My "Late Life Crisis"!

['69Novajoe]

So, in order to put hundreds of miles on the clutch, I had two “trips” planned. One of which was to go see friends in another town about 50 miles away. The other was to head up to a friend's shop to run the car on their chassis dyno, another 50+ mile trip. You see, after driving around locally for a few days, I decided to check the plugs to see what they might look like. I was kind of surprised to see them looking pretty dark, which in my mind meant she was running rich. I thought by running it on their dyno, we could check the air/fuel ratio (AFR). I was hoping they could use the bungs I had welded into the collectors to get an accurate reading, but they said they could just stick a “probe” up the tailpipe to check it. I’m still not convinced that it was that accurate, but at least we got some numbers.

['69Novajoe]

They did a couple of pulls and noticed that it was pretty close as far as the AFR was concerned. They even bumped the timing up a couple of degrees and picked up a few more horses!! (Terry, in the video, said it picked up 20, but it was actually 13, plus they ran it to a higher RPM) As a side note, when we had the motor at the dyno shop previously, there was no attempt to adjust the timing, which might have put the motor over 500 HP??!! Another thing that’s puzzling to me is the discrepancy of both the engine dyno and the chassis dyno. I know that you can’t really compare the two, but to have 549 on the engine dyno and what we ended up with here, 402 at the wheels, seemed like a big difference. They did mention that it was a pretty “bad air” day, so that might have been the problem?? But, as you’ll see, I’ve got another “problem” to contend with now.....

[napa68]

Really nice Joe!

There is so much that can effect the "result" from an engine dyno then going to a chassis dyno. The correction factor on each is a big one as is the air the way you mentioned it. I'm a little surprised they did not adjust timing in the engine dyno session to begin with. On the bright side, it seems as though your fuel system is up to the task. That would certainly show up on the chassis dyno. You are also driving the fan and accessories in addition to the drivetrain.

My history with different combinations (engine dyno) were to start with 32 degrees (safe) just to make a pull and see where EGT's / AFR's are. Then start adjusting the carb and timing as needed. We'd always go in 2 degree increments to see how the engine responded. 36-38 seems to be the sweet spot. My only exception was the L88 in the HM Camaro where it liked 40. That L88 though had a camshaft and cylinder heads from the stone age

[dykstra]

Originally Posted by napa68

Really nice Joe!

There is so much that can effect the "result" from an engine dyno then going to a chassis dyno. The correction factor on each is a big one as is the air the way you mentioned it. I'm a little surprised they did not adjust timing in the engine dyno session to begin with. On the bright side, it seems as though your fuel system is up to the task. That would certainly show up on the chassis dyno. You are also driving the fan and accessories in addition to the drivetrain.

My history with different combinations (engine dyno) were to start with 32 degrees (safe) just to make a pull and see where EGT's / AFR's are. Then start adjusting the carb and timing as needed. We'd always go in 2 degree increments to see how the engine responded. 36-38 seems to be the sweet spot. My only exception was the L88 in the HM Camaro where it liked 40. That L88 though had a camshaft and cylinder heads from the stone age

That's one of the many things that make that car so flipping cool!!

['69Novajoe]

Originally Posted by napa68

Really nice Joe!

There is so much that can effect the "result" from an engine dyno then going to a chassis dyno. The correction factor on each is a big one as is the air the way you mentioned it. I'm a little surprised they did not adjust timing in the engine dyno session to begin with. On the bright side, it seems as though your fuel system is up to the task. That would certainly show up on the chassis dyno. You are also driving the fan and accessories in addition to the drivetrain.

My history with different combinations (engine dyno) were to start with 32 degrees (safe) just to make a pull and see where EGT's / AFR's are. Then start adjusting the carb and timing as needed. We'd always go in 2 degree increments to see how the engine responded. 36-38 seems to be the sweet spot. My only exception was the L88 in the HM Camaro where it liked 40. That L88 though had a camshaft and cylinder heads from the stone age

I, too, for one, was surprised more "tuning" wasn't done on the engine dyno?? They were going off of what the carburetor builder suggested, which was 34 total degrees. At the chassis dyno they bumped it up to 36 and David (the son) wanted to try even more but Terry said just to leave it there. That's when we saw 13 more horses!! (but that also included revving it higher in the RPM range)

['69Novajoe]

Now, after driving it for over the recommended number of miles (for the clutch break-in), I started noticing an oil leak. I actually fixed one early on which just happened to be coming from the valve covers. This one, however, is coming from the back of the block. I snugged all the pan bolts, checked the valve covers again, checked the distributor and oil pressure sensor, but it didn’t stop the leaking!! I even saw a drip of oil on the oil pan flange at the back of the motor. At this point I’m trying to give my engine builder the benefit of doubt. He’s forgotten more about the SBC than I’ll ever know!! I sent him a text message but never heard back. I’ll be paying him a visit whenever I get a chance, to get his input.

In what little research I did, I was wondering if I could have a PCV valve that’s not keeping “pace” with the crankcase “pressure”, and allowing it to push oil past the pan gasket?? What’s in there now is just a stock type PCV for a stock engine.



I then found out about the M/E Wagner Dual Flow adjustable PCV valve, which has helped others with this problem. I’ve since ordered and received one, and am in the process of getting it dialed in. They also mentioned that it could even be adjusted so much that it might even pull oil out of the valve covers (depending on the baffling in the covers) and introducing it into the intake manifold under the carburetor. However, my valve covers do have adequate baffling and I'll be keeping my eyes on the plugs for fouling.





For that problem though, they suggested installing an oil catch can between the PCV valve and the vacuum fitting under the carb. I found one on Amazon (of course!!) and am now in the process of making a bracket to bolt it in and make it look “factory!!” It might be “overkill”, but I don’t want any more issues! I might even invest in 02 sensors to be able to monitor the AFR in real time.

[66cayne]

I know you don't want to hear this, but hopefully it's not a rear main seal infant mortality issue. How much and what kind of oil are you filling it with? One way to localize a rear of engine leak is to raise the engine to a 30 degree angle or so so the oil is now sitting in the rear of the pan and leave it there for a few days. Check for dripping frequently. If it starts to seep get under the car and try to identify if its from the pan or possibly from the RMS. A RMS leak will likely leave a 'starburst' pattern on the engine side of the crank flange, but you will only see that after some extended driving and checking. I hate engine leaks. Love the car, good luck .

['69Novajoe]

Originally Posted by 66cayne

I know you don't want to hear this, but hopefully it's not a rear main seal infant mortality issue. How much and what kind of oil are you filling it with? One way to localize a rear of engine leak is to raise the engine to a 30 degree angle or so so the oil is now sitting in the rear of the pan and leave it there for a few days. Check for dripping frequently. If it starts to seep get under the car and try to identify if its from the pan or possibly from the RMS. A RMS leak will likely leave a 'starburst' pattern on the engine side of the crank flange, but you will only see that after some extended driving and checking. I hate engine leaks. Love the car, good luck .

Yes, I don't want to hear that, but I also know it could be a possibility!!

One guy I talked to had the opinion that if the rear main seal is installed correctly, pressure from the crankcase would only allow it to "push" harder on the main surface? But that doesn't account for a mismatched parting joint.

Per the engine builder, I'm running Valvoline VR1 20W-50, 5 quarts in a stock pan.

I will try your "technique" also to see if I can isolate the problem.

I'm also wondering if it might be possible to create enough "suction" with this adjustable PCV valve to overcome oil trying to escape past the pan gasket (if, indeed, it's coming from there!!). I'm also wondering if I can measure crankcase "pressure" through the oil dipstick opening, while closing off any other opening, like the valve cover breather locations?? If, so, what might the correct or acceptable amount be??

I, too, hate oil leaks.......and on a brand new engine to boot!!!

Thanks for your input and the kind words about the "build!!"

['69Novajoe]

Originally Posted by 66cayne

One way to localize a rear of engine leak is to raise the engine to a 30 degree angle or so so the oil is now sitting in the rear of the pan and leave it there for a few days. Check for dripping frequently. If it starts to seep get under the car and try to identify if its from the pan or possibly from the RMS. A RMS leak will likely leave a 'starburst' pattern on the engine side of the crank flange, but you will only see that after some extended driving and checking. I hate engine leaks. Love the car, good luck .

Okay, I've elevated the car up on jack stands to see if I'll notice any seeping of that "dinosaur juice!!"

I checked the crank flange for the "starburst" pattern you mentioned and didn't see any tell-tale signs there, so I'm assuming that's a good thing!!?? The motor now has over 500 miles on it, so I'm thinking that would be enough to see other areas of concern??

I'm still going to try that adjustable PCV valve just in case it might be able to help though.