Quote:
Originally Posted by tomtom72
Craig, thanks for letting me watch! 
This is waaaay over my head. Number of motors that I ever assembled: 4, and they were all 350 sbc's 
So, I guess that with our motors you can't be very far off in cam timing and have the valves survive, and/or have good compression even if the valves don't hit?
How come the cam looks like it has spots all over it? Is that just the metal, or is that something else?
How did they assemble & time the cams at MerCruiser? Did they have to do what you you are doing using those "pins"? What's with the "gear set" at the chain end of the cam, is that how the timing is determined?
 sorry, I'll try not to ask too many Q's. |
Hi Tom,
I don't have much to share as a novice but I figured there might be someone more novice than I; especially since our cars are changing hands lately more than ever with the economy and great prices.
Hey, you have more than me. I have only really worked on 2 SBCs and 1 BBC....about 30 years ago (my age is showing now).
I went into the garage just now to look at the pics versus reality and yes, there is like shading on the lobes but not as bad as it looks on the pics. I have a neighbor coming over in the next hour to help me break the bolts loose on the camshafts as I was afraid when trying this by myself. The color appears to be the metal and does not coincide with wear area on the lobes. I don't know what new or correct looks like, but I'm sure the folks with a lot of experience will comment about the spot appearance. I'll try to take better pics of my progress and what it looks like under the heads. A few have asked to see the bearings for mains and con rods too.
I'm pretty sure that mine did not hit valve/piston and if it did still amazingly strong motor with all considered before teardown. The left side that was off had compression about 25-30 lbs less that the correctly timed side. I am hoping anyway.
Yes, everything I have read and seen the cams are timed this way with the pins from the factory; so every ZR-1 has power to be gained with more accurate timing if untouched from the factory. The factory settting is not very accurate so I will degree them and use Marc H and Jim Milstead's instructions on the registry and Marc's site. I can see why the factory did not take the time and I'm sure Ferrari, Lambo, etc. don't use the good enough approach. I can also see why it cost a lot to degree in these cams as it does take time and I probably won't get it right the first time. I'm going to buy extra bolts just in case since you can only use them once when torqued. I think you are talking about the vernier plates near the gears and yes, those are the actual timing adjustments, again using pins. The factory will line up the cams with the retainer pins and the vernier plates with pins but I consider it just a baseline and good enough. If you degree the cams then you will find these settings are off. I'll get offline with you more on this.
Glad if I can help, but again.....I just a novice trying to learn.