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Type I, Type II and Group 19 camshaft

Printed From: TheAMCForum.com
Category: The Garage
Forum Name: AMC V8 Engine Repair and Modifications
Forum Description: AMC-made V8 engine mechanical, ignition and fuel from basic repair to high-perf modifications
URL: http://theamcforum.com/forum/forum_posts.asp?TID=106908
Printed Date: Sep/30/2020 at 3:26am


Topic: Type I, Type II and Group 19 camshaft
Posted By: ccowx
Subject: Type I, Type II and Group 19 camshaft
Date Posted: Jul/29/2020 at 12:24pm
Hi! This should be a quick one. I am trying to settle a debate on camshafts for 1970 V8's. The type 1 camshaft was installed in all 360's and 390's (up to sept 26th, 1969) had 266 duration and .457 valve lift. After that, the 390's got a type II cam, with a bit more duration and lift, but the 360's stayed with the type I, correct?

Someone has some incorrect information that the type II cam was the Group 19 unit with 302 duration and .477 lift. I am positive that this cam was not installed at the factory in anything. Does anyone have the specs for the type II camshaft in later 1970 390's?

Thanks!



Replies:
Posted By: purple72Gremlin
Date Posted: Jul/29/2020 at 12:40pm
Just a guess, and from reading on this stuff, but Im thinking that when AMC came out with the Machine, that had the 340 HP 390, and the bigger cam was for that 
The 302 cam wasnt factory.  


Posted By: ccowx
Date Posted: Jul/29/2020 at 12:50pm
This is a fact check for an article going in a magazine, and much as I enjoy the many AMC myths, I am trying to set it straight. Somehow they got the Group 19 specs in there as the Type II cam. I am hoping to get the right specs for that one. I agree, the Group 19 was never in anything from the factory.

The new cam was introduced in September ,69, I thought the Machine was a bit later than that? Either way, that cam was desperately needed because the Type I was a total pussycat in a 390!

I am hoping to provide the correct specs for the type II for this article.

Thanks!

Chris


Posted By: Trader
Date Posted: Jul/29/2020 at 2:35pm
I am assuming you want paper documentation and not a camshaft. There are several grinds of 3180259, an AMC blank as far as I know. The one I have sitting on the bench has other paint markings and 0.496" lift.
I posted, asking before:  http://theamcforum.com/forum/3180259-rv-cam_topic97293.html" rel="nofollow - http://theamcforum.com/forum/3180259-rv-cam_topic97293.html
It is the largest lift from a factory cam blank I have ever come across. 


Posted By: SC397
Date Posted: Jul/29/2020 at 2:53pm
Originally posted by ccowx ccowx wrote:

Hi! This should be a quick one. I am trying to settle a debate on camshafts for 1970 V8's. The type 1 camshaft was installed in all 360's and 390's (up to sept 26th, 1969) had 266 duration and .457 valve lift. After that, the 390's got a type II cam, with a bit more duration and lift, but the 360's stayed with the type I, correct?

Someone has some incorrect information that the type II cam was the Group 19 unit with 302 duration and .477 lift. I am positive that this cam was not installed at the factory in anything. Does anyone have the specs for the type II camshaft in later 1970 390's?

Thanks!

I think that you are correct.
https://flic.kr/p/WhoSJC" rel="nofollow"> https://flic.kr/p/WhoSJC" rel="nofollow - AMCcamList1 by https://www.flickr.com/photos/149168736@N07/" rel="nofollow - Rick Jones , on Flickr


Posted By: Sonic Silver
Date Posted: Jul/29/2020 at 3:16pm
Originally posted by ccowx ccowx wrote:

Hi! This should be a quick one. I am trying to settle a debate on camshafts for 1970 V8's. The type 1 camshaft was installed in all 360's and 390's (up to sept 26th, 1969) had 266 duration and .457 valve lift. After that, the 390's got a type II cam, with a bit more duration and lift, but the 360's stayed with the type I, correct?

Someone has some incorrect information that the type II cam was the Group 19 unit with 302 duration and .477 lift. I am positive that this cam was not installed at the factory in anything. Does anyone have the specs for the type II camshaft in later 1970 390's?

Thanks!
The Type 1 cam was used throughout 1970 in the 360 engine with 266 advertised duration and .425 lift. The Type 2 was advertised as the same 266 duration with .457 lift, and was in the 1970 390 engines after the date you listed. You are correct about the Group 19 not being installed in engines from the factory. I have seen that 196 duration at .050 listed for the Type 1 (266 duration) cam forever. 

   One thing that I will say about the factory 401 camshaft. I sent an NOS one to Cam Motion about 40 years ago to be read by their Cam Doctor machine. They sent me a printout that showed 207/208 duration at .050 and .456-.458 lift on 114 degree lobe centers, with 4 degrees ground in advance (110 and 118 centerlines). I have no direct information on the Type 2 cam, but have always wondered if it wasn't the 401 cam, since it had the same lift. I have never seen a cam with only 196 degrees at .050  have .457 lift with 1.6 rockers.


Posted By: SC397
Date Posted: Jul/29/2020 at 4:09pm
Here is some fun stuff from one of the cam drawings.
  https://flic.kr/p/2jr6QhM" rel="nofollow"> https://flic.kr/p/2jr6QhM" rel="nofollow - IMG_3751 by https://www.flickr.com/photos/149168736@N07/" rel="nofollow - Rick Jones , on Flickr
https://flic.kr/p/2jraUii" rel="nofollow"> https://flic.kr/p/2jraUii" rel="nofollow - IMG_3752 by https://www.flickr.com/photos/149168736@N07/" rel="nofollow - Rick Jones , on Flickr
https://flic.kr/p/2jr9yum" rel="nofollow"> https://flic.kr/p/2jr9yum" rel="nofollow - IMG_3753 by https://www.flickr.com/photos/149168736@N07/" rel="nofollow - Rick Jones , on Flickr


Posted By: mramc
Date Posted: Jul/29/2020 at 4:45pm
OK, The group 19 cam was a period crane fireball cam shaft. It has 302 duration listed and I'm not sure of the duration. The type II camshaft your talking about is the white stripe or Rebel Machine camshaft . Off the top of my head it I recall correctly the cam was listed as a 296 /302 duration. Note back in the day they only used base circle on camshafts , there was no at 50 thousands measurement. So it a lot like comparing apples to oranges , one camshaft cam with 302 degrees would be radical, and anothers would be mild as milk. that is why they started the @ .50 thing. The stock cams of the late 60s and early 70's were the very mild 266, and into the emissions era a lot of stock cams were 262 or 264 degree cams. Really milk toast cams. There is a whole section on this topic some here on this forum including the SAE report from AMC on the Rebel Machine and the Camshaft posted in it's entirety.  It listed in the SAE document BUT AMC used the Rebel Machine camshaft in the last 2 quarters of 1970 and the first quarter of 1971. AMC listed no change in horsepower but desktop dyno  puts it at an extra 25 Horsepower. LRDaum  


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LRDaum


Posted By: WesternRed
Date Posted: Jul/29/2020 at 4:58pm
Since I am on a bit of a manual quest at the moment, I can post the following excerpt from the 67-71 parts manual:



As you can see, the Group 19 camshaft has a different part number to any of the standard production camshafts. Type 1 to type 2 is a production change based on engine sequence number, so it would appear that all 390's built after that got the type 2 camshaft and it is not specific to the Machine. Also note that the 1970 390 type 2 camshaft is the same as the 71 401 camshaft. The 71 TSM lists the lift at 0.286", intake duration as 296.25 deg and exhaust duration as 303.5 deg. Note that the 71 304 and 360 camshafts are also dual pattern and differ from the earlier camshafts. 



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I've finally given up drinking for good...........now I only drink for evil.


Posted By: ccowx
Date Posted: Jul/29/2020 at 6:16pm
Thanks guys, we can all take a bow for helping to dispel the many myths of AMC! I will pass this along!

As for the milk toast camshafts, you are correct. I drove my car for a few months with the stock cam, but a Group 19 version certainly woke it up.

Thanks again!

Chris


Posted By: Steve_P
Date Posted: Jul/30/2020 at 9:48am
Originally posted by mramc mramc wrote:

OK, The group 19 cam was a period crane fireball cam shaft. It has 302 duration listed and I'm not sure of the duration. The type II camshaft your talking about is the white stripe or Rebel Machine camshaft . Off the top of my head it I recall correctly the cam was listed as a 296 /302 duration....... LRDaum  



The Group 19 cam is different from the Crane Fireball cam. The duration and lift are the same, but the timing is different. I made this mistake years ago just looking at the lift and duration and was corrected, and when I looked at the timing I saw the difference.
I have a NOS 68, 70 type 1, 70 type 2 cam and will someday get the specs on them and compare the .005 and .050 duration and lift profiles


Posted By: purple72Gremlin
Date Posted: Jul/30/2020 at 12:22pm
Originally posted by Steve_P Steve_P wrote:

Originally posted by mramc mramc wrote:

OK, The group 19 cam was a period crane fireball cam shaft. It has 302 duration listed and I'm not sure of the duration. The type II camshaft your talking about is the white stripe or Rebel Machine camshaft . Off the top of my head it I recall correctly the cam was listed as a 296 /302 duration....... LRDaum  



The Group 19 cam is different from the Crane Fireball cam. The duration and lift are the same, but the timing is different. I made this mistake years ago just looking at the lift and duration and was corrected, and when I looked at the timing I saw the difference.
I have a NOS 68, 70 type 1, 70 type 2 cam and will someday get the specs on them and compare the .005 and .050 duration and lift profiles
Interesting. 


Posted By: SC397
Date Posted: Jul/30/2020 at 12:53pm
More cool drawings.
https://flic.kr/p/2jrqPUo" rel="nofollow"> https://flic.kr/p/2jrqPUo" rel="nofollow - IMG_3758 by https://www.flickr.com/photos/149168736@N07/" rel="nofollow - Rick Jones , on Flickr
https://flic.kr/p/2jrmHDM" rel="nofollow"> https://flic.kr/p/2jrmHDM" rel="nofollow - IMG_3757 by https://www.flickr.com/photos/149168736@N07/" rel="nofollow - Rick Jones , on Flickr
https://flic.kr/p/2jrqPTB" rel="nofollow"> https://flic.kr/p/2jrqPTB" rel="nofollow - IMG_3756 by https://www.flickr.com/photos/149168736@N07/" rel="nofollow - Rick Jones , on Flickr


Posted By: Sonic Silver
Date Posted: Jul/30/2020 at 2:13pm
Originally posted by Steve_P Steve_P wrote:

Originally posted by mramc mramc wrote:

OK, The group 19 cam was a period crane fireball cam shaft. It has 302 duration listed and I'm not sure of the duration. The type II camshaft your talking about is the white stripe or Rebel Machine camshaft . Off the top of my head it I recall correctly the cam was listed as a 296 /302 duration....... LRDaum  



The Group 19 cam is different from the Crane Fireball cam. The duration and lift are the same, but the timing is different. I made this mistake years ago just looking at the lift and duration and was corrected, and when I looked at the timing I saw the difference.
I have a NOS 68, 70 type 1, 70 type 2 cam and will someday get the specs on them and compare the .005 and .050 duration and lift profiles
I'm going to take a guess that the 68 and the 70 Type 1 are identical and have 196 duration at .050 on 111 lobe centers with .425 lift, and that the Type 2 will be the same as the 401 cam, and have 207/208 duration on 114 lobe centers with .457 lift. 

My guess on open/close numbers at .050 are:
Type 1
IO: -(11)
IC:   27
EO:  31
EC: -(15)

Type 2 (if it is same as 401)
IO: -(7)
IC:   34
EO:  42
EC: -(14)


Posted By: SC397
Date Posted: Jul/30/2020 at 3:23pm
Reference material. The WG1115 is the stock cam.  Not sure if it is 100% exact but I used the WG992 as the Group 19 cam.
https://flic.kr/p/2jrsU3u" rel="nofollow"> https://flic.kr/p/2jrsU3u" rel="nofollow - IMG_3759 by https://www.flickr.com/photos/149168736@N07/" rel="nofollow - Rick Jones , on Flickr


Posted By: WesternRed
Date Posted: Jul/30/2020 at 5:12pm
I meant to post this up yesterday with the parts catalog listing:




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I've finally given up drinking for good...........now I only drink for evil.


Posted By: Steve_P
Date Posted: Jul/31/2020 at 10:58am
Originally posted by Sonic Silver Sonic Silver wrote:

Originally posted by Steve_P Steve_P wrote:

Originally posted by mramc mramc wrote:

OK, The group 19 cam was a period crane fireball cam shaft. It has 302 duration listed and I'm not sure of the duration. The type II camshaft your talking about is the white stripe or Rebel Machine camshaft . Off the top of my head it I recall correctly the cam was listed as a 296 /302 duration....... LRDaum  



The Group 19 cam is different from the Crane Fireball cam. The duration and lift are the same, but the timing is different. I made this mistake years ago just looking at the lift and duration and was corrected, and when I looked at the timing I saw the difference.
I have a NOS 68, 70 type 1, 70 type 2 cam and will someday get the specs on them and compare the .005 and .050 duration and lift profiles
I'm going to take a guess that the 68 and the 70 Type 1 are identical and have 196 duration at .050 on 111 lobe centers with .425 lift, and that the Type 2 will be the same as the 401 cam, and have 207/208 duration on 114 lobe centers with .457 lift. 

My guess on open/close numbers at .050 are:
Type 1
IO: -(11)
IC:   27
EO:  31
EC: -(15)

Type 2 (if it is same as 401)
IO: -(7)
IC:   34
EO:  42
EC: -(14)



D'oh! You're right on the 68 and 70 type 1 being the same- brain fade on that one. I have a NOS 68, NOS 70 type 2, and also a used 401 cam as a future comparison project. But it looks like the pictures above take care of the 68-70E cam. Thanks for posting that!


Posted By: ccowx
Date Posted: Jul/31/2020 at 11:41am
The Blue Racer '992 is extremely close, but not quite the same. The Group 19 cam was installed slightly retarded while the '992 looks to be straight up. Other measurements such as duration at .050 and lobe centers are probably slightly off too. 

Chris 


Posted By: Trader
Date Posted: Jul/31/2020 at 2:38pm

These pages shows up in previous posts, what cam is this?




Posted By: ccowx
Date Posted: Jul/31/2020 at 3:41pm
The first one is the factory spec sheet for the Group 19 cam and the other one seems to be the AMA specs as issued right around the changeover from the Type 1 to the Type 2 cam in the 390 in fall of 1969. 

Chris 


Posted By: Trader
Date Posted: Jul/31/2020 at 3:57pm
I used an online calculator to reverse obtain the other per-tenant information:
Your amc GR19? has an Overlap of 98.00 degrees and has in Intake Duration of 302.00 degrees. The Exhaust Duration is 302.00 degrees. Your Lobe Separation Angle is 102.00 degrees. The Inlet Cam has an Installed Centerline of 105.00 degrees ATDC. The exhaust cam has an Installed Centerline of 99.00 degrees BTDC.

Very radical cam, but the numbers work.




Posted By: ccowx
Date Posted: Jul/31/2020 at 5:10pm
Trader, do those values hold true even if you are looking at advertised duration instead of at .050"? 102 lobe center seems very very narrow, I was under the impression that the Group 19 cam was more like a 110 or 112 center. 

It is a fairly radical cam for it's day, though it is old tech. I have one for years. It tends have low vacuum due to the large overlap, but the lift and duration is otherwise moderate. It has gentle ramps which gives it a lot of overlap and therefore very rough idle etc. The duration at .050" is around 224 degrees and the lift is moderate. I find it acts like a bigger cam than it is, and the overall power is good but not great. It has nice mid range scavenging properties though, especially when paired with a set of proper tuned headers. A modern cam would likely give better idle and low end properties with equal or better WOT power, though it was pretty good for it's time. 

Chris 


Posted By: Trader
Date Posted: Jul/31/2020 at 6:38pm
The values hold true and at 0.050" it's 266. I have one of these also. It has a pink or orange dot and white dot on the back with a red paint blotch interior.
Yes it calculates out to have very poor vacuum, I would not think it could idle below 1300 RPM, but at high RPM runner, approx 3200 to 7300 RPM.
Speculate this was the Trans-Am cam that they would have to document somewhere with other factory parts.

The other factory cam I have with 0.47x" lift (worn) 110.5 LCA, 266 duration, white/red stripe would be more like I would expect for the Gen 2 performance cam. I choose it for purchasing an off the shelf cam that was the closed grind for my own 401.
Thanks Greyhound, your chart made that quite easy. 
Though I have to admit I was disappointed that Lunati listed a cam with 0.484" lift and came with 0.494" lift. The extra lift made no difference on my build except draw HP and stress components. Works fine, but what is advertised is what you should expect.


Posted By: ccowx
Date Posted: Jul/31/2020 at 8:33pm
I think something has gotten a bit crossed, the duration at .050" is not 266. I also will dispute that the LC are 102, I have never heard of that narrow a LC on any V8. Not trying to be argumentative, but those numbers are not quite passing a sniff test with me. I also have some contradictory information. 

FYI, I can say the characteristics are rough, but not quite as much as you mention. I have my idle at 850, with 11" of vacuum. It pulls from about 3200 but it should be shifted at around 5500-5800. I would not run that cam and valvetrain to 7300, let alone an otherwise stock AMC short block. It is well paired with an R4B and a set of old Thorley headers. 

Thanks!

Chris 


Posted By: Sonic Silver
Date Posted: Jul/31/2020 at 9:17pm
Originally posted by ccowx ccowx wrote:

I think something has gotten a bit crossed, the duration at .050" is not 266. I also will dispute that the LC are 102, I have never heard of that narrow a LC on any V8. Not trying to be argumentative, but those numbers are not quite passing a sniff test with me. I also have some contradictory information. 

FYI, I can say the characteristics are rough, but not quite as much as you mention. I have my idle at 850, with 11" of vacuum. It pulls from about 3200 but it should be shifted at around 5500-5800. I would not run that cam and valvetrain to 7300, let alone an otherwise stock AMC short block. It is well paired with an R4B and a set of old Thorley headers. 

Thanks!

Chris 
I agree, but I did notice that the Group 19 is apparently ground 3 degrees retarded from the figures in the one paper. The intake and exhaust centerlines aren't listed for the Group 19, but they would have to be opposite from all the Wolverine cams listed. Without going back to look at the Wolverines, I think all but one or two are ground with 5 degrees advance. 


Posted By: Trader
Date Posted: Jul/31/2020 at 9:26pm
Hi Chris, not trying to be argumentative either. 
There seems to be a lot of legitimate documentation from the period and physical evidence of it. Trying to sort this out for an article based on fact, I believe nearly impossible.
Take all the know "facts" and known "documentation" and known "physically existing" is a PITA to say the least.
Writing the known and the odd existing of the period would just show AMC was doing a lot of R&R at the time and some other's In furture!


Posted By: ccowx
Date Posted: Jul/31/2020 at 9:39pm
Of course not, this is an intellectual debate between us polite Canadians! Wink

Seriously, I have a cam ground from very old masters that I am pretty sure are the original Group 19 cam. It is listed as 224@.050 and 110 lobe centers. We did a big debate on this subject a year or two back and there was some discussion that it might be 112 centers and we may be off a degree or two at .050, but this is pretty close. The Fireball and the WG-992 are also in that ballpark. I will not die on this hill, as my data is only 90% certain, but I can not imagine specs as radical as you suggest. 

BTW, You mention the racing cams. They did not use the Group 19 cam for racing, but I do have some listings from various race teams that might give you some idea of what they did use. 

Thanks!

Chris 

PS: I do have what I am fairly sure is a Group 19 cam, but unfortunately the place I live does not have any shop with the ability to measure it accurately. 


Posted By: Trader
Date Posted: Aug/01/2020 at 1:31pm
I was all over this cam today and it's as close to that 401 spec sheet as you can be. Maybe a visual will show you how radically this cam is:





Posted By: ccowx
Date Posted: Aug/01/2020 at 1:39pm
Video of what? Not being a smartaleck, but I have two still pics here. 

Here is a discussion of lobe centers. Not a super technical or precise one, but I found it in 3 minutes of looking. Note that these guys are saying that 106 is very radical, so you can see why I am skeptical of a derived value that gives 102. 

https://www.jalopyjournal.com/forum/threads/camshaft-guys-explain-lobe-centers-to-me.31093/" rel="nofollow - https://www.jalopyjournal.com/forum/threads/camshaft-guys-explain-lobe-centers-to-me.31093/

Thanks!

Chris 


Posted By: Heavy 488
Date Posted: Aug/01/2020 at 1:45pm
Originally posted by ccowx ccowx wrote:

Video of what? Not being a smartaleck, but I have two still pics here. 

Here is a discussion of lobe centers. Not a super technical or precise one, but I found it in 3 minutes of looking. Note that these guys are saying that 106 is very radical, so you can see why I am skeptical of a derived value that gives 102. 

https://www.jalopyjournal.com/forum/threads/camshaft-guys-explain-lobe-centers-to-me.31093/" rel="nofollow - https://www.jalopyjournal.com/forum/threads/camshaft-guys-explain-lobe-centers-to-me.31093/

Thanks!

Chris 
It doesnt say video, it says visual.LOL


Posted By: Trader
Date Posted: Aug/01/2020 at 2:07pm
That's "visual" of cylinder #2 intake and exhaust. Just trying to show how tightly packed the lobes are.
Between those machine squares with the cam in v-blocks is approximately 1.418" and the lobe small diameter is 1.392".
 Never seen an AMC cam like it, or any V8 cam for that matter.

Should add, that measuring with a dial indicator the intake and exhaust open and close as per the "cam card" posted within a degree and @0.050" I get 262 degrees intake and exhaust.

I don't have a 1" travel dial indicator or a lathe large enough to hold the cam, so cannot provide more exact numbers.




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