A few weeks back, I built a 445 for a customer. At the same time, Jay was talking about his clear valve covers on this forum, so I shot him a message and asked if I could borrow them for a dyno session. The timing was right, as he was wanting to do some outside testing on them to see how well they seal up.
I got them in and since it was the day before the dyno session, I went ahead and popped the customer's valve covers off just to see if I would need different length fasteners. Got the left side cover off and just happened to notice that one pushrod wasn't even touching the rocker arm. This particular engine was a hydraulic roller engine, that uses non-adjustable rocker arms. Obviously, once the pushrod length is measured, the rockers are just bolted on and you're done. Turns out, when I had rolled the motor over to stab the distributor, the spring pressure pushed the lifter down and due to a manufacturing defect, the lifter plunger would not come back up under its own power. If I primed the oil pump, it would slowly come up, but it was very easy to push it back down with a finger WHILE priming the pump.
If I had not tried Jay's covers on, it would have went to the dyno and made a bunch of racket....maybe bent a pushrod.
Intake came off, lifter pair came out, new lifter pair went in, intake went back on.
Fast forward a week, dyno time comes back around.
Got the engine on the dyno, got it started, and during the break-in time I usually walk outside and look at the exhaust. I noticed a few wisps of steam coming out of the right side but wasn't overly concerned at this point as sometimes water/condensation can get down into the dyno mufflers and then the hot exhaust steams it back up. Just to be safe, I went into the dyno cell, pulled all of the spark plugs on the right side, and rolled the engine over with the starter. Nothing came shooting out at me, so I felt good. All the plugs had a little color in them and didn't look like they had been getting washed off. Pistons had color as well.
Got some break-in time in, and started putting pulls on the engine. Oil pressure looked great, oil temperature looked great, adjusted timing, put more pulls on. Walked back outside, still getting a wisp out of the right side. By this time, I was getting a little concerned. Pulled the valve covers and saw some milk up top. Now sometimes there are reasons for that, that shouldn't cause worry. I had driven an hour and 15 minutes that morning with the engine in the back of the truck. It was 30 degrees the entire time and it was so cold that holding onto the valve covers would actually make your hands start to throb. I told myself that it was plausible that the engine had been sweating inside and just hadn't got the moisture out of the oil yet. We fired it back up and I let the engine run at 2500 rpm with a 100 lb-ft load on it for about 10 minutes until the water temp was 190° and the oil temp was 210°. Shut it down, pulled valve covers. Still milky. That was a "poop the bed" moment.
At this point, I knew that I was going to have to do some serious investigation but I went ahead and screwed Jay's valve covers down so I could honor my word to him and see if they would seal up across some dyno pulls.
Here's what I saw:
https://www.youtube.com/watch?v=IfhEuGwkYb8 With no baffles and a very open breather, it was very apparent that we were getting some steam from inside the engine. The valve covers also showed immediate moisture (and milkshake) as the pulls went on.
I pulled the engine off the dyno and immediately ran it over to a buddy's shop (Ray's Crack Repair) and we pressure tested the entire engine. We blocked off every orifice and by the time we were through, we had introduced 25 lbs of pressure into the coolant system. No sounds out of the spark plug holes, no sounds out of the exhaust ports, and no bubbles around the intake manifold gaskets when I sprayed soapy water around them with the valve covers off.
Took the engine home, drained the oil, and before any oil came out, a coffee mug full of water came out first. sad.gif
I went ahead and tore the engine down.
Monday evening I dropped the bare engine block, heads, and intake off with Ray so he could pressure test each piece individually. He called me at 8:20 last night to tell me that he found two cracks, one below #8 cylinder on the inside of the block, and one below #4 cylinder on the inside of the block. He had to pressure the block up to 30 lbs to get them to leak, but we figured under running engine temperature, they opened up a lot easier.
Smoking gun.
A few notes that I can make here:
*This is what really stinks about dynoing and this is why I can't sleep well the night before the session. You can do everything right, even pressure test the block BEFORE assembly, and you never know what may happen.
*Jay's valve covers did not leak and are excellent testing tools. I highly recommend them.
*Even with making a water pump out of the oil pump (hurt some bearings), this engine made 460 hp @ 5200 and 520 lb-ft. It was a rather mild engine, 445ci, as-cast BBM heads, a Performer RPM intake, 9.5:1 compression, and a custom hydraulic roller stick, 227/227 @ /.050", 112/106, .570"/.570". Destined for a pickup truck, it used a 5 quart Milodon oil pan, along with a standard volume oil pump.
*With the SV/SP pump, oil pressure climbed throughout the pull, to 5500 rpm, with the oil pressure peaking at 60 psi. This engine used new non-adjustable rocker arms with a set of ARP stand studs and POP end stands. With no restrictors and no drip tins, the oil level didn't even get up to the valve spring locators in the heads, as can be seen (if you look through the moisture, hahaha) from the YouTube video. Each rocker did spray a nice little jet of oil at the inside roof of the valve covers. Main/rod bearing clearances were all at .0022-.0023. Used Valvoline VR1 10W-30.
*The customer will get a different engine block and we will re-assemble. I will post back with the new results.