From a solid roller to hydraulic roller

[HQM383]

That said, with 540 CID, it seems torque isn't the issue.
It could be time related as suggested.
And now there's evidence is some unhappiness at 1750....

Yep. If it’s not happy @1750rpm then get it out of there with diff gear change so its living in the range where it’s happy. Or as mentioned earlier leave O/D for highway efficiency. Going to a lot of trouble for the engine to accommodate the gearing.

[Geoff2]

Tom68,
Try reading what I posted. The cams tested were identical except for LSA & ground by the same company for the sole purpose of seeing what LSA did. The LS test used Crane cams; the Chev test used Isky cams & was supervised by Joe Sherman.

[Geoff2]

So, what has changed. The thinking at Crane cams, it seems.
I have a 1984 catalog. Looking at the SBC hyd flat tappet grinds listed, there is only one cam on 106 LSA out of a total of 13.

I also have a 2010 Crane catalog. Out of a total of 47 SBC HFT cams listed, 14 are on 106 LSA or tighter. One, a short duration 194/204 @ 050 is on 104 LSA.
And it says it has good low & & mid range tq & hp.
Hmm...

[CamKing]

So, what has changed. The thinking at Crane cams, it seems.

And their thinking, sent Crane Cams the way of the dinosaurs.
There is no "tight" LSA, and there is no "Wide" LSA. There's only the correct or incorrect LSA for an application.
Almost all our circle track SBC cams are on an LSA between 104 & 108, because that's what their applications call for. Sometimes we have to deal with a limited tire rule, and we will be as wide as 110 LSA. These are normally applications that run from 4-5K off the corners to 7-8K at the end of the straights. They don't run part throttle in traffic at 1.700rpm.
For a street application, it's better to reduce the duration a little, and widen the LSA. This will increase power below peak Torque, and still hold onto the power on the top. For street applications, the average power between peak torque and peak HP, isn't as important as the average power from idle to max RPM.

Here's a really good running street engine.
355" SBC
10:1 with ported 492 heads, Performer RPM, and Holley 600.

RPM---TQ--BHP
3200--436--266
3400--443--287
3600--445--305
3800--444--321
4000--443--337
4200--440--352
4400--440--368
4600--441--386
4800--441--403
5000--432--411
5200--422--418
5400--412--423
5600--400--426

The cam is 216/220, on a 112 LSA, and 108 ICL

I could go to a cam with a tighter LSA, and it would pick up peak torque, but it would lose power below peak torque, and require a higher stall speed.

[Walter R. Malik]

Bill Metzger at Lazer Cams had a "Street Rod Series" of cams which were small, (205/210 @.050"), which had 104 to 106 separation simply because they would SOUND bigger at idle but, smooth right out when cruising.
They were simply the compromise which was needed for THAT particular application; yes, merely the compromise needed for THAT application.

[skinny z]

Here's a really good running street engine.
355" SBC
10:1 with ported 492 heads, Performer RPM, and Holley 600.

RPM---TQ--BHP
3200--436--266
3400--443--287
3600--445--305
3800--444--321
4000--443--337
4200--440--352
4400--440--368
4600--441--386
4800--441--403
5000--432--411
5200--422--418
5400--412--423
5600--400--426

The cam is 216/220, on a 112 LSA, and 108 ICL

I could go to a cam with a tighter LSA, and it would pick up peak torque, but it would lose power below peak torque, and require a higher stall speed.

This is hitting closer to home Mike.
Is there a significant change one way or the other with an aggressive profile like like your EHR series vs your regular hydraulic rollers when taking the same .050" numbers into consideration? That being shorter seat timing yet the same 050" number.

[CamKing]

This is hitting closer to home Mike.
Is there a significant change one way or the other with an aggressive profile like like your EHR series vs your regular hydraulic rollers when taking the same .050" numbers into consideration? That being shorter seat timing yet the same 050" number.

Not really, because it's all based on seat duration, not .050" duration. All my calculations are for the actual opening and closing points(Seat Duration).

I list the .050" durations, because that's what everyone looks at, but I don't use them for any calculations.

[RevTheory]

I was thinking the other day about something like this on a 110 LSA so that both camps think it's wrong by the same amount

Bullet Cams HR301/390 301 246 167 .3900 CRA Intake .663 with 1.7 rockers
Bullet Cams HR307/370 307 250 169 .3700 CRA Exhaust .630 with 1.7 rockers

[af2]

This is hitting closer to home Mike.

I list the .050" durations, because that's what everyone looks at, but I don't use them for any calculations.

So true! And the fact everyone says that your cam is too small..............

[In-Tech]

This is hitting closer to home Mike.
Is there a significant change one way or the other with an aggressive profile like like your EHR series vs your regular hydraulic rollers when taking the same .050" numbers into consideration? That being shorter seat timing yet the same 050" number.

Not really, because it's all based on seat duration, not .050" duration. All my calculations are for the actual opening and closing points(Seat Duration).

I list the .050" durations, because that's what everyone looks at, but I don't use them for any calculations.

Totally agree Mike,
The rub is you know your lobes. It still amazes me how people want to compare numbers using a different manufacturer...oh Mikes is 296 so I'll get my 296 from comp/crane/isky

[hoffman900]

This is hitting closer to home Mike.
Is there a significant change one way or the other with an aggressive profile like like your EHR series vs your regular hydraulic rollers when taking the same .050" numbers into consideration? That being shorter seat timing yet the same 050" number.

Not really, because it's all based on seat duration, not .050" duration. All my calculations are for the actual opening and closing points(Seat Duration).

I list the .050" durations, because that's what everyone looks at, but I don't use them for any calculations.

Totally agree Mike,
The rub is you know your lobes. It still amazes me how people want to compare numbers using a different manufacturer...oh Mikes is 296 so I'll get my 296 from comp/crane/isky

This!

[Bishop540]

I have finally had enough with my 10:1 compression 540 solid roller on the street. Runs very good at WOT but not very streetable in the cruising rpm's, especially with the A/C on and cruising the freeway with my OD trans (at those low rpm's there just isn't any torque). My current SR is 286/296 - .255/.263 -.685/.680 - 107/101 .030 lash - 1.7/1.7. For a Hydraulic Roller, Comp has recommended 299/303 - 245/249 - .654/.659 107/103. - 1.7/1.7 (the 107 LSA is at my request) and beehive springs. The Lobes are the QXX which I hear are not real aggressive.

I only want to spin my engine to 6500 redline (Scat 9000 crank). I realize that I currently have too much exhaust duration for my AFR 325cc heads (2101-1) with my current SR. Over the years I now realize my heads don't need extra EX duration, but only about 4 degrees.

The Comp lobes give me about the same lift as I have now, minus lash, but the duration @ .050 is 10 and 14 degrees smaller. The overlap, however, is 87 compared to my 77 I have now. Seems like this new cam will be tamer than my SR but with the extra overlap I'm not sure I am going in the right direction. I am not gonna spread the LSA wider. If anything I would use less duration or a Single Pattern cam.

Of course I don't want to loose any power (730hp@6100 /692tq@4500) but would like to gain more low end torque for better street cruising. My question is: Will this new HR cam, and the extra overlap, give me more low end torque without the expense of giving up too much HP? Thanks!

(and I am not here to debate the LSA. For street performance I have always been happy with the narrow torque-y powerband it offers. I'm not spinning it to 7000+)

Do you have a flow sheet for your heads?

Stan

Bishop540_CamMaster.gif

Do you have a flow sheet for your heads?

Stan


YES SIR. THIS IS FROM AFR's WEBSITE:

AFR 325cc w/ 100% CNC Chamber Flow Chart

.200 .300 .400 .500 .600 .700
Int 155 227 281 319 346 368
Exh 135 195 240 254 262 266