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Cam Failure In Mack E7

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Has anyone experienced CAM FAILURE / BREAKING in a E7 350/380 HP , also was there any prewarning or did it just go.

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Has anyone experienced CAM FAILURE / BREAKING in a E7 350/380 HP , also was there any prewarning or did it just go.

I'm a little late, but yes we just had a cam failure get pulled into the shop. As far as I can tell it looks like the front cam bearing was the first to go. Then without the support of the bearing, flex broke the cam off before the second lobe. This made some noise early on. The driver called us and was able to drive it to the shop before it gave away on a test drive around the block. It made lots of racket before it let loose, Dad said he heard it clattering off the houses on the sides of the road as they drove by. Too bad they didn't know where the noises were coming from before they took off... The driver said he thought it was the tranny clunking under load. :wacko:

I took a couple pics, I'll post them in a bit.

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e7cam.jpg

e7cambrg.jpg

I pulled the covers off the top and found 4 broken rocker arms and some bent pushrods. No chance of an easy fix on this one.... :(

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E7 early engines had alot of cam problems but if that engine was mine i would replace the dampler on the crank if the block is ok. In most cases vibrations break the cam and then it will get the front brg because nothing to suport it.my 2 cents glenn

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Mack had a lot of trouble with bad cams I think between 99 and 02. Factory wised up to the fact that it was faulty metalurgy in production of some cams. Quite a bit were recalled under warranty, Mack replaced them. I got an 01 CH with an E7 427 2 years ago. My dealer brought up the vin. before I bought it, and had already been swapped out by a Mack dealer. Well, 6 mos. ago I noticed a squalling at idle, right in the center of the block, resonating up through the turbo. Took It to the dealer. BAD CAM!. Nos. 3 and 5 exhaust lobes were transferring metal. So in with a new one. Hope they solved them this time. They're not cheap by any means. It takes a while to make that back in trucking! I think some were never changed out either, you could have one that finally just gave out. No consolation though,right? Good Luck

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This one is in a 94 dump truck with a lot of miles. I'll post up more as I dig into it. Bad part is the truck just recently had the whole top end done at Mack.

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This one is in a 94 dump truck with a lot of miles. I'll post up more as I dig into it. Bad part is the truck just recently had the whole top end done at Mack.

I'd be taking a close look at the damper as

Glenn stated The early E7 cams wen't problematic!The Eteck cam that started this post was.

We had failures as low as 50000 kms.They still fail from time to time! not droping like flys thou!

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Heard the miles are around 600 thou. Damper seems like new, liquid type by the looks of it.

I'm still thinking the front cam bearing went out first. Once the cam broke, it stopped running almost instantly. All that was left of the bearing was in the pan though. Looks like it was wearing for some time before the breakage. Once the bushing fell out the leverage pulling on the cam broke it.

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Heard the miles are around 600 thou. Damper seems like new, liquid type by the looks of it.

I'm still thinking the front cam bearing went out first. Once the cam broke, it stopped running almost instantly. All that was left of the bearing was in the pan though. Looks like it was wearing for some time before the breakage. Once the bushing fell out the leverage pulling on the cam broke it.

The cam bushing out should have droped the oil preasure some!

V8s would some times get the front cam bushing riped out by the crank shaft counter weight!

it would cause an instant 10 psi drop in oil preasure and did not affect the engines runing other wise.

we had one run for months like that till the guy found the bushing in the pan on an oil change!he came asking what it was!We called Mack on it they said O ya Just put a new bushing back in with lock tight it will be fine that was it ran for years beyond that!

this may be a total diffrent story who knows.

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Now the trick is to figure out a way to keep the lifters up while I pull the cam. :(
years ago when i worked alot of macks we had a can of black hard grease that you could put under the lifter and it would hang all day. I dont know about a E7 but the little cummins we use chop sticks to hang from the top.

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years ago when i worked alot of macks we had a can of black hard grease that you could put under the lifter and it would hang all day. I dont know about a E7 but the little cummins we use chop sticks to hang from the top.

What Glen said! we had a can of black hard grease that you could put under the lifter and it would hang all day. I dont know about a E7 but the little cummins we use chop sticks to hang from the top.

There are magnet sticks for this job !Grease is the get by way!Just geter done.

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I bought a bunch of little 5 lb magnets at harbor freight tools today. ;)

We just heard about the wood dowels for the B-series Cummins a couple days ago. The last one of those we did we pulled the side cover and put gas line size hose clamps on the tops of the lifters to hold them up.

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I bought a bunch of little 5 lb magnets at harbor freight tools today. ;)

We just heard about the wood dowels for the B-series Cummins a couple days ago. The last one of those we did we pulled the side cover and put gas line size hose clamps on the tops of the lifters to hold them up.

The magnet stick kit from Kent tool is quite pricy! if you got pocket magnets from your tool source thous will work just ducky.I just hope your block is not damaged.

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Well, the truck owner priced the parts to fix it, and has shifted his search to a used engine. :( Oh well, at this point I just want to get it running and out of the shop.

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Well, the truck owner priced the parts to fix it, and has shifted his search to a used engine. :( Oh well, at this point I just want to get it running and out of the shop.

Is the block damaged?

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I don't see any damage to it. He claimed the parts alone were over 3 grand and he says he's found a complete engine for around 4. We'll see...

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Now the trick is to figure out a way to keep the lifters up while I pull the cam. :(

Come on just about any trick you can muster up will work, I use the old stand by clothes pins......

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Come on just about any trick you can muster up will work, I use the old stand by clothes pins......
Cloths pins will work on a E6 but then you have to pull the fuel pump and covers. And a E7 dont got any covers. glenn

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I'm ready to pull the engine out. All I can say is this vintage has got to be the most miserable truck I've ever tried to pull the engine out of! Man! Took most of the afternoon just to get the top 4 bell housing bolts out! Must be why later year trucks raised the cab higher off the frame. Oh well, out if comes in the morning!

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my 1994 mack rd688 did this last week its a e7 350 with about 700,000 miles on it truck was towed in to my shop i pulled the valve covers found broken rocker arms and dropped push rods i pulled the push rods up and cranked the engine over by hand heard the push rod hit the oil pan removed pan and found camshaft broken just like the photo

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