durabond cam bearing spit holes

tonka.scout800a

tonka.scout800a

Member
Here is a couple pics that show the size of new durabond cam bearing spit holes to the rocker assemblies.


First the right bank:


Now the left:


The holes line up......but.....
Definately need to be enlarged imo. I will be using a die grinder to do so once I have a chance. (gotta get a new one!!!)
 
This subject was again discussed around the campfire at the rallye Saturday nite!

Set each head in place without a gasket, then sight down through each spit hole. Describe what ya see and if there appears to be somewhat of an "offset" to the entire passage.

Then flip the heads side-for-side and see if the offset (if present) is better....or worse....or no change.

I'll be doing the same on an engine next week (I hope). We know that many engines have holes that barely align, those would offer much room for improvement. I need to get a overall length measurement for a drill bit to be used for straightening out those oil paths, an aircraft bit I "think" is too short so we'll have to source from somewhere else.

If the oil holes are fairly in line, then a "chamfer" can be ground into each head block where the holes meet to minimize any restriction at that interface.

Good pics, we can see the "problem" regarding the bearings very well!
 
That's one clean looking block for sure. I still have a 304 I'm getting rid of. Nice block if anybody wants some parts, just no more room to store it anymore. Its list in the free section.

Hyjack over.

Looking at my other block the oil holes are lined up and the bearing ported to the correct size. I guess I need to open that box of new cam bearings to see what size holes they have. One thing I like about the bearings in my old block is they have a groove in the center to allow the oil to flow in a bit early and late. This seems to be an industry norm when looking at other manufauctures. But I have seen other post of cam bearing with out the groove:( what up there?
 
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The durabond set in11 cam bearings I delivered to ihon from our new warehouse distributor has the "ramped" spit holes in all bearings except for bearing position #1. Since that hole only shoots the cam drive/distributor drive inna forceful shot, my conjecture is that it doesn't need a "ramp up and down", extended duration feed.

However, regarding the last several sets of in 11 I've played with, the two spit holes in that shell are the worst as far as block alignment goes...one or the other will line up, but not both, so one needs to be fudged after install with a die grinder. Maybe that won't matter in the big picture...but it's simple enough to hand finish for peace of mind.
 
My question is, why do you guys want to get more oil to the topend of the engine? If anything the factory design allows too much oil up top robbing it from everywhere below. Myself, I left the smaller hole for the rockers and enlarged the holes feeding the cam and mains.
 
71 Scout 2 said:
my question is, why do you guys want to get more oil to the topend of the engine? If anything the factory design allows too much oil up top robbing it from everywhere below. Myself, I left the smaller hole for the rockers and enlarged the holes feeding the cam and mains.
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I don't think it's a matter of getting "more" oil to the top end. I think it's getting the correct amount. The stock cam bearing spit hole is larger than the ones that are on the durabond bearings. From what I have seen is that these engines suffer from a lack of oil to the top end. Maybe thats just because of age,improper maintenance, not to mention the gunk buildup in the rocker shafts etc,but the smaller hole could at some point be a restriction. My rocker shafts were destroyed from lack of oil....... I don't want to take any chances:gringrin:
 
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Finally got word dhl paid for my replacement head and it's in route. Thought I needed to "fix" my cam bearing spit holes.
So today I broke out the dremel and heres the outcome

And ........


Just a little bit oblong on this last one but I think it'll be ok. Kinda hard to get the dremelin there:icon_eek:

one more wash and...
Time for final assembly!!!!
 
Yore spit hole matching is just fine tonk!!!

The key here is no overhang in the hole matchup anywhere. Either in the oil going in, or the oil going out, or oil going up and oil coming down by gravity. Unimpeded flow. That's the ticket!

No turbulance/restriction, no offset that allows gunk to gather over time, etc. I seriously doubt that your engine will ever develop any of the lubrication-related syndromes we've been kicking around here for the last several weeks simply because the oil will be changed onna regular basis and you will maintain the motor as it should be! Great pics of the process involving difficult access!

There is nothing "wrong" with the oem lubrication design if the engine is simply maintained. Only the Scout II had any lubrication-related "fault" and that was created by the funkee double-hump oil pan sitch to allow 4x4 steering axle clearance, none of the other applications of the sv engine had that type of concern.

And the top end oiling issue would not exist either for engines which had regular service.

Last Tuesday, I pulled apart approximately twenty rocker assemblies and separated the components as future candidates for reconditioning. This batch included several nine stand assemblies that were set up oem with boat rockers, some were set up as five stand assemblies, and a few were a mix of both types of rockers! Some were so badly gunked and sludged, I had to give up and bring 'em home to soak in tyme before they will come apart.

And yes, both the welded rocker shafts and the boat rockers shafts each showed the same type of extreme wear pattern, that is caused by lack of lubrication due to restricted oiling passages and paths, not by design issue.

More info on that sitch will be posted in this thread:

http://www.forums.IHPartsAmerica.co...I-4-sv-engine-non-oiling-rocker-assembly.html
 
Looked again down the shafts and saw a really small lip from the bearing on one of the holes(oblong one). So I will correct that. Battery ran down on the dremel and had some honeydoo's otherwise that would be done already.

Yep, erl will be changed regl'ur. I know 'ol tonk sat neglected for more than a few years before I got her. No tell 'n how often the po changed fluids ......if ever!!

Now I gotta get on the ball first thing Monday and give ihon a call to see if they can supply me (I hope) with some rocker assemblies to replace my current "trash":gringrin: I'm just itch'n to put her back together again!!!
 
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New boat-style rocker assemblies (minus the stands and bolts) are in stock now at ihon and on the shelf.

I now have at least 200 rocker stands of all three types at my location, these will all be reconditioned and put on the shelf at ihon in sets of both nine and sets of five. Individual stands will also be available for replacement of damaged units when needed.

So if ya need some stands (or a full set), I'll fix ya up with the number you need and dropship from my shop, the new stuff will come from ihon.

Spacers (used in both styles of assemblies), and springs (used only with the five stand assemblies) are being reconditioned also and will be available in either sets or individually, of course, those parts are also available as new.

Companion reconditioned push rods for both welded and boat style rockers will also be available, in both lengths.

We will also have a few "options" available, such as reconditioned nine stand assemblies using boat rockers (with appropriate push rods) and a modified used rocker shaft. So anyone should call and discuss (or use this forum to hash it out!) what they are looking for when planning to service the rocker assemblies in any engine, that way all appropriate reconditioned components can be custom-assembled and budgeted for before getting into a project too deep!
 
Damn man,wish I'd a kept all the v.covers w/assemblies I had.had a bus full down 1 side,3 shelves tall,the lenght of the bus.piled ontop a each other.how many wuda that been Mike?lol.Jeff:mad5: :gringrin:
 
michael mayben said:
new boat-style rocker assemblies (minus the stands and bolts) are in stock now at ihon and on the shelf.

So if ya need some stands (or a full set), I'll fix ya up with the number you need and dropship from my shop, the new stuff will come from ihon.

Companion reconditioned push rods for both welded and boat style rockers will also be available, in both lengths.

We will also have a few "options" available, such as reconditioned nine stand assemblies using boat rockers (with appropriate push rods) and a modified used rocker shaft. So anyone should call and discuss (or use this forum to hash it out!) what they are looking for when planning to service the rocker assemblies in any engine, that way all appropriate reconditioned components can be custom-assembled and budgeted for before getting into a project too deep!
Click to expand...

My stands are ok, I think. Gonna double check' em this afternoon. I have a pair of assemblies off of a donor motor and that should be enough to replace any defective stands. I'll let ya know if I need a couple though (thanks).

I'd like to stay with the welded style, just to use the pushrods I have. But if it comes down to it I will switch over. I intend to replace all questionable parts with known good parts.

I'll re-post later and give ya the results. Gotta couple errands to run first!
 
Stands look ok....just need to clean 'em (got 'em soak'n in cleaner now)



Here's the rusty donors: (just in case I need a couple)



If I go with the boat style I'll need pushrods.....got any reel cheap?:) mine are 8 3/4 long (304e)

or can we cobble together a set of welded style?
 
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The set of rusty units is the "later" design stands, see the oil "slots" as compared to the oil "holes"?? But totally interchangeable.

I haven't sorted all the pushrods yet...but I have several hundred to go through and divide up by length and tip design. So yes, push rods are not a problem, and new ones (both designs/both lengths) are readily available also.

I've got the first batch of rocker stands soaking in tyme now, only takes about 2 hours, ya don't wanna leave aluminum in the stuff overnight. I sort the push rods tomorrow. I gotta get several sets of rocker stands back down to ihon hq asap!
 
michael mayben said:
I haven't sorted all the pushrods yet...but I have several hundred to go through and divide up by length and tip design. So yes, push rods are not a problem, and new ones (both designs/both lengths) are readily available also.

I've got the first batch of rocker stands soaking in tyme now, only takes about 2 hours, ya don't wanna leave aluminum in the stuff overnight. I sort the push rods tomorrow. I gotta get several sets of rocker stands back down to ihon hq asap!
Click to expand...

I might need some pushrods if I switch to boat style.

Soaked the stands in berryman's for a couple hours and just got done washing them and spraying with brake cleaner. The 3 on the bottom row appear to have end mill marks but you can't really feel them by dragging a fingernail over them. Gonna check 'em with a caliper to be sure they haven't been tampered with though. Here are the result's:
 

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This is a cool thread, as it gets into the heart of these engines. Oil flow:gringrin: I know we all think we change our oil often enough in our daily drivers, but do we?
From my limited experience with these motors, (not like Mike and Jeff ) it's like the oil is getting burnt and then these "crusty" are building up all over making the oil flow problem worst.
Maybe it all starts with lack of coolant maintenance, which causes the motor to run hotter then it should, plus longer oil drain intervals creates even more sludge.

I'll get that Picture later tonight of the half blocked drain hole caused by the stock head gasket.:icon_eek: would be nice to see what the fel_pro guys did, so tonka that will be your job:smilewinkgrin:
 
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Yore right on Craig! And we need to get dick the swepco dude involved in this too!

That heavy "varnish" we see in these beaters is from oil being overheated. Since a huge amount of engine cooling is handled by the lubricant, it's obvious what is going on. But that is not peculiar to just IH stuff, and is extremely common regarding air-cooled engines in general.

An example is the major accumulation of hard, crusty, oil-based carbon that forms in the center cylinder push rod holes adjacent to the exhaust crossover passages where the manifold meets the head ports. Pic attached of that. That means the oil's "flash point" was exceeded, but I'm sure dick has a better explanation.

The varnish accumulation is not an issue as long as it remains "stuck" to the components, though no doubt it does affect heat transfer to a degree. But it also provides "tooth" for the particulate to adhere to which would normally return to the sump and gather (that is a good thing and what the "sump" is for!), then the goop goes out of the pan inna oil change.

But, the varnish will affect lifter operation over time, especially when these motors sit non-rotated for long periods (typical of how we find 'em!).

And the closed end rocker shaft grunging is not just an IH thang...any engine which uses the similar design will experience the same thing. But periodic maintenance and use of quality lubricants will make that a non-issue inna rebuild!

The bigger picture for me is spending the time to "match" components just like tonk is doing. There can be huge differences amongst various engine component castings (and as we've seen, replacement engine parts also!). That is the kinda detail that pro engine builders pay attention to, and is not done in the production shops to any degree unless the customer is paying extra for that service.

Most of us playing with this stuff are not trying to make a living from engine building, since we are hobbyists for the most part, we can spend whatever time is necessary to do stuff like this right!
 

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