The DD Known As "Chunk"

[Michael Mayben]

michael, I'm sure you're way ahead of me on this one, but I'll throw this out and see if it sticks.
I was having similar symptoms with my rig when I got it going. It too is 9.0-1, but the block was zero decked and a composite head gasket used (.041" compressed). Despite what Robert kenny said about quench, I still experienced more knock than I expected (no offense Robert. It sounds like your stuff runs fine!).
When it came time to smog it, I needed a functional egr, and lo and behold, the knock stopped when I got it hooked up. I went from 5 deg btdc to 12 at idle. By 3000 rpm, the Mark is off the scale so I can't say what my total is, but I'm running a mallory unilite w/ vacuum advance (a swap meet score many years ago). I guess I could pull the vacuum line and see what the centrifugal contributes. Or borrow someone's dial-back light.
Bottom line, this made a huge difference in driveability. A friend says this is actually cooling the intake charge (hard to believe...)
also, I too am against running an IH motor on anything higher than 87 octane. Just doesn't seem right. Which isn't to say I wouldn't, but I get your vibe.
Good luck. Hope you get it sorted.

You are absolutely right about the egr deal...deal!

I run into this constantly when "optimizing" these old junkers by "correcting" the emissions guapo! The distributors are curved for egr (along with the oem cam timing).

On a stock motor, I know what to do to the Holley distributors after much trial and error to eliminate the part throttle/full load detonation. And that mod is much easier to effect if running a delco distributor since the springs and weights are right on top and easily accessible with no teardown...not so on a Holley or prestolite.

And also, since I'm normally setting up a replacement performance-oriented carb on those engines and not dealing with a smogcarb, jetting and a two-stage power valve selection will take care of the detonation just fine. So the combo of carb jetting and distributor re-curve takes care of the egr elimination-related detonation.

Also,...all this is based upon the use of the oem iron egr intake manifold. This egr-related detonation situation was totally eliminated on my beater 392 by swapping to the rpt aluminum intake and running the propane intake gaskets which block the exhaust heat crossover. The rpt intake rejects heat just as efficiently as a heat exchanger!!! In a hot engine shutdown, the bimetallic element on the electric choke cap will close far enough to activate the first step on the fast idle cam within five minutes, even while the carb is still trying to percolate! And that is with no air exchange under the hood.

Setting up the proper curve for the distributor/ignition to match the carb/cam/compression is essential, I've just not had to do this seat of the pants before onna motor with both a cam and compression, only on stockers that are semi-tired. I have a mag-trigger Holley distributor almost ready to install, the mechanical advance has been diddled with but until I run it up I won't know if I diddled the right direction or not!

 

[Chris Pucci]

I'll take it chris, put a hold on it!

The 6a is the only one I use, who needs the rev limiter guapo onna IH motor??

Done.

 

[Robert Kenney]

It too is 9.0-1, but the block was zero decked and a composite head gasket used (.041" compressed). Despite what Robert kenny said about quench, I still experienced more knock than I expected (no offense Robert. It sounds like your stuff runs fine!).

When it came time to smog it, I needed a functional egr, and lo and behold, the knock stopped when I got it hooked up. I went from 5 deg btdc to 12 at idle. By 3000 rpm, the Mark is off the scale so I can't say what my total is, but I'm running a mallory unilite w/ vacuum advance (a swap meet score many years ago). I guess I could pull the vacuum line and see what the centrifugal contributes. Or borrow someone's dial-back light.
Bottom line, this made a huge difference in driveability. A friend says this is actually cooling the intake charge (hard to believe...)
also, I too am against running an IH motor on anything higher than 87 octane. Just doesn't seem right. Which isn't to say I wouldn't, but I get your vibe.
Good luck. Hope you get it sorted.

No offense taken but lets get the facts straight in the context of quench detonation and egr function .
The quench deal in not my theory. It is a known engine building technique. The fact that you had detonation on a motor that was calibrated to run with an egr and an in-op egr had nothing to do with compression.
An egr engine can take a far different advance curve due to the fact that the exhaust gasses introduced into the air fule charge retards burn rates, combustion temperatures, inhibits nox formation and prevents detonation to an extent.

Effect of proper quench.
An engine at 8-1 and poor or non existent quench (more than .060) can detonate while a properly setup quench engine @ 9-1 will not with similar calibration.

The last 392 was 9-1 an egr engine originally but had a non egr federal manifold put on it. Correct calibration and no detonation. A tickle at some point according to the customer so the timing was pulled back to 34*. Advance is also set to come in a little late on this rig. An easy spring change.

I have never had access to a dizzy machine for the most part only made relative changes to advance based on results.

 

[Dealbreaker74]

Yeah, copy that Robert. The point I was getting to was a functional egr will (inadvertently) reduce detonation, no matter the condition of the combustion chamber. For michael, that May or May not be an easy fix. Just throwing it out there.

As far as distributors, I put some medium-heavy springs in my mallory, trying to bring full advance in late too. I was going on their install instructions which indicated full advance in by 3000 rpm. I can't confirm that's where its at. I need a dial-back light. Do you think that's a good place to be, or should it be later still? The motor will cruise about 2000 rpm, so I'm a little hesitant to go higher. And like I said, with the egr functional, I am out of detonation in most situations. I still have more futzing to do. Secondary q-jet timing, off idle stutter, etc. When all of that is dialed in, I'll revisit the curve.

Know any good trans shops around here?

 

[Robert Kenney]

I agree that for mm all of the horses are out. Should get better cruise milage with the 9-1 assuming the cam is not to big.

3000 is a good starting point. Remember that at cruise you will have 10-15* of vacuum advance in so the centrifugal is less important till you are running at high to wot power settings.

Possible you will have ping at partial mid power settings after you dial wot timing due to the vacuum advance reducing late. That is the tough part about dialing an analogue ignition system, without an adjustable vacuum advance diaphragm there is no easy way to alter that.

 

[Michael Mayben]

Now that the sumbitch seems to be somewhat reliable (gotta freshly rebuilt starter and alternator in the spares box from js supply in u-jerzee, high end stuff, not chinee), an attempt was made to make some cold air before kathy comes home to start drivin' the pile for a few weeks.

Had a hard time locally locating the correct retrofit adapters for the r-134a conversion, I'd used up all the prototype/oddballs I had over the last 10 years of doing other folks stuff. Finally located a pair of the atco items I was looking for, very high end and steel. These are 90* swivel fittings for use in tight clearance locations, exactly the situation on the IH systems that use manual service valves.

The crap package on the left is the typical retrofit kit seen in most parts houses, those are primarily for GM applications and ain't worth shit in my book for anything.

 

[Michael Mayben]

And here's a shot of the tight clearance sitch. Not much different compared to the same setup onna Scout II.

This pair of manual service valves have no schraeder valves installed, that is the reason for using the manual valves. Therefore, there are no r-12 schraeders to remove/discard to allow the retrofit conversion ports to function properly. But the manual valves do have to be position-manipulated correctly for both system discharge/evacuation and diagnostics.

 

[Michael Mayben]

Since this is a poorboy retrofit (and not really "legal" in the epa-scope of things), I did what any good redneck would do...removed as much oil from the compressor as possible. Since the system was non-pressurized, I did not have any r-12 or residual to recover.

Not willing to remove the compressor for draining (a cci/york unit has an actual crankcase which allows the oil level to be verified with a homebrew dipstick), I used the harbor freight pneumatic brake bleeder to pull as much oil out of the crankcase using a thin teflon tube inserted in the fill port on top. Only got about 2 oz. Of oil out, that tells me the compressor was real short on oil over time, so no doubt it May not be long for the world. I was hoping to remove about 6oz.

Then I dumped in 8oz. Of poe oil, which is used only when there is residual mineral oil still in the system. The current crop of new cci/york compressors for use in r-134a service use pag oil. Due to the design of the cci compressor, they are not oil-charge sensitive (within reason), so not having an exact volume of oil installed is not a dealbreaker.

Next up was to evacuate for three hours. All our research in the development of retrofit proved that a minimum of one hour evacuation was required to boil off any residual r-12 (chlorine) entrained in the refrigerant oil, it's residual chlorine that kills the ability of the compressor to lubricate in a retrofit environment, no matter what lubricant is used.

A vacuum hold test was done for first five minutes and then twice more for fifteen minutes, during that period, no change in vacuum level was noted indicating that the plumbing does hold vacuum (that does not mean that it will hold pressure indefinitely however).

 

[Michael Mayben]

Next up, I dumped in 28oz. Of r-134a on the low side (using existing receiver/drier) and fired it up.

Pressures are kinda "low" based upon the ambient at the time of service. That indicates the compressor is real tired to me and the numbers are supported by a fairly significant amount of compressor noise (more so than the normal banging these items create).

Soon, the compressor began cycling at a discharge temp of only 64*f in a very repeatable manner. That means the electro-mechanical thermostatic control switch is either crapped or is way out of tolerance. I was hoping for a cycling temp in the 48*f range.

So...out came the thermo-switch for inspection, it's real easy to access on the fullsize stuff, all that is needed is dropping down the glove box.

After scraping off the sealant used top lock down the calibration screw on the back of the unit, I tweeked it to increase the temperature cut point to see what effect that had. Compressor cut point temp increased to 69*f.

Yeah, that is ihc-produced factory rot on the cowl seams ya see, same as all squarebodies came oem. This one has daylight showing through the plenum!

So I then adjusted the sensor to the lowest calibration point...that brought the cycling temp down to 54*f. Still not what I hoped to see, but certainly ballpark for a dam tired compressor! I May play around with re-locating the capillary tube in the evaporator core which will fool the unit into staying online in order to provide a lower discharge temp, very easy to do simply by dropping down the glove box and pulling up out of the hole.

So we'll run it like this until the compressor craps, hopefully it will get kathy through September and then I'll set up a proper a/c system over the winter using a modern compressor and controls.

Yeah, that is daylight ya see through the rot in that cowl/plenum seam! Same rot that was oem on all squarbody rigs outta ihc back in the day.

 

[Michael Mayben]

A/c continues to do well. We've figgered out that the poor vent temps created with the oem thermostat sensor position in the evaporator core is an issue that can be improved. The workaround for that currently is to pull the probe half way up out of the case and leave it there. I'm currently trying to source replacements for this device that has a lower temp setpoint that will work much better for r-134a conversion.

I have temporarily bypassed the thermostat in chunk so that the compressor will not cycle. After approximately 45 minutes at highway speed on a 90f day, the evaporator core will freeze as it should. That proves that the "poor cooling" claim that unknowledgeable folks bs about regarding r-134a is just that...bullshit...as I've always said. However...due to the massive amount of "air leakage" through the oem discharge ductwork due to poor engineering/manufacturing, discharge temperature dilution is the big problem,...not the refrigerant.

The oem hvac system is of sufficient capacity to both warm and cool the Travelall interior, especially in light of the extreme window exposure. While temperature "pulldown" on a rig that has heatsoaked with an interior temperature of 160f is not in the same league with modern systems, it certainly is well within acceptable parameters. A complete insulation package in the floors, sidewalls, and headliner would result in a huge interior temperature improvement on the "cold" side.

A CPT compressor conversion mount is now on hand and will be used to mock up an overall modernization of the underhood portion of the a/c stuff over the winter. I don't wanna take the climate control stuff offline right now to do that since it's working so well.

The pos has now accumulated 1500 miles since the last episode of failure. Refreshing of the failed junkyard d60 rear axle that had been installed is underway and will be back under the rig in the next few weeks.

The electrics for the towing package are now completed with proper brake control and charging provision for the trailer batteries. Chunk is gonna be used for toad duty for the annual IHSTO camporee in September, and then a three week run down to ihon for the Sierra Fall Rallye.

Keep chipping away at the drivability issue...we're almost there! An msd 6 series cd box ripped off from chris at the Binder Bee swap meet has been installed along with a companion e-core coil that can take advantage of the output characteristics of the cd add-on, it's a package deal. While still triggered by breaker points (a mag trigger distributor conversion is in the works), the improvement in idle quality and tip-in is striking and very noticeable. At the same time, msd helical-wound plug cables were installed and a prestolite distributor cap was modded to properly fit the Holley distributor so that the advantages of the male terminal studs could be realized. The secondary cables haven't been properly dressed yet but I have the materials on hand to do so. Replacement plugs are yet to be installed and will be gapped to 0.045" in order to take advantage of the cd ignition system.

Once the ignition system is totally dialed in and locked down, the carb will be jetted for the final time. We're still a tad on the Rich end of the scale. Both cold start and hot restart of the currently installed 4150 is a vast improvement over the oem 4160 emissions carb that was so troublesome for this engine. However...that emissions carb certainly didn't go to waste...it was handed off to a new IHSTO club member who is bringing to life a 392 squarebody pickup for his first ride (turned 16 last Friday!). Got word yesterday that he was able to actually drive it around the block for the first time after staying up all night making the install and correcting a po-botched electric fuel pump conversion.

This week's task list...remove and plug the a.I.r. Rails, dress the plug cables, make a test-tow of the trailer to calibrate the brake controller, and make another monthly 250 mile run up and back to the IHSTO club meeting.

 

[Robert Kenney]

Michael, I've never run a plug gap bigger than .035 on a msd and a mallory big patern coil. Don't think firing energy will be increased but voltage will. Did the coil recommend .045?

Oh yea!! This is just my observed experience and for the most part cr over 10:1 and or blown apps. Low cr's take less current to fire through so you May be fine

 

[Michael Mayben]

michael, I've never run a plug gap bigger than .035 on a msd and a mallory big patern coil. Don't think firing energy will be increased but voltage will. Did the coil recommend .045?

Oh yea!! This is just my observed experience and for the most part cr over 10:1 and or blown apps. Low cr's take less current to fire through so you May be fine

That coil (along with most all "e" core coils wound for use with add-on cd boxes) is a low resistance primary item. Actual measured primary resistance at 80f ambient is 0.50 ohms, though msd rates it a bit lower. Measured primary resistance at typical underhood temp after a long test drive (235f) shows the primary resistance remains stable.

Taking the systems approach with this stuff...the coil matches the output characteristics of the cd box (not the oem ignition junk). And the msd-recommended plug gap for that coil (and similar items) varies with anticipated engine rpm , compression ratio, etc. As you indicated...in this case a max of 0.045".

I've found over the years that a gap of 0.045" is optimum for the IH motors with a similar ignition system setup. And that is the maximum I'll open a plug if it's a "conventional" side electrode design since any wider gap can lead to mechanical failure of the ground electrode. Using a cd box with a properly matched coil will provide a service life of a typical autolite 85 or 303 plug in the neighborhood of 50k miles+ on an engine in average state of tune.

 

[Michael Mayben]

Now ain't this justa superbitch?

Finally got a few minutes to jerk the carrier out of the d60 semi-floater axle that was supposed to be a new axle installed back in 1987 (and has under 3000 miles on it). An axle "supposedly" obtained by the dealership through ihc service parts distribution but in reality it was a boneyard part and the customer got bent over.

So the real problem is...both axle bearings are definitely noisy and on their way out the door. But the major noise source is the driver side carrier bearing. It couldn't be more rotten! And it shows signs that the outer race actually attempted to spin in it's cap at some point.

I have a d60 trac-lok rebuild kit sourced from ihon ready to install. But now I ain't gonna scruu with this myself. It's going over to dave the gear man for some pro-level tlc.

Update:

after discussing the d60 parts pile with dave, he advised me of the failure mode here. Dave is of the opinion that the carrier bearing cap "crush" is insufficient to properly retain the thrust side carrier bearing (the side shown in the pic). That is/was a manufacturing issue on the part of spicer/Dana and is common on any d60 or d70 differential assembly used in vehicles that see continuous heavy load/overload such as in commercial duty and towing applications. That allows the bearing race to spin (and subsequently fail the bearing) and also damages the thrust surface inside the axle housing. The extreme noise I heard when the rear axle went into failure mode was the bearing race actually breaking loose in the cap/housing interface.

The fix for this is to machine the cap to increase clamping force on the bearing outer race, along with installing a "case saver"-type shim set (aftermarket part set) to salvage the housing thrust surface. That of course calls for an entire r&p setup since new bearings must be installed and some machine work is involved. And most likely the pinion bearing is also beyond use. So all internals will be replaced (except for the actual r&p which is serviceable).

 

[Lyle Wiese]

It's a good thing you opened the boneyard pumpkin up and found the mess before it turned completely to toast on the way to ihcs or, worse yet, IHSFR. The d70 in my dodge was making low speed noise so I took it in to holbrooks. They told me there was the possiblity of race spin, but fortunately it was just time for new bearings. I dodged the bullet on that one.......yeah, I know, not very funny.

Lyle

 

[Michael Mayben]

it's a good thing you opened the boneyard pumpkin up and found the mess before it turned completely to toast on the way to ihcs or, worse yet, IHSFR. The d70 in my dodge was making low speed noise so I took it in to holbrooks. They told me there was the possiblity of race spin, but fortunately it was just time for new bearings. I dodged the bullet on that one.......yeah, I know, not very funny.

Lyle

Remember...this axle failed on the way home from the May club meeting at the same time the water pump took a hike!

Today I took the time to dig deeper into that dodge dually d70 that I'm freshening to send over to curt. Other than the discoloration of the varnish deposits from not having had the lube changed on a regular basis, everything in it looks ok. The carrier bearing cap bolts were way tight and no sign of race spin or any other problem. So it's going to be cleaned internally and then bolted back together. With a fresh pinion seal of course.

On a more positive note, I finally accomplished something ez! Blew some penetrant on the a.I.r. Tube nuts in the heads and then let it sit awhile. Then got out all the tools I normally use for removal. Put the "best" wrench on the first flare nut...it was only finger tight! Then moved on to the rest of the nuts and they were all finger tight! How kool is that??? So air tubes off, plugs slathered with anti-seize, and wrenched in the holes in under thirty minutes!!! From the looks of the tubes, they were replaced with new when the motor was built in '87.

 

[Lyle Wiese]

Oh yeah, that's right, it did fail.

Glad to hear something went easy on that rig for a change. Sounds like it was due to a mechanic not finishing his job, but I'm sure you'll take "easy" any way you can get it on this rig.

Lyle

 

[Michael Mayben]

Dave completed chunk's d60 last week, so I tossed it on yesterday.

In addition to all the other failure points on that boneyard rear axle, it had contained water in the past and someone had removed the inner axle end seals also. While that was a production change made in Dana semi-floaters at some point (cost reduction due to eliminating the inner seals on each side), that is not the thing to do on axle housings not designed to be run without inner seals.

And...the d60 semi-floater is three inches wider housing flange-to-housing flange than a comparable d44 used under a pickup/Travelall. In turn, that makes the tread width front-to-rear near identical. So now the rear whee/tires fill the hole much nicer and the stance is greatly improved...kinda like a larry Craig "wide stance".

Dave also drilled/tapped the boss in the bottom of the pumpkin and installed a flush-head drain plug that makes axle lube maintenance much nicer for the future.

The trac-lok discs were pre-soaked in friction modifier before assembly, then the remains of the bottle were poured in along with an additional quantity of modifier. Drove the rig a few miles straight ahead to mix the lube and additive, then did many tight donuts each direction to seat the limited slip system for break-in.

New shocks were fitted all around also, the overall ride is vastly improved.

This completes the under-frame freshen for this ride and it's now ready for tow service after having the equalizer head raised to an appropriate height for this ride. The brake set is totally new parts, the rear axle is fresh, the springs are aftermarket beef-up items, and the receiver and trailer wiring harness are all optimized.

The entire front axle (including ball joints and tie rod ends) was freshened 4000 miles/22 years ago. The front hubs and brakes were also redone by myself recently.

Springs all around are a custom fab, I have no idea what the spring rates are at this time other than the po obviously had the chassis beefed for trailer duty but much of the work was not done correctly by either the independent garage or the IH dealer who performed all the work. None of the four shocks were mounted correctly which in turn caused 'em to bind during articulation and quickly turned 'em to scrap.

The aftermarket carpet in the cargo area was tossed out, considerable rust is present in the perimeter overlap seam at the rear. The undercarriage part looks real nice since all the rot damage was hidden by the undercoat though the rot is now appearing through the undercoat material. That will all be cut out and replaced in the future.

A extra-heavy duty 4'x8' "cargo mat" used with hard plastic bedliners was found at brooks at half-price! This is that blended "sticky rubber" stuff used on water shoe soles. Absolutely a perfect fit for the cargo floor. With the rear seat folded down, it covers the entire metallic surface like factory! When the seat is folded up, then the excess material simply rolls up between the seat back and the dawg screen.

 

[Rusty Scout]

What shocks did you go with on chunk? They look like the napa monroe gas magnums.

 

[Michael Mayben]

Yep, gas mags all around as the least expensive, proper application for a trailer dragger with the spring setup that is mounted. It had a set of the same installed way back when and then it was parked after only a couplea hundred miles. Those were completely frozen when I went to r&r the axle.

I found all four shocks incorrectly mounted by the "dealership" back in '88, spacers were not in the correct positions top and bottom, wrong spacers used, found a washer stack instead of the spacer in two mounts, the rear shocks were each in a different hole at the top, etc. Could not have been scruud up any worse if midas had done it!

The oem shock length works just fine with the spring lift (custom springs, not "lift" springs) that is on the ride now. Since the rear/upper mounting point on pickalls is adjustable over a range of 3", the working length can be compensated.

I have no complaints about the performance of these shocks at all. And they certainly are way more than adequate for the gross vehicle load including trailer. I equalize about 600lbs. Onto the front axle when the trailer is connected, at the next hookup I May increase that another 200lbs. And see what happens.

With the front lift as it is now, I have a slight roll steer issue that was induced, Jeff has a more appropriate pitman arm here that we're gonna install and see if we can correct that issue. With no trailer, the roll steer is noticeable, with the equalizer set tight, the roll steer goes away.

 

[RobertC]

Found a washer stack instead of the spacer in two mounts.

What's wrong with that that's what I did when I lost spacer(s) not keeping on top of keeping the shock bolts tight...

Fortunately, Darren cut some new spacers from bar stock when he put the bilsteins on my t/a to replace my washer stack(s).

Since the rear/upper mounting point on pickalls is adjustable over a range of 3", the working length can be compensated.

Doesn't the stock upper front shock mount have 3 holes on your vehicles?

The stock ones on my 1210 t/a had 3 mounting holes...

 

[Michael Mayben]

what's wrong with that that's what I did when I lost spacer(s) not keeping on top of keeping the shock bolts tight...

Fortunately, Darren cut some new spacers from bar stock when he put the bilsteins on my t/a to replace my washer stack(s).



Doesn't the stock upper front shock mount have 3 holes on your vehicles?

The stock ones on my 1210 t/a had 3 mounting holes...

Problem witha washer stack? How about the wrong diameter washers placed on the wrong side of the shock mount so that the shock itself was trying to bend in the middle during articulation instead of move in a single plane! That in turn allowed the shock bushings to self-destruct fairly quickly and seized the piston inside the tube.

The other shock was mounted exactly the opposite way but the net effect was the same, both were damaged no doubt within a thousand miles of jounce/rebound before the rig was parked for life. And that was just on the front, the rear was equally fooked inna different manner with the wrong top mounting bolts used also.

 

[RobertC]

problem witha washer stack? How about the wrong diameter washers placed on the wrong side of the shock mount so that the shock itself was trying to bend in the middle during articulation instead of move in a single plane! That in turn allowed the shock bushings to self-destruct fairly quickly and seized the piston inside the tube.

The other shock was mounted exactly the opposite way but the net effect was the same, both were damaged no doubt within a thousand miles of jounce/rebound before the rig was parked for life. And that was just on the front, the rear was equally fooked inna different manner with the wrong top mounting bolts used also.

Wow that takes talent (or drugs)...

at least my washer stack was the correct size and mounted in the correct position...