440 blown intake valley pan cause?

[Tony Tee]

This blown out valley pan subject got me thinking. Put a vacuum / pressure gauge under the dash to monitor the crankcase pressures or vacuum to keep tabs on the pcv system. Or does this exist already?

 

[4406bbl]

That was real common back in the 70s on 440-6bbl engines, too much timing, bad gas, high compression and detonation caused exactly this, no holes in the pistons either....but when you pulled the pistons out the ring lands fell out in your hands. Ran nearly perfect otherwise, then boom crankcase explosion and the pan wrapped the intake.

 

[RemCharger]

This truck probably sees 40-50 hours of drive time a year (under 300 miles), so I'm asking for another 100-150 hours out of this powerplant before I pull it for a refresh/swap. Had the wrong carb gaskets so ill try to get a video of it idling today with the aforementioned blow-by. Have to do some light driving to get a trans log of some different shift scenarios anyways

Throw a crank evac kit on it.

 

[Geoff 2]

While YOU might not think the blow by excessive, it obviously is.....& is bad enough to collapse the intake gasket. There is nothing else that can cause the gasket to blow OUT.

 

[505Coronet]

That was real common back in the 70s on 440-6bbl engines, too much timing, bad gas, high compression and detonation caused exactly this, no holes in the pistons either....but when you pulled the pistons out the ring lands fell out in your hands. Ran nearly perfect otherwise, then boom crankcase explosion and the pan wrapped the intake.

Interesting knowledge, I think i have timing all in at around 35 degrees, I do only run 91 in it and its 10.3:1 compression.

I couldn't get a good video but its not smoking at all at idle-3500rpms that i took it for the trans tuning log yesterday.

This blown out valley pan subject got me thinking. Put a vacuum / pressure gauge under the dash to monitor the crankcase pressures or vacuum to keep tabs on the pcv system. Or does this exist already?

The PCV system exists but not a gauge with a monitor, I'm out of dash space with my current gauges set-up however i do think the MSD atomic has a vacuum monitor reading, ill take a look today.

While YOU might not think the blow by excessive, it obviously is.....& is bad enough to collapse the intake gasket. There is nothing else that can cause the gasket to blow OUT.

My man, did I upset you in a past life? Were all here as enthusiasts and putting forth common experience to help answer each others individual scenarios and help solve problems. I'm sorry i don't agree with your proposed reasoning, doesn't mean your wrong but it just doesn't appear to add up like the other possibilities do.

The intake gaskets were well sealed when i pulled the valley pan off, the RTV that was on the front and back of the engine was still sealing, however i do agree there was some type of internal explosion/pressure build-up.

But the general consensuses/experience seems to be related to the PCV being a restriction/not properly vented crankcase. based on what i can see and the general conditions of how the engine is running that does seem like the plausible solution.

 

[pnora]

[[[[[[[The intake gaskets were well sealed when i pulled the valley pan off, the RTV that was on the front and back of the engine was still sealing]]]]]]] Where did all the oil come from then???

 

[4406bbl]

At idle with the pvc working properly it should hold a business card down on the valve cover where the breather goes. Under high load a worn engine will pressurize and needs that breather cap hooked to the air cleaner to get some suction, or as someone else said to an evacuation kit that goes down to the headers. In short if you have a pvc, a worn engine, and just an open breather cap it could build up enough fumes to do this.

 

[RemCharger]

 

[oldkimmer]

U can buy an adjustable pcv valve. The name escapes me but I think it starts with M. Maybe someone else will chime in with the name. Kim

 

[POMONAMISSEL]

run your cover breathers to the exhaust system through that pcv away , that really pulls the crank cast and sets the rings down on the pistons , much like a vac pump .

 

[Geoff 2]

505Coronet.

You didn't upset me in a past life...or present life. Do not know what your problem is. You asked for reasons why the intake gasket blew out & I told you. There can be no other reason other than excess internal pressure, which comes from blow by past the rings. Other 440s are not punching out the int gasket, yours did. Have you pulled apart/measured a PCV valve? I have, to modify them to work with low vac cams. There is no way a faulty/blocked PCV could cause your problem because the area inside the PCV is tiny. Pull one apart. The problem occurred on WOT runs where there is less time for these pressure pulses to dissipate, pressure builds up & finds the weakest link. Another symptom is the dip stick pushed out/up. Unless you address ring seal, the problem will happen again, & find the weakest link. The oil leak you got was also indicative of blw by looking for a way out....
A lot of race engine do not use PCV......& they are not having these problems.

 

[dvw]

I installed a 440 recently for a customer. He bought it used. The valley tray looked just like this one. It was bowed, but not split. Neither the customer or the guy he bought it from had noticed it. The motor had not been cleaned in any way. There was no evidence of any oil film next to the breather. I swapped the tray and put the engine in the car. It runs perfect. Has zero smoke on start or heavy acceleration. No oil mess out of the valve covers either. It was recently rebuilt before owner #1 bought it. Intake and exhaust ports appeared dry with no oil. Is it perfect shape? Probably not, but it runs fine. Why did it happen? Something pressurized it. When I worked at a Chevy dealer many years ago the used car porter was trying to start a SB Chevy pick up with eyther. It blew the valvecovers up at both sides of the intake. Ripped the metal around the inner bolts. I put new covers on it and changed the oil. ran fine.
Doug

 

[505Coronet]

[[[[[[[The intake gaskets were well sealed when i pulled the valley pan off, the RTV that was on the front and back of the engine was still sealing]]]]]]] Where did all the oil come from then???

I dont know how we got redirected to intake gaskets, probably my poor explanation lol. The valley plan blew open, if you look at the posted picture it has a hole in the sheet metal. that's where the oil came from. all gaskets/tv was sealed and not leaking.

run your cover breathers to the exhaust system through that pcv away , that really pulls the crank cast and sets the rings down on the pistons , much like a vac pump .

I like this idea a lot, especially for the off-road scenario that this engine lives in. I ran traditional filtered breathers for awhile but the dust accumulation in the engine compartment is bad enough without adding oil for the dirt to stick too. Probably going to weld some ports to the header and and let it do its thing. Great suggestion.

I installed a 440 recently for a customer. He bought it used. The valley tray looked just like this one. It was bowed, but not split. Neither the customer or the guy he bought it from had noticed it. The motor had not been cleaned in any way. There was no evidence of any oil film next to the breather. I swapped the tray and put the engine in the car. It runs perfect. Has zero smoke on start or heavy acceleration. No oil mess out of the valve covers either. It was recently rebuilt before owner #1 bought it. Intake and exhaust ports appeared dry with no oil. Is it perfect shape? Probably not, but it runs fine. Why did it happen? Something pressurized it. When I worked at a Chevy dealer many years ago the used car porter was trying to start a SB Chevy pick up with eyther. It blew the valvecovers up at both sides of the intake. Ripped the metal around the inner bolts. I put new covers on it and changed the oil. ran fine.
Doug

Were thinking along the same train of thought. I think something abnormal happened. Thanks for chiming in. Have another trans log parameter i need to do today so ill try that again.

Not to derail but man the 8hp75 is such a trick unit. the 727 was just not the right application for the uses/weight of this rig. It was totally fine for slow crawling and its worked great in my past drag cars, but knowing what i know now, ill be swapping an 8hp into whatever car i get into next.

That is if a hand shaker isn't an option. >

 

[POMONAMISSEL]

it works great , make sure your tubes in your exhaust are cut on an angle on inserted on an angle . it all helps draw out the pressure . my boss 302 was modified a bit , lol . and the only way i could get it to stop blowing the dip stick out of the tube was this system to suck the crank cast free of pressures

 

[Budnicks]

Not that you may care
not trying to pick on you either
it may be an easier fix or diagnosis than you may think
for your own peace of mind, may want to check into it...

sorry if it's getting a bit to **** retentive
But;

***You can always do a leak-down test too
& tell exactly where the bypassed 'air', is coming from
or that 'blowby' is coming from
& the actual %'s of what & where it is leaking, definitely, with no guessing...
It's well worth the $$ spent, & a great tool...

***if hissing from inside the motor or out the valve covers,
the compression rings are going bad or they are already toast
(rings are probably gone if it has more than a 15% leak, burn some oil
have leaky valve covers or smoke out the breathers, but it'll still run,
20% it's a granade with the pin pulled, at 25% lands may be lifted &/or broken rings
scratched cylinders, that no PCV or Evac system will compensate enough for that
& could sign either, the 1st comp. or 2nd compression rings are toast/gone
the top compression rings are usually the ones that lift lands &/or break
& good race motors it's at 5%, leakage they all get replaced or it's taken down & fixed)
the oil rings are probably already toast

***sometimes a blown head gasket between 2 cylinders not by the water jackets
can do it too... (a whole nother discussion then) those 2 cylinders will probably show
near 100% leakage, when ones at TDC valves closed it'd leak over to the other joining cylinder
it's not a good situation ever...

*** if hissing in the intake a possible bent intake valve
or a gummy/varnish or build-up from fuel additives
or oil that doesn't ever belong in the combustion chamber
or it just needs a good valve job
(bad intake valve seal on the seat, can wreak havoc, exhaust charge
getting in the compression stroke or intake stroke igniting/heating it in the intake,
neither is ideal... 'ever see NHRA Blower explosions', most are intake valve
or a hole in a piston/broken of lifted rings, related)

***if hissing in the exhaust a possible carbon buildup,
a burned or bent exhaust valve
(exhaust gases going by the valve heating & pressurizing the intake charge,
among other things you don't ever want)
or needs a good valve job, maybe even new valve seals, springs & neural the sloppy guides
while you're at it too
none of which are really good

 

[moparedtn]

PCV on one side valve cover, breather in the other valve cover.

 

[505Coronet]

Update on this:

Finally got the 8 speed shifting like i wanted, modern turning is a wild world. few numbers here and there make a world of difference. ANYWAYS why that's relevant is i finally got to do a few more WOT passes, and the cause of the leak revealed itself, i have an intake backfire on deceleration after the pull. AFR is 12.5 at WOT however, the PCV system is not what i thought and is basically allowing air back into the intake, creating a lean condition, hence the pop.

Which would also explain the controlled explosion of the valley pan with no signs of carnage. It did it again except this time i had the PCV system off the breathers and the puff came from the breathers not the valley pan (which fortunately sealed well)

I ordered the moroso evac kit to the headers, my neighbor has a similar set-up on his 63 nova running low 9s and its very clean.

Question on that:

Could one not run vacuum assist brakes T-d into the evac line? This would in theory provide the vacuum where i need it most at high rpm where the intake drops off due to the cam. Am i thinking right here?

 

[pnora]

Update on this:

Finally got the 8 speed shifting like i wanted, modern turning is a wild world. few numbers here and there make a world of difference. ANYWAYS why that's relevant is i finally got to do a few more WOT passes, and the cause of the leak revealed itself, i have an intake backfire on deceleration after the pull. AFR is 12.5 at WOT however, the PCV system is not what i thought and is basically allowing air back into the intake, creating a lean condition, hence the pop.

Which would also explain the controlled explosion of the valley pan with no signs of carnage. It did it again except this time i had the PCV system off the breathers and the puff came from the breathers not the valley pan (which fortunately sealed well)

I ordered the moroso evac kit to the headers, my neighbor has a similar set-up on his 63 nova running low 9s and its very clean.

Question on that:

Could one not run vacuum assist brakes T-d into the evac line? This would in theory provide the vacuum where i need it most at high rpm where the intake drops off due to the cam. Am i thinking right here?

Intake backfire on deceleration???? The throttle would be closed. Having an internal backfire does not seem possible. Post a picture of your current PCV and vent system? Is the valley pan pushed up again?

 

[505Coronet]

Intake backfire on deceleration???? The throttle would be closed. Having an internal backfire does not seem possible. Post a picture of your current PCV and vent system? Is the valley pan pushed up again?

From a WOT when I let off, that's when it happens. Not a controlled deceleration, essentially a throttle dump.

Valley Pan is fine, very nice piece from Hughes.

Ill get a picture tonight when I get back to the truck, with the engine cage and the shock reservoirs its hard to get clear pictures but ill try

 

[pnora]

From a WOT when I let off, that's when it happens. Not a controlled deceleration, essentially a throttle dump.

Valley Pan is fine, very nice piece from Hughes.

Ill get a picture tonight when I get back to the truck, with the engine cage and the shock reservoirs its hard to get clear pictures but ill try

What makes you think it was an intake backfire? An evac kit will not do anything to stop what you call an intake backfire. All that kit does is help evacuate crankcase pressures which I believe you have a lot of.