#21  
Old 09-09-2019, 11:38 AM
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....Impending rain I'd think makes for some "bad" air

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Old 09-09-2019, 01:42 PM
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I don't have any modern tight lash cams to check, so I don't not how they compare.

My Engle was a 55 year old design and was 6.55 degrees difference

The data I have from 45 years ago from helping someone else on a 302 Z28 stocker with a Lunati cam is 5.19 degrees difference. (Lash Called for 0.010" Intake and 0.012" Exhaust)

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  #23  
Old 09-09-2019, 07:27 PM
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Quote:
Originally Posted by Lee View Post
With a somewhat similar UD 288/296 cam in my old 455, I lost e.t. rapidly if I shifted past 5300.

IMHO start low on shift points, and work your way up. No sense in exposing your engine to unnecessary RPM.
My RAIV headed 400 though with an UD 288/296 HP peak was 6100.

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  #24  
Old 09-09-2019, 08:04 PM
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For most solid cams Mike Jones uses a .012 ramp, resulting in less 'difference' between hyd and solid. Most Ultradyne solids used a .017 ramp.

Below two images labelled 'twelve' and 'seventeen' for different solid ramps, my 12 numbers are within 1 degree of Mike's, he likely used a different rod/stroke ratio. Mine are symmetrical lobes.

Quote:
by CamKing » Mon May 08, 2017 9:39 am
Here's a hydraulic cam with a .006" hydr ramp, compared to a mechanical cam, with a .012" lash
ramp(*.018" Hot lash w/1.5 rockers).
Both cams with have the exact same valve lift curve, and will perform the same, as long as the valvetrain is
correct.
Both cams will have a seat duration of 288 degrees(.006" HYDR. / .018" hot lash MECH), and .570" net lift
with 1.5 rockers.
Duration
@ Lifter: HYDR./MECH.
@ .020": 261/268
@ .050": 235/239
@ .100": 206/209
@ .150": 182/185
@ .200": 158/161
@ .250": 134/137
@ .300": 106/110
@ .350": 69/74
Mike Jones
Jones Cam Designs
Attached Thumbnails
Click image for larger version

Name:	TwelveRamp.jpg
Views:	135
Size:	28.7 KB
ID:	519817   Click image for larger version

Name:	Seventeen.jpg
Views:	110
Size:	18.6 KB
ID:	519818  


Last edited by pastry_chef; 09-09-2019 at 08:24 PM.
  #25  
Old 09-10-2019, 04:06 AM
ponchorob ponchorob is offline
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hi tc you send me a private message regarding my 428 if i find i new cam...

sadly had no time to finish my 428 with th 60919 cam...

what makes me wonder that you lost 5 mph changing to 60919 cam..

this is a lot...i think ...maybe there are unnown changes...compression lost ...carb change. ignition timing...

  #26  
Old 09-10-2019, 08:46 PM
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Quote:
Originally Posted by ponchorob View Post
hi tc you send me a private message regarding my 428 if i find i new cam...

sadly had no time to finish my 428 with th 60919 cam...

what makes me wonder that you lost 5 mph changing to 60919 cam..

this is a lot...i think ...maybe there are unnown changes...compression lost ...carb change. ignition timing...
Read post 17.....

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  #27  
Old 09-10-2019, 09:01 PM
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Is there any value in 1 3/4" headers?

  #28  
Old 09-11-2019, 06:49 AM
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I was wondering the same thing as I think 1 5/8" headers are counter productive above 4800 rpm.
The inlet to the header tube needs to be atleast 1/16" of a inch larger all the way around the perimeter of the Exh port flange!

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  #29  
Old 09-11-2019, 06:39 PM
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Quote:
Originally Posted by TCSGTO View Post
Swapped a RAIV for a 247/252 112 Crower SFT in a .030” over 455 and gained nothing. It ran identical times and drove on the street the same. In my case it acted like a solid flat version of the RAIV.
Quote:
Originally Posted by joes455 View Post
Made the switch from a ram air 4 cam solid lifter to a Crower 60311 solid 48 52 duration picked up very little
I have the 60311 on my list for the other 428, guess I'll take it off.

Quote:
Originally Posted by jamaca85 View Post
as expected you would lose some bottom end switching to a hyd from a solid cam. the solid cam has a true 532 lift. the hyd lift due to the lifters you lose about .30 lift or more . so that 470 lift cam ends up being a 440 lift cam. less lift =less power for those ported heads....
I did not know that we lose .030 lift with hyd lifters.

Quote:
Originally Posted by HWYSTR455 View Post
The 919 does give up earlier than one would expect though, you may just be seeing typical results. With your setup, you can easily go bigger.

My understanding is that with iron heads, depending on the porting, you generally don't see much flow gain over around .500-.525 lift. So duration is your friend with iron heads. In stock form, iron heads' flow rounds out @ .470-.490 lift. At least that's my understanding..
The longer duration idea is why I put the 60919 in.

Quote:
Originally Posted by steve25 View Post
34 degrees total is low for the closed chamber in the 670 heads.I would have liked to have seen you try 38 had it not rained on you!
I should have just posted iron heads as I opened up the chambers on these 670's

Quote:
Originally Posted by Cliff R View Post
The 60919 cam is a bit too much for a 428 build with only 9.7 to 1 compression, but should be OK. The 428's are considerably more efficient that the undersquare 455's so I like to tighten up the LSA some and put more cam in them. They will easily make the power numbers of a 455 without a lot of additional RPM's.

I can see that a RAIV size cam would produce a "flat" power curve in a 428 and not surprised it doesn't really work quite as well as expected. 12.20's still isn't bad for the combination....IMHO......Cliff
My worn lobe SFT cam was 110 LSA. I'd like a better idle, so I thought I'd try 112 or 113. I was hoping I'd get some et's from others as this cam is talked about a lot.

Quote:
Originally Posted by Lee View Post
With a somewhat similar UD 288/296 cam in my old 455, I lost e.t. rapidly if I shifted past 5300.

IMHO start low on shift points, and work your way up. No sense in exposing your engine to unnecessary RPM.
I will next time out!

Quote:
Originally Posted by STEELCITYFIREBIRD View Post
....Impending rain I'd think makes for some "bad" air
Yeah, hit rain when I arrived at the track 1&1/2 hour drive. Sat for an hour, cleared up enough for two test runs, then started raining again.

Quote:
Originally Posted by ponchorob View Post
what makes me wonder that you lost 5 mph changing to 60919 cam...
Hope to figure that out too.

  #30  
Old 09-12-2019, 05:11 AM
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"My worn lobe SFT cam was 110 LSA. I'd like a better idle, so I thought I'd try 112 or 113. I was hoping I'd get some et's from others as this cam is talked about a lot."

"Rough" idle is simply a by-product of tight LSA. You either have to raise the compression ratio or wider LSA to offset the overlap, "reversion" and lost efficiency at idle speed, just the laws of physic with these things.

Tuning plays a HUGE roll in idle quality when using pretty decent size tight LSA camshafts in these engines. They are going to want/like/need more timing at idle and more fuel to the mixture screws to make them happy.

Recently had a 350 SBC build come in here that idled poorly but made great power off idle. The owner/builder had consulted with me on cam selection and I recommended the GM LT4 "Hot" cam for it, on a 112LSA. He called Comp and they sent their version of that cam to him on a 110LSA. He was using trick flow aluminum heads but only 9.7 to 1 compression so it didn't idle all that well, but made somewhere around 435hp and pretty stout torque numbers for a little 350 SBC build.

I spent about half an hour with the carburetor increasing idle bypass air and putting more fuel to the mixture screws. Night and day difference in idle quality when we put the carb back in place. It tamed the cam pretty good and reduced the "stinky" exhaust from being a tad too lean.......Cliff

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  #31  
Old 09-12-2019, 07:36 AM
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Quote:
Originally Posted by tc View Post

The longer duration idea is why I put the 60919 in.
My point was go bigger than a RAIV type cam.

Crower lists the peak HP RPM as 4800 with the 919.

The VooDoo HFT 705 is like one step up (241/249), and you could get it cut on a 112 if you wanted. But with your gears, you could get away with bigger. True your SCR may impact it some, but the recommendations are very 'centered' between iron and aluminum heads.

.

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Old 09-12-2019, 09:35 AM
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A 4.250 stroke engine with 260 cfm heads, Performer RPM intake, large Q-jet and headers made peak power at 5300 rpm on the dyno with the 60919 cam. I would presume a shorter stroke would have a higher peak rpm.


.

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  #33  
Old 09-12-2019, 10:07 AM
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Quote:
Originally Posted by Steve C. View Post
260 cfm heads
The OP here said 670 ported, curious who did the work and are the numbers up there also?

Would be nice if Crower was precise with their numbers, seems to be much confusion where their ADV rating is..

  #34  
Old 09-12-2019, 12:53 PM
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Way back in 2004 with my old 455 and Crower 60919 cam we made peak HP at 5600rpm's with the new (at that time) KRE heads.

4,400 539.4 451.9
4,500 537.4 460.4
4,600 534.9 468.5
4,700 532.5 476.5
4,800 523.5 478.5
4,900 518.9 484.1
5,000 511.4 486.9
5,100 501.6 487.1
5,200 492.7 487.8
5,300 485.4 489.8
5,400 478.1 491.6
5,500 471.9 494.2
5,600 463.6 494.3

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  #35  
Old 09-13-2019, 02:33 AM
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I wouldn't change the recipe, just the procedure and conditions your cooking with/in firstly.

  #36  
Old 09-14-2019, 09:51 AM
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Quote:
Originally Posted by HWYSTR455 View Post
My point was go bigger than a RAIV type cam.

Crower lists the peak HP RPM as 4800 with the 919.

The VooDoo HFT 705 is like one step up (241/249),
.
On the next 428, something like this may work. Can some of you respond to the idea mentioned before that the HFT cam loses .030 lift because of the H lifters?

Quote:
Originally Posted by pastry_chef View Post
The OP here said 670 ported, curious who did the work and are the numbers up there also?
.
I did, at .300 lift 200/140, .500 lift 250/180

.

Quote:
Originally Posted by STEELCITYFIREBIRD View Post
I wouldn't change the recipe, just the procedure and conditions your cooking with/in firstly.
Correct.
Driving around town, I felt that the car accelerated very well. I was impressed!
This thread was because I was expecting some great 1/4 mile numbers. The night before I ran the 1/4 mile, (results in my first post ) I ran on a different track that is 1/8 mile. Even with slight tire spin the car ran
60 ft 1.656
1/8 et 7.731

Being a parent, I should have followed my own rule. If you don't expect anything, you won't be disappointed.


Last edited by tc; 09-14-2019 at 10:13 AM.
  #37  
Old 09-14-2019, 10:13 AM
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"Can some of you respond to the idea mentioned before that the HFT cam loses .030 lift because of the H lifters?"

Related:

https://forums.maxperformanceinc.com...intron+testing


.

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  #38  
Old 09-14-2019, 11:55 AM
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Post 24, per Mike Jones. He would have discovered long ago if there was a necessary hyd plunger compensation factor required.
Quote:
Both cams with have the exact same valve lift curve, and will perform the same, as long as the valvetrain is correct.
Some lift is lost due to deflection.


Last edited by pastry_chef; 09-14-2019 at 12:07 PM.
  #39  
Old 09-14-2019, 01:38 PM
Steve C. Steve C. is offline
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"Some lift is lost due to deflection"

Deflection ? As in the one example of pushrod flex ?



.

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  #40  
Old 09-14-2019, 01:55 PM
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Quote:
Originally Posted by Steve C. View Post
one example of pushrod flex ?
Pushrod is one.

Others

Rocker arm Deflection
Rocker Stud Deflection
Cam Core Diameter

Quote:
This meant that with the dual spring in place, our valvetrain had somehow lost 0.030-inch of lift.
https://www.enginelabs.com/engine-te...st-valve-lift/

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