I've built Chevys in the past and on a Stock build I would not be concerned. This is not a Chevy the valve lash was off, so I ordered adjustable push rods. My valve stems are not the same length, they very about .060. I ran the pre-start compression test Low cylinder was 115 (a bit low) and the high 140. With the compression It should 9.4:1 be, I should see 140 pre-start and 160 after the ring seat. What I'm concerned with is the range "25". Should I be?
did you crank the same amount of revolutions for each? is the carb butterfly open? i wouldnt worry about it. i would break it in and after about 200 miles check it.
Thanks, yes, and yes yes, I plan to check it after the rings seat. I thought about rerunning the test after the valve lash is correct.
You need to drive the engine for 500 miles, then change the oil and filter,,,, then another 500 and change the oil and filter.... using zddp each time.... and each time the oil is changed,,,, forever.... The hydrolic lifters are designed to compensate for unequal valve stems and components.... Actually the rings are not fully seated for something like 1500 to 2000 miles... then the engine is ''broke in good''..... Have confidence in your rebuild....
Thanks, I think I need to explain the build, the original build is sitting on a shelf, this build is the other peoples abandon projects build, all the parts are from craigs list or evil bay or v8buick. When buying the short block I noticed before I bought it the rod caps where on backwards. That wasn't the worst of it. #2 main had a bolt broke. I don't Know who did the machine work but if my work as a kid had been of the same quality My Dad would have taken me to the wood shed!. So, I've gone threw everything and repaired what i could, it's not perfect but it will make a nice driver.
Been there , done that,,,, i have built several ''hand grenade'' engines in my time...:Brow: so far they have all held up very well.... a buddy of mine had a ford truck that I built 15 years ago , ,,, the engine was full of crud,,, he did not want to hot tank the engine... I told him, the warranty would be to the front door.... it is still going....:Brow:
Not quite that bad. The blocks mains are all good "stuff not right"#5 and #6 out of round .0015 #8 taper .0035 Rod clearance #7 and #8 are.0025 the book said 17 +-3 the rest are at 20. The oil pressure test was good 45psi. Royal purple synthetic break in oil. Valve stem vary .060, hypertech pistons Suff I like, The block was square decked, deck hight was .026 to .031 from piston , end play was good, rod bolts good, mains are studed heads are too. I was told the rotating assemble was ballanced. Heads milled 10, stainless valves and harden seats 2.13 intake 1.65 exhaust, older Lunati 112 degree 268/278h cam "not the voodoo" simular to a ta 290-94h It should run ok
Updates,-- The adjustable pushrod came in while setting them up on I found that the original push rods where different lengths. What’s up with that? Also, I ran the oil psi test again using the front seep, 55psi. I set the new rods using the base and dial gauge used for degreeing cams on a metal plate. The initial setting is 0.010 less than the shortest pushrod.
Doc, you are a very wise Buick man but I am going to have to disagree with you on the engine break in. Unless you have a Delorean and go back to the 60s to machine your parts this is a much better way to break things in: http://www.mototuneusa.com/break_in_secrets.htm I have personally broken in several V8s using this theory and it works great...Leak down tests, compression tests and track times have all proved it to me. Since the article is centered around motorcycles here is what I normally do. Regular flat tappet cam break in (10 minutes at 2K or so) check for leaks let it cool down check for anything abnormal....then push it hard. The key is to do several WOT runs to almost redline and then let the motor slow you down to about idle/cruise. If you don't have good ring seal in 50 miles of proper break in you never will experience the full potential of your motor. Hey, it's the internet and everyone is a quarterback! These are just my opinions and experiences take it or leave it. Won't hurt my feelings a bit if someone disagrees.:laugh: Josh
Thanks, Great link Ring seal on #8 cylinder could be an issue because of the taper have you had this issue before?
Actually, Josh, I dont disagree with you,,,,:Smarty: the method that I laid out is what the factories said do back then... and...I know that lubricants and metals have changed since then...:Brow: and in the normal course of driving what you described will happen... On a engine that has been used enough to be rebuilt, the rods will already be streched, and stresses put into the other components... now,,, when you put it to the floor to get on the interstate, that stresses the parts,, when you drive at hwy speeds that stresses the parts... The stuff about reving a engine up way high at initial start up, I think is a bunch of hog wash, but the aftermarket cam manufacturers started that.... not the factories...''back when'' we would start a engine up and just let it idle at a normal idle untill it warmed up and never ever lost a cam.... were the cams better made then????? was the oil better???? now everybody screams if you dont rev the engine like a B29 bomber engine at take off.... go figure.... I have seen the valve train in the strobe lights inside a running engine... all the flexing and squirming of parts boggles the mind... we wondered how a engine stayed together over 10 mph.... Actually , you are calling ''break in'' what we called ''initial start up'' and I am calling Break in the whole period of initial start up untill 1000 actual driven miles are up.... savvy????:Brow: :laugh:
