#1 was the lowest at 140psi, #2 was the highest at 170. For an engine with a stock bore, fresh rings and a hone job I think it's pretty good. Plugs look pretty decent imo as well. Been in the engine for 5500 miles, since rebuild.
The comp test looks good, now what you should do is do a leakdown test and see if it is really sealing up good. It is a better test. Show the top of the plugs at the "J" strap looking down like this You see the "J" strap has a line on it showing how hot it is. This plug is a YR5 NGK Look at this site for plug reading www.dragstuff.com/techarticles/how-to-readplugs.html
Leakdown test will be done next weekend. I'm a youngin, so I buy tools as i can afford them. I've stumbled across that site/article before, good read. Stuff I never knew, nor really put much thought into.
#1 is 17.5% less than the highest cylinder, looks like 160 is closest to typical though and is still 12% lower than those. Ideally you shouldn't have more than 10% variance between cylinders. Do a wet compression test on #1 cylinder to see if it improves, if it does you may have an issue with the rings on that cylinder?
I wouldn't think so, the plug on #1 looked the best out of all of them, was the only one without liquid on the threads, best color, etc.
I mean overall the engine runs perfectly fine, has a shimmy to it at 1100rpm and below, 1200rpm and up is fine. Doesn't knock, smoke, tick, nothing. Don't even burn oil. Exhaust doesn't smell rich or lean (hot metal smell), it just smells like a car.
So probably a valve in that cylinder that doesn't seal as good as the other 7? The wet test would tell you that it was or wasn't the rings that are making that cylinder low on psi.
Numbers don't lie. 17% is too wide a spread. It may "feel" like it is running good, but many people drop dead of heart attacks feeling fine right up to the point they exit. The wet test and leak down will help. Another is running good vacuum diagnostics. Doing the full monte on vacuum tests will tell you things about all sorts of hidden issues. If you did nothing to the heads and a "wet test " does not change the numbers to any great amount, look at the valves, and that is where the vacuum test will be of assistance.
If anything it is the heads. They're 100% stock. Didn't have the time, nor money to get them done at the time and it is/was my only car, just needed it to work as well as I could get it to. Sounds like some backyard shade tree jackassery, but I used a green scuff pad until the rust was gone on the seats, fine steel wool, then I lapped them with course then fine lapping compound using a rubber hose, two hose clamps, and a drill. About 10-15 seconds one direction, unseat, check, 10-15 seconds in the other direction. Under their own weight they sealed well enough to not have brake cleaner leak through, so I went with it. It's not a perfect build, I wish I could've done more to it, it being an SP and all, but I just didn't have the time or money. The thing has 17" of vacuum at idle with a crower lvl 3 cam, set straight up. The needle fluctuates between 16-17", but it behaves normally. Drops to zero when quickly revved, etc. either way, this weekend leakdown + wet test on #1 will be done. What's the best way to get oil into a cylinder through the plug hole? Bottle and a tube? How much? I think I read a table spoon is enough to do the job... On another note... why is #2 so high? Comparatively, if #1 was at 150 or 155, it wouldn't be that much of a concern I imagine.
About a tablespoon will do it. A leak down tester is not too much money you can get them from Summit. You just need a compressor that can hold 100 lbs thru the tester. There are calculations for lower pressure readings if the compressor can't hold 100 # Everything looks good you could of had a small piece of dirt causing the seal to not be good in the low cylinder. I wouldn't put too much into the test if the car runs good The leak down and the oil test will confirm what could be wrong.
That is not "shade-tree jackassery", that's "old school" and you deserve respect for doing what you have. When you mentioned "since rebuild", I assumed a shop rebuild, hence my remark. If you had a shop rebuild the engine and had that large a variance, it would be a concern. Given you did the work yourself, you did well. So, I will eat my plate of crow in silence while you enjoy driving your car.
I took it apart, and "re built it". but seriously. I took it down to the bare block, filed away any flash (looking at you lifter valley...) that bothered me, had it cleaned out and TA bearings installed, honed, reused original bottom end with new rings and bearings, (clearance was .002 on rods and mains with standard size bearings, had old discontinued clevites in there when I got the engine), top end was done up as described above. Basically the only "machine" work done was the cleaning and the cam bearing install. everything else I did in my garage during Novemeber of last year. With no heater.
