TedH

Machine shop installed my valvetrain pieces on the heads this week (1.430" springs, damper, inner spring, PC seals, keepers and locks) with a fresh set of DART-spec guides, new steel exhaust seats, and shimmed the springs to set the valves up.

What remains to complete the retro-roller conversion:

1. The 'carbon composite plastic' dizzy gear has to be tapped and installed on the Accel performance distributor.
2. Remove crank damper, timing cover and crank gear
3. Remove the Cloyes true roller timing set and the Energizer cam
4. Install the roller cam, double roller timing set, button and canton timing cover
5. install the roller lifters and verify the Comp pushrods are correct length
6. Instal the pushrods and ultra pro magnum 1.52 ratio rockers
7. dress the engine back out with intake/carb, dizzy, and all of the accessories and hoses

I've installed the heads and worked on some detailing/cleaning of the other parts on the engine and got to thinking....

I have a perfectly reliable Crane Energizer 272H10 grind hydraulic flat tappet cam in the engine right now. I've put the lifters, in order, on my workbench under a shop rag.

I COULD stop where I am and install my new balancer/damper, the old lifters/pushrods, the Ultra Pro Magnum rockers and re-install my iron dizzy gear and button everything back up.

OR, I could forge ahead. But, I'm thinking... MAYBE, MAYBE, I'd like to pull the engine in another 8-10 years when I retire and have a lot more time on my hands. I'll plan to do a FINAL engine refresh, pulling the engine and building it around either this block .030 over or a new shortblock, fresh FORGED rotating assembly, a nice set of 200cc cylinder heads, the retro roller kit, stainless headers I've purchased and a fresh header-back dual exhaust; with all of the other parts refreshed/replaced.

So, MY QUESTION: Can I run the dual valvesprings on the heads with my Crane Energizer 272H10 grind hydraulic flat tappet cam and lifters? The dual valve springs are the comp 986-16 items with following specs:

Valve Springs, Dual, 1.430 in. Outside Diameter, 322 lbs./in. Rate, 1.150 in. Coil Bind Height. These are considered 'standard' valve springs.

I got them with the mild retro roller kit "COMP Cams Xtreme Energy Retrofit Cam and Lifter Kits K12-422-8" as I didn't want to get too crazy with the 33 year old shortblock; I refreshed it about 30k miles ago back in 1999.

So, safe to use the dual valve springs on my Crane Cam?

Required Spring Specs on my cam from Crane... are these maximum numbers???
Spring Requirements:
Part Number 99848
Loads
Closed 114 LBS @ 1.700 or 1 45/64
Open 303 LBS @ 1.270

Spring pressures on the new dual springs from Comp (from Comp):
Loads
Closed 132 LBS @ 1.750
Open 293 LBS @ 1.250
Bind 1.150 322 LBS

This tells me I won't wipe a cam lobe when the valve is fully open... 293 @ 1.250 vs the single spring open load 303 lbs @ 1.270. Correct???

pauldana

Run the beehives.... I run to 7000 RPM on them


I did not take the time to look up your cam specs... But im running almost .6" lift


Also if your replacing the hb, I love my fluiddamper hb!

Also, spend the little extra $$ and get the lightest push rods cc makes... Good choice on the rr's. they are what I run also

TedH

Can I run what I have; the dual spring kit installed on the heads?

pauldana

Can you? If all the specs are correct yes..... I was down this road once... Was going flat at 5000 rpm..... Then 63mako and little mouse got me through it... The beehives were the answer.,,,, amazing springs, it's what they run on the new c6zo6's..... I run straight up to 7000. Rpm with them, no float.... Less seat pressure... You won't be disappointed with them

TedH

ok. This is a driver and I rarely push it over 4k rpm. Different purpose. I'll stick with the dual springs.

Thanks for your feedback.

pauldana

cool...i understand.... but keep in mind, they function fine at the low rpm's also... and if you ever need/want them... well.

and the cost is not that much of a difference...

good luck in you build...

63mako

If that is your driving style the springs wil likely be fine but the heads are off. It is not that much more work at this point to change out the cam. Why the hesitation?

MotorHead

You should always use the exact spring for the cam you are using recommended by the manufacturer and have them set up properly by a machine shop, I even had mine setup by a machine shop, it's not as easy as you think. There are a few measurements that have to be spot on and a special mic which I didn't have.

I would never use a single spring on any type of motor, if it breaks the valve will usually drop ( dual springs will usually keep the valve up) creating carnage in the motor and valve train to the extent the motor could end up a lousy boat anchor if the cylinder is damaged, let alone the valve train

gkull

132# seat is on the upper end of H-flat lifters, but you are correct that the open pressure is less.

Those springs are pretty worthless with a max lift of .500 Your originals are even worse at .430 max lift.

Springs loose pounds with time, but you could look at your heads and see if all the springs have shims. Some springs you can unshim and go with taller installed height. Like 1.780 or 1.800 inches and it lowers the seat pressure and increases the max lift an equal amount. The pound level at max lift is also slightly lower

TedH

Max lift comparison:
Crane is .454/.454 flat tappet
Comp is .495/.502 roller

From your comments, the single springs I had when new were not even up to .430 lift requirements. With my Energizer's .454 max lift and a touch more with the 1.52 rockers implies the dual springs I now have appear closer to the requirements of my flat tappet cam than the needs of the .495/.502 roller cam. Correct?

TedH

I started this project assuming that the valvetrain noise was due to failed/failing lifter(s) and or cam. Neither proved true. However, I did find that #4 I/E lifters were showing some perimiter wear. The flat spot on the lifters was smooth; nust a couple nicks around the edges so I replaced them.

What I found to be the issue causing the valvetrain noise coming from driver's side of engine was #3 and #7 exhaust guides were worn severely laterally so bad the valves literally wobbled in the valve bores. And, all exhaust valve seats had failed. Also due to the looseness on #3 and #7 exhaust, those umbrella seals were destroyed and in pieces under each exhaust spring. Shop installed all new steel exhaust valve seats, all-new I & E guides and installed the dual springs and other k-kit pieces.

So, I figured why remove a perfectly satisfactory cam, lifters, push rods, timing set and install a carbon gear on the distributor? I can get quite a few more years of enjoyment from this mill. Say, ten years from now when it's really tired (and when I plan to retire), I'll build a replacement engine on my engine stand with all-new pieces including the roller kit and finally replace the L48 engine... or resurrect it for my retirement with all-new internals.

Matt Gruber

sounds like a fun experiment! 2 theories to test out 1st hand!
1. can the cam take more seat pressure?
2. Will the 2 new lifters wipe out on a used cam with the extra pressure?
My cars have the oil filter bypass plugged, so metal shavings won't likely reach the bearings. I don't drive it under 35F. So with a similar precaution, have some fun and see if it works. and how long. I had a similar dilemma in my 61, most of the brand new lifters had tiny craters, about 1/16" in diameter in the lobe path clearly they were seconds. rejects. sent out rather than trashed. I could of sent them back. I've been using them since '94, so i was lucky. See, now i have a story to tell, ........it worked.
Good Luck!

63mako

To me these are 2 reasons not to use the old cam. The heads are off, springs are set up, the cam, lifters, pushrods and rockers are bought and sitting there. Might have surface rust or stuck lifter internals in 10 years. The amount of extra work to change it out now is a couple hours. The amount of work to go back in after those too strong springs wipe out one of those unmatched new lifters on an old lobe. is to much and can take out other things with it. I would not be experimenting with my #s matching 1971 LT1 engine with 30,000 on the rebuild. You do know the right thing to do.

gkull

I was wondering who thought those roller cam springs matched your cam? I personally never run springs right at the max rated lift. The springs get hotter and don't last very long. I have a set of 1.460 H-roller springs from AFR that were 140 pound closed and .600 max lift. The shop that did your heads might be worth talking to and explain to them that you want higher lift springs to go with your setup. Your lower end springs aren't all that much money.

Like these are 1.800 installed height for .550 max lift.

http://www.summitracing.com/parts/cca-987-16/overview/

Matt Gruber

987 spring binds at 1.15
1.75 installed height
-1.15
_______
0.600 max lift

the shop was listing pressure as installed, not max.

gkull

You don'trun springs to coil bind. your max lift is generally .100 above coil bind. I did come across this for the 987 spring. .550 max lift at .050 above coil bind. This would be pulling out the shim like I posted earlier

Installed Height (in): 1.800 in. Seat Pressure at Installed Height (lbs): 121 lbs. Open Height (in): 1.200 in. Open Pressure (lbs): 343 lbs.

Matt Gruber

agreed. we don't run springs to coil bind. so you think .098" to coil bind is terrible, but .100 is just fine i'm not worried about 2 thou.
my comp cat(old) says 987 1.8" is 130# 325 at 1.25
.
986 120# 1.8" 290# 1.25,
coil bind 1.10.
now i see in post #1 it is the 986

63mako

Comp matched the springs to the cam. They came as a kit. I do like to see .100 or more "cushion". If a cam has 2 recommended springs always choose the stronger, higher lift capacity option.

TedH

Proceeding with the original plan (retro-roller install). Thanks for the feedback. I had not considered that I may lunch the cam and the engine.

Cstraub69

You want to run springs as close to coil bind as you feel comfortable. In the 80's I was taught the same, around .100" but that is not true as testing equipment has gotten much better and Spintrons have helped us improve valvetrain.

Spring "rebound" was found to be one of the largest contributors to harmonics. Rebound is the continuing of the wave of energy the spring has when compressed. At max cam lift this wave doesn't stop, it continues down the spring, hits the seat coil (the last one) then rebounds. The greater the distance between max cam lift and coil bind the greater the rebound wave is and the more harmonics.