Plenum repairs

[BradTN]

I recently got started on a water pump gasket/timing chain repair on my 95 Ram. I had done the service bulletin procedure vacuum test for the plenum...it tested as OK and I had oil in the intake also. When I removed the intake of this 217K engine the plenum was still sealed up. The point being, oil in the intake is not a trustworthy indicator of a bad plenum pan gasket.

I decided to take off the heads while I was this deep and do a valve job and new head gaskets. It's good I did, because the heads were cracked at all the end cylinders between the valves. So, I have a spare 96 5.9 around with 168K on it and I take the heads off that(5.2 and 5.9 are interchangeable) and those heads are cracked even worse ! So, my suggestion to anyone that has the intake off, is to consider pulling the heads, as they are notorious ! I've seen an estimate that about 70-90% of Magnum heads are cracked and my 5.9 showed evidence of water in at least one of the cylinders.

The point is- be concerned about the cylinder heads as much, or more, than the plenum gasket.

 

[Silver Tex]

Brad,
Was it visible without removing the heads? I had read this before. I sure would like to be in the 29.9 - 9.9% that don't have the cracked head issue. Not ready for that.

Any comments on minimizing the potential of snapping off an intake bolt(s).

Thanks guys,
Scott.

 

[Merc225hp]

Cracked heads are not visible without removing the heads, 50/50 call if they are cracked, 50/50 call if the plenum gasket is blown out. The plenum gasket should always be considered bad and just good preventative maintenance by fixing it.

If you go to change the heads look for thicker cast heads, not just rebuilt heads.

 

[Silver Tex]

Well, despite the warnings I'm not going to pull the heads.

No time and no real evidence other than probabilities at this point. Coolant level is stable and no evidence of water in oil. These probably don't tell the whole story.

I'll have to take my chances. I am going to do a compression check on all cylinders before we tear into it. Pull the coil wire so she don't start - am I thinking about this right?

No comments on how to avoid snapping the intake bolts during removal? Should I soak what I can down with PB Blaster the night before?

 

[Merc225hp]

Well, despite the warnings I'm not going to pull the heads.

No time and no real evidence other than probabilities at this point. Coolant level is stable and no evidence of water in oil. These probably don't tell the whole story.

I'll have to take my chances. I am going to do a compression check on all cylinders before we tear into it. Pull the coil wire so she don't start - am I thinking about this right?

No comments on how to avoid snapping the intake bolts during removal? Should I soak what I can down with PB Blaster the night before?

A comp test is a great thing to do before you start this work, an leakdown test would be better if you can do that. If you have cracked valve seats/heads you will burn off a very little bit of antifreeze over time. You won't smell it out the pipe nor will you see it in the oil.

Comp test yes unplug the 12v supply wire to the ign coil and remove the fuel pump relay or its fuse found in the pdb. Throttle set to wot as well for this test.

I like to recommend new roller lifters when doing the plenum gasket, about $120 more in parts, this is great preventative maintenance and no time is better. Ma Mopar part number is Roller Lifters P5249862.

Note all the part numbers that start with P denote Performance parts, sometimes they are cheaper than just the stock Mopar parts.

Hands down the best penetrating oil is 50% atf and 50% Acetone, you will just have to see how it goes bud some have zero problems with breaking bolts other's oh my, most times you can get the broken bolts out after the intake is off.


Edit: A wet/dry vac is a great way to clean out the lifter valley keep that in mind.

 

[Silver Tex]

Merc,

You know this started out as a harmless endeavor to fix the plenum in my sons truck and to give him a little exposure to what one can do with a little mechanical aptitude and some good forum insight (he is 16 and just got his license).

His truck now is going to have, and it is actually running pretty well.

Plenum fixed
Completed tuneup
New exhaust from manifolds to muffler - cat replacement
New timing set
New water pump
New oil sending unit
Steering sector brace - yeah, I had a '99 diesel, I understand the wander
New overhead map light wiring harness - the guy we bought it from couldn't figure out why the interior lights wouldn't go off so he took out all the light bulbs. Door switch...
New tailor fit seat covers - I recommend Seat Covers Unlimited - not cheap, but really fit well and look good!

A lot of this gave me good bargaining power, but should have went a little lower.

Nah, I kid about all this. It has been fairly inexpensive however I'm going to stop by tonight and get the timing chain tensioner suggested and call it good. Would love to put in the lifters and roller rockers, I'm just not willing to spend any more money on this thing right now.

I do appreciate everything everyone has weighed in on and I think it has prepared us better to gittr' done.

thanks,
Scott.

 

[Merc225hp]

I wish you all the best with your work coming up on the motor. I love the fact that you and your son are doing this together, for both quality time and the teaching/learning part anything to help keep the cost down is great labor wise. In my op these are great motor's to learn on, basic simple old school four stroke.

Edit: When installing the timing chain with the tensioner, it is a very tight fit to get the chain on, take your time it will fit.

 

[dodge dude94]

Merc,

You know this started out as a harmless endeavor to fix the plenum in my sons truck and to give him a little exposure to what one can do with a little mechanical aptitude and some good forum insight (he is 16 and just got his license).

His truck now is going to have, and it is actually running pretty well.

Plenum fixed
Completed tuneup
New exhaust from manifolds to muffler - cat replacement
New timing set
New water pump
New oil sending unit
Steering sector brace - yeah, I had a '99 diesel, I understand the wander
New overhead map light wiring harness - the guy we bought it from couldn't figure out why the interior lights wouldn't go off so he took out all the light bulbs. Door switch...
New tailor fit seat covers - I recommend Seat Covers Unlimited - not cheap, but really fit well and look good!

A lot of this gave me good bargaining power, but should have went a little lower.

Nah, I kid about all this. It has been fairly inexpensive however I'm going to stop by tonight and get the timing chain tensioner suggested and call it good. Would love to put in the lifters and roller rockers, I'm just not willing to spend any more money on this thing right now.

I do appreciate everything everyone has weighed in on and I think it has prepared us better to gittr' done.

thanks,
Scott.

Wish I had my dad to help me with my truck...
Kudos to you for teaching the boy to do his own work! Even if he's just watching, it will still give him a sense of responsibility when he drives it.

 

[Silver Tex]

I've been where you are coming from DD. Our lives are shaped for a purpose. It's up to us to find it and follow it.

My best to all of you!
Scott.

I don't get the sense you post the wealth of information you have to hear (see) yourself, I suspect you do it because you are sharing your experience. That's what its all about.

 

[BradTN]

Brad,
Was it visible without removing the heads? I had read this before. I sure would like to be in the 29.9 - 9.9% that don't have the cracked head issue. Not ready for that.

Any comments on minimizing the potential of snapping off an intake bolt(s).

Thanks guys,
Scott.

The heads must be removed and disassembled to mag flux the cracks that tend to happen at the 2 end cylinders. I understand your reluctance to yank the heads...because heads and head work can get expensive. Hopefully your heads will be OK, or, if cracked, maybe they won't leak for a long time.

I had one Intake bolt break. The ones at the ends seem to be the most likely.
I drilled it out and cleaned with a tap. I think leaking intake gaskets at the coolant passages are the cause. Not much you can do to prevent it. If the corrosion has happened, the bolt will be likely to break. You can prevent future problems by using anti-seize compound and/or stainless intake/exhaust bolts.

My 96 Ram head- Note the crack between the valves and the corrosion in the exhaust port and on the valve seat.

 

[dodge dude94]

What symptoms did you notice before you pulled the heads? Or did you pull your heads when you did the plenum?

I'm pretty sure my heads are fine as my truck runs fine and doesn't use much coolant. Then again, I've still got a timing cover leak...

 

[Silver Tex]

Yea that is what I'm hoping for Brad. Did that crack show up under some cleaning process? It is very visible. I'll be interested also if there was any indicator or symptom.

I did discover another issue tonight. It appears the radiator has a leak. I can't see exactly where, however the seam at the drivers side where the fins meet the "plastic" side chamber has evidence of leakage, there is pooling down around the lower rubber mounting, oh and the puddle on the ground.

Do these radiators have a failure reputation in this area?

One other question. The Cloyes timing set allows for advancing or retarding the timing by 2 degrees in addition to the stock setting. Is there any benefit to set the cam/crank advanced or retarded?

This is becoming quite the adventure!

Thanks,
Scott.

 

[dodge dude94]

The radiators do have a habit of failing in that location, on either side usually.

I've heard that advancing the cam timing helps low end torque, but I've also heard the opposite. That and when you mess with that, you've got to reset the fuel sync, which is the reason I've finally decided I won't do that when I get mine replaced.

 

[Merc225hp]

Yea that is what I'm hoping for Brad. Did that crack show up under some cleaning process? It is very visible. I'll be interested also if there was any indicator or symptom.

One other question. The Cloyes timing set allows for advancing or retarding the timing by 2 degrees in addition to the stock setting. Is there any benefit to set the cam/crank advanced or retarded?

This is becoming quite the adventure!

Thanks,
Scott.

Most of the heads I have taken off the Mangum motors you can clearly see the crack by just cleaning the area between the valves with a wire brush, magflux was not needed.

As for the timing set it at zero and forget it, nothing will be gained by going + or - with it.

 

[Silver Tex]

Thanks again to all of you. Your input is invaluable.
Scott.

 

[Silver Tex]

D-Day
So...pulling the PVC valve out, stinkin' thing snapped at about VC level. Retrieved little spring assembly, but will the plate I'm thinking is at the bottom of the valve fall into the rocker area?
Anybody have a "slick" way for removal w/o pulling VC?

Thanks,
Scott.

 

[quadcab]

The valve cover is easy enough to remove. I can change mine in about 20 min.

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[Silver Tex]

thank you!

 

[Silver Tex]

Got manifold out, only broke one bolt - front left.

Is it recommended to chase the threads in the block with a tap prior to reassembly? Can I spray some penetrating oil down in the threaded holes?
Any other precautionary things I can do ahead of reassembly?

Plenum gasket was bulged, intake was full of oil...it was time.
Thanks,
Scott.

 

[quadcab]

Do chase the threads first. Do not use penetrating oil but some antiseize is a good idea. Just remember it will affect your torque a little.

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