drilling" of the crank required, all journals are already drilled to receive oil. The term cross drilling in this post refers to drilling the block so that journals 2 & 4 get direct oil pressure rather than via the crank passageway. You may still want to tap the crank plug holes, and yes, the crank is nitrided and therefore very tough (in a metallurgical sense). Many shops just don’t want to do it. I referenced earlier in this post a shop here in LA that does it, no help to you in PA unless you want to ship it out; there must be a better local alternative for you.
Good Luck
Wil Painter

[cstlhn]

After performing several searches on the cross drilling of Nord style blocks I found several threads but no real DYI information. Everyone seems to know what is done but nobody has said how it is done?

Over the weekend I dug out a big right angle plate in my tool crib and machined 11mm holes into the vertical section that are the exact center to center spacing of the main bearing caps. I then removed the caps and used my Snap On stud remover tool to remove the main bearing cap studs.
The studs are 10mm but I made the openings 11mm to allow some movement to indicate the block level.
The first photo shows the block upside down and the angle plate being attached. I used four 10 X 110 X 1.50 bolts that threaded right into the threaded bosses that the main bearing studs did.
The second and third photos show the plate/block mounted in the Milling machine. After calculating the bearing centers I realized that standard jobber length drill bits would not go deep enough to do the job. I am drilling a 4mm passage way because that is what I measured as the feed diameter to the existing Mains.
I have never done this before but I decided to document this project and hope that others join in with questions and comments?

David

[genericwood]

Good luck with your project. I have a trusted machine shop that does this modification for me, but I'm always interested to see how others tackle a project. I can see how your set up will allow you to drill accurately straight down the main, but I'm curious how you plan to set up for the intersecting feed line down from the main oil galley?

On a previous (very old) post, Wil referred to the fact that drilling the block is the idea, not the crank. But it is possible to drill the crank from the #2 and #4 mains back to the #2 and #3 rods. Of course they normally feed only from the #3 main. But since you now have direct feed to #2 and #4 mains, you can feed the rods from both directions. Complete overkill, of course!

Erik

[cstlhn]

Quote:

Originally Posted by genericwood Good luck with your project. I have a trusted machine shop that does this modification for me, but I'm always interested to see how others tackle a project. I can see how your set up will allow you to drill accurately straight down the main, but I'm curious how you plan to set up for the intersecting feed line down from the main oil galley? Erik

[genericwood]

Sound like you have the right idea!

Erik

[George Willet]

Erik, a small aside on the oiling of the #2 and #4 mains in a stock engine.

The number two main is fed from number one main through number two rod bearing, and number 4 main is fed from number 5 main and through number 4 rod bearing.

The purpose of cross driling the block at number 2 and 4 main is to get fresh filtered and cool oil directly from the oil galleries. Of all the engines with failed bearings. the number 4 main is always the one that is scorched. The rear main is farthest from the oil pump and also carries the weight of the flywheel, so that oil gets hotter and has to feed the #4 rod first, then the hot oil has to lubricate the #4 main.

That being said, unless the engine is for racing at high RPM or is a very hot street engine, (like John William's) then I haven't seen the need to cross drill street blocks.

A small aside, mike the top of number 4 main bearing web in the block if there is any scorching of the bearing. You will generally find it has gotten thicker than the other three from the heat and pounding. Time for a new/different block.

Sports fans in general: blocking the oil pressure regulator or shimming the pressure relief spring will only increase line pressure when the engine oil is cold. As soon as the oil gets to operating temp, the pressure is determined by the oil viscosity and the leak down rate from the bearings. (For a given pump volume)

[cstlhn]

The long 4mm drill bits arrived today from MSC. To simplify things for this article I calculated the drill depths for both #2 & #4 bearings (they are different). I did #4 first and from the cast surface drilled down 98.48 mm.

I first use a centering drill then the standard 4mm drill. Use plenty of lubrication and raise the quill frequently to keep the drill bit clean. I was able to then switch to the long bit after lowering the table. Keep the X & Y axis locked. The drill reached 98.4 mm I raised the quill and that operation was done. With the table still in the same position insert the letter "R" and chase the same hole down 12mm. I removed that bit and inserted the 1/8 NPT tap and threaded the hole.

[cstlhn]

Next step. Move the table from right to left 182 mm. The oil filter boss is higher than the boss for number 4 so drilling #2 is longer. Therefore the depth from the cast surface is 113.4 mm. Repeat the steps for the previous hole.
The block can come off and get set up for drilling the intersecting holes. I happen to have a big parallel block that is about a half an inch thicker than the cylinder head studs so with the block upside down I clamped the block to the table with the paralell block between the block and milling machine table.
Using the clamps to level the oil pan rail I ran a dial indicator up and down the rail until I had less than 0.005' difference from end to end.
#2 & #4 bearing journals are 20 mm wide. Center the drill 10mm from the edge. Since this passage is only 19 mm deep the shorter drill was fine. I did use the centering bit first. When the drill reached a depth of 19mm I could feel it break through in to the passage made during the previous step.
Using a strong light above the hole I last drilled, I looked through the side and could see the intersection was very good. I then used a manual countersinking tool to cut a small chamfer on the surface.
Success!

[genericwood]

Not entirely sure why, but I noticed my machine shop drills the #4 oil passage from the exhaust side on the 2L. But the #2 oil feed appears to be drilled from the intake side.

Erik

[cstlhn]

My block is a 101 series 1300. I have noticed from pictures in various threads that there are differences in year and displacement. The #4 boss does not appear on certain blocks?

David