Valley Pan Inverted

So first a little back story, a while back I was having a little street fun with my boss and had a run with his challenger on an empty highway. I was cruising about 40mph then gave the old girl about a 2/3 throttle blast, it blew the tires loose, and it began immediately walking away from his car revving up to about 6500 RPM 125-130ish MPH. Around that time I felt a little hesitation and an off rhythm, idle cycle then normal, but that had subsided not long after. For the rest of the trip home from work I didn’t think much of it. That is until I got home and did my post trip checks, and saw my Valley pan became a Hill Pan. Naturally, after this discovery I was very confused, still runs great and has a boat load of power. (Literally since it’s a C-Body haha) It sat in storage for a while and I finally was able to get back to starting to diagnose this, but I still come up empty on a cause from the basic external diagnostics I’m able to do in a self storage unit. The car is the build from this post: https://board.moparts.org/ubbthread...-ram-68-fury-build-opinions-welcome.html

Compression Test Results: 1: 160PSI 3: 165PSI 5: 160PSI 7: 165PSI 2: 155PSI 4: 160PSI 6: 150PSI 8: 165PSI
Also no smoke or engine noises heard.

Anyone have anything like this happen to them and figure what it was?
Also should the car still be driven or am I at risk of losing everything in the engine?

Thanks in advance for any and all help.

I had the same thing happen to me when I built my first 440. I did not have adequate crankcase venting - to much pressure internally in the motor, you will probably have some oil leaks also from the pressure. Make sure your breathers on the valve covers are installed correctly and not clogged. Should be an easy fix - good luck!

Had that happen when a few pistons came out in more than 1 piece. Your compression numbers look good to me, so I'd check PCV valve, breather(s), if the breather is big enough, something wrong with the baffles. Anything clogged?

Thanks for the replies, this is how my breather and PVC system is ran. Do you see any red flags of how I set it up? Should I ditch the PVC and just run breathers or maybe even one of those crankcase blow off valves?

Is that a breather or an oil cap on the driver side, still needs more breathers that what you have.

internal pressure from a backfire... seen it happen on a new 440-6 engine back in the 70's seems like it took out the fuel pump best i remember ....

That’s a breather, where else can you mount them? The Direct Connection covers only have the 1 hole on each side, or do I have to ditch the PCV for a breather, or lose the DC covers for something else?

That's a lot of rubber fuel line. Once you have the valley pan sorted out, I'd start replacing that with hard line or at least braided line.

Any idea what would of caused the back fire if the cylinders are sealed with decent compression?

Pull the breather out & take a picture of the underside for us, & the hole size it goes into

Gotcha, would that be for longevity’s sake or am I asking for trouble with something else?

That's basically the same setup I've been using for years, and aside from from what I mentioned above, I've never had any problems

I’ll try and swing by the unit today and get the pictures. Those pictures are from a while ago, but I’m still running the same layout currently just with one of the extended breathers on it just don’t have recents of that.

Edit: I forgot, I also swapped on an old set of Moroso Valve covers we had lying around for one reason or another. This event was about a year ago and it stopped me from driving it any further until I figured out what happened. So it just sits in the unit until. Lights right off with a turn of the key though when I went back to it this past week. Haha

I've seen fuel pumps leak internally and cause an explosion in the crankcase. Usually blows a valve cover off but the engines I witnessed did not have a valley pan

Here’s the pics. Thanks for helping me out with this!

Based on those last pics, it’s not vented nearly enough for an extended WOT blast.

There is likely nothing wrong with the motor, it just needs better venting.

Do you think I should open up the flap on bottom and lose the baffle?

Just to add more info to the situation here’s how the oil looks, doesn’t smell like gas, it’s still thick, and a proper golden. (The little specks/dots in the picture are air bubbles.) Spark plugs are also model citizens.

Yep, I have 3 breathers going to a catch can on my car, no PCV for my set up.

Doesn't it seem like the cap would have blown off before the valley pan deflected that way?

hi

that just happened to my car last weekend .

not sure what the cause was ?

same motor been together sence 1986

maybe fuel pump ?

only have stock breathers / vale covers .

replaced dist cap , cleaned carb, replaced valley pan car runs but not like it should ! vac and idle not steady like it was before backfire .

The breather locks were bent and it is very loose/wiggly now in the tower. So it’s possible if it was just a push in it might of done that, but the pressure did have to make it through the cover baffle first too. First thing in the path is that valley pan and it’s got a lot of surface area, but I really have No idea haha.

That’s the odd thing I thought I’d see some lack of performance after, but it’s still a ball of fire. Did you compression test it?

hi

have not did comp test yet .

gona do all the easy stuff first ecu, dist change out ect as heders will be blocking some plug acces .


happened on race day 2 time runs at 109 mph, eliminations 1 st round big backfire with smoke out all sides of hood and filled driver compartment then suddenly takes off and runs 108 mph ?

3/4 sec. off my dial ?

now not running normal and exhaust not sounding right ???

I always opened the slits in the breathers all the way to 90° on my dual 4bbl 383. Never had a valley pan grow into a hill pan.

Yeah I think I’m just gonna open up the breather/baffles and run it. From what I hear I may have been somewhat lucky, though I do think I want to limit my Revs going forward haha. Does anyone know of a Rev Limiter set up that works with the orange box and OEM style Mopar Distributer? It definitely winds to quick for me to mechanically regulate with the 4.10 rear she’s got.

There's a cpuple companies that make an ignition box with a rev limiter built in.

FBO is one, Rev-n-nator is another.

If it has cast pistons I would be looking for broken ring lands on the pistons.

Do you know if the Rev N Nator is still being made? It says out of stock on the site unfortunately. The issue with the FBO is that it doesn’t have the ability to limit lower than 5200 RPM. Does anyone know if the “Pertronix 600 Digital Rev Limiter” would work inline with the orange box?

On your deal having excessive crankcase pressure I would do a leak down test also now to see if it is possibly ring seal, especially after doing a good compression test
Crankcase pressure ( a lot of it) is the only thing that will cause that to happen, invert the intake valley pan

A Crankcase Evacuation System before the mufflers will do that also ! LOL

A long time ago (high school actually) I installed a new set of valve covers on my car. The valve covers did not have breathers and I didn't think anything of it since that was how they came. The valley pan looked like a microwave popcorn bag after driving the car.

Engines build a fair amount of pressure in the crankcase, even if the rings are in good shape. It is fairly common to see engines push the dipstick out or push breathers off at WOT.

My 1963 Plymouth 415 HP M.W. with 25,000 miles on the original pistons would push one or both stock breather caps off on almost every run, I ended up having them safety wire on so I didn't lose them after several times of having them fall onto the track during a run

AKA as a crankcase pressure system with mufflers on

Hey every bit of change is useful to me with this issue haha. Thanks everyone for you help with this! Unfortunately there’s no access to air at the unit it’s at so it’s gonna be difficult to perform a leak down on her, and on top of that it’s not Insured/reg’d since it’s been sitting for over a year thinking I had a blown engine. Wouldn’t the grade A compression readings indicate good ring sealing?

Also she’s running single chamber Super 10 Flowmasters, do you think a Crankcase Evac to the header extensions would still build too much pressure? Those are barely even mufflers haha.

Why would you want a limit lower than that?

Any rev limiter that says it will work with an inductive ignition will work. MSD 8728 is an example but a bit pricey. There should be others still available. Just don't get one that is made for any kind of CD ignition.

I’d have it set to 4000ish RPM as a right foot limiter during break in process haha. Its all to easy to go light years past that just cruising with the low rear it has in it. Going 65mph on the highway on my way to work it would be spinning 3500 RPM, one accidental down shift from partial throttle kickdown and it would scream immediately. I know this current engine is already broken in, but in the worse case of something failing I want to not worry about the next one.

It’s surprisingly not as loud as you’d think due the c-body sound padding haha but the neighbors probably don’t like me very much...

Pertronics 600 rev limiter is for inductive ignitions and is adjustable from 100 to 9900rpm.

Thanks a lot, your helps very appreciated! So just to be sure and as a redundant check before I pull the trigger on buying it, the Pertronix 600 is able to be wired directly into the Orange Box & Distributor ignition circuit and they will play nice together?

hi

i use the msd on 3 of my cars .

i stick in a 3000 chip once a year to test them !

According to their website it will work.
https://pertronixbrands.com/products/pertronix-600-digital-rev-limiter

Actually nothing gets wired to the ecu or distributor.

Non-HEI type systems. (FIGURE 1)
1. Attach the BLACK wire to a good engine ground. Make sure to remove
any dirt or paint beforehand.
2. Attach the RED wire to a 12 volt power source controlled by the ignition
switch.
3. Attach the YELLOW wire to the coil’s negative terminal.
4. The ORANGE wire is not used for Non-HEI type systems. Use the provided
end splice to isolate this wire.
5. The WHITE wire is a tachometer output, compatible with most modern
tachometers

Thanks!

The photo of the valley pan reminds me of my cousin. Probably around 1977 or so he had a 69 RR that he blew up a bunch of 383's in. He had bought a junk yard 383 and put it in the car. We couldnt get it to start and he was turning the distributor as I was cranking it. The engine popped, blew the valley pan up and almost blew the valve covers off, they were junk after that LOL.

R.I.P. Wade, I miss you buddy.

Small update on the car, I’ve been driving it around and giving out small beatings here and there, so far it’s seems fine. Had a small breaking up ignition issue but that apparently was just the rev limiter having issues with the Orange Box. Thanks again for everyone’s help forgot how much fun it was to drive the old girl.

Rev limiters work by NOT firing random cylinders. If you run it up against the limiter it will in fact "break up". You can't use it like a governor or cruise control.

Gotcha, It was breaking up at about 3000 RPM it was set for 5700 RPM. In the future I’ll eventually just upgrade to a MSL style box and it may work with that.