Lifter info

[Robert Wilson]

While trying to decide what offset lifters and pushrod lengths I was going to need for my current project, I had an opportunity to compare 3 types of solid lifters and thought I would share the information.
Viewing from left to right in the picture below, we have shielded foot Crower solids, then Comp Cam solids, and lastly #1241 aluminum top Iskys.

Lifter Weights (set including link bar):
Crower 232.8 grams
Comp 232.62 grams
Isky 219.65 grams

Diameters:
Crower .8416"
Comp .8411"
Isky .8420"

Push Rod Length required (Measured with TA heads on 0153 Block):
Crower 9.270"
Comp 9.270"
Isky 7.800"

I decided to use the Isky lifters in my combo. I first wanted the Isky because my lifter clearance was going to be over .003" with the Comps but, as you can see, I am also getting the benefit of less weight and a 1.470" shorter pushrod.

Special thanks to Kip for the mock up pieces

 

[Nasty Wendy]

Good info. Thanks. Amazing that the tall Iskys are lighter than the cut-away bodied Comps and Crowers.

 

[gnxtc2]

Which Isky's are you getting?

I am probably going to take out my Comps and so with the Red Zones (middle ones)

http://www.iskycams.com/ISKY-RedZoneEZRoll3.pdf

Billy T.
gnxtc2@aol.com

 

[BlownV6]

Over the years ive used them all. Years ago I started using the iskys because of the weight but mostly because I see less scuffing of the lifters them selves
and for the benifit of the much shorter pushrods. Thanks for the info on the new Isky lifters. I use the extra tall (bowtie block version)red-zones with .185 off-set and 7.650 pushrods. Great info!! Mike

 

[Robert Wilson]

Which Isky's are you getting?

I am probably going to take out my Comps and so with the Red Zones (middle ones)

http://www.iskycams.com/ISKY-RedZoneEZRoll3.pdf

Billy T.
gnxtc2@aol.com

I did not go with the Red Zones, I just went with the Endurance Plus version. I figured I would be lucky to put 300 street miles a year on the engine so I feel the standard version should suffice.

 

[Jeff Rand]

I also have Isky solid lifters (not installed yet) because they transfer less oil to the heads compared to the Comps. Kenny D recommended I use the Isky lifters because of the drain back issues with the TA heads and block. It was a pleasant surprise to see the shorter push rod length and the reduced weight.
Jeff

 

[Robert Wilson]

Hadn't heard about the oil drain back issues with the TAs. Glad the Isky lifters will help.
Here is a picture of the final install with the Isky lifters. I ended up with Smith Brothers 3/8" to 5/16" single tapered pushrods to finish out the valve train.

 

[gnxtc2]

Hadn't heard about the oil drain back issues with the TAs. Glad the Isky lifters will help.
Here is a picture of the final install with the Isky lifters. I ended up with Smith Brothers 3/8" to 5/16" single tapered pushrods to finish out the valve train.

Looks good. Exactly the same thing I want to do.

Are the pushrods restricted?

Check your PMs

Billy T.
gnxtc2@aol.com

 

[Nasty Wendy]

Hadn't heard about the oil drain back issues with the TAs. Glad the Isky lifters will help.
Here is a picture of the final install with the Isky lifters. I ended up with Smith Brothers 3/8" to 5/16" single tapered pushrods to finish out the valve train.

Why do you have offset lifters on the exhaust side of the #2 and #5 cylinders?

 

[Robert Wilson]

Looks good. Exactly the same thing I want to do.

Are the pushrods restricted?

Check your PMs

Billy T.
gnxtc2@aol.com

If you asking if the pushrods are oil restricted, they are not. I will answer you PMs tonight.

Robert

 

[Robert Wilson]

Why do you have offset lifters on the exhaust side of the #2 and #5 cylinders?

I might have gotten away with centered lifters on these 2 cylinders but the push rod clearance was better with the offsets. I mocked up every cylinder with centered and offset lifters along with a checking pushrod to make sure what I wanted.

 

[ijames]

I assume you used the tapered pushrods because straight 3/8 rods wouldn't fit? The holes in my TA heads are 1/2" so I was hoping that 3/8 rods would be ok, but I haven't got that far in the assembly process yet.

 

[Robert Wilson]

I assume you used the tapered pushrods because straight 3/8 rods wouldn't fit? The holes in my TA heads are 1/2" so I was hoping that 3/8 rods would be ok, but I haven't got that far in the assembly process yet.

Yes, I used the tapered because the 3/8" straight did "touch" the pushrod hole on a couple of cylinders. I believe I could have made the 3/8 straight work with some minor clearancing but I already had the heads torqued down when I discovered it.
Although I personally cannot tell you from experience, there may be some other benefits in a tapered design. I used Smith Brothers but this link from Manton describes some benefits Manton Pushrod Info

 

[lazaris]

I assume you used the tapered pushrods because straight 3/8 rods wouldn't fit? The holes in my TA heads are 1/2" so I was hoping that 3/8 rods would be ok, but I haven't got that far in the assembly process yet.

Carl,

I had to do some clearancing for the 3/8" on mine.

 

[ijames]

Thanks, guys.

 

[Alky V6]

Good info. I think your setup is perfect.

Some additional things to consider. The weight of the valvetrain on the lifter and pushrod side of the rocker is not nearly as important as the weight on the valve side of the rocker. Particularly if high rocker arm ratios are being used. It has to do with the mechanical advantage of the rocker arm ratio that multiplys the spring force that ends up keeping the lifter and pushrod side under control better. With that being understood, I went with a larger diameter body lifter that also came with a larger roller pin and larger diameter needle bearings. All in the interest of a stronger lifter setup. I also went with a 3/8 to 7/16" single tapered pushrod for maximum stability. With the Crower lifters, the pushrods were long, but the design made up for any shortcomings due to length.

 

[Alky V6]

I also run a lighter spring pressure than most would feel comfortable with on a roller cam with as big a lift as I could get away with for the duration I'm using.

The secret is keeping it light on the valve and spring side of the rocker. Because I run alcohol for fuel, the exhaust temps stay reasonable for using titanium exhaust valves, along with Ti intakes too. Ti retainers also. The valve sizes are uncommonly small for what I'm doing which also helps keep weight down, along with the benefit of avoiding valve shrouding with a small cylinder diameter.

 

[Jeff Rand]

Don,
What spring pressure are you running? Are you using the behive springs what is the total lift ?
Thanks,
Jeff

 

[Alky V6]

Don,
What spring pressure are you running? Are you using the behive springs what is the total lift ?
Thanks,
Jeff

My cam is not very radical. If you're running a 9,000 rpm capable stage II headed setup, don't even think the following specifications are going to work for that.
Spring OD: 1.550".
The lift at cam lobe is .420"int/.417"ex.
Rocker ratio: 1.7:1.
Lift at valve: .714"int.
Spring is a standard dual spring w/damper. Crane part# 99885.
Installed height: 1.960".
Pressure on seat: 195-210#.
Spring rate: 621# per inch.
Pressure at full lift: 625-635#.
Operating range for the cam is 3600-7400 rpm. Valve float predicted at 8000.
Anywhere between 6900-7400 works out to be a good shift point for my cam.

My duration and overlap specs are not important since most of you don't believe in the theory of resonant pressure pulse tuning with a turbo engine. Which also requires careful intake and exhaust manifold specifications for proper resonance tuning. Again, most of you are not willing to go through that exercise.

Lifter diameter is .903". Weight is 268.6gms. per pair w/tie bar.
Pushrod weight is 121.4gms.
Retainer weight: 17gms.
Intake valve: 68.3gms.
Exhaust valve: 59.6gms.
Locks: 7.3gms.
Lash caps: 1.8gms.
Rockers: 143.3gms. (body only)
Springs: 145.3gms.

In an earlier post I mentioned that the weight on the valve side of the rocker was most important. That includes the rocker body also.

Special note: Obtaining a large lift figure with a small duration cam is a very hard thing to do. It would require very harsh ramp speeds and would be hard on the valvetrain. Every duration figure is going to have a maximum obtainable lift value associated with the lobe profile inorder to maintain sane ramp rates. When the cam designer strays outside normally accepted max ramp rates, you can bet big springs will be part of the picture.