Shifting at 7,000 is not commonplace on this engine. It was purely by accident. However, i will say, the thing pulled hard all the way to it.
Thanks again.
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Shifting at 7,000 is not commonplace on this engine. It was purely by accident. However, i will say, the thing pulled hard all the way to it.
I can tell you this: I have tested that POS cam extensively. This is what I found on my BBC, from 5900 RPM to 6100 RPM I lost 70 HP, many spring combinations and lifter sets were tried, YOU WILL NEVER MAKE THAT POS WORK. I went back after days of testing to my tried and true cam, peak HP was @ 6500 RPM. Lunati is completely out of line with that junk, never Lunati again. BTW with that spring pressure your lucky you didn't drop a valve.Machtuck wrote: ↑Thu Nov 02, 2017 3:40 pm I may have screwed a good engine. Before i tear into this thing, i thought i may ask the experts.
Here it is:
.030 454
Sealed power hypers with small dome ( can’t remember size)
9.6 to 1 - .050 squish
Ported 781’s
Lunati hyd roller 60212 231/239. .600/.600 110 with matching springs,retainers,locks.
I have 135lb on the seat and 360lb open
Lifters are howards max effort (not morels but not junk)
Trick pro pushrods
Comp ultra pro rockers
Installed straight up
Cast crank and factory rods/ all balanced
800 double pumper on eddy perf rpm
Msd street fire dizzy
Here’s what occurred:
I reset the timing at 18 initial but didn’t check total as i had always thought this msd had 18 degrees mechanical advance- Wrong! It has 22. Stupid me. Should had checked the total.
20 mph launch in first and i accidentally let it go to 7,000 before i shifted. Right about the shift, i heard what sounded like float. Took it around block and another 20 mph launch in first. Went to 6,000 and it broke up again before i shifted. Took it home and heard a noticeable tapping sound from pass rear. Not crankcase but more like lifter. Pulled pass side cover. Rockers, retainers locks, pushrods and springs all look good. Yanked rockers and set zero lash on that side. Looked to be full movement on all valves. Still tapping but definitely coming from #8. Checked compression on pass side. All within 10 percent of 187psi. Plugs look normal, no black flecks. Oil looks great. I brought the timing back to 34 degrees total. Good oil press. At idle it is a noticeable tapping but revs fine and seems to subside when revved. I have not put it under load since i readjusted valves. Other than the tapping, the engine still runs and idles fine.
1) i’m wondering if i was detonating up top during the shift instead of valve float and did some rod/ piston pin damage
2). The break up did not sound like a can full of marbles, (detonation) more like low fuel press and car fell on face.- valve float i suspect.
3) its 4100# with me, 3000 converter, th400/ 3:42 12 bolt. 1 3/4 header with 2.5” exhaust flowmaster super 40’s
The only thing that i changed was advancing the timing about 2 degrees more from what it was and i unplugged vacuum advance. And over revved.
Looking for some suggestions on what i might check before i yank intake.
Sure appreciate any advice
What was the spec difference from the Lunati to your replacement cam?vortecpro wrote: ↑Sun Nov 05, 2017 8:48 pmI can tell you this: I have tested that POS cam extensively. This is what I found on my BBC, from 5900 RPM to 6100 RPM I lost 70 HP, many spring combinations and lifter sets were tried, YOU WILL NEVER MAKE THAT POS WORK. I went back after days of testing to my tried and true cam, peak HP was @ 6500 RPM. Lunati is completely out of line with that junk, never Lunati again. BTW with that spring pressure your lucky you didn't drop a valve.Machtuck wrote: ↑Thu Nov 02, 2017 3:40 pm I may have screwed a good engine. Before i tear into this thing, i thought i may ask the experts.
Here it is:
.030 454
Sealed power hypers with small dome ( can’t remember size)
9.6 to 1 - .050 squish
Ported 781’s
Lunati hyd roller 60212 231/239. .600/.600 110 with matching springs,retainers,locks.
I have 135lb on the seat and 360lb open
Lifters are howards max effort (not morels but not junk)
Trick pro pushrods
Comp ultra pro rockers
Installed straight up
Cast crank and factory rods/ all balanced
800 double pumper on eddy perf rpm
Msd street fire dizzy
Here’s what occurred:
I reset the timing at 18 initial but didn’t check total as i had always thought this msd had 18 degrees mechanical advance- Wrong! It has 22. Stupid me. Should had checked the total.
20 mph launch in first and i accidentally let it go to 7,000 before i shifted. Right about the shift, i heard what sounded like float. Took it around block and another 20 mph launch in first. Went to 6,000 and it broke up again before i shifted. Took it home and heard a noticeable tapping sound from pass rear. Not crankcase but more like lifter. Pulled pass side cover. Rockers, retainers locks, pushrods and springs all look good. Yanked rockers and set zero lash on that side. Looked to be full movement on all valves. Still tapping but definitely coming from #8. Checked compression on pass side. All within 10 percent of 187psi. Plugs look normal, no black flecks. Oil looks great. I brought the timing back to 34 degrees total. Good oil press. At idle it is a noticeable tapping but revs fine and seems to subside when revved. I have not put it under load since i readjusted valves. Other than the tapping, the engine still runs and idles fine.
1) i’m wondering if i was detonating up top during the shift instead of valve float and did some rod/ piston pin damage
2). The break up did not sound like a can full of marbles, (detonation) more like low fuel press and car fell on face.- valve float i suspect.
3) its 4100# with me, 3000 converter, th400/ 3:42 12 bolt. 1 3/4 header with 2.5” exhaust flowmaster super 40’s
The only thing that i changed was advancing the timing about 2 degrees more from what it was and i unplugged vacuum advance. And over revved.
Looking for some suggestions on what i might check before i yank intake.
Sure appreciate any advice
Of course theres more in the spec to consider but that .050" and on 109 is definetly going to make some more steam up top and hit the tq harder to boot.
Did you re-check the spring pressures at seat and nose hieghts? Worse possible scenario for spring failure/ loss of pressure is floating them. How did the lock grooves on the valves and locks themselves look? Any rounding of the lock grooves? Lock to retainer interface still smooth and dull?Machtuck wrote: ↑Mon Nov 20, 2017 8:51 am Some resolution and outcome. I pulled #6and #8 pushrods and rockers and inspected carefully. I looked down at associated lifters- all looked good. Re-did lash on those cylinders and the noise has gone away. I’m guessing some junk in one of the lifters. Thanks for the replies guys.