Plenum plates done! Installing this weekend if all my parts come in today! Will post some plenum gasket pics over on the other thread!

 

Doug,
Would you be willing to share said DXF with me. We have a waterjet at work and I need to do this to my truck and it would save me some down time.
If so my email is tggnatsum@gmail.com

Thanks,
Chris

 

My truck has 96000 miles on it and I did the plenum plate this weekend. I also did the water pump, timing chain, and power steering pump. One thing I want to mention here: The dorman intake kit comes with the same plenum bolts as factory, the thermostat seems to be 180 degrees, and the dorman bypass hose busted within 30 miles of installation.

I did noticed that the plenum gasket had been replaced by the previous owner but reinstalled the factory plate and factory bolts. I replaced it with the plenum kit on ebay. I had a large puddle of oil in the intake and the runner for the #8 was wet with oil as well. The oil seems to settle to the rear of the intake which probably explains why the #8 plug fouls out.

The truck is much smoother now. The ping is gone, it climbs inclines without needing to downshift. I'm very happy.

 

So was the gasket intact or ripped and blown? oil will puddle at the rear its the lowest point...It could be from a faulty pvc valve or even breather if gasket had no sign of actual failure.

 

Here's my outcome:
1. plenum gasket was not blown out. (ie-no chunks missing-pc in the oil in pic was where I broke off part of gasket) I will say that the gasket was bulged out nearly to the edge of the steel plate in several places which I suspect would blow out eventually.
2. You see the oil puddled near the back of the motor. Also #7 and #8 plugs had oil on the threads.
3. Intake bolts weren't super tight. plenum bolts weren't really tight either.

I replaced the plugs, wires, rotor button, and pcv. I can't see how the pcv would leak that much oil into the intake but if so, I've got a new one on there and I've got the thicker plate installed to compensate for stock bolts/shallow holes so I shouldn't have a problem. One of my big questions is if let's say I have a leaky cylinder: will oil get sucked into the intake through the PCV if I have a leaky valve seal or leaky cylinder?? Again,
I'm no expert on this stuff and this was as far into an engine as I've ever been. It was a great learning experience and I'm now brave enought to swap out pretty much anything that craps out on the engine!

 

I'm no expert either but it looks like your gasket was loose and shifted judging by the curves where it appeared to be pushed on between bolts..

 

Gasket was not blown out but it did appear to have vapor streaks from the front corner of the plenum. Like I mentioned there is a definite difference now and I did not replace the plugs/wires either. It's like having a new truck.

 

You should cut out a bunch of those plates and sell them to members here!

 

again...sounds like it could have been a loose gasket from bottomed out bolts.. or possibly what Zman mentioned with stock plate not applying good pressure between bolt holes due to lack of plate rigidity... Hopefully someone will do some testing at some point to determine which is the real issue.. the plate works but it would still be nice to know the real cause especially for those who are really tight on repair funds.

 

^^^ I do plan on doing some tests in the near future but I need to get my testing procedures right before this happens, and I need to buy a crap load of gaskets for repeatability tests. and an old oven.

My 2 cents on this.

Is there anything wrong with the intake design No

Is there anything wrong with the use of the steel plenum plate No

Is there anything wrong with the bolt length No

Is there anything wrong with the gasket material YES

Sealing multiple types of metal using a gasket is not new tech it’s been done for decades on different types of machinery. The key is what gasket material is used to achieve and maintain that seal. Dodges choice was a paper gasket bad choice on their part. From the get go the gasket should have been made from solid material or of a constant seating stress gasket design.

In the many pix of blown or leaking plenum gaskets the gasket has been pushed out from the intake, that’s contradictory on the way it should fail. It should be sucked into the intake as it’s in a negative pressure state. Remember it is pulling oil into the intake when the gasket fails so it would make sense the gasket would be sucked in as well.

So what would cause the gasket to be pushed out? I came up with this, at one point an intake valve was stuck open and the pressure from the cyld was feed into the intake when the tb butterflies were closed causing a buildup of pressure in the plenum area pushing a week part of the gasket to be pushed out. Two; A backfire through the intake would push the gasket out. Three; the gasket has weekend by oil or gas/additive contamination add swelled to the point of pushing itself out from between the intake and steel plate.

These are my observations and testing will help to clarify this.