Valley Pan pushed up

[moper]

Too rich is as bad as too lean. It sounds to me like you broke a ring or ring land. Engine will still run. Might not even smoke. But I'd test it.

 

[Garys1969RR]

I will check leakdown on Sat, then will post the results here.

 

[vintage chromoly]

I pieced together a dry sump system for my offshore boat engine for around 1500.
Barnes 5 stage pump with a custom pan and tank.
I’m pulling 7” of vacuum with a Peterson relief valve.

What kind of money are ya talkin bout?

 

[Garys1969RR]

Sounds great! I'm going to find out what's causing the excessive pressure first. I had this happen on a 413 once, due to poor venting from the valve covers. THIS motor has a heater hose coming off each valve cover thru the oil separator, and leading to a welded in fitting at each header collector. That should be plenty of venting for the crankcase.

 

[dvw]

If your running 100LL fuel on a 14-1 @ 38 degrees it's got to be in detonation . May have damaged a piston or 8.
Doug

 

[PRHeads]

Good call Doug.

As said, leak it down.

If that checks out, try not running the vac-u-pan, and just run the breathers open.

 

[Garys1969RR]

If your running 100LL fuel on a 14-1 @ 38 degrees it's got to be in detonation . May have damaged a piston or 8.
Doug

Previous owners wife claimed 14 to 1, but I find that hard to believe. I had a 451 running 13.5 to 1, that ran fine on 100 LL, Since I'm I'm at 5500 feet. That's like running 12 to 1 at sea level. A motor loses alot of power up here due to the rarified air. It has to compress a little before it even gets back to std atmospheric pressure. You can get away with a good point or more of compression up here in Colorado, compared to sea level.

 

[Garys1969RR]

Now I'm thinking that when I test drove it after putting on the tunnel ram, I tested it on the street with the mufflers on there. That may have created enough back pressure in the vac u pan hoses that it didn't let the crankcase pressure out fast enough. But I have a cylinder leak down tester ready to go now, and will be checking that aspect of the problem tomorrow. Results coming soon!

 

[Garys1969RR]

Good call Doug.

As said, leak it down.

If that checks out, try not running the vac-u-pan, and just run the breathers open.

Ok, I'll try that too. I'll also check the fitting at the header for proper operation. Thanks!

 

[PRHeads]

Vac-u-pan and mufflers often don’t work well together.

 

[Garys1969RR]

Vac-u-pan and mufflers often don’t work well together.

Yea, that makes sense. I had the mufflers on for a short time, but opened it up to see how it would run. Prob happened then, just didn't notice it right away

 

[Garys1969RR]

OK, just got done checking the leak down. Not good. Although I bought this test set from Harbor Freight, and I don't know how accurate it is, here are the results. #1-3-5 -7, were 47%-50%-47%-40%, respectively. 2-4-6-8 were 42%-55%-55%-50%. Hissing sound coming from the dipstick tube, nothing anywhere else. The gauge said it was in the marginal range. HA! I don't think so! Then when I put the plugs in and turned it over by hand, I could hear the leakage past the rings. It would leak down within a second or 2 when rotated into the compression stroke. So it"s definitely time for a disassembly and rebuild. My 451 would leak down over a period of several seconds, when rotated. So that's where the excessive crankcase pressure is coming from. Rebuild time.

 

[moper]

Yup. It's done. I wouldn't plan to reuse the pistons either.

 

[PRHeads]

I’d be verifying the gauge by trying it on another motor that’s known to not have any issues.

Is it a dual gauge style tester?

If so, let’s see a pic of the gauges?

 

[Garys1969RR]

I’d be verifying the gauge by trying it on another motor that’s known to not have any issues.

Is it a dual gauge style tester?

If so, let’s see a pic of the gauges?

Yes, it IS a dual gauge set up. From Pittsburgh Tools, Harbor Freight Tools. I could hear it leaking past the rings on every cylinder.

 

[PRHeads]

The reason I mentioned it is, I have had numerous people not use that style tester correctly, and end up with poor looking results, only to tear the motor down and find nothing wrong.

My older dual gauge tester has two intentical gauges.

Some of the newer ones I’ve seen have the leak down gauge face where the numbers are backwards.
The needle swung all the way to the right reads “0”.

In order for the leak down percent to be accurate, the inlet pressure gauge must be set so it’s right at 100psi during the test.
When the hose isn’t connected to the engine( no air flowing thru tool), when the inlet pressure gauge is right on 100psi, the leakdown gauge should lined right up with “0” percent leakage.

I know of people using small home compressors that only go to 90psi max, and with the tester hooked up the pressure drops to like 75-80psi.
In that scenario, you cannot not use the reading off the leakdown tester directly.

 

[Garys1969RR]

Yes, this one doesn't seem real accurate. The compressor only went to about 90 pounds. But when it would cycle back on, and the pressure would go up, leakdown would also gradually increase. May take this back, and order one from Summit. I'll try and post a picture of the gauge.

 

[Garys1969RR]

 

[Garys1969RR]

All the readings were in the yellow, or moderate range. Showing 40 to almost 60%. I feel if I had more pressure from the compressor, then readings would be even higher. And with the plugs in, and turning the engine over by hand, each cylinder leaked down rapidly with each quarter turn of the crank. Others engines I have built would take 5 or more seconds to leak down all the way. Anyone want a set of 383 pistons? 1.320 C Height Im pretty sure. Im going to a 400 block on the next motor, use this 4.25 inch crank and rods, build a 512 stroker.

 

[Garys1969RR]

Also, PR heads. What do you think of these Mopar Stage 6 heads? They came with the car, and appear to be CNC ported. I may use these on the build, rather than the Stealth heads the 496 has on it now.