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Broken Rocker Arm How long can I drive before causing significant damage to the Cam shaft

75088 Views 28 Replies 6 Participants Last post by  TaxiGirl
This is the second time that this has happened. Last time, i had a mechanic replace #3 and #5 rocker arms ($500). and later when the familiar tick came back I used MMO and no longer had a problem. Now, the tick is back with a vengence. I was trying to hold out until this Thursday. I have a loss of compression as well when accelerating. And I still have a high pitch or medium high pitched gurgling sound when accelerating also.

Btw i changed my oil yesterday, when mechanic opens the head, does he have drain oil out to replace rocker arms?

2011 dodge grand caravan 3.6 Pentastar
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317K is great for any assembly with high cycles so I take my hat off to the engineers. Maybe I am old school but I sort of remember cam forces and the dynamics of lift on plate cams (of which these are compared to box cams which encapsulate the followers) and that the hot rod cams with big bumps were the ones that bent the push rods and busted the rocker arms and one would have to go with solid lifters and all that stuff. So, the rise on these cams must be pretty mild in comparison. Well, it is true that when they went with double overhead cams, one has a cam profile for intake and one for exhaust so there is probably the goodness. But everything takes up room so more things make for smaller things.
Forget oil additives since the radial forces on the cam follower are probably shearing that little pin of which it rotates on. If one has hydraulic lifters, the only adjustment I remember doing on the small block V-8 is to tighten until the noise of the lifter stops and 1/4 turn more. It was the solid lifters in which one adjusted the lash since there is no compensation. I need to get an assembly in my hands.
 

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Discussion Starter · #22 ·
317K is great for any assembly with high cycles so I take my hat off to the engineers. Maybe I am old school but I sort of remember cam forces and the dynamics of lift on plate cams (of which these are compared to box cams which encapsulate the followers) and that the hot rod cams with big bumps were the ones that bent the push rods and busted the rocker arms and one would have to go with solid lifters and all that stuff. So, the rise on these cams must be pretty mild in comparison. Well, it is true that when they went with double overhead cams, one has a cam profile for intake and one for exhaust so there is probably the goodness. But everything takes up room so more things make for smaller things.
Forget oil additives since the radial forces on the cam follower are probably shearing that little pin of which it rotates on. If one has hydraulic lifters, the only adjustment I remember doing on the small block V-8 is to tighten until the noise of the lifter stops and 1/4 turn more. It was the solid lifters in which one adjusted the lash since there is no compensation. I need to get an assembly in my hands.
I know hundreds of guys driving these and most all if them have to replace transmission or engine at around 150k miles. However, if you take care of it, you can make it last. i want to at least get 500k out of it. it is a v6 though.
 

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I don't want to say it but this is a very interesting thread (like discussing cancer). From what I researched, the followers rotate on tiny needle bearings (good since this type of bearing was designed for radial loads and no axial loads); so they must be tiny. I am hoping that the bearing are uniquely designed with the shaft as it was delivered to mfg. Then the video makes sense since the guy shows that the bearings have failed and the roller is sitting off center (doesn't sound correct/good since the needle bearing material went somewhere and hopefully not into the cylinder). Anyway, here is a good MOPAR article;
CAMSHAFT/FOLLOWER REPLACEMENT | Mopar Magazine (at https://www.moparmagazine.com/2016/06/camshaftfollower-replacement/ ). It even goes through the removal of the cam shafts from the heads.
 

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Discussion Starter · #24 ·
These rockers look to be the same design as used in prior Engines going back to the 1988 2.2/2.5.

I guess they reached the limit of "lightness" as I haven't really heard of rocker failures in even 2.7's.

Any chance you just need rockers or are the cams tore up as well??

Best of luck TaxiGirl!!

Thanks
Randy
the more I think about this repair, the more i want to try and just do it myself. Is it really that difficult to remove all 4 camshafts actuators, oil pump, timing chains guides solenoid vales install what valve lifters thar are bad and replace all the rocker arms? the rngine does not have to come out does it? Do i nee special tools to get all back toether and workinh correctly?
 

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DOHC V6 Engines are not for the inexperienced when it comes to anything related to the timing chains.

Swapping rockers and lash adjusters would have a reasonable chance of success.

Keep us up to date!!

Good luck!!

Thanks
Randy
 

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While I have no personal experience with the 3.6, I would try to swap rockers without loosening the cams.

Here is a picture of a spring compressor used on older Engines just for this purpose.

Might have to buy or make something for the 3.6

Thanks
Randy

 

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Discussion Starter · #27 ·
While I have no personal experience with the 3.6, I would try to swap rockers without loosening the cams.

Here is a picture of a spring compressor used on older Engines just for this purpose.

Might have to buy or make something for the 3.6

Thanks
Randy

I already ordered all of the parts. They are coming from New York. I definitly do not have any thing that looks like that.
 

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Here is a video on timing the cams on a Pentastar, this one clean and not in a vehicle.

I have no idea on your skills but this is very involved and there is no allowable error.

Starting, or attempting to start, an Engine with incorrect cam timing can result in severe damage.

Rockers on the other hand not so complicated.

The tool I showed is like the one I have used when changing rockers/lash adjusters on many OHC Engines.

The "hook" grabs the cam and the other end compresses the valve spring enough to R&R the rockers.

Pressure must be exerted on the red handle to apply the force needed to compress each spring.

Thanks
Randy



 

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Discussion Starter · #29 ·
Here is a video on timing the cams on a Pentastar, this one clean and not in a vehicle.

I have no idea on your skills but this is very involved and there is no allowable error.

Starting, or attempting to start, an Engine with incorrect cam timing can result in severe damage.

Rockers on the other hand not so complicated.

The tool I showed is like the one I have used when changing rockers/lash adjusters on many OHC Engines.

The "hook" grabs the cam and the other end compresses the valve spring enough to R&R the rockers.

Pressure must be exerted on the red handle to apply the force needed to compress each spring.

Thanks
Randy



Thank you. There is no way I would attempt to do this repair..
 
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