'65 Nova with built SBC

N

novadude

Joined
Jan 16, 2003
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Location
Shippensburg, PA
I recently had Blackstone do a used oil analysis on my '65 Nova. I am running a SBC (355) with Bi-metal King bearings, Hypereutectic pistons, GM performance aluminum self-aligning roller rockers. Aluminum came back high (35 PPM). I cut the filter open and didn't see any unusual particles. I didn't see any other alarming wear metals. Spark plugs look mint with no deposits or signs of oil getting in the cylinders, and there is no blow-by. No unusual mechanical noises coming from the engine.

The high Aluminum is confusing, as this thing runs great. Oil pressure is the same as it was when I built the engine. I am wondering if maybe this is the coming from the aluminum rockers.... maybe where the roller wheel guides that keep the roller tip centered on the valve stem rub against the rocker body? I'm not going to worry about it, but I was curious what the BITOG community thinks.

Screenshot 2025-12-12 084857.webp
 
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What kind of oil? Do you have a VOA of it for a baseline? Do you have previous used oil analysis, and if so, what was/were the level(s) on those?
 
Valvoline High mileage 10W-30 blend. ~1600 miles, but that it with a lot of storage period and plenty of full throttle runs through the gears. About 1.5 years of use. I do have one previous analysis with Mobil 1 High Mileage 10w30 with similar miles on the oil, and aluminum was 16 PPM in that analysis. No significant particles in the filter that would lead me to believe that there are major issues.
 
35 isnt too terrible.
How many miles and OCIs on this build
Hypereutectics are aluminum you could be getting some skirt contact.
Whats the rocker ratio and spring pressure? Usually the pocket/ tip is hardened steel so there isnt steel/ aluminum contact.
I'd just monitor it.
 
UncleDave said:
35 isnt too terrible.
How many miles and OCIs on this build
Hypereutectics are aluminum you could be getting some skirt contact.
Whats the rocker ratio and spring pressure? Usually the pocket/ tip is hardened steel so there isnt steel/ aluminum contact.
I'd just monitor it.
Click to expand...

About 12k miles on the build. Ratio is 1.5, and springs are beehives (PAC 1215) set-up for 130 lb seat / 290 lb open. These are self-aligning rockers with the "washers" on both sides of the roller tip to align the roller wheel on the valve stem (no guide plates). I am wondering if those "washers" are wearing against the rocker body as they rotate in operation. Side loading would have these rubbing against the aluminum rocker body. Whatever is wearing, it isn't wearing much, as the filter was very clean. A few minor particles, but nothing alarming. I cut the element and spread out the pleats and didn't see much of anything. Piston skirts are coated (speed-pr0 H815ACP)
 
UOA results are great for tracking trends. Yes, examples exist where something shows up and there is a real problem.

However, after 40 years of this on aircraft engines and 30 years of it in automotive field, the following is is my experienced opinion:

1) UOA results do not indicate rates of wear, actual measurement is required
2) High metals often have nothing to do with pistons/cylinders or camshaft/lifters
3) Wear particles from a failure are often large enough to be 100% missed by UOA and found in the filter
4) Oil coolers, fuel pumps, distributor drives and even the fuel used can contribute to unusual readings
5) UOA results are for trend monitoring
 
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