Rocker arms on piston 4 broke after 2 days

robertp2alt · **Posted:** Wed May 23, 2018 4:26 am

Dear friends!

I have look for this in the forum and I haven’t found the answer to my problems. I hope that you guys can steer me in the correct direction.

My CRD overheated because of the fan clutch even though a new unit was installed. Because of this the head gasket needed to be replaced. Right after doing that when the cylinder head is installed and the timing is set, piston 4 break the 2 admission rocker arms.

A total of 8 has been broken, all of them belonging to piston 4. The cam was measured by a Jeep technician and he says that the measurements of it are accurate. The cylinder head was taken to a reputable machine shop.

I do t know what else to do.

Please advice!!!!

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flash7210 · **Posted:** Wed May 23, 2018 5:39 am

I suspect that whoever is working on your engine doesn’t know how to set the camshaft timing.

rancherman · **Posted:** Wed May 23, 2018 8:53 am

robertp2alt wrote:

Dear friends!

I have look for this in the forum and I haven’t found the answer to my problems. I hope that you guys can steer me in the correct direction.

My CRD overheated because of the fan clutch even though a new unit was installed. Because of this the head gasket needed to be replaced. Right after doing that when the cylinder head is installed and the timing is set, piston 4 break the 2 admission rocker arms.

A total of 8 has been broken, all of them belonging to piston 4. The cam was measured by a Jeep technician and he says that the measurements of it are accurate. The cylinder head was taken to a reputable machine shop. Please clarify; you said a total of eight (8) have been broken on cylinder #4, on admission side. This is confusing.
There are only 2 rockers per cylinder on each 'side' , so has this happened 4 times in a row, or are you saying all 8 rockers on the whole admission side been broken?

I do t know what else to do.

Please advice!!!!

Sent from my iPhone using Tapatalk

robertp2alt · **Posted:** Wed May 23, 2018 11:47 am

rancherman wrote:

robertp2alt wrote:

Dear friends!

I have look for this in the forum and I haven’t found the answer to my problems. I hope that you guys can steer me in the correct direction.

My CRD overheated because of the fan clutch even though a new unit was installed. Because of this the head gasket needed to be replaced. Right after doing that when the cylinder head is installed and the timing is set, piston 4 break the 2 admission rocker arms.

A total of 8 has been broken, all of them belonging to piston 4. The cam was measured by a Jeep technician and he says that the measurements of it are accurate. The cylinder head was taken to a reputable machine shop. Please clarify; you said a total of eight (8) have been broken on cylinder #4, on admission side. This is confusing.
There are only 2 rockers per cylinder on each 'side' , so has this happened 4 times in a row, or are you saying all 8 rockers on the whole admission side been broken?

Yes, this issue has pass in 4 occasions. Damaging only the intake side. Sorry for the confusion.

I do t know what else to do.

Please advice!!!!

Sent from my iPhone using Tapatalk

Sent from my iPhone using Tapatalk

robertp2alt · **Posted:** Wed May 23, 2018 11:48 am

flash7210 wrote:

I suspect that whoever is working on your engine doesn’t know how to set the camshaft timing.

Sent from my iPhone using Tapatalk

robertp2alt · **Posted:** Wed May 23, 2018 11:49 am

robertp2alt wrote:

flash7210 wrote:

I suspect that whoever is working on your engine doesn’t know how to set the camshaft timing.

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That is a possibility since this is the first time for him to work on that engine. If you have a link on how to time the camshaft please share it with me!

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robertp2alt · **Posted:** Wed May 23, 2018 11:51 am

rancherman wrote:

robertp2alt wrote:

Dear friends!

I have look for this in the forum and I haven’t found the answer to my problems. I hope that you guys can steer me in the correct direction.

My CRD overheated because of the fan clutch even though a new unit was installed. Because of this the head gasket needed to be replaced. Right after doing that when the cylinder head is installed and the timing is set, piston 4 break the 2 admission rocker arms.

A total of 8 has been broken, all of them belonging to piston 4. The cam was measured by a Jeep technician and he says that the measurements of it are accurate. The cylinder head was taken to a reputable machine shop. Please clarify; you said a total of eight (8) have been broken on cylinder #4, on admission side. This is confusing.
There are only 2 rockers per cylinder on each 'side' , so has this happened 4 times in a row, or are you saying all 8 rockers on the whole admission side been broken?

I do t know what else to do.

Please advice!!!!

Sent from my iPhone using Tapatalk

Yes, this has happen 4 times all of them with cylinder 4. I bought 8 and all of them broke. Sorry for the confusion.

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WWDiesel · **Posted:** Wed May 23, 2018 12:04 pm

Where are you located, your sig. does not say?
If it is breaking rockers, timing is way off and valves are hitting pistons which breaks rockers.
The rockers are by design, designed to break when a valve makes contact with the top of the piston.
Something is wrong, don't keep doing this, the engine is not timed correctly. :banghead:

Very few mechanics are familiar with these engines and how to properly time them. :roll:

See these series of YouTube videos on timing belt replacement. 5 parts
https://www.youtube.com/watch?v=5o_FJpBEKjk

APC9199 · **Posted:** Wed May 23, 2018 12:10 pm

Follow this guide exactly.

http://colorado4wheel.com/content/KJ_TB.html

There are also videos on Youtube here,

Part1: https://www.youtube.com/watch?v=5o_FJpBEKjk
Part2: https://www.youtube.com/watch?v=cjhhxMzzyh8
Part3: https://www.youtube.com/watch?v=mbi3rRSEdA4
Part4: https://www.youtube.com/watch?v=-_uOjVG1XEs
Part5: https://www.youtube.com/watch?v=jcVb_lWPLR4

Hope that helps!

rancherman · **Posted:** Wed May 23, 2018 1:44 pm

Has anything else been done to this engine recently?
New pistons?
Rods?

robertp2alt · **Posted:** Wed May 23, 2018 8:20 pm

Thanks for all the replies!!!!

I lived in Puerto Rico
I will check the videos tonight.
The bearings of the crankshaft were replaced as well as water pump, rollers, belt tensioner, thermostat, fan clutch... I think that covers all.

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rancherman · **Posted:** Thu May 24, 2018 12:45 pm

robertp2alt wrote:

Thanks for all the replies!!!!

I lived in Puerto Rico
I will check the videos tonight.
The bearings of the crankshaft were replaced as well as water pump, rollers, belt tensioner, thermostat, fan clutch... I think that covers all.

Sent from my iPhone using Tapatalk

how soon after the bearing replacement did the rockers first start breaking? or were they breaking before the bearing change?

I'm just eliminating any 'far out' type scenarios. If the piston was put back in 'backwards'.. the valve reliefs are different sizes(???) and the smaller exhaust relief would now be hitting the larger intake valves. Again this is 'far out'.. not implying anything. Just asking ahead for future reference.

Use those links to the videos to confirm your timing first..

Rocker arms on piston 4 broke after 2 days

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