My buddy purchased a soda blaster for his business, which came very handy for cleaning the engine. Definetely not a fun process, but it’s worth it.
After lapping the valves, I did another leak-down test. The results were much better this time, but still pretty inconsistent. The worst cylinder had 25% leakage and the best 7%. I put a little engine oil in the cylinders to see if it would seal a little better, but I noticed no improvement. You could clearly hear the air passing through the piston rings. Since my build is on the budget, I decided not to continue with the cylinder job. The scrap yard was nice enough to take the engine back and give me a full refund. It was a little disappointing as I spent quite a bit of time on it.
For the next engine I decided to spend a little more and get an L33 aluminum block. These came with 799 heads, which are pretty much the same as the ones that came on LS6 Corvette engine, minus the sodium filled valves. It was a little overpriced at $1200 CAD, but I couldnt afford to sit around waiting for a good deal. The engine looked pretty clean, and only had 80,000 miles.
I took the heads apart and as expected the valve faces and seats were pretty gunked up and pitted, not to mention all the crap and leaves that were in the cylinders. Since I didn’t have money to get the valves recut, I decided to lap them. Most people are against this, but this is a budget build, so screw it. I used a hand drill and a little piece of air hose to do the job. Again, most people advise against this, but there was way too much pitting to do it by hand.
I decided to check the engine to see what kind of condition its in and if it would need a tear down. We built a leak down tester from some parts my dad had laying around and hollowed out a spark plug to make a fitting (I will do a full write-up on how to build one). Long story short, all the cylinders but one had zero compression. You could pretty much hear the air coming from all the valves, so I decided to take the heads off for a some cleaning.