Crank turned without timing chain, issue?
Tech Contributor
Joined: Jan 2007
Posts: 19,454
Likes: 1,162
From: Dyer, IN
Lucky, I'm not following what you are saying. The crank doesn't care about compression or exhaust. 360° puts the crank in the same position. The cam does care and takes 720° with the chain connect of crankshaft to put the cam back to its 360° position. As long as the cam sprocket dot is facing down and the crank sprocket dot is facing up, connect the chain the engine is timed correctly. Even if someone put the cam sprocket dot facing up with the crankshaft sprocket up the timing will still be correct.
Glad you stepped in to clarify.
Banned Scam/Spammer
Joined: May 2007
Posts: 15,685
Likes: 1,330
From: Machineguns, because I don’t compromise
Just saw this thread... my thoughts?
Your lack of starting has nothing to do with the cam being spun while not connected to the crank. I just got done with a cam swap on the engine in my avatar and I can tell you the crank was spun several times to get at each piston top for cleaning. Now, when you reassemble, the cam is key'd (by way of the dowel pin) to the cam gear and the crank's gear has it's own dot. If they are lined up like in previous posts you are good to go.
So with that being said, you tore the engine down again for no reason except now you can clean the pistons/heads.
Your issue of not firing can be anything from fuel and spark, but it's not valve timing/air.
When you get it all back together you'll be back to where you started. Make sure you hook up all grounds... You will be at square one checking that you have fuel pressure, and then checking that you're getting spark. One of those two elements are your problem.
Your lack of starting has nothing to do with the cam being spun while not connected to the crank. I just got done with a cam swap on the engine in my avatar and I can tell you the crank was spun several times to get at each piston top for cleaning. Now, when you reassemble, the cam is key'd (by way of the dowel pin) to the cam gear and the crank's gear has it's own dot. If they are lined up like in previous posts you are good to go.
So with that being said, you tore the engine down again for no reason except now you can clean the pistons/heads.
Your issue of not firing can be anything from fuel and spark, but it's not valve timing/air.
When you get it all back together you'll be back to where you started. Make sure you hook up all grounds... You will be at square one checking that you have fuel pressure, and then checking that you're getting spark. One of those two elements are your problem.
Melting Slicks
Joined: Jan 2009
Posts: 3,181
Likes: 286
From: Puyallup Washington
After further clean up and investigation it looks like the valves are bent. They do have a common scuff on all the valves and 3 of 4 are not seating ... with a gap big enough to see through in one of them. 
So, it looks like the answer to the original question: Was the timing effected when the crank/cam moved
was yes, the timing was off enough to damage the valves.
Oddly enough, I turned the motor by hand before using the starter and it had no out of ordinary resistance and when I used the starter I couldn't hear any piston/valve slap.
Thanks guys! I'll keep it updated...
So, it looks like the answer to the original question: Was the timing effected when the crank/cam moved
was yes, the timing was off enough to damage the valves.
Oddly enough, I turned the motor by hand before using the starter and it had no out of ordinary resistance and when I used the starter I couldn't hear any piston/valve slap.
Thanks guys! I'll keep it updated...
[QUOTE]Your lack of starting has nothing to do with the cam being spun while not connected to the crank.
So with that being said, you tore the engine down again for no reason except now you can clean the pistons.[QUOTE]
The above quote from Sidewinderx7 indicates the valves are bent. I think he did have reason to pull the engine apart.
Banned Scam/Spammer
Joined: May 2007
Posts: 15,685
Likes: 1,330
From: Machineguns, because I don’t compromise
[QUOTE=Kmcoldcars;1579600653]From Joshua
[QUOTE]Your lack of starting has nothing to do with the cam being spun while not connected to the crank.
So with that being said, you tore the engine down again for no reason except now you can clean the pistons.
The above quote from Sidewinderx7 indicates the valves are bent. I think he did have reason to pull the engine apart.
Hmmm, missed the post about valves.
Ouch.
[QUOTE]Your lack of starting has nothing to do with the cam being spun while not connected to the crank.
So with that being said, you tore the engine down again for no reason except now you can clean the pistons.
The above quote from Sidewinderx7 indicates the valves are bent. I think he did have reason to pull the engine apart.
Ouch.
Thread Starter
Racer
Joined: Jul 2008
Posts: 254
Likes: 0
From: Everett WA
lol, yeah they bent... plus it did need a good cleaning.
I wouldn't think it would effect the timing since they both moved, and I continued moving them until the dots were aligned again, but apparently something went wrong because the valves did hit the pistons.
I wouldn't think it would effect the timing since they both moved, and I continued moving them until the dots were aligned again, but apparently something went wrong because the valves did hit the pistons.
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
This is obviously a lesson for everyone that as someone else mentioned already, always loosen the rocker arms first, before rotating anything on the cam or crank assemblies. I'm thinking that most assume there wouldn't be any contact but on these engines, there isn't enough clearance.
Racer
Joined: Feb 2003
Posts: 418
Likes: 28
From: Evansville IN
Your point is, and correctly so, as long as it Dot to Dot, or 12 and 12 O'Clock it doesn't matter.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
