<-------- IS NOT HAPPY

so after about 20 minutes of total run time, mostly just idling in my driveway, a few revs to setup my BOV, i pulled the valve covers to hotlash the comp r's i run (i know i know) because the valves were making god awful noises, come to find out, 4 of the springs are broken on the top coils!

these springs are the comp 26120's good for about .600 lift, 155 lbs on seat, 377 open, 1.880 installed height, coil bind at 1.280

my cam is a custom cammotion cam, 234/234 .576/.576 on a 114 lobe center, 112 centerline

rest of valvetrian, Comp R lifters, Comp 7.200 hardened pushrods, GMPP guideplates, Comp magnum 1.6 RR's, Comp beehive retainers, cups, and 10 degree locks

i installed the springs as close to 1.880 as possible, intakes were all spot on, and exhaust were about 1.870~875 (hard to read the mic)

the noise existed from the first time firing it up! i couldnt belive what i found when i pulled the valve covers off...comp warranty dept says send them back for inspection and possible replacement, or upgrade, which i fully plan on doing, im just looking for some insight here, i dont get it, if anything, these springs were overkill, the comp tech guy was trying to sell me the smaller beehives, but because of past valve float experience from crappy springs, i opted for the larger ones....

man this sucks..20 minutes on a new motor, and this is what i get...and BTW, my cometic MLS gaskets are seeping...coolant pooled in my heads

 

If the springs are installed at 1.880 and coil bind is at 1.28, then the most lift I would run with them would be .550. At .600 lift these springs will be at coil bind. You need about .050 clearance between your max lift and coil bind for safe measure.

 

Is that the lift for the 1.5's or with the 1.6's?

 

I didn't want to be insulting, but that was exactly what I was thinking. Most cam cards for SBC cams are written with valve lift calculated for 1.5:1 rockers. I guess they figure that if you installing "non-standard" rockers ratios that you will think of that. Four broken springs implies a bad batch of springs or an installation error. The latter is much more likely.

Regardless, a word to everyone: you need to check EVERYTHING when assembling a motor. Don't assume anyone else did their job right. In the case of valve springs, here's what I do wrt checking that specific component. First, I do a good visual inspection of each spring. I am looking for visible defects (a ding or other surface defect spells death as a stress riser) and that all the springs appear the identical (a wrong spring slipping in is not uncommon). I then measure OD and ID to see if that is in line with the spec. Again, I am looking to see if I have the right spring or perhaps discover a defect. I then use a square to check and be sure the spring is straight. Then, I put them all in the spring tester. I want to be sure they are all close to spec in terms of pressure, both closed and open. Again, looking for a bad or incorrect spring(s). Never fully compress the spring (to the point that the coils are stacked). After checking, they may be installed. Once the motor is mocked up,. You need to turn it over and check for coil bind, interference with other components (rockers contacting the retainer on the inside edge and valve seals are common areas of interference), as well as verifying proper pushrod length by observing the motion of the rocker tip across the tip of the valve.

Rich

 

Definitely sounds like something was not figured out quite right.

 

stroked makes a very good point. The other thing that jumped out at me was 7.200 pushrods with a 1.880 installed height how was your geometry? On an installed height that tall I would have expected custom length pushrods to be necessary.

 

First thing I thought is "how did you measure the installed height"

Cause you took them to coil bind, that's how they broke.

Bret

 

im sorry, typo, coil bind is at 1.230, giving .650 of lift before bind, which is where they get their .600 max lift from (0.050 clearence). according to Cam motion, cam specs were with 1.6 RR's, .576 lift would be adeqate then... I used a comp valve height micrometer to measure install height, and once all were installed and the heads were on the motor, i turned it by hand to check all the clearences, never saw any interference or coil binding, ie. i could see light thru each coil when fully compressed, as it should be because my cam is within specs of these springs.

as far as spring install height affecting geometry of the valve train?! that is impossible, chanding install height is done by adding shims under the springs so they are more, or less compressed when installed. the valve stem was still in the same spot, that doesnt change, therefore i dont see how it is possible for the install height to effect valve train geometry...maybe i am missing something though?

 

Did ya add the step in the valvespring mic into your measured height... you need to setup the installed height with that mic .150" HIGHER than what it says if the retainer fits in that step. You wouldn't see that with the hyd lifter because that lifter compresses enough to not run into coil bind.


1.880" indicated minus the .150" will give you 1.730" installed height, minus the .576" lift = 1.154" which would break the springs really dam quick. Pushrods are probably bent too.... check that out.

Bret

 

That just seems like an aweful tall height so I figured somewhere along the line was changed more than just shims.

 

exact specs from cammotion

Duration At .050

Intake - Rocker Ratio 1.6
Lash 23 24 25 hyd

Exhaust - Rocker Ratio 1.6
Lash 23 24 25 hyd

Intake

valve open = 5.7 btdc
centerline ---112 atdc
valve close = 48.6 abdc
duration ---- 234.4 crank deg
lobe lift = .36012 in.
VALVE LIFT --- .57619 in.

Exhaust

valve open = 53.7 bbdc
centerline --- 116 btdc
valve close = 48.6 abdc
duration --- 234.6 crank deg
lobe lift = .36063 in.
VALVE LIFT --- .57701 in.

am i correct here? this should be within these springs specs, after all, the comp tech guy sold me on 'em

 

Did you get valves that are longer than the ones TFS supplies with the heads? Because you CAN'T get to 1.880" installed height without longer valves.

See post above.

Bret

 

umm no i didnt know about that...i followed the instructions for the mic, im thinking it was build into the mic though, because when it was 0-ed out, it wasnt quite 0 on the dash

no bent pushrods though

 

Yep... that's what I thought. Try and set it up with that extra .150" your going to need valves that are longer than stock to do that most likely.

Bret

 

manley extreme duty stock length valves