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1979 ENDT 675 camshaft


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Apparently my camshaft was also damaged in the major engine breakdown I had last fall.  I did inspect the best I could the cam lobes in # 4 where a valve spring keeper broke and dropped the exhaust valve..  The lobes appeared and felt ok, but a real good visual inspection of lobes or lifter I wasn't able to do, but the engine was only run for a matter of seconds after the incident occurred. Over the course of the last several months I was beginning to notice a tappet noise and wasn't able to keep the valve lash in spec on #4. Half way thru my day last week the noise got real bad and the suddenly the engine had what felt like a serious miss.  Took the inspection cover off the side for the rear head and noticed that the intake push rod had broken and I virtually  all but had no valve lift on the exhaust.

Currently in the process of tearing the engine down to pull camshaft. Had to replace radiator anyway and fabricate mounting being direct replacement no longer available, so that part of the job wasn't actually extra work LOL.

My questions are, is there anything I really need to pay attention to when tearing down outside of the timing marks on the gears for when I reassemble?  What in particular should I be paying close attention to when it comes to putting back together other than the timing marks?  I know they (whoever they is) say that a new cam needs new lifters also.  The new lifters for this engine are no longer available and when they were, were incredibly expensive. Actually going to relace all intake push rods being the dealer says they cant' order just one, but have to all six. I plan on using a high quality engine assembly lube at the time of reassembly.

Again, I appreciate this forum immensely and everyone's help and insight over the last 10 months of me being thrust into being a heavy truck engine mechanic.

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Parts engine would be a good investment for this job. You probably have a broken carbide face on the lifter tappet that wiped the lobe off. Common failure.  Sounds weird to me that they can't order a single pushrod.  

Last cam we did we stole from our parts engine, stole cam and one lifter. No need to replace all of the budget doesn't allow.

Lifters need to be held up with magnets taped to wooden dowels in the pushrod holes, to keep them up while the old cam.comes out and new one goes in.

I think there's a company "Berry Cams" somewhere in the country that can weld new lobe on your old cam, but I have no experience with them.

You'll be dropping the oil pan and looking for bits in there, you'll probably find a partial disc from the carbide face.

Front engine mount is the timing cover so you'll need to pull oil pan, block the engine up on the block skirt before you can pull the timing cover.  Good time to plastigage the crank bearings just to be sure you aren't due for new ones.

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Forgive me JoeH,,  He can take the side covers off and hold the lifter with small spring clips, like the ones at harbor freight, days ago guys would use cloths pins..  I wish the side covers were used after the E-7..

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Just now, Joey Mack said:

Forgive me JoeH,,  He can take the side covers off and hold the lifter with small spring clips, like the ones at harbor freight, days ago guys would use cloths pins..  I wish the side covers were used after the E-7..

Cloths pegs

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I have and ENDT 673 non-engine brake boat anchor in my parts area.  are those cams the same? 

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12 hours ago, Joey Mack said:

Forgive me JoeH,,  He can take the side covers off and hold the lifter with small spring clips, like the ones at harbor freight, days ago guys would use cloths pins..  I wish the side covers were used after the E-7..

I can get the rear side cover off, but the front one would require the injection pump be removed

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Posted (edited)
12 hours ago, JoeH said:

I'd be shocked if a new cam is available, last time we tried getting one for our 1980 DM686SX they weren't available. 5-6 years ago on that one.

I picked up a new cam that was listed as being for my engine last January just on a gut feeling I might need it. Hopefully the description was correct.  It didn't state whether it was an engine brake or non engine brake cam.  From what I read somewhere during my learning journey with this engine is that the 675 cams were the same either way.

 

Edited by RS Disposal
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Yea you can run it without engine brake. Where did you get the cam??

I'm a little perplexed that you bent/destroyed a pushrod and wiped a lobe.  Be careful adjusting the valves, they have to be done "by the book"! One cylinder at a time.  A colored marker on the damper wheel is a big help to see the timing marks and which cylinder numbers you're at...

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6 hours ago, RS Disposal said:

I can get the rear side cover off, but the front one would require the injection pump be removed

Get this stuff  Lucas Oil 10153 Assembly Lube - 8 oz. 

Wonderful shit ! It will stick the lifters in place! Im playing about with a VW right now same scenario lifters stayed put during assembly !  

Buy the way the E7 lifter is the same!    MAK72GC357

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19 hours ago, Joey Mack said:

Forgive me JoeH,,  He can take the side covers off and hold the lifter with small spring clips, like the ones at harbor freight, days ago guys would use cloths pins..  I wish the side covers were used after the E-7..

appreciate the  "days ago " and NOT years ago. I feel younger already. LOL yes we did use clothes PINS to hold lifters when side covers were removed 

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7 hours ago, RS Disposal said:

I can get the rear side cover off, but the front one would require the injection pump be removed

I knew that ; just didn't want to upset the teacher !LMAO ,, not only can't access bottom row of cover bolt with pump in the way ; but gaskets broke major challenge to clean completely the gasket behind injection pump. 

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4 hours ago, JoeH said:

Yea you can run it without engine brake. Where did you get the cam??

I'm a little perplexed that you bent/destroyed a pushrod and wiped a lobe.  Be careful adjusting the valves, they have to be done "by the book"! One cylinder at a time.  A colored marker on the damper wheel is a big help to see the timing marks and which cylinder numbers you're at...

I got the cam shaft off of ebay from a truck parts surplus place.  He stated it was for the 673, 675 & 676

 

1 hour ago, fjh said:

Get this stuff  Lucas Oil 10153 Assembly Lube - 8 oz. 

Wonderful shit ! It will stick the lifters in place! Im playing about with a VW right now same scenario lifters stayed put during assembly !  

Buy the way the E7 lifter is the same!    MAK72GC357

 

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1 hour ago, fjh said:

Get this stuff  Lucas Oil 10153 Assembly Lube - 8 oz. 

Wonderful shit ! It will stick the lifters in place! Im playing about with a VW right now same scenario lifters stayed put during assembly !  

Buy the way the E7 lifter is the same!    MAK72GC357

I do have some "high performance assembly lube" (not sure of brand name, but I like Lucas stuff so I ordered a bottle anyway.  I did see that that lifter was also compatible, but was told by two suppliers that those were also unavailable new

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4 hours ago, JoeH said:

Yea you can run it without engine brake. Where did you get the cam??

I'm a little perplexed that you bent/destroyed a pushrod and wiped a lobe.  Be careful adjusting the valves, they have to be done "by the book"! One cylinder at a time.  A colored marker on the damper wheel is a big help to see the timing marks and which cylinder numbers you're at...

When I have adjusted the valves it was definitely one cylinder at a time in the firing order.  I would double check the marks on the vibration dampener to make sure I was at TDC.  Once I found TDC on #1, I would rotate the engine one tooth at a time via the ring gear.  It has 119 teeth so that divided by 3 is just under 40 teeth.  I would count 39 1/2 teeth and then check my marks in the front of the engine and adjust it accordingly.  kinda a pain in the rear to crawl under 6 times, but I wanted to make sure I as at the TDC.  Bumping the engine with the starter I could never even get close.

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If you do a Google search lots come up ! Ebay  ag kits  ect  just phone around try stay away from used  the original lifter was not the best! The one with the stepped face is the best!

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2 minutes ago, RS Disposal said:

When I have adjusted the valves it was definitely one cylinder at a time in the firing order.  I would double check the marks on the vibration dampener to make sure I was at TDC.  Once I found TDC on #1, I would rotate the engine one tooth at a time via the ring gear.  It has 119 teeth so that divided by 3 is just under 40 teeth.  I would count 39 1/2 teeth and then check my marks in the front of the engine and adjust it accordingly.  kinda a pain in the rear to crawl under 6 times, but I wanted to make sure I as at the TDC.  Bumping the engine with the starter I could never even get close.

If the truck is standard you can put in hi gear jack up a back wheel and bump it with the drive line if no air you may have to cage the brake on that wheel!

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3 hours ago, JoeH said:

An ENDT"B" engine I think would have Mack's Dynatard camshaft. Not sure how the Dynatard worked.

this is the "B" engine. Not exactly sure if the two had different cams or not.  threads I have read on other forums have mentioned that it was their belief that both versions of the engine had the same cam.  I will definitely be checking closely and comparing the two once I get the old cam out (if the stinking weather would cooperate, I have to work outside)  Have been able to actually find any specs, etc. as to what the differences would be

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1 minute ago, fjh said:

If the truck is standard you can put in hi gear jack up a back wheel and bump it with the drive line if no air you may have to cage the brake on that wheel!

it is a standard and I thought of that also,  but for me it just seemed easier to count teeth  LOL

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12 minutes ago, fjh said:

If you do a Google search lots come up ! Ebay  ag kits  ect  just phone around try stay away from used  the original lifter was not the best! The one with the stepped face is the best!

AG kits and a few of the other vendors I have used are saying out of stock and the ones that did have in stock the lifter is $225 each.  I did find a supplier, Premium Trucks Parts, on ebay that has a few for $155 each,  Right now my budget for truck repair took a serious hit last fall when the exhaust valve dropped and hit piston.

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5 hours ago, JoeH said:

Yea you can run it without engine brake. Where did you get the cam??

I'm a little perplexed that you bent/destroyed a pushrod and wiped a lobe.  Be careful adjusting the valves, they have to be done "by the book"! One cylinder at a time.  A colored marker on the damper wheel is a big help to see the timing marks and which cylinder numbers you're at...

As far as the broken push rod, it is the same cylinder where the exhaust valve dropped and hit piston.  My thinking is that the force of the impact traveled thru the valve train and damaged the lifter or cam lobe.  as that damaged progressed it affected the intake lifter or cam lobe.  There was a pretty serious tinny, tapping noise just before the engine started missing. I'm thinking for whatever reason the tolerances went south and the pushrod was just sorta banging around which caused it to break.  If it would stop raining/snowing I can finish tearing down and see what I might see

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For anyone's future reference, that lifter part number supersedes to 20705596, and is available in Mack's warehouses at the moment. Interesting. 

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