E6-285 2VH problems and solutions

[allfritz123]

We have a 1981 RD Mack with the airbox (series charge air cooling I believe it is called).  It has been a great truck and always strong.  We recently went through some rough ground on the farm with it  loaded and it developed a tick in the engine.   We parked it and have now put it into the shop and are trying to figure out the problem and solutions.  

This engine has the dynatard brake.  It has great oil pressure, still starts good and always was a good puller in and off the field.  It always leaked a minor amount of oiI but not an oil user.  (Oil coming out of interfaces.)   Exhaust always looked good and blowby - I would consider normal.  I think someone set up the pump before we got it as it will throw a heavy black smoke when you stop on the pedal.  As well,  pyrometer has to be watched if pulling hard as it can climb rapidly under heavy load.  We always suspected the pump was set up but we watch it carefully.  Loaded truck on gravel road could be around 58,000 lbs.   With a load that heavy, we typically have kept temp down by limiting speed.   Try to keep it below 1100 degf and typically 1000 or so degf by not driving as fast.   Empty truck is typically 900 degF although if you step on it hard, it will move up!

I have taken the tappet covers off and have found all springs in good condition.  I ran the engine to see if the tick could be located.  I think it is coming more from the rear of the engine - hard to tell.  I am wondering if I should use a stethoscope?   I did notice the exhaust lifter rod on number 1 runs right on the edge of the cylinder head casting.  All the others appear to have at least 1/16" clearance.  This one is very close. With tappet covers off and running,  the push rod is close enough that the oil wants to seep out over the gasket interface as it is that close.  It doesn't appear to be the source of the tick but nonetheless it is a concern I have.  Bent push rod or guides wore?  The rod is rotating nicely and lubrication is good and have ruled out a bent push rod as the distance should change with rotation.

We are wondering if we could be getting a wrist pin slap.   The engine is aging and the oil pressure is really good yet.  If a problem with a shell, I would expect oil pressure to have deteriorated.  One thing I tried (because it was easy) was to crack each injector off the pump to see if there was any change in the tick.  There was no difference on any cylinders.

I tried checking tappet clearance - chart on engine block says Intake .016, exhaust .024.  I have a Mack service manual and it says pointer is in line with the 2 studs on the front cover (approximately?). Degrees are marked on the dampener.  I have no pointer.  I also have no markings a third of the way around the dampener like they talk about measuring and marking.  So I lined this up so I could check 1 and 5.  Intake on 5 seems tighter than that, intake on 1 seems good.  Dynatard with tappet pushed onto exhaust rod appears to give about .034 on 1 or 5.  It wasn't jaking as hard as it used to (and maybe never did).  It is working.  I was just doing rough checks so far.  I would have expected higher clearances with wear and not less on intake 5.   It was strange to me that #5 intake is tighter than .016, maybe it is .012.  I was just a doing a preliminary quick check!

We have another engine.  It is out of a 1985 truck we think and it is likely a 4 valve E6-300.  It has an air to air intercooler.  It also has no jake brake. We are thinking it is out of a superliner (cab over) garbage truck? as it has an extended dipstick tube and a different throttle linkage.  I assume if it had a jake, it would have an additional module on the cylinder heads like our E7s have as it is newer.   Our 2VH has the dynatard system with brass pickups located on the inside of the tappet cover.    We would put this engine in but the additional radiator at the front would not fit under the fibreglass hood of our existing truck as it becomes longer.   Thus a dilemma.  Can we strip and move and leave internal bottom end?  I did note the injectors on this donor engine are on the same side as the injector pump while our E6-285 is on the other side.  The turbo is higher up as well.   Maybe someone knows if we could move the liquid cooled air cooler from one engine to the other swap turbos and make it work to fit under our hood?

We love our Macks and we fondly call this truck Bucky because of its unique multi-reverse gearing, secondary bull low gear and the unique engine characteristics when picking up gears (its Bucky and we can't live without it!)  All our other trucks are E7s.

   

[BOBWhite]

I would say that if it isn't valve clearance it could be a lifter. There is a cam/lifter cover on the right hand (turbo) side of the engine, that's where I would look next if I was chasing a tick. Post some pictures maybe someone on here can spot something. 

[mrsmackpaul]

Does the tick change with the revs ?

Would assume it does 

I feel if it was a lifter or valves that I would be unlikely to hear it ticking as I'm pretty deaf or the motor is pretty loud

Ticking to me after driving over rough ground would be something on the outside of the motor 

So fan, water pump, alternator, clutch housing

I would be thinking a about what could shift that makes a ticking noise, there really isn't much

 

Paul

[Joey Mack]

Maybe an exh. manifold gasket leak? 

[JoeH]

10 hours ago, allfritz123 said:

stethoscope?   I did notice the exhaust lifter rod on number 1 runs right on the edge of the cylinder head casting.  All the others appear to have at least 1/16" clearance.  This one

Sounds like you have a bent pushrod.  I'd be checking valve lash on everyone.  Common problem on these engines is the carbide faces on the lifters breaking and then what remains shaves the lobe right off the camshaft. Berry Cams I think can weld and grind a new lobe onto the cam for you if you don't have a spare cam.  You'd have to come up with a new lifter tappet, and replace the bad pushrod.  Truck could have weak valve springs that allowed the pushrod to come loose and get bent in a high rev situation.  I'd drop ol pan, look for tappet face it there and get eyeballs on the cam from underneath.  Valve covers and oil pans show you a lot of what's going on in there.

[JoeH]

The marks on the damper wheel are etched in, you have to wire brush it to see them.  Pointer should be on the timing cover, around a 10 o'clock position as viewed from front of vehicle.

[fjh]

26 minutes ago, JoeH said:

The marks on the damper wheel are etched in, you have to wire brush it to see them.  Pointer should be on the timing cover, around a 10 o'clock position as viewed from front of vehicle.

If you can post some pictures of what your setting to! damper and pointer!  Im gathering the pointer is missing! also number 1 and 6 are sister cyl if six is rocking  your checking set on one! if two is rocking you are setting 5 and so on in firing order! Im leaning toward a lifter failure  Pull the pan to check this ! however I have seen the engine brake slaves fail on these and wear in on one cyl ! I will also note that a lifter failure is ( usually) accompanied by a popping sound in the intake!  air cleaner!

[allfritz123]

The tick does increase frequency with rpm.  I will get some pictures today.  Maybe a video of the tick!  I had the side cover off over the tappets once to put a gasket in. It seems the people that had the truck before had not got it in place (sagged) and it was leaking oil bad.   Can I see the cam from there or do I have to look from the pan? It sounds like pan has to come off.   The only time I ever saw a bent pushrod it was quite obvious.  Number 1 exhaust appears to rotate and I don't see change in clearance during its rotation. If it does, it is subtle or my eyes aren't picking it up.  However, as mentioned if it has effected the cam lobe and flaked off on the cam lobe end, I guess that will have to be determined.   I just don't feel the tick comes from number 1.  I have an old stethoscope, will see if I can pinpoint closer where sound is loudest!  

I will get picture of front and also finish cleaning off dampener to see if I can find the other 2 positions at 120 degrees.  I should check my donor  engine as it is out and I could see what it the 1985 engine has for a pointer!  Maybe I can even move it if it is attached to the 2 studs.  My manual seems to tell me there are 2 versions of pointers.  It is a Mack original printed Feb 1981 and I have the 12th printing 1994. E6/672 C.I.D Engine 2VH.   Great Ideas.  Thanks. 

I am going to see if I can't video it,  before going in to deep. That way I have a reference point.  I really don't want to rip everything apart until I have properly diagnosed it with everyone's help!   Side cover comes off easy!

[JoeH]

We mark our engine dampers with yellow marker 1 | 6 , etc, where the | marks that the pair is at TDC.  Each pair is 120° (1/3) apart from the next pair.  You check the valve clearances in the firing order.  If you get one rocker that's got too much Freeplay then you need to pull the pan and check that lifter.  All it costs you is an oil pan gasket and an oil change to pull the pan.  

No you cannot see the cam from the tappet covers.  Valve covers (which are a nightmare of plumbing to remove) and oil pan.

For reinstalling valve covers, do it BY THE BOOK! Dry, no silicone, no gasket adhesive.  DO NOT overtorque valve cover bolts, it makes the sides flare out, and you'll have leaking valve cover gaskets.

[JoeH]

Had to take a screenshot of the picture to get it to load.... 

You can barely make out a 4 | 3etched in where the yellow marker is. That's what you're looking for on the damper wheel.

The firing order 1-5-3-6-2-4 is cast into the block above the rear tappet cover.

[JoeH]

Pairs on the damper are 1-6, 5-2, 3-4.

In 2 rotations you'll hit the whole pattern in order. I'm hoping your spare engine can donate a timing pointer. 

[Joey Mack]

any chance the marks are on the flywheel in that year??  i dont know when they started using the flywheel. 

[JoeH]

Don't think so. This spare is a 1981 endt676, same year and engine he's working on.

[Joey Mack]

ok..

[JoeH]

22 hours ago, allfritz123 said:

I think someone set up the pump before we got it as it will throw a heavy black smoke when you stop on the pedal.  As well,  pyrometer has to be watched if pulling hard as it can climb rapidly under heavy load.  We always suspected the pump was set up but we watch it carefully.  Loaded truck on gravel road could be around 58,000 lbs.   With a load that heavy, we typically have kept temp down by limiting speed.   Try to keep it below 1100 degf and typically 1000 or so degf by not driving as fast.   Empty truck is typically 900 degF although if you step on it hard, it will move up!

Doubt anyone set up the pump, the fuel pump has a slave cylinder that governs fuel until intake pressure from the turbo jumps. It is tied into an aneroid? valve on top of the intake manifold on the rear head.  These fail and get deleted, resulting in full access to fuel regardless of boost pressure.  Rolls coal til the turbo catches up then it clears right up.  On this engine the pyrometer should say Downshift at 1125° so you're fine at 1100. If it keeps pushing passed 1125 then change your air filters. This engine setup uses 2.

[JoeH]

Took me a few minutes to remember the systems name: Puff Limiter.

[allfritz123]

I had a good day today on the engine.  My 1985 donor engine did have the pointer on it - so I moved it over to this engine!  So that is a great help.  I located all timer marks and did mark them with a paint marker.  It was my first time working with valve lash on a Mack.   Mack is different than CASE when it comes to setting valve lash.  They must use a different cam cycle.  As pointed out above, you have to move the crankshaft to 6  120 degree rotations. to cover firing.  My other 6 cylinder engine you can set all lash with 1 rotation and stopping twice on TDC (2 to 1 ratio).    Any comments on why Mack is different?  Different gear or different lobes.

Aside note.  I followed Mack instructions and measured accordingly as specified.  I noted  the exhaust on some others while making the measurement on a particular cylinder did exceed greatly the set gap (on the exhausts anyway). I could even see .100 at times.  My engine plate says intake I=.016,  exhaust E=.024.

My results were: 

Cylinder 1:    I=.019  E=.037  Cylinder 5: I=.019  E=.033   Cylinder 3:I=.021, E-.034,                                                                                                           

Cylinder 6 :    I=.019, E=.036, Cylinder 2: I=.020, E=.040   Cylinder 4: I=.017, E=.033

All the push rods looked good. What I saw as close tolerance on number 1 exhaust was actually the cover gasket laying next to it and so it wasn't bent at all!  When I took  off gasket, everything looked good and nothing unusual!   Although not now to specs, could this be causing problems. There was some gases coming off the rear 5 and 6 cylinders and as well some oil seepage there.  Could exhaust gasket create the noise?

I also noted that the rear bank Dynatard solenoid is not functioning.  I pushed the front solenoid and it jaked and maintained an oil seal. When I pushed the rear solenoid, it leaked oil out (see picture) and did not function.  So, we have been running the jake with only one working set. I assume the seal must be gone.  Here are 3 videos I have taken of the drive train functioning with the noise.

https://www.youtube.com/watch?v=QXIPY63tczY

https://youtu.be/kAetRPELwoY

https://www.youtube.com/watch?v=GWCbu1FjH7s

                                                  

[Joey Mack]

the lash 'results',,,   is that what it was before you adjusted them?   Did you start on #1 TDC?  you can be 180 degrees off if not..  there is an easy way to tell if you are up on #1..  Jojo

[JoeH]

Just to clarify, is it a Mack Dynatard or a Jacobs engine brake? I'm not familiar with the solenoids of either one, but I believe they're fairly different.  

Good news on the valve lash check.

Generally a failing exhaust gasket will have a chirping sound. There's 6 individual gaskets, and to replace you can loosen all the studs and take off the manifold/turbo assembly or if you're by yourself and can't lift that much weight you can leave a couple nuts on and cut notches in the new gasket bolt holes so you can drop them in from the top. If one is leaking you'll have black soot around it, and with engine running you'll feel air puffing there. Our e7 exhaust manifold rusted the mating surface on #6 and hydrolocked, fortunately didnt break anything, had to take the manifold off go weld/grind it back up. Our '79 endt676 over the years always needed the exhaust manifold nuts tightened periodically, and one time broke a stud! Annoying, but it the threads in the head spun right out by using a broken drill bit spinning backwards. I may have had to center punch it in a few places to give it some texture for the bit to grab.

I also have a steel dash R model with a 237 endt675 that has a head gasket that's been chirping for maybe 10 years? Its a truck that gets used about 3 times a year here at the yard.  

[JoeH]

This motor does not use hydraulic lifters, that's probably the difference in procedure between this and what you're used to.  You have to have the cylinder at TDC so there's no force applied from the cam lobes to the rocker assembly.  Each cylinder's valves are only in this resting position at TDC on the combustion stroke.

[Licensed to kill]

On 11/9/2023 at 3:05 AM, mrsmackpaul said:

 

Ticking to me after driving over rough ground would be something on the outside of the motor 

So fan, water pump, alternator, clutch housing

I would be thinking a about what could shift that makes a ticking noise, there really isn't much

 

Paul

^^^^^This. The first thing I would check is the exhaust manifold bolts. One may have broken off causing a leak. There is always a chance that the tick starting when you drove over rough ground is just a coincidence but I don't believe in coincidence so I would be focused on things that bouncing and/or  twisting of the chassis may cause to move/change/break. 

[allfritz123]

I haven't adjusted any valve lash yet. I just recorded the measurements.  I definitely was on the compression stroke when I did my measurements.  This is a Mack Dynatard system not a Jacob.  Like I showed in the picture I took, definitely the rear Dynatard solenoid is leaking oil rather than acting on the valves on that head. I just did a manual push down with my finger.  If you look closely, you can see the oil escaping and not being directed to pressure up the hydraulic lock components of the exhaust system to effect the timing.  The front 3 cylinders operated correctly and no oil bypassed and it correctly functioned when I pushed or enabled it with my finger. 

The manual talks about using a special tool to set the exhaust valves.   I assume I can do it with just a feeler gauge and pushing down on the tappets and loosening off the nut and turning until I get it where it needs to be.  I don't have a special tool but I don't think it is rocket science - maybe just a little more time consuming.

If you look near the end of the first video I posted you can see a sign of the mist or smoke? coming from the rear of the valve head looks closer to 5 than 6.  I am wondering if I have a leaking head gasket and if that could cause the tick.  There looks to be oil drool near 5 and 6. The tick gets more pronounced as the engine heats up and the oil is warmer.  It is not so noticeable when you start up the engine and then it gets worse when you rev it to 1000.  I don't really see exhaust leaking from an exhaust gasket. Look at the very end of this video (last 5 seconds and you can see a mist from near cylinder 5).

https://www.youtube.com/watch?v=QXIPY63tczY

Could I have a crack on the valve to the oil jacket on the exhaust and could that cause a tick?   I want to check the water and see if there is any oil in there.   

[fjh]

59 minutes ago, allfritz123 said:

The manual talks about using a special tool to set the exhaust valves.   I assume I can do it with just a feeler gauge and pushing down on the tappets and loosening off the nut and turning until I get it where it needs to be.  I don't have a special tool but I don't think it is rocket science - maybe just a little more time consuming.

All you need is a 5/8 box end and 11/8 box end to set the valves! don't waste money on the the tool even if you can find one! This is the method used to find it!  If you think you have a head gasket leak or exhaust leak   set the valves up  this should help clean up the smoke issue then fix the dyna tard or ring or solenoid ( Note you have one old style and one new style solenoid) the old one is the leaky one! ( Also check to see if that sol is tight )  they can come loose!  put the valve covers on ! start the engine while its still coolish run a garden hose around the area you suspect the leak is when you reach the the bad spot the sound will go away or change! Have seen these  H G  leak between the heads on occasion! 

[allfritz123]

Continued the saga yesterday.  Adjusted valve lash.  The tick didn't go away at idle.  It seemed however to not be as prominent at higher rpm.  Ran it for a number of minutes.  I did change out the broken o-ring on the rear Dynatard Bank at the same time i adjusted valve lash.  The engine brake was working as I tested it.   That was the only plus!

Ran the truck again so that my brother and I could listen to it once more.  We revved it up and it was almost like the tick disappeared.  We thought then that maybe we had fixed the problem!  Maybe we were hearings things all along!!!!  We brought back to an idle and continued to play with it but the tick returned.  Then, without any warning, the engine seized!  No bang, just stopped.  

Pulled the pan, nothing in the pan.  However cylinder 6 was on its way up on exhaust stroke and the valve lobe was in contact with that valve. via lifter and was hard on it.  All other lifters were rotating by hand.   I backed off the tappet.  The rod is not bent but my initial thought now is  that the valve ran into the piston and it was likely somehow sticking and made contact.   Not sure the mechanics of how that can happen but I guess if a valve sticks open slightly and then piston helps close it, eventually causes a catastrophic failure!

Drain the antifreeze and pull the head is my next step!  I guess I will eventually get to the bottom of it or maybe the top of it!  Gear train looks good.  As I said early, cold oil pressure was very good and dropped to 60 or 70 psi when warm.   Pan is fairly clean with no metal parts.

[fjh]

Well that sucks  I have heard of valves sticking on occasion ! guess you will find out as you pull it down!  Does your unit have a chassis mounted charge air? (bonus) or tip turbine style intercooler😪 ! ?