[tom s]

HELL YES!Everyone wants to use what is just enough and like you I have found virtually no downside from having more.Sometimes we find that just enough might be the diff of a few hundred RPMs of added HP.A cam that gives up at 6000 with 160 on the seat might go 6500 with more.I was told by my guy at Comp to treat a hyd roller cam with solids as a solid roller cam.As I have found now with the advancement of hyd roller lifters with better tolerances and proper oil and springs they will make HP to 7000 with the right springs and induction.Tom

[Steve C.]

I've been fortunate over the last 20 years or so. I've only had one instance with a solid rollar application that almost led to issues... I broke the inner coil on a dual valve spring and limped home.

We have always run adequate spring pressure, checked the pressure and the valve lash once a year. Keeping in mind my application is a limited street, use hobby car application. NOT a dalily driver !

Again. You lose enough spring pressure and the lifter loses contact on the lobe as the valve closes, if this the situation after time the springs will further deteriorate to the point it can cause issues other than nosing over at rpm. When people call it 'valve float', more often than not this is what happens.

Gentlemen, remember a solid roller lifter on a hydraulic roller lobe IS IN FACT a solid roller cam application !

.


.

[jonmachota78]

I haven't seen you guys mention it unless I missed it. My understanding is that the hybrids live longer on the street because of the tight lash they run so the lifter bearing don't get hammered constantly like a solid roller cam does. It's the lash that hammers the lifters. Hybrids and hydraulics are easier on parts.

[Steve C.]

I had a lifter fail in a BBC and broke the block. It was a comp cams roller and the recomended lash was .028 and .030 so that is what I ran..I thought that was too loose but figured the cam company knows more than me ..well now I am paranoid .My new engine has a Crane grind and the cam card said .026 and .028..but to be safe I set them at .017. My question is...will this hurt anything? I used to think that the recomended lash was just whatever made the best power on the dyno...but since reading this board the last few months,I gather from the posts here,that the lobes on the cam are designed for a certain lash....that it isn't just a tuning thing.So, what effect(other than making the engine think it has more cam) will running a considerable amount less lash than recomended have?

Answer......

It depends on how the clearence ramp was designed. It'll either have no effect on valvetrain stability, or it'll help. It won't hurt anything but performance.

It's not the tightness of the lash, it's the velocity of the cam at that point that dictates how hard the lifter hits the cam. You can have a cam designed for a looser lash that has less velocity at the lash point then a cam designed for a tight lash.

Source: http://speedtalk.com/forum/viewtopic.php?t=8265



( Does this relate to the typical .006" lash used on the Hybrid set up with the solid roller lifters ? And a fwiw, my comments here regarding valve spring pressure are for the most part regarding the solid roller set up not using hydraulic roller lifters. Nor do I have a issuew with the Crane spring as long as it measures correct and used in conjunction with adequate pressure for the intended use )


.

[Dave Bisschop]

Originally Posted by Steve C.

It's not the tightness of the lash, it's the velocity of the cam at that point that dictates how hard the lifter hits the cam. You can have a cam designed for a looser lash that has less velocity at the lash point then a cam designed for a tight lash.

Source: http://speedtalk.com/forum/viewtopic.php?t=8265

.

I'm not convinced that statement is 100% correct, I know from experience with our race car, that when the springs were getting to the end of their life (borderline valve float going through the traps) if we tightened the lash up a few thou from the .028/.030" recommended by the cam manufacturer it would help at least finish the race weekend, which leads me to believe that less lash reduces lifter bounce.

When it comes to requiring more spring pressure on the hybrid set-up vs. running a hyd. roller lifter with all things the same and no more rpm is being sought with the solid roller lifters there's no reason why more spring pressure is required (lots of smart people at Comp Cams and other cam companies, but there seems to be a lot less smart people answering tech questions a lot of the time and you can call and talk to 10 different people and get 10 different answers). I did a back to back, same day dyno test with a 246/252 .400" lobe lift hyd. roller cam in a 468ci engine swapping from hyd. to solid roller lifters and there was no indication of valve float turning the engine up to 6200-6300rpm, using the 99893 springs set up around 1.800". The solids showed 6-8 more hp over the hyd. above the torque peak. Maybe if we backed the lash way off there might be something there, but until I actually see some solid back to back data to prove that the solid lifters need more spring pressure I'm just not buying it.

Valve, retainer and spring weight all have to be taken into consideration when figuring out how much spring pressure is required for an application along with how aggressive the cam lobe is and how much rpm the engine needs to turn to optimize the combo.

[Will]

I'm not understanding this math. If hot lash is .006 x rocker ratio how could the required lash ever be .003"? .006 x 1.5 = .009.

What am I not understanding?

[grandville455]

Originally Posted by Will

I'm not understanding this math. If hot lash is .006 x rocker ratio how could the required lash ever be .003"? .006 x 1.5 = .009.

What am I not understanding?

What Mike was saying is if your hot lash is more then .006x rocker ratio, in this case 1.5 ...which is 009, you don't want to be higher then that total hot
, so if u have to set them at .003 or whatever x ratio to stay under that .009 , then that's what u do. In my case I was using 1.65's ...the .003 is just a example...but I ran mine at .003 cold, n we all know how my 4550 lb car ran!

[Will]

Originally Posted by grandville455

What Mike was saying is if your hot lash is more then .006x rocker ratio, in this case 1.5 ...which is 009, you don't want to be higher then that total hot
, so if u have to set them at .003 or whatever x ratio to stay under that .009 , then that's what u do. In my case I was using 1.65's ...the .003 is just a example...but I ran mine at .003 cold, n we all know how my 4550 lb car ran!

OK, thanks for clarifying!

[Larry Navarro]

hmmmm......using 1.65 myself, I just finished setting the lash at .003" COLD.......ouch

Guess I better go and change direction.

[GOAT WHORE]

Dave is a bad mutha trucker! Top notch work and will always answer email questions aka hold your hand

[Dave Bisschop]

Originally Posted by GOAT WHORE

Dave is a bad mutha trucker! Top notch work and will always answer email questions aka hold your hand

Thanks, how's grandma's car coming along? Will it be at the nationals in Seattle this summer?

[GOAT WHORE]

Originally Posted by Dave Bisschop

Thanks, how's grandma's car coming along? Will it be at the nationals in Seattle this summer?

Car is coming along slowly but surely! My goal is to have it done and at the Nationals.

[grandville455]

I ran Daves Road paver, with his 290 heads with the hybrid setup, and if u put my setup in a 3500 lb car it would've been mid 10's, that was only 10.7 comp.I don't think that's average at all.

[PAUL K]

Originally Posted by grandville455

I ran Daves Road paver, with his 290 heads with the hybrid setup, and if u put my setup in a 3500 lb car it would've been mid 10's, that was only 10.7 comp.I don't think that's average at all.

I think more people would find that to be impressive and a lot faster than mid-elevens. IMO

[ponjohn]

Originally Posted by PAUL K

I think more people would find that to be impressive and a lot faster than mid-elevens. IMO

His Grandville was 4100 lbs.

[PAUL K]

Originally Posted by ponjohn

His Grandville was 4100 lbs.

I think it was heavier than that. Darby's cars are good examples of what can be accomplished when you "raise the bar".

[Formula8]

Wow. I have been buried at work and been off line for a couple of days and my email is packed with notifications! Anyway, thanks Paul, Dave, Tom, Steve, Darby and everyone else that contributed to this thread. The subject has bounced around a bit but lots of great info.

For me, I ran my SD/KRE heads with my SFT cam and it was everything I ever wanted. For whatever the reason, It was clear my iron heads were leaving some serious power and driveability on the table so they were sold and I have absolutely no regrets about that decision. Well...... outside of I should have reinstalled by rev limiter. My SFT cam quickly was showing signs of going flat under the increased spring pressure used with these heads so I needed to replace a cam and lifters anyway. Yes, I used VR1 with either EOS or ZDDP. Even so, it makes little sense to mess with the flat tappet stuff nowadays so I made the decision to go roller and the OF is a proven cam in many similar combinations.

Given that my block is not fitted with oil restrictors and I was hoping to retain the new pushrods I bought when I installed the KREs, I thought a lifter that provided oil restriction, pin oiling and relative to most hydraulic lifters, seems to be quietly and reliably going about their business in many engines would be a good choice for my application. I prefer solid lifters as there is no monkey business over the preload so Crower's 66260H was chosen as it meets all the criteria and does not break the bank.

Soooo.....that is how I arrive at an aluminum KRE/SD D-port, OF cam and Crower solid lifter being the best solution for my situation and car. I would certainly hope that a dedicated drag car could absolutely walk around my car with iron head and a HFT cam. But. I am not interested in a drag car, working over 40 year old iron heads or playing chemist with oil to keep the cam alive. So, I think this combo will suit my needs in a easy to deal with package like Dave suggests.

[ponjohn]

I went 11.98 @ 109 @ 3680 w a 9.3-1 463 220 cfm dport.
xe284 dynod at 443 hp and yes it went flat at 4700 rpm.

So with a better cam or springs it would have run better.

[77 TRASHCAN]

Originally Posted by ponjohn

I went 11.98 @ 109 @ 3680 w a 9.3-1 463 220 cfm dport.
xe284 dynod at 443 hp and yes it went flat at 4700 rpm.

So with a better cam or springs it would have run better.

Do bears go #2 in the woods?
Do bee's bee?

[PAUL K]

Originally Posted by ponjohn

I went 11.98 @ 109 @ 3680 w a 9.3-1 463 220 cfm dport.
xe284 dynod at 443 hp and yes it went flat at 4700 rpm.

So with a better cam or springs it would have run better.

Ruh-roh..the dreaded XE word! I've used that cam before in a few builds. It fits good in compression challenged 455's. Has a great sound and as you know needs a bit more valve spring. Nothing at all wrong with 11.98 @ 109. I would think the mph is down because of the springs. Shim them and let us know how much you pick up!