Motor won't rev over 5200-5300rpm... WTF???
- Thread starter yullose
- Start date
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Just another quick update...
After a few more test runs... I don't believe the valve float is gone completely... Seems it was just raised from 5200 to 6000-ish.
I ordered a height mic the other day, which just arrived this afternoon. I wanted to verify the accuracy represented on my build sheets.
Well... they are off... The installed heights all measuring TALLER than what was on the build sheet....
Adjusting spring pressures using faulty, inaccurate info on the build sheets was just plain stupid. I made the mistake of ASSuming the info was correct.
I should have verified the installed heights and compared them against the build sheets weeks ago.
All the valvespring hardware is getting tossed in a box as a reminder of this nightmare.
I have a whole new set of springs(26120 beehives), retainers, locks, locators, etc... on the way. I will build these heads myself...one spring at a time, one shim at a time... and chalk this up as a learning experience.
According to my calculations... my 26120 beehives will get installed @ 1.840" using +.050 retainers with .060 locators and no shims...and at full open, will be .062" away from coil bind. My current retainers are +.050 and give me a 1.900 installed height w/o shims or locators.
The 26120 beehives are rated 155lbs @ 1.880 and 377lbs @ 1.280... they coil bind at 1.230.
I will be installed @ 1.840 closed and 1.292 open... so it sounds like these 26120 beehives should fit and work great.
After a few more test runs... I don't believe the valve float is gone completely... Seems it was just raised from 5200 to 6000-ish.
I ordered a height mic the other day, which just arrived this afternoon. I wanted to verify the accuracy represented on my build sheets.
Well... they are off... The installed heights all measuring TALLER than what was on the build sheet....
Adjusting spring pressures using faulty, inaccurate info on the build sheets was just plain stupid. I made the mistake of ASSuming the info was correct.
I should have verified the installed heights and compared them against the build sheets weeks ago.
All the valvespring hardware is getting tossed in a box as a reminder of this nightmare.
I have a whole new set of springs(26120 beehives), retainers, locks, locators, etc... on the way. I will build these heads myself...one spring at a time, one shim at a time... and chalk this up as a learning experience.
According to my calculations... my 26120 beehives will get installed @ 1.840" using +.050 retainers with .060 locators and no shims...and at full open, will be .062" away from coil bind. My current retainers are +.050 and give me a 1.900 installed height w/o shims or locators.
The 26120 beehives are rated 155lbs @ 1.880 and 377lbs @ 1.280... they coil bind at 1.230.
I will be installed @ 1.840 closed and 1.292 open... so it sounds like these 26120 beehives should fit and work great.
275/60's on 15x7's
- Joined
- Feb 18, 2006
- Messages
- 10,084
I be watchin for some results. Keep us posted. 
The entire beehive setup (16 of everything) was $301 shipped to my door. (I wanted spares)
I've got $6k+ into this car since August... so what's another $300 at this point ?
I'm just fortunate that I use to build cylinder heads in a machine shop 25+ years ago and still remember a few things.
If I had to pay a shop to do all this work 2-3 times over... I'd be livid.
The installed height discrepancy isn't much (only .020") and it's probably due to the keepers and retainers getting settled-in to each other.
I think the biggest problem is just these dual springs and heavy steel retainers... combined with the installed heights loosening up... just made for a bad valvetrain combination.
Looking at Comp Cams website, the 26120 beehives are a premium spring listed for a 6500rpm hyd roller BBC. The BBC uses 2.19/1.88 valves with 3/8 stems...
I really think this next batch of springs will be my last.
Dusty Bradford
Well-Known Member
- Joined
- May 24, 2001
- Messages
- 5,802
Your doing exactly what I do to all my heads. I pressure check each spring at installed height. Then assemble the heads myself so I know exactly what the spring pressure and installed height is. Spring pressure and valve control is everything with a turbo motor.
With my new big block heads. The 1st thing I'll do when I put the engine together will be to disassemble these new heads and check everything.
With my new big block heads. The 1st thing I'll do when I put the engine together will be to disassemble these new heads and check everything.
Just check them every few months and see if your losing any tension.
Well... now I gotta figure out where I'm 'gonna find room for these beehives.
The installed heights are coming in @ 1.780 with a .060 locator and +.050 locks.
It looks like I need to find another .100"... or another set of springs.
Intalling them at 1.780 would put them too close to coil bind. (within .002)
I wonder if it's possible to machine the locators thinner ? Say from .060 down to .020-.030 ???
The installed heights are coming in @ 1.780 with a .060 locator and +.050 locks.
It looks like I need to find another .100"... or another set of springs.
Intalling them at 1.780 would put them too close to coil bind. (within .002)
I wonder if it's possible to machine the locators thinner ? Say from .060 down to .020-.030 ???
Mike Licht
I was here first
- Joined
- May 23, 2001
- Messages
- 4,642
check out the 26918 spring I prefer the Pac spring but the specs are the same, it may be close for you
Mike
Mike
Well... now I gotta figure out where I'm 'gonna find room for these beehives.
The installed heights are coming in @ 1.780 with a .060 locator and +.050 locks.
It looks like I need to find another .100"... or another set of springs.
Intalling them at 1.780 would put them too close to coil bind. (within .002)
I wonder if it's possible to machine the locators thinner ? Say from .060 down to .020-.030 ???
Cut the spring seats deeper. Comp 4719 seat cutter. Measure how high the valve guides are from the current spring seat so i can tell you if the cutter i listed will work. It may not reach the seat if the guide sticks up too much. We will have to find a different seat cutter. Actually im not sure the 4719 will work since its for a .630 guide. You need it for a .570 if i remember correctly. Look at comps seat cutters. They should have one that will work
He has too high a ramp speed imo to get the 26918 to work at high rpm/boost. If they did work they would be short lived.
Well... I just put it back together with the old springs.
The season is just about over, so I'll just take it easy the next few weeks.
I found a handfull of .015 hardened shims... and tried one beehive spring using just the shim and no locator. I got it on and the installed height was still tight, but workable.
I just didn't trust it... and couldn't take the risk of eating thru the shim or having the spring walk around, chewing up the spring pocket.
The 26120's will just have to wait until I can do it right.
I was tempted to order a 26918 setup for the time being... but that would just be throwing more good money after bad.
Once I park the car for the Winter, I'll pull the heads off and fix them correctly. There should be enough meat under the springs to cut the pockets another .100 deeper. Then I'll be dead-on with 1.880 installed heights... Which is where these springs need to be.
I will also probably yank this cam out, in favor of something with more duration and less lift.
I probably won't go to a solid billet roller, because I've been down this road before... If I keep getting carried away with this car, it will no longer be fun or practical to drive on the street... the whole reason I don't have my 8-sec BBC's anymore.
The season is just about over, so I'll just take it easy the next few weeks.
I found a handfull of .015 hardened shims... and tried one beehive spring using just the shim and no locator. I got it on and the installed height was still tight, but workable.
I just didn't trust it... and couldn't take the risk of eating thru the shim or having the spring walk around, chewing up the spring pocket.
The 26120's will just have to wait until I can do it right.
I was tempted to order a 26918 setup for the time being... but that would just be throwing more good money after bad.
Once I park the car for the Winter, I'll pull the heads off and fix them correctly. There should be enough meat under the springs to cut the pockets another .100 deeper. Then I'll be dead-on with 1.880 installed heights... Which is where these springs need to be.
I will also probably yank this cam out, in favor of something with more duration and less lift.
I probably won't go to a solid billet roller, because I've been down this road before... If I keep getting carried away with this car, it will no longer be fun or practical to drive on the street... the whole reason I don't have my 8-sec BBC's anymore.
The other problem I'm seeing is... there are no +.050 locks or retainers for the 26918 spring.
If I use a standard retainer/lock combo, I will have install heights @ 1.730, using the .060 locators. I think the 26918's want to be installed @ 1.800.
I see coil bind on the 918's is 1.100... and I'd be @ 1.182 open, using the tighter installed heights.
1.730 - .548 = 1.182
Only problem is, they are only 318lbs @ 1.200.
I just don't think they are enough spring for my combo.
As a side note... I called a buddy of mine this afternoon (Andy Jensen) and talked to him for 20 minutes about this problem.
In a nutshell... his opinion was... hydraulic rollers and lots of boost don't mix well.
He said once you get enough spring pressure to overcome the boost, you begin to overwhelm the hydraulic lifters. He suggested using solid lifters on my current profile if I insisted on keeping this grind in the car.
I think I'll get this corrected over the Winter with a different cam profile and spring pockets cut for the taller springs.
The TSM points leader last year ran a hydraulic and used the 16920 springs so i dont see the hydraulic lifter being the problem if the car will be going less then 145mph in the quarter. Running solid lifters will open up more potential problems and cost a lot more since you will need springs anyway, shielded foot solid lifters, new pushrods and a lot of time installing. If i was in your position id get the 16920's to work or switch to a different cam.
