worked up spread sheet that details the Cam and Valve events for
1) stock 83 D-150 cam
2) what I have found on the Guzzi Cam, if I get close to this set up I know I made a wrong turn somewhere
3) HyperPac cam
4) RV 10 Mechanical
5) RV 15 Mechanical
6) Erson E470301 , a classic Erson RV Cam
7-8-9) Oregon 1333 hydraulic, intake and exhaust profiles reversed, intake center held at 102, lob separation varied from 110 to 106
10-11-12) Oregon 640 hydraulic, intake and exhaust profiles reversed, a little less lift with simular duration to the 1333, intake center held at 102, lob separation varied from 110 to 106

http://www.flickr.com/photos/13718356@N ... 884804468/

Notes, from reviewing the David Vizard "Be the Cam" article,
1) he recommends choosing overlap first,, with 10 to 40 being street towing, 30 to 60 regular street,, he states, when under valved select towards the larger number.
So looking at overlap there are several in the 40 to 60 range
2) after overlap, Dave V looks at Lobe Center Angle, AKA LSA...
here he has a formula and chart, based on displacement and intake valve size,, 106-107-108 good numbers here
3) from that he calculates duration as: overlap/2 plus LCA times 2,
in my example, works out to duration of 262,, which is right in the zone that was recommended by Josh. We are half a country apart and I believe I know where the numbers came from,, I like that.

The question is, does a 50 degree over lap sound reasonable,
considering my stock cam has an overlap of 18
I'm looking for torque in the 1000 to 3000 rpm range
engine mods will be
1) os engine builder valves,
2) head will get bowl work
3) mopar M-1 intake / 2 bbl intake
4) dual Dutra exhaust, free flowing duals, 2 cats
5) HEI,,,,

Truck is a 833 / OD, 235x15 tires, clocks 2100 rpm at 60MPH,
gets 18 to 19 mpg on highway with stock motor,, want the torque to be able to use the D-150 as a tow vehicle,, plan to tow with one of the hitches that carries only the front wheels of the towed vehicle,, like what dart270 has.

so again,, folks with street / torque cams,, does the 50 overlap sound right?

whaleMstr,, for comparison, will add your cam specs to the spec list but will need a overlap or intake / exhaust center line to make the calculations calculate.

I appreciate that you've been doing your research on this. Did you run across David Vizard's lobe centerline chart? It's all about cylinder volume to intake valve diameter. Since we have a fairly large cylinder for the valve size the optimum centerline is pretty narrow. With a 1.70" valve in a 225 the optimum is 107°. With the stock intake valve it's 106°. I didn't know you were going for the bigger valves.

Since you plan to tow, have a very wide ratio transmission and your cruise RPM is so low I think the 640 reversed, on 106° is going to have the best sweet spot. If the vehicle were lighter and had a little higher cruise RPM I'd use the 1333 reversed.

Also, I think the advertised duration of the Oregon 1333 exhaust lobe might be 262° rather than 268°. It's probably worth a call to Ken and ask if it's a Comp XE profile because the lift and duration at .050" are the same, but the advertised is not. If so your overlap numbers would come down 3° for the 1333R cam we're proposing.

_________________
Joshua

thanks for the reply

yep, this project is about to start, I understand that motors are air pumps and work best when built around the cam.

1) I'll give Ken a call Monday and ask about the duration question
2) One thing, I am questioning myself on, is the Oregon spec sheets list .006 duration and a .050 while the dyno sym accepts an advertised duration and the .050 I have been plugging in the measurable .006 where dyno sym requests the un defined advertised duration,, it seems like the answer is going to be close,, but what ever I will get for overlap will be + that error,
3) the 640 and 1333 will be an interesting comparison,, about the same duration at .006 but the 1333 is longer at .050, so the 1333 must ramp a lot quicker between .006 and .050, certainly the 1333 ultimantly has a larger lift, and lift is free as long as the spring coils don't go solid.

ya got me
what I posted is all the info I got
can't even find the cam card for it now!

ran the 83 D-150 engine characteristicks of the
1) stock motor
2) stock cam, upgraded intake, exhaust, carb, valves, porting
3) Oregon 1333 / profiles reversed with the upgrades
4) Oregon 640 / profiles reversed with the upgrades
5) Rv-10 with the upgrades
6) Rv-15 with the upgrades
into dyno sim

sumarized the results on this spreadsheet
http://www.flickr.com/photos/13718356@N02/5381710509/

for the stock set up, the dyno sim agreed with the factory information for rpm levels, on where peak torque and HP would occur,, and was within 11% of the torque and 8% of the horsepower reported. The dyno sim outputs that I used were the "wheel" values.
For the cams on this sheet I averaged the torque and HP for the RPM range of 1500 to 3000. That is the operating range where I want to maximize the D-150's performance.

It appears that I could do that, by keeping the stock cam, and doing the engine upgrades,, however, just beyond 3000 the torque really drops.
In the 1500 to 3000 rpm range the torque and HP for the average of the 4 cams is within 3 % of each other. So any of these would be a good match. The reports also shows the smaller cams do make more torque at the lowest RPM levels. The bigger 1333 and Rv-15 cam likely need more carb and RPM's to really show their stuff.

Just want to say this thread is awesome. Great info. Thanks for doing this research and sharing it!

called and spoke with Bill at Oregon,, Ken was on the other line.
on the 1333 exhaust duration question,, Bill confirmed that it is a Comp xe grind, he also stated that Ken checks the profiles when they arrive from Comp or Crane or where ever and Oregon puts on the spec sheet what the profiles actually are. Bill pulled the report from the 1333 profile and confirmed that it did check at 268.
also the web site shows the hydraulic grinds from 10 /2003. Bill is to fax over an updated listing.

also changed the name of this posting, as it had moved on from the question of mechanical vs hydraulic profiles and is now focused on picking a cam profile

thanks

That graph is very interesting. Considering that most street driven slant sixes never get above 3500 RPM, it seems like much can be done just with the stock cam and induction and exhaust work. Seems like on a street motor money would be better spent on compression and port work and oversize valves before any upgrades to the camshaft.

Reed,

I agree that much can be done with the stock cam. I really woke up my Valiant with cylinder head, induction and exhaust work. My '67 Valiant's cam isn't even as hot as the later stock mechanical cam. But if the engine is being rebuilt and needs a cam anyway there are gains to be had in most cases.

http://www.slantsix.org/forum/viewtopic ... 049#200005

_________________
Joshua

got the updated hydraulic cam spec sheet from Oregon,,there was one page of grinds, now there are two. thats progress
picked out grind 1527, which is listed as an xe250.

added it on to the cam log in two versions, reversed cam profiles and normal

http://www.flickr.com/photos/13718356@N ... 884804468/

also ran both versions through dyno sim

http://www.flickr.com/photos/13718356@N ... 884804468/

looks like the 1527 in the normal profile performs very much like the rv 10,, I dropped the 1333 and Rv-15, I had a gut feel those were bigger cams than what I am needing on this build.
I am going to work with the 1527 a bit more, adjusting advance and retard, I'll see if this dyno program has enough resolution to pick up a difference.

The 1527, right now anyway is my choice,,
those of you with more experience in this arena,, if you see something different, or I something just plain missed, feel free to say something here, this is my first go at this.
What I see is it looks like I can maintain the great low rpm torque that the stock cam had at 1500 RPM and instead of it peaking there, have the torque continue to build. Will be nice.

DT,

Which sim did you use?

Bill

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Dadtruck,

Clarification on Reed's and my cams. After calling Delta Cams again,
their regrind is called a 254S which is a symmetrical grind, both lobes are the same. The specs are 212@.050 on 110 degree lobe centers with .435 lift. The intake center-line is suppose to be at 106 degrees with no advance ground in.

I am not sure if this changes the calculations much, but it would be interesting to see the difference between this one, a stock cam and the RV10. After using it the last 7 years or so it is very spunky and powerful from idle up to 2500 rpm. Could you run it through your program?

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Wait a minute, I specifically gave them the RV10 cam profile, and now they are admitting that that isn't what they gave me?!?! That kind of ticks me off. I should have known that they said they had the exact grind I was looking for too quickly. That might be what screwed up my dynamic compression ratio calculations and made my brother's motor ping. Ugh. Now I need to go back through all the dynamic compression ratio calculations again.

I am liking the numbers coming up with that 1527 grind. That is a hydraulic profile, right? I know the motor in my brother's Duster will never see higher than 3500 RPM, so I am much more interested in the numbers in the 2k-3k range.

Welcome to the world of custom cam grinding...
You see.. any cam grinder will always know more about what you need for your engine... then you will. (not true, especailly with a inline 6 (120 degree engine))

You really have to spend some time, when working with cam grinders... to be sure you get what you order.

The best thing to do is to ask for a profile "simulation sheet" before they grind the cam and then get the actual profile "plot" (Cam Doctor) read-out once the cam is ground.

To be honest, the standard "cam card" you usually get with a cam, does not really tell you that much about it.
DD

Wjajr,,I am using Desk Top Dyno 5,, I believe 5 is still the most current one available. The graphics are nice, you can overlay the performance outputs of an engine with 4 different settings on one graph assuming the program is accurate, you can see what makes a difference.
Aggressive Ted,,, I'll can put those cam settings in, will be interesting to see how it compares to the other cams.
if you want to send the specifics of your build
over bore, over stroke, head porting, carb CFM, timing curves,,,
I'll load in your build info,,,

it will be this weekend before I can put much time to it.