Little Tommy

the 525s and 6oos are stock GM lifters what does that tell you

Raylar

It probably tells you that they will last on average at least one year! Brunswick is a shareholder driven company like most big US corporations. Profit is the driving force!

Ray @ Raylar

abones

I have to agree with Little Tommy, the stock lifters are just fine for most 6000 rpm applications, maybe I have just been lucky for the last 5 years, and 100 hours, but I have been running a 600 lift cam at 5800- 6100 rpms with no lifter problems, just need to replace valve springs every 2 seasons to assure the valve train stays stable!!!! Why pay Xtraaa for all the aftermarket stuff. (I can understand cams, and roller rockers) everyone makes thier own choices!!

rmbuilder

We did some A/B testing on a HP 500 upgrade package using AFR heads with a custom cam and Edelbrock intake and Holley HP carb. Initially we reused the HP 500 lifters. After 14 pulls we determined there was instability in the valve train at certain RPM levels. The lifters were changed out for the Morel Hyd-Rollers and picked up 12 HP, cleaned up the fuel curve, and pulled to 6200 without any sign of float. I can also say the Morel lifters are doing very well this season in some P class boats.
As for the 525 EFI and 600 SCI the cam card for the 525 EFI specifically states that the long body lifters must be used with the cam, and the 600 SCI has a very mild cam that barely exceeds .570” on the exhaust side only.
The Morel axels are 9310 and the wheel is 8620 with a wheel diameter of .750” vs. .720” for the OEM. They are fully machined from bar stock vs. cast iron and centerless ground to an OD tolerance of +/- .0003". All heat treat is done in house. They also use a $500,000 CNC process to keep bore concentricity to incredible tolerances. Tighter tolerances result in reduced lifter bleed off associated with higher spring forces and less plunger deflection will net more effective lift at the valve. Best of all the Morel is fully rebuild able where the OEMs and most aftermarket go in the trash.
Bob

abones

Hey now you guys have me all messed up. The stock G.M. lifter is not the same as the hp500 is it? I thought the hp500 used and aftermarket lifter. I believe the same is true for the 525 and the 600, some one please clairify!!!

jdnca1

abones:

I went though this myself earlier this year. I believe the "stock" HP500 lifters are the Crane 16535's. The reason I believe that is they are the only company I could find that made the "dog bone" retainer style lifters. The stock 500EFI cam is 230/236 .598/.610" lift which is beyond max recc lift on a GM lifter and I wouldn't think Mercury knowingly exceed those parameters. There was a serious run on those lifters earlier this year so I went with the Crane 13532 retro fit lifters. Those lifters are $100.00 cheaper but you'll be spending that savings on REQUIRED new pushrods. Those are Crane part #13628. Hope that clears it up a little.

rmbuilder

JDNCA1,
Correct, the "Blue" motors run the aftermarket lifters for the reasons stated. Some of the "Black" motors ran the spider/dog bone setups. Morel does offer a drop in replacement for the dog bone that will accommodate lifts up to .650" with all the features of the vertical link bar setup.
Bob

rmbuilder

Sutphen 30,
The information posted was derived from dyno testing a customer motor. The original lifters were checked and found to be in good working order. During the course of the first ten pulls it became apparent the HP’s were not maintaining proper valvetrain stability. It made no sense to purchase a new set of HP’s when the Morels were readily available. It was apparent the originals did not RPM well with the seat forces of the Manley NexTek springs being used.
The decision to switch was not made on this one test. There was a ton of cumulative data to support the choice. Spintron testing by a major cam company has shown that the Morels will accept higher seat and open load spring pressures so that damping of the lifter at high rpm can happen without collapsing the plunger assembly. This also equates to higher rpm without getting into valve float, especially given the weight of the BBC valvetrain. That’s the reason Morel makes lifters for Isky, Cam Motion, Bullet, Lunati, Comp Cams Etc. Much of the same materials and technology that go into these consumer products are used in the lifters used by Roush, Childress, Hendrick, (Busch/Truck) and Force etc. If there’s a better mousetrap out their Bill, I’m all ears.
Here’s a photo of the lifter that’s won multiple T/F and Funny Car Championships. The link bar assy should look familiar and the upper wheel/axel are the same material that comes standard in your Morel lifter.
http://www.powerandperformancenews.c...&Store_Code=CC
Bob

wkd1

Ok so I have a gen6 502.....with the stock lifters in it right know...I did have the comp cams in with .001-.002 clearance between the lifter bore and conecting bar....
I changed the lifters becuase when I would come off full throttle run it sounded like a box of marbles was dropped into the motor.
It didnt do it right away it took about 10 passes @5k-5500 then started...I found out later that the springs(comp cams) had failed.
I was planning on reinstalling the comp cam lifters again.(which are new comp cams/CP performance replaced them on my request.Because there was no time on them).But I am also planing on running a different cam.less duration to aviod reversion.
Or should O purchase a different set?

Thunderstruck

The motor that RMBuilder refers to is one of mine. The Crane lifters were not changed when the motors were rebuilt because they only had 20 hours on them before the rebuild. The Morels saved the project because the Crane's started floating at ~5600 rpm which is close to max HP for the setup which robbed HP and created a reliability issue for me. RMBuilder can explain if he would like. Since installing the Morels and taking all of RMBuilders advice, I have run 3 hard 200 mile poker runs with periods 5-10 minutes at WOT with no lifter issues. Picked up 6-8 mph depending on the conditions with AFR heads with 500HP short blocks.

Tom