[Steve C.]

Anybody know for a fact where Crower rates their hydraulic flat tappet cams at ? Is their seat duration really at .006"


.

[Jay S]

I don’t think my opinion is very different from Crocie. I like a little bigger cam.

With regard to the difference in designing a cam for a manual, I usually go a little bigger and pull the LSA in some becuase the gears are closer together. If you have a wide ratio, let it wide. Only exceptions I make is a very high compression pump street engine or restrictive exhaust. My W72 4 speed is out on 114.

I have done a bunch of the summit type grinds. I have lost count.

I don’t really have a pony in the race for pointing someone toward a cam company. I like Cranes HMV series, but I mostly do custom Bullet/Ultradynes. Most of the comps have to much lifter rise early off the base circle. I really do not use comps flat tappet that much anymore.

I have recommended that HMV 278/290 Crane cam before. I don’t think I have gotten anyone convinced to use it yet. But that particular grind is one of my favorites in a 400. There is also a bigger Crane solid cam that I use that I think is awesome in 455s.

IRC, you subtract 6 degrees on the HMV cranes like that on to get to .006. So it would be
272/284 222/234 @.050 .467/494
It is asymmetric 5 degrees from .004-.050”
.2” 133/144

I said to use the lunati 702 with 1.6s. Out at the valve with 1.6s it looks like this.
268/274. 222/230 .521/.537
It is asymmetric 8 degrees from .004-.050”
.2” 132/140, (not adjusting for the bigger rocker, IRC it adds 4 or 5 at .2.
Not a lot of difference except the wider 114 lsa and the lunati would have more lift. Good flowing head that would make a difference. Stock, not so much.

Lunati claims they have the 702 rated at 262. It use to be 267 at .006. I assume that it is still 267 at .006.

[Jim Moshier]

Ken

Is the Crane #283801 better suited for the 400 with 9 to 1 compression than a 455 9. To 1 compression for a straight street car?

[Jay S]

Originally Posted by Steve C.

Anybody know for a fact where Crower rates their hydraulic flat tappet cams at ? Is their seat duration really at .006"


.

FWIW..The 60240 looks to me like it is rated at .006. But like I said, not a cam I have used or checked. It appears to have some decent intensity. Probably one of the reasons Cliff has seen good results in low compression combos.

Their 60918 appears to be rated at .004, I think it about the only small cam rated different from Crower. Which is Crowers version on the summit 2801.

[400 Lemans]

Originally Posted by KEN CROCIE

You will be disappointed if you use anything smaller than the Crane 283801. ALL of the above cams are just not worth the effort of installing. You must change valve springs. Use the Comp 988. These go in at stock installed height and fit the stock retainer. We ( H-O Racing) sold hundreds of these cams to very satisfied customers. The dist. advance curve will need to be modified, and the carb should be re-jetted. Usually at this point, a fuel system upgrade is advisable . I recommend the Carter P4594 elec. or P 4602rv which is the P4594, but includes a bypass check valve that allows you to run just the mechanical pump and switch on the electric when needed. Considering the age of the car, the fuel pick up strainer (sock) is probably mush, and pick up tube should be checked for internal rust. Larger pick up tubes are available. Classic Industries is one source.

I have also used the Crane 283801 cam in two different 400 builds before. Worked so well in the first one, i wanted the same cam for the second. First 400 had 68 16 heads and second one had only 75 6x heads but still ran well.
Highly recommended.

[SD455DJ]

Here are some real-world results of a stock rebuild W72 that was relatively low miles (under 50,000) and losing the original cam. This was Dan’s red ’79 TA W72 (that he subsequently traded for his current 25,000 mile all original black WS6 TA). Dan pulled the engine due to a little rocker noise and discovered all of cam lobes starting to wear, so decided to tear it down, install new rings and bearings, resize the stock rods, polish the crank, and re-balance the stock rods, pistons, & new rings. His intension was to keep it stock, so he needed a new cam and ordered a custom ground Comp Cams that is somewhat close to the factory cam with 202/219 (255/261 adv.) duration at .050” lift with .420”/.450” lift ground on a 110 lcl. Dan degreed several lobes of the original cam at 199/216 @ .050 and .397”/.406” in worn condition.

He didn’t deck the block to preserve the piston size stampings and measured the factory pistons to be and average of .0114” down (yes, the pistons have the perimeter chamfer). The 6X-4 heads got a slight cut of .002/.003” to true up and new guides and seals with the original valves and springs (that checked out great). The heads measured 91.8 cc’s average and the valve reliefs, above ring and chamfer measured 9.8 cc’s that calculated out to 8.1 to 1 static compression…just as advertized. Dan used .046” head gaskets to keep the compression at factory advertised and quench at a high .0574”. Using the Felpro 1016 gaskets with .039” thickness would bump the compression up to 8.22 and lower the quench to .0504”.

After he reassembled and broke-in the engine he took it to the engine dyno to see what it would do…in 6 variations:

1) With the original ’79 exhaust manifolds through the factory Y-pipe, no ac base
2) With the original ’79 exhaust manifolds through the factory Y-pipe with ac base
3) With ‘71/72 A/F-body exhaust manifolds with dual 2.25” headpipes with ac base
4) With factory A/F-body Ram Air manifolds with 2.5” mandrel headpipes with ac base
5) Same as 3 with TA air cleaner no scoop
6) Same as 3 with TA air cleaner with scoop (not opened up)

Dyno results (2800 to 5000 rpm):

1) 397.3 tq @ 3400 / 300.0 hp @ 4900
2) 402.0 tq @ 3400 / 305.6 hp @ 5000
3) 413.0 tq @ 3400 / 328.8 hp @ 4900
4) 420.2 tq @ 3700 / 335.3 hp @ 4800
5) 417.6 tq @ 3400 / 331.8 hp @ 4800
6) 412.2 tq @ 3400 / 322.8 hp @ 4700

I guess the moral of the story is if you are going to run the stock heads and compression, the Summit 2800 cam (204/214/112 @ .422”/.444”) will be fairly close to these numbers. Since this cam has the quicker ramps it did build cylinder pressure faster, so is a good cam to use with really low (under 8.5) compression. The Crower 60240 cam is a good choice too, but maybe a little softer down low. Once you start to modify your heads, the bigger cams Cliff, Ken, Jay and others recommend are more appropriate. Dan was interested in seeing what a very-close-to-factory-original W72 400 would make for power. Installed back in the heavy (loaded) TA with the factory exhaust manifolds, Y-pipe, and test pipe in place of the catalytic convertor, it felt like a low 14 sec. car.

Dennis

[Gary H]

Originally Posted by SD455DJ

Here are some real-world results of a stock rebuild W72 that was relatively low miles (under 50,000) and losing the original cam. This was Dan’s red ’79 TA W72 (that he subsequently traded for his current 25,000 mile all original black WS6 TA). Dan pulled the engine due to a little rocker noise and discovered all of cam lobes starting to wear, so decided to tear it down, install new rings and bearings, resize the stock rods, polish the crank, and re-balance the stock rods, pistons, & new rings. His intension was to keep it stock, so he needed a new cam and ordered a custom ground Comp Cams that is somewhat close to the factory cam with 202/219 (255/261 adv.) duration at .050” lift with .420”/.450” lift ground on a 110 lcl. Dan degreed several lobes of the original cam at 199/216 @ .050 and .397”/.406” in worn condition.

He didn’t deck the block to preserve the piston size stampings and measured the factory pistons to be and average of .0114” down (yes, the pistons have the perimeter chamfer). The 6X-4 heads got a slight cut of .002/.003” to true up and new guides and seals with the original valves and springs (that checked out great). The heads measured 91.8 cc’s average and the valve reliefs, above ring and chamfer measured 9.8 cc’s that calculated out to 8.1 to 1 static compression…just as advertized. Dan used .046” head gaskets to keep the compression at factory advertised and quench at a high .0574”. Using the Felpro 1016 gaskets with .039” thickness would bump the compression up to 8.22 and lower the quench to .0504”.

After he reassembled and broke-in the engine he took it to the engine dyno to see what it would do…in 6 variations:

1) With the original ’79 exhaust manifolds through the factory Y-pipe, no ac base
2) With the original ’79 exhaust manifolds through the factory Y-pipe with ac base
3) With ‘71/72 A/F-body exhaust manifolds with dual 2.25” headpipes with ac base
4) With factory A/F-body Ram Air manifolds with 2.5” mandrel headpipes with ac base
5) Same as 3 with TA air cleaner no scoop
6) Same as 3 with TA air cleaner with scoop (not opened up)

Dyno results (2800 to 5000 rpm):

1) 397.3 tq @ 3400 / 300.0 hp @ 4900
2) 402.0 tq @ 3400 / 305.6 hp @ 5000
3) 413.0 tq @ 3400 / 328.8 hp @ 4900
4) 420.2 tq @ 3700 / 335.3 hp @ 4800
5) 417.6 tq @ 3400 / 331.8 hp @ 4800
6) 412.2 tq @ 3400 / 322.8 hp @ 4700

I guess the moral of the story is if you are going to run the stock heads and compression, the Summit 2800 cam (204/214/112 @ .422”/.444”) will be fairly close to these numbers. Since this cam has the quicker ramps it did build cylinder pressure faster, so is a good cam to use with really low (under 8.5) compression. The Crower 60240 cam is a good choice too, but maybe a little softer down low. Once you start to modify your heads, the bigger cams Cliff, Ken, Jay and others recommend are more appropriate. Dan was interested in seeing what a very-close-to-factory-original W72 400 would make for power. Installed back in the heavy (loaded) TA with the factory exhaust manifolds, Y-pipe, and test pipe in place of the catalytic convertor, it felt like a low 14 sec. car.

Dennis

Grreat post with interesting information. Do you know if they made any jet changes when trying different manifolds and air cleaner combinations? Also, does anyone know what the original factory cam's LSA was? I'm guessing 114ish. Just curious.

[phil400]

Originally Posted by Gary H

Grreat post with interesting information. Do you know if they made any jet changes when trying different manifolds and air cleaner combinations? Also, does anyone know what the original factory cam's LSA was? I'm guessing 114ish. Just curious.

In 78 the LSA 113.5, and the intake lobe LCA was 118.5, was retard built in.

["QUICK-SILVER"]

Originally Posted by Gary H

Also, does anyone know what the original factory cam's LSA was? I'm guessing 114ish. Just curious.

Interesting factory cam info here on John Wallace's site. Especially lobe centers for 77, 78 &79.

http://www.wallaceracing.com/camcode1.htm

Clay

[Jay S]

Originally Posted by SD455DJ

Here are some real-world results of a stock rebuild W72 that was relatively low miles (under 50,000) and losing the original cam. This was Dan’s red ’79 TA W72 (that he subsequently traded for his current 25,000 mile all original black WS6 TA). Dan pulled the engine due to a little rocker noise and discovered all of cam lobes starting to wear, so decided to tear it down, install new rings and bearings, resize the stock rods, polish the crank, and re-balance the stock rods, pistons, & new rings. His intension was to keep it stock, so he needed a new cam and ordered a custom ground Comp Cams that is somewhat close to the factory cam with 202/219 (255/261 adv.) duration at .050” lift with .420”/.450” lift ground on a 110 lcl. Dan degreed several lobes of the original cam at 199/216 @ .050 and .397”/.406” in worn condition.

He didn’t deck the block to preserve the piston size stampings and measured the factory pistons to be and average of .0114” down (yes, the pistons have the perimeter chamfer). The 6X-4 heads got a slight cut of .002/.003” to true up and new guides and seals with the original valves and springs (that checked out great). The heads measured 91.8 cc’s average and the valve reliefs, above ring and chamfer measured 9.8 cc’s that calculated out to 8.1 to 1 static compression…just as advertized. Dan used .046” head gaskets to keep the compression at factory advertised and quench at a high .0574”. Using the Felpro 1016 gaskets with .039” thickness would bump the compression up to 8.22 and lower the quench to .0504”.

After he reassembled and broke-in the engine he took it to the engine dyno to see what it would do…in 6 variations:

1) With the original ’79 exhaust manifolds through the factory Y-pipe, no ac base
2) With the original ’79 exhaust manifolds through the factory Y-pipe with ac base
3) With ‘71/72 A/F-body exhaust manifolds with dual 2.25” headpipes with ac base
4) With factory A/F-body Ram Air manifolds with 2.5” mandrel headpipes with ac base
5) Same as 3 with TA air cleaner no scoop
6) Same as 3 with TA air cleaner with scoop (not opened up)

Dyno results (2800 to 5000 rpm):

1) 397.3 tq @ 3400 / 300.0 hp @ 4900
2) 402.0 tq @ 3400 / 305.6 hp @ 5000
3) 413.0 tq @ 3400 / 328.8 hp @ 4900
4) 420.2 tq @ 3700 / 335.3 hp @ 4800
5) 417.6 tq @ 3400 / 331.8 hp @ 4800
6) 412.2 tq @ 3400 / 322.8 hp @ 4700

I guess the moral of the story is if you are going to run the stock heads and compression, the Summit 2800 cam (204/214/112 @ .422”/.444”) will be fairly close to these numbers. Since this cam has the quicker ramps it did build cylinder pressure faster, so is a good cam to use with really low (under 8.5) compression. The Crower 60240 cam is a good choice too, but maybe a little softer down low. Once you start to modify your heads, the bigger cams Cliff, Ken, Jay and others recommend are more appropriate. Dan was interested in seeing what a very-close-to-factory-original W72 400 would make for power. Installed back in the heavy (loaded) TA with the factory exhaust manifolds, Y-pipe, and test pipe in place of the catalytic convertor, it felt like a low 14 sec. car.

Dennis

Very nice post Dennis. It really did good to hold on to the power as far as 5000, especially with a cam running more overlap and about 10 degrees more of advance than the original cam. The 255deh and a oem w72 cam running a 1.65 rocker would have very close specs for lift and durations out at the valve. IRC, the DEH comps more of a symmetrical cam. The 77 4speed W72 ran a 112 LSA, it had the narrowest LSA of the W72s. The 255deh would be the closest to the 77 WA cam engine.

The advantage to the asymmetric type cams on low compression engines is they create more cylinder fill with the same compression. You can run a little bigger cam and really not loose much bottom end, and it fills the cylinders more. That is why the HMV Cranes, Ultradynes, ect still work on a lower compression engine even though on paper they look big. A comp XE, Crane max intesity, Bullet tq lobes, take it on step further and slam the valves shut to build more cylinder pressure yet. But it almost always comes at a cost. Extra wear and extra valve terrain noise. Then if they are not a big enough profile they struggle to match up power wise on the top end to a smaller symmetric cam like the 60240.

[Steve C.]

Adding to Jay's comments regarding UltraDyne lobes. If anyone is interested in some very interesting tech information from a old UltraDyne catalog here is a link for it.
Go direct to Harold Brookshires post number 11 here....

THE CAMSHAFT AND ITS PROFILE
THE HOWS AND WHYS OF THE UNSYMMETRICAL CAM

https://www.chevelles.com/forums/155...check-out.html

.


.

[SD455DJ]

Originally Posted by phil400

In 78 the LSA 113.5, and the intake lobe LCA was 118.5, was retard built in.

Dan measured just under 114 degrees due to wear.

Dennis

[SD455DJ]

Originally Posted by Gary H

Grreat post with interesting information. Do you know if they made any jet changes when trying different manifolds and air cleaner combinations? Also, does anyone know what the original factory cam's LSA was? I'm guessing 114ish. Just curious.

Gary, Dan found 42 primary jets/72 primary rods, F-hanger, CH secondary rods (.05675) in the Q-jet made the best power for the baseline pulls. I attached the best runs of each combo so you can see how the BSFC dropped as the exhaust became more efficient. Low compression likes more fuel and the numbers reflect that.

Dennis

[pastry_chef]

Originally Posted by Steve C.

THE HOWS AND WHYS OF THE UNSYMMETRICAL CAM

Thanks Steve,

Harold used the same lobes for both intake and exhaust.

When Mike Jones customizes lobes, his exhaust lobes are the opposite of Harold's - slow opening and faster closing on the exhaust, he says they will make more power.

[78w72]

Originally Posted by 1979 TA Y89 W72

Hello, new to the forum. Thank you in advance for your help!

79 W72/400 4 speed cam recommendations?

What cam is everyone using for an upgrade on a 1979 W72 4 speed TA?

My car is all stock, except for Ram Air 2.5 exhaust manifolds and 2.5 true dual exhaust with X-Pipe.

Don’t plan on doing any headwork at this point and stock compression will remain.

Anyone using these cams:

Crower 60240 cam?

Comp XE cams XE 262 & XE268

Summit 2801 or 2801

Or what did you use and why?

Would like input on what your results were and what exactly you did? Video of car idling would be great as well.

I won’t be going all out on this engine, just want to wake it up a bit.

Thanks in advance!

im late to this thread but thought id mention my experience with the xe268 cam in a W72 4speed 78 t/a. i am by no means a cam expert & i realize most here including cliff hate the xe cams but...

i picked the xe268 for my W72 400 before i knew about how much cliff hates them... motor is .030, slightly shaved heads, speed pro forged pistons, should be a tad under 9:1. headers & 2.5" exhaust. the xe268 idles & runs great with zero tuning issues or detonation etc. cliff built the factory q-jet for it & out of the box the car runs great! thats a compliment to cliffs carb but also the xe cam in general. im very happy with it for the ~10 years its been in.

ive read all the negative comments on the xe cams over the years & am even considering a cam change to the crower mentioned by cliff. it is very close to the xe268, the xe has more duration at .050 & more lift, & the advertised duration is very close between them. but, since the xe runs so good & has no issues i havent really thought much more about a cam swap. the car ran a 13.7 at 103mph on hard old bfg street tires & a soft launch off idle & short shifts since its not a race car & is a low mile #'s matching 78 w72 t/a. unless im just lucky with the xe i dont really see why everyone hates them so much. & butler swears by the xe cams.

just some info for the OP who asked about this cam. heres a vid of idle & a little burnout leaving the track.

https://www.youtube.com/watch?v=lQVWNo5jCZU

https://www.youtube.com/watch?v=zozMBMWCwJU

[phil400]

Originally Posted by SD455DJ

Dan measured just under 114 degrees due to wear.

Dennis

Oh ok, I just took the info from John Witzke's historical paper on w72.

[KEN CROCIE]

JM I'd be glad to give you a consult re: cams for your ride. call me anytime.

[Cliff R]

"I've read all the negative comments on the xe cams over the years & am even considering a cam change to the crower mentioned by cliff. it is very close to the xe268, the xe has more duration at .050 & more lift, & the advertised duration is very close between them. but, since the xe runs so good & has no issues i havent really thought much more about a cam swap. the car ran a 13.7 at 103mph on hard old bfg street tires & a soft launch off idle & short shifts since its not a race car & is a low mile #'s matching 78 w72 t/a. unless im just lucky with the xe i dont really see why everyone hates them so much. & butler swears by the xe cams."

One has to consider that with pretty much any cam these engine make decent power, but for sure with some cams you are leaving a lot of power on the table.

The WORST cam you will ever put into one of these engines will be a relatively "small" or short seat timing on a tight LSA. Especially with the 455 builds. NOTHING with less than 230 @ .050" goes into any of my 455 builds and that even goes for the lower compression versions.

If you follow Butler's cam recommendations for example, notice how in the last couple of years they started offering custom ground cams on wider LSA's. That came after I sent them an email with the dyno chart attached below, and a note on how it came to be. The "famous" XR276 HR cam is a very popular choice for these engines. It even made HPP a few times. However it's too small for a 455 build with decent flowing heads on it and any attempt at raising the compression much past 9 to 1. Too good at cylinder filling early in the RPM is the biggest issue.

I've had several cars brought here to date with that cam in their 455's and every one of them pinged pretty hard on pump gas and none were over 9.5 to 1 compression. By the time I yanked out timing and added enough fuel to make them happy power production was pretty lame. With one of those test sessions (455 Super Duty with the XR276 cam and slight dome on the pistons for 9.5 to 1 compression) I just happened to have a set of Harland Sharp 1.65 ratio rockers laying here and replaced the 1.5's. This was after ALL efforts to get the engine to run well were exhausted and we were down to 26 degrees total timing, wouldn't tolerate more than 8 degrees from the VA or pinged at part throttle, and carb was pretty "fat".

The high ratio rockers IMMEDIATELY allowed me to put more timing in that engine and brought back some power. It did not completely correct the issues we were having but I noticeable improvement. This told me that it wanted a bigger cam to make things happy. Back then I hadn't discovered that also going to a wider LSA with later closing intake would have also helped that scenario, but at least that early testing put me in the right direction for choosing camshafts for these engines.

What muddies the water even further with this sort of thing is that once in a while you'll get a positive report from an XE cam. We actually had a customer use one (XE274) early on in a 455 build with heavily ported iron heads and switch to 45 degrees intake seats. His engine made power pretty much on par with the more successful cams we were using at that time, which included the Wolverine 5059, Crane 234/244/112, and the RAIV and it's copies.

Even with that said right on the same dyno I use I've observed 455's with ported iron heads at 9.5 to 1 compression only make 400hp with that same cam, and 430 with the larger XE284. A near identical engine with a Crane 234/244/112 or Crower 60919 will make closer to 1hp/CID and a even more important up at 5000rpms where the XE cams were quitting they made nearly 80ft lbs MORE torque and pushed HP up to 5400-5600rpms. The first XE274 cam dyno I witnessed quit at 4900rpm's. It also made peak torque clear down at 3200rpms where the Crane and Crower cams are closer to 4000rpm's. This clearly shows us (if you are paying attention to things) that the short seat timing and tight LSA pull power DOWN in the RPM range. They also spike it much higher, which raises octane requirements all else being equal.

Well, enough XE cam bashing, my results are well known on this website.......Cliff

PS: the second dyno chart is from a 455 Super Duty I did here, 3rd pick is the cam card, stock compression, intake, carb, etc. Note that it idled dead smooth and making over 13" vacuum at 700rpms despite having a 230/236/112 HR cam in it with high ratio rockers on it.

[Jay S]

I was noticing earlier I had the lift wrong on the 702 Lunati. Lift numbers were for the 703 and not the 702. Apologies. Too many numbers in my head.

Just to add to what Cliff said. The “short seat timing cams” hft cams are the Comp XE, Crane Z, Howard’s 3HF (rattler), Bullet CTA, CTS. I don’t count the lunati voodoo as fast ramp yet, on the edge. But Lunati has some high lift flat tappets that I consider fast ramp. Most cam companies have them, those are the ones I usually run across. Some are better than others. The comp XE has a XE profile on the intake and a magnum profile on the exhaust. Most of the noise and the issues are coming from the intake part of the XE cam.

Part of the issue with comp is they recommend a 995 spring and it only has 115-120 seat pressure most of the time, and the need closer to 130-140 for that profile and a 30 degree intake. Not unusual to see the seat pressure get down to 90-100 lbs when they are set up wrong and not checked, especially after they get some time on them. Not such a big issue with the XE 268 in a low compression 400 because it won’t really want to rev much past 4500 rpm. But usually some place after 4000 on any engine that runs 30 degree intake seats with not enough spring pressure the intake valve starts to bounce, and the HP noses over. If you know want to listen for you can even hear the sound of the engine change. Kind of hard to describe, it make is sound as though your winding the engine more than it is.

Really the better solution to those tight fast ramp cams is to go with a little less intensity and make up the intensity difference with a bigger rocker arm ratio. Use an intensity (.006-.050) from 48 to mid 50s. I think the HMV Crane, some of the Ultradynes and most of the Crowers work good yet even with a 1.7 rocker with a 30 degree seat and good spring pressure.

The other option for the fast ramp cams is to switch to 45* intake seats from the 30*. What Cliff described on the more successful fast ramp cams. Or tolerate the valve terrain noise and run more seat pressure. Street engine, even a low compression set up designed to build compression, there really is no reason tolerate those issues with the right set up.

[Steve C.]

"Part of the issue with comp is they recommend a 995 spring..."

There might be a similar situation with a XE HFT lobe using the popular Crower 68404 spring rated 113 at 1.600".

.