95' Junker Drag Truck

Joesixpack said:
So when you say you can't get .0015 anywhere along the length but can get a .004 dip between cylinders is telling me that's too much over a short distance.

I can respect a budget but I'd get it surfaced.
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When the straight edge is parallel with the head, it has .003" between 4 & 5. It has .0015" between 3 & 4 and no detectable straightness issues anywhere else.

When the straight edge is diagonal across #1 intake side to #6 exhaust side, it had .004" between 4 & 5 .001" between 5 & 6 and .001" between 3 & 4, no detectable straightness issues anywhere else.


I'm going to check the block, and if it has a little hump between 4 & 5, I'm going to run the head as-is with some copper coat. (My thought is if there is a little hump there, over the past 245K miles it's slightly warped the head to conform to the block and the current slightly warped state is a perfect match. If the block comes back dead flat, I think I'll get .005" cut off the head to clean it up.
 
The machine shop I use, will suface a head for about 35 bucks. pretty budget minded for most. weighed against the cost of a gasket kit, and the abuse planned for it. I certainly would surface it.
 
What caused the scuffing on the cyl walls? Coolant entering the cyl or high rpm/high egt? :confused:

If the coolant caused it I will be studding mine when I go to twins. I dont want to hurt the rotating assembly for $400 studs.
 
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I cleaned up the block and checked it with a machinist's straight edge. The block has a .002" hump in the center that slowly tapers to nothing at both ends. This is almost the mirror opposite of the head, making me think that the head's slight dip in the middle is probably the result of 245,000 miles of heat cycles being bolted tightly to the slightly convex profiled block.

In short, I've decided to keep the "Junker Budget" theme and run the head and block as-is without machining. To help ensure the head gasket fire rings have more stability during high cylinder pressure, I've decided to add a .041" stainless oring.

A fellow Competition Diesel member lent-out an Isky Groove-o-matic tool to me so I could o-ring the block. This was the most cost effective way to add o-rings to this Cummins motor setup. The traditional method is to o-ring the cylinder head, not the block. The tooling to do this at home is cost prohibitive so I chose to oring the block.

Below are a few pictures of the groove and the Isky tool itself. The tool was correctly setup by the previous user and tool owner, however, I double checked the cutter depth using .030" feeler gauges under the (4) guide tabs which placed the cutter flush with the deck surface. Then, when using the tool, the feeler gauges are removed resulting in a .030" deep cut which calculates to .011" oring wire protrusion.

Only cylinder #2 is complete so I need to spend a couple of hours to do the other (5) cylinders.

Isky1.jpg


Isky2.jpg


Isky3.jpg


Isky4.jpg


Isky5.jpg


Isky7.jpg


Here is a closeup of the depth tab that also adjusts outward with the large central cam-plate/nut setup to act as a centering guide on the bore. There are four tabs act as both the depth guide and the bore centering guides.


Isky8.jpg


The guides above hold the cutter square and at a consistent depth, then the carbide blade can be set to whatever depth is desired with this adjustable depth locking allen head bolt.


Isky6.jpg



And finally a closeup of the cutter in the groove.


Isky9.jpg
 
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Love it! I would love to see a video of it in action.

Is there enough room under the cowl to spin the handles? I see they come off but if im picturing it correctly it wont swing in there.
 
Im picturing it with the handle hitting the fire wall. Easy fix just curious I have never seen one of those tools.
 
nice work, I wish I saw that tool a couple months ago, lol.

You should bust out the die grinder and do a little junker port job.
 
It actually cut the grove pretty fast you could do it in 2 hrs at the most if you didn't get tired.
 
I spent a few minutes with a piece of .041" wire and straight edge. The groove depth on the one cylinder I have completed is so consistent, I can't measure any tolerances or depth changes. I'm sure with specialized measuring equipment, some variation could be detected but I'll bet it's within .001".

I also checked the clearance on cylinder #5 & 6. #5 is 100% clear, on #6, the handles hit the firewall, probably about 1" of interference. I just need to pick up a couple of bolts to turn it on #6 and it should be good to go.

As far as cutting pressure, it doesn't really take much down force or twisting force to cut the groove. With moderate pressure, it cuts about .0015" per pass.
 
Good god, that thing is only $300?? I'm pretty sure one shall reside in my toolbox soon... What are you planning to run for fasteners? I've been having pretty darn good luck with Socket Head Cap Screws on budget built customer trucks, and even my own compound equipped truck since I like to test things before selling them. Heck, I'm pretty sure SHCS's are cheaper then new stock bolts :poke:
 
BlackSkyRacing said:
Good god, that thing is only $300?? I'm pretty sure one shall reside in my toolbox soon... What are you planning to run for fasteners? I've been having pretty darn good luck with Socket Head Cap Screws on budget built customer trucks, and even my own compound equipped truck since I like to test things before selling them. Heck, I'm pretty sure SHCS's are cheaper then new stock bolts :poke:
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On average how much torque can you get on the SHCS's before they just stretch?
 
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