Valve Timing Questions
Time for a comp test.
Edit: Check all your timing marks make sure all is right,HB to block to dizy to number 1 wire. Any back fire or pop out of the TB?
Edit: Check all your timing marks make sure all is right,HB to block to dizy to number 1 wire. Any back fire or pop out of the TB?
Last edited by merc225hp; Aug 11, 2012 at 03:05 PM.
Well the heads are freshly built and the plugs are wet. Compression should be great unless my cam timing is off somehow. This is frustrating. Tons of $ have gone into this and kinda feels like a waste. I'm gonna check to make sure #1 is at tdc compression stroke and that my rotor is pointing in the correct position.
Well the heads are freshly built and the plugs are wet. Compression should be great unless my cam timing is off somehow. This is frustrating. Tons of $ have gone into this and kinda feels like a waste. I'm gonna check to make sure #1 is at tdc compression stroke and that my rotor is pointing in the correct position.
[QUOTE=merc225hp;2844131]Need to check and verify that, and yes do check the rest.[/QU
Cam timing was off, 10 of the 16 pushrods were slightly bent. Luckily my valves were still straight. I'm going to get a compression tester tomorrow and make sure all cylinders are good across the board. I went ahead and made sure my distributor was lined up with tdc #1 and it was spot on. I believe I may have advanced the cam too much or something to throw the valve timing off like it was. Its on point now though. I did 6 revolutions by hand and tdc #1 marks on my timing gears always lined up on the top of the compression stroke. I'm not 100% sure how I ****ered this all up but thankful I only damaged the pushrods and not my freshly built heads.
*Lesson learned, I will never buy an adjustable timing set again lol*
Cam timing was off, 10 of the 16 pushrods were slightly bent. Luckily my valves were still straight. I'm going to get a compression tester tomorrow and make sure all cylinders are good across the board. I went ahead and made sure my distributor was lined up with tdc #1 and it was spot on. I believe I may have advanced the cam too much or something to throw the valve timing off like it was. Its on point now though. I did 6 revolutions by hand and tdc #1 marks on my timing gears always lined up on the top of the compression stroke. I'm not 100% sure how I ****ered this all up but thankful I only damaged the pushrods and not my freshly built heads.
*Lesson learned, I will never buy an adjustable timing set again lol*
Last edited by MeanMagnum99; Aug 12, 2012 at 12:08 AM.
Sorry to read this! The comp test will tell you what's going on, I will keep my fingers crossed for you, three other people that this happened to had bent valves. The setting of the chain at +4 did not cause this I have run +4 and -4 with no problems. What chain set did you use please.
Edit: When doing the comp test remember to keep it at WOT.
Edit: When doing the comp test remember to keep it at WOT.
Last edited by merc225hp; Aug 12, 2012 at 12:29 AM.
Sorry to read this! The comp test will tell you what's going on, I will keep my fingers crossed for you, three other people that this happened to had bent valves. The setting of the chain at +4 did not cause this I have run +4 and -4 with no problems. What chain set did you use please.
Edit: When doing the comp test remember to keep it at WOT.
Edit: When doing the comp test remember to keep it at WOT.
Edit: This is just purely a thought, but when my heads were built last week the guy shimmed the springs to get a higher spring rate. He said it would help overall with a good seal of the valve seats and help keep compression up. Would the higher spring rate be too much for my stock non hardened pushrods to handle?
Last edited by MeanMagnum99; Aug 12, 2012 at 06:04 AM.
There is some debate on that too..... I have seen it stated in various locations that they are indeed non-interference motors, yet, we had a member here bork his cam timing, and waste a selection of valves.....
Roll the pushrod across a sheet of glass. If it wobbles, it's bent.
Stock cam height may indeed be non-interference, but that's only .432" lift on a 5.2L with the stock pistons .050" in the hole, I believe. The 5.9L gets significantly more clearance due to the dished piston, and only a .418" lift on the stock cam.
I never actually measured the depth of the combustion chamber on my heads, but my gut says it's pretty close to touching in the stock configuration at the two extremes. Add a performance cam, and it could easily go over.
Did you use that JP Performance set? The crank sprocket is double marked for clarity, the 0 on the outside circle should face straight up to the cam sprocket mark, the 0 on the inner circle is for the crank key way. I'm wondering if you transposed those somehow.
Stock cam height may indeed be non-interference, but that's only .432" lift on a 5.2L with the stock pistons .050" in the hole, I believe. The 5.9L gets significantly more clearance due to the dished piston, and only a .418" lift on the stock cam.
I never actually measured the depth of the combustion chamber on my heads, but my gut says it's pretty close to touching in the stock configuration at the two extremes. Add a performance cam, and it could easily go over.
Did you use that JP Performance set? The crank sprocket is double marked for clarity, the 0 on the outside circle should face straight up to the cam sprocket mark, the 0 on the inner circle is for the crank key way. I'm wondering if you transposed those somehow.
Last edited by aim4squirrels; Aug 12, 2012 at 11:14 AM.










