Slant six builders...Lets talk Cams

-
Bewy said:
Don't know if you guys know this about David Vizard....but a lot of his early racing success was with.....Chryslers! Specifically the Chrys 4 cyl Avenger in the UK. 26 wins out of 26 races in two years with a OHV engine against OHC competition.
Click to expand...

What struck me was he actually was a scientist before his racing hobby sort of took over his career. His scientific background was used in his development of engine building. He did carefully constructed design of experiments to create the curves and mathematical equations that could be used in the design process. Anything else I found was more of a recipe book where a build of items were found to work well together but it could not really be explained why. Being a design engineer myself the later drove me crazy. I just kept saying "why", "why", "why" in my head will reading their book/article.
 
my 819 just showed back up from Oregon Cams. Other than shipping costs pricing wasn't too terrible. Cost me $42 and 2 weeks, for the PO to get it out there (2x what I expected/ in cost AND time, both) $45 for UPS to get the cam + 12 O/S valves and a set of new solid lifters to show back up at my door. Damn!!!
Lifters in an unidentified white box..... wish I had a brand on them.

the sheet that came with shows alot more specs than I would have thought. most of them make no sense to me.

Since I aint great with computer stuff (It would be easier to scan the sheet in instead of copying it manually for sure) here goes...
see if you guys can make sense of things I can't...
Lobe Separation 110 Lobe Center Line Int 106 Exhaust 114
how can lobe centerline and Lobe Separation "not" be the same as each other? 1st thing that doesn't make sense.
Cam lobe Lift .291 on both intake and exhaust.
Advertised Duration (.012 TR) HUH? left blank.
Duration at 0.002 318 both Intake and Exhaust
at 0.006 289 both
at 0.012 ("0.012" "penciled in") 264 both
at 0.020 248
at 0.026" 240
at 0.050 219
at 0.100 187
at .200 125

Valve Clearance 0.012" both (isn't that a bit "light," on the exhaust side?)
Checking tappet Dia 0.904" Tappet type Mech Flat
Cam timing @0.050" tappet rise OPEN CLOSE
INTAKE 4* BTDC 36* ABDC
EXHAUST 44* BBDC -5* ATDC
(penciled in) -1* overlap@0.050"

theroetical valve lift (with .000" lash) with specific Rocker Ratio .436" on both valves....so that would mean really 0.424" lift when the valve clearance is figured in?

when I looked at Oregon's chart (either here or in the "346" cam thread) the line on no cam, gave this much info.
so when I degree it in, would I go for the 106 figure or the 110 figure? (higher up in this post)
Did I mess up with this choice of cam for my intended usage? There is a chance that I might put this motor into my Volare, if it don't work out in the truck, though my orig plan for the Volare, was a V8 swap..... orig slant 6 car, with 2.71 gear/ ran surprisingly well with the original (now long gone) engine, that engine was definitely "enough" to get it down the road.

I chose this cam for the truck engine, after talking both on-forum and in PMs to a couple of different guys on the /6 site that have this cam in their /6 in a truck.
I need to replace my converter anyway, (ring gear issue) when the engine goes in. would stock stall, work out OK with this cam? It still has the original converter in it, this is a 727 lockup. Wont know til I get it out, if it is stock "hi-stall" or "lo-stall" in there now. how much difference is there between hi and lo stall?
Ive detailed what I want out of this build more than once.
and as I have said before, looking at cam numbers makes my head spin, very confusing to me. And that after a bad experience on "too big" of a cam on my 1st build years ago (a 318 in a Cordoba OK, go ahead, laugh) back in the 80s has made me "chicken out" on cams, on subsequent builds......
 
volaredon said:
my 819 just showed back up from Oregon Cams. Other than shipping costs pricing wasn't too terrible. Cost me $42 and 2 weeks, for the PO to get it out there (2x what I expected/ in cost AND time, both) $45 for UPS to get the cam + 12 O/S valves and a set of new solid lifters to show back up at my door. Damn!!!
Lifters in an unidentified white box..... wish I had a brand on them.

the sheet that came with shows alot more specs than I would have thought. most of them make no sense to me.

Since I aint great with computer stuff (It would be easier to scan the sheet in instead of copying it manually for sure) here goes...
see if you guys can make sense of things I can't...
Lobe Separation 110 Lobe Center Line Int 106 Exhaust 114
how can lobe centerline and Lobe Separation "not" be the same as each other? 1st thing that doesn't make sense.
Cam lobe Lift .291 on both intake and exhaust.
Advertised Duration (.012 TR) HUH? left blank.
Duration at 0.002 318 both Intake and Exhaust
at 0.006 289 both
at 0.012 ("0.012" "penciled in") 264 both
at 0.020 248
at 0.026" 240
at 0.050 219
at 0.100 187
at .200 125

Valve Clearance 0.012" both (isn't that a bit "light," on the exhaust side?)
Checking tappet Dia 0.904" Tappet type Mech Flat
Cam timing @0.050" tappet rise OPEN CLOSE
INTAKE 4* BTDC 36* ABDC
EXHAUST 44* BBDC -5* ATDC
(penciled in) -1* overlap@0.050"

theroetical valve lift (with .000" lash) with specific Rocker Ratio .436" on both valves....so that would mean really 0.424" lift when the valve clearance is figured in?

when I looked at Oregon's chart (either here or in the "346" cam thread) the line on no cam, gave this much info.
so when I degree it in, would I go for the 106 figure or the 110 figure? (higher up in this post)
Did I mess up with this choice of cam for my intended usage? There is a chance that I might put this motor into my Volare, if it don't work out in the truck, though my orig plan for the Volare, was a V8 swap..... orig slant 6 car, with 2.71 gear/ ran surprisingly well with the original (now long gone) engine, that engine was definitely "enough" to get it down the road.

I chose this cam for the truck engine, after talking both on-forum and in PMs to a couple of different guys on the /6 site that have this cam in their /6 in a truck.
I need to replace my converter anyway, (ring gear issue) when the engine goes in. would stock stall, work out OK with this cam? It still has the original converter in it, this is a 727 lockup. Wont know til I get it out, if it is stock "hi-stall" or "lo-stall" in there now. how much difference is there between hi and lo stall?
Ive detailed what I want out of this build more than once.
and as I have said before, looking at cam numbers makes my head spin, very confusing to me. And that after a bad experience on "too big" of a cam on my 1st build years ago (a 318 in a Cordoba OK, go ahead, laugh) back in the 80s has made me "chicken out" on cams, on subsequent builds......
Click to expand...

I would not worry about it, this is not the wrong cam for what you want to. My money is on if you drove this and the 2106 back to back you would have a hard time telling the difference. Like someone said all the cams that have been talked about here are very close in the simulation. Is there a theoretically better cam for what you are doing, by a tiny margin maybe. Will it be very noticeable in the real world, doubt it. I am not sure I am understanding the torque converter question... At higher stall speed converter just means it slips more so it is less efficient.. If you are doing hole shots with the truck and want it to launch at the peak torque point it would be useful, for just driving around I would stick with the stock TC.
 
whitepunkonnitro said:
You can take an easy .100 from the head/deck and keep the stock pushrods.
Cam? KEEP IT SMALL!
The Slant is handicapped from birth with too small a bore, (for the stroke) and too long a rod.
Result..below 3000 rpm or so, it will be a dead suck pig no matter what you do.
Look at the Comp Cams RV grind they have listed on Summit.
Click to expand...

Rubbish!!!!

 
crap.... lost what I started. I hate redo's.
Jim Kueneman said:
No kidding.... with what I did with mine it will outrun my small blocks off the line... it pulls hard.
Click to expand...

That was basically one of my hopes/thoughts with this build. My truck, being an 85, was built during some of the most weak noodled V8s ever built. Mopar and everyone else, too. A 318 was what 140HP? a 360 was 150-155ish. Pathetic. Typical "gearhead" thinking is "dump the 6, swap in V8". I always liked "different".
along that line, my hope for this build was to build up a /6 to at least "stock for that day" HP and TQ of a V8 that "could have came in that truck back then".
I've been a member here since '10. Longer than I thought. Ive been on the /6 site even longer. I got away from both as not having a vehicle that "qualified" to the purpose of the site but came back once I got this truck and "rediscovered" the /6....
I have spread out my thoughts and hopes for this build, all over various threads here.... I have done the same over there/ but I have 1 thread over there, that kinda sums up my build.... what I'm building, what I want it to do, etc if anyone wants to check it out instead of me "again" putting bits and pieces in many threads here...
My thread over there is called something like "planning an engine build... thoughts and ideas welcome" I have another about "valve size" over there that pertains to this build as well. and I know there are others here, that go to both places. long, dry, boring maybe.... but it's my "record" of sorts that I can look back on down the road if I have any questions once it's running about "where my head was" along the way.....

and though I have yet to own one, I STILL want a Dart Sport, Demon or Duster and a 67-72 Valiant 2 dr and/or Scamp. maybe next lifetime.....
in this lifetime I wound up with a Volare instead that has been in pieces for too long.
 
volaredon said:
my 819 just showed back up from Oregon Cams. Other than shipping costs pricing wasn't too terrible. Cost me $42 and 2 weeks, for the PO to get it out there (2x what I expected/ in cost AND time, both) $45 for UPS to get the cam + 12 O/S valves and a set of new solid lifters to show back up at my door. Damn!!!
Lifters in an unidentified white box..... wish I had a brand on them.

the sheet that came with shows alot more specs than I would have thought. most of them make no sense to me.

Since I aint great with computer stuff (It would be easier to scan the sheet in instead of copying it manually for sure) here goes...
see if you guys can make sense of things I can't...
Lobe Separation 110 Lobe Center Line Int 106 Exhaust 114
how can lobe centerline and Lobe Separation "not" be the same as each other? 1st thing that doesn't make sense.
Cam lobe Lift .291 on both intake and exhaust.
Advertised Duration (.012 TR) HUH? left blank.
Duration at 0.002 318 both Intake and Exhaust
at 0.006 289 both
at 0.012 ("0.012" "penciled in") 264 both
at 0.020 248
at 0.026" 240
at 0.050 219
at 0.100 187
at .200 125

Valve Clearance 0.012" both (isn't that a bit "light," on the exhaust side?)
Checking tappet Dia 0.904" Tappet type Mech Flat
Cam timing @0.050" tappet rise OPEN CLOSE
INTAKE 4* BTDC 36* ABDC
EXHAUST 44* BBDC -5* ATDC
(penciled in) -1* overlap@0.050"

theroetical valve lift (with .000" lash) with specific Rocker Ratio .436" on both valves....so that would mean really 0.424" lift when the valve clearance is figured in?

when I looked at Oregon's chart (either here or in the "346" cam thread) the line on no cam, gave this much info.
so when I degree it in, would I go for the 106 figure or the 110 figure? (higher up in this post)
Did I mess up with this choice of cam for my intended usage? There is a chance that I might put this motor into my Volare, if it don't work out in the truck, though my orig plan for the Volare, was a V8 swap..... orig slant 6 car, with 2.71 gear/ ran surprisingly well with the original (now long gone) engine, that engine was definitely "enough" to get it down the road.

I chose this cam for the truck engine, after talking both on-forum and in PMs to a couple of different guys on the /6 site that have this cam in their /6 in a truck.
I need to replace my converter anyway, (ring gear issue) when the engine goes in. would stock stall, work out OK with this cam? It still has the original converter in it, this is a 727 lockup. Wont know til I get it out, if it is stock "hi-stall" or "lo-stall" in there now. how much difference is there between hi and lo stall?
Ive detailed what I want out of this build more than once.
and as I have said before, looking at cam numbers makes my head spin, very confusing to me. And that after a bad experience on "too big" of a cam on my 1st build years ago (a 318 in a Cordoba OK, go ahead, laugh) back in the 80s has made me "chicken out" on cams, on subsequent builds......
Click to expand...

The lobe separation is the distance between the peaks of the intake and exhaust lobes in degrees. It is ground in and cannot be changed. Your lobe separation angle, or LSA, is 110. The intake center line is reference to WHERE the camshaft is to be installed in the engine. An intake center line of 106 with a camshaft of a 110 LSA means the camshaft should be installed 4* advanced from the LSA, or at 106 intake center line, or ICL. It MIGHT be there when you install dot to dot. Sometimes you get lucky. You will need to degree the cam to be sure. Machining tolerances between the camshaft keyways, sprokets and crankshaft keyways are rarely "spot on" as far as being "degreed" correctly. When you degree a camshaft, you are assuring the camshaft is installed in the correct place per the cam card. Once you've done it a time or three, it becomes very simple. It's all based on grammar school math referencing 360 degrees in a circle. There's really nothing to it. All of the major cam companies have instructions on how to degree on their web site. I don't even use a stock cam anymore without degreeing it to assure it's in the "right place".
 
Last edited:
Jim,
In one of his books he says he trained as an aero space engineer. if you want to read a really interesting book, his book on head porting should be on the list.
He argues that measuring all valve lifts at fixed depressions, say 28", is misleading & his arguments for same are very convincing.
 
RustyRatRod said:
The lobe separation is the distance between the peaks of the intake and exhaust lobes in degrees. It is ground in and cannot be changed. Your lobe separation angle, or LSA, ia 110. The intake center line is reference to WHERE the camshaft is to be installed in the engine. An intake center line of 106 with a camshaft of a 110 LSA means the camshaft should be installed 4* advanced from the LSA, or at 106 intake center line, or ICL. It MIGHT be there when you install dot to dot. Sometimes you get lucky. You will need to degree the cam to be sure. Machining tolerances between the camshaft keyways, sprokets and crankshaft keyways are rarely "spot on" as far as being "degreed" correctly. When you degree a camshaft, you are assuring the camshaft is installed in the correct place per the cam card. Once you've done it a time or three, it becomes very simple. It's all based on grammar school math referencing 360 degrees in a circle. There's really nothing to it. All of the major cam companies have instructions on how to degree on their web site. I don't even use a stock cam anymore without degreeing it to assure it's in the "right place".
Click to expand...

Yes my OCG cam the dots did not line up but when we degreed it, spot on.
 
Bewy said:
Jim,
In one of his books he says he trained as an aero space engineer. if you want to read a really interesting book, his book on head porting should be on the list.
He argues that measuring all valve lifts at fixed depressions, say 28", is misleading & his arguments for same are very convincing.
Click to expand...

Yup I have it and have skimmed it. On of these days I will sit down and really digest it.
 
Jim Kueneman said:
Yes my OCG cam the dots did not line up but when we degreed it, spot on.
Click to expand...

I've had a "few" that were right on the card stabbed in dot to dot. I've had one off by like 12 degrees retarded. lol I wheeled that one like twelveteen times to be 100% SURE it was not me. It wasn't. That right there is why I say it pays to degree every single one. It can make a really big difference.
 
Bewy said:
Jim,
In one of his books he says he trained as an aero space engineer. if you want to read a really interesting book, his book on head porting should be on the list.
He argues that measuring all valve lifts at fixed depressions, say 28", is misleading & his arguments for same are very convincing.
Click to expand...
IIRC what David V talks about is using a higher pressure drop at low valve lifts and a lower pressure drop at large lifts to better simulate what is actually happening in the port.
And that is some of the theoretical insight that one gets by reading David V books and articles. Is it all practical? That depends upon how comfortable one is with being precise and exacting in their port work. We all know that very good results can be attained with less than perfect execution. And that is fine.
But if your quest for knowledge and information goes beyond that, David V’s port and flow test book will give you port flow ideas to ponder.
 
I went to the local barnes and noble a couple of weeks ago looking for info on porting and saw none.
Yesterday I had to take my wife and mother inlaw to a Dr appointment and instead of sitting there in the hospital parking lot for who knew how long, I checked out the Eastwood store not very far from there. (About an hour from home) among all the paint products, powder coat stuff, specialty tools and such I walked by a book rack and here was Vizard's head porting book on the top row.
I bought it, and read parts of it when I got home. Just started to get into the "meat" of it I think. (Won't know til I get farther to know)
 
RustyRatRod said:
Like nobody else's experience matters? Lets all bow down and kiss David Vizard's butt. You missed a spot. Good GAWD.
Click to expand...

I want to clarify this statement some. NOT back pedal, because I meant it maybe just not like everybody inferred it. It seems sometimes people think there's only this way or that to do things. Or that only a handful of people know anything.

We have people right here on this forum that are absolute geniuses when it comes to automotive. Right here among US. I meant no disrespect to Vizard. That's not the direction I was goin. At all. I've read some of his work. He's a smart guy. Dutra's a smart guy. But they ain't the end all be alls. There ARE other ways of doing things that WORK and other people whose ways of doing things are just as good.....some perhaps better. Just because "the little guys" don't have anything published doesn't mean they don't know anything.

I grew up around an elderly gentleman that couldn't read or write a lick. I got news. That old guy knew more about how to build engines and different combinations for different purposes than anyone I've ever come in contact with since. He was a local dirt track legend. He knew exactly what it took to get one strong going into or coming out of the turns, down the straights, you name it. He never read a tech manual on anything. All 100% self taught. He taught me a lot too. I wish my stupid *** had paid more attention.

That's all my comment was about. I wasn't trying to come off as harsh toward anyone. I have much respect for everyone here and everyone we're discussing. It's just that sometimes I think we forget the "little guys" that ain't really so little.
 
volaredon said:
Well though I have been working on cars for a living since the late 80s most of what I have been doing is stock replacement stuff. I've rebuilt a few slants over the years, but again, stock /but machined to clean up and bring clearances back to where they should be. Done a little performance work on small blocks but even, then mostly stock.
Looking at cam charts, overlap, duration, etc makes my head spin. So on that part of this build I am leaning on others, who know and between here and the /6.org forum, the consensus is about the same for picking a cam, and what hardware to use with it.
Not trying to argue at all, RRR, but to be honest I have had more say that 318 springs are basically "std issue" replacement for /6springs, you're the 1st that I've had say different. IDK how much lift it takes to coil bind 318 springs on a /6 but this cam that I am wanting to run is right around .435 -. 440" lift. This is for a truck that will be used like one, I doubt it'll ever see 4000 rpm.
While I'm here, what would you run then, I wanna do this exactly once.
Click to expand...

I got the closed chamber slant six head back today from having it machined for the 318 valves. It's going to set up about 1.840" spring height. I'm going to just run the Comp 911 single spring. They set up at 122@ 1.9, so seat pressure at 1.840 will probably be "around" 150 which is perfect for what I have planned.
 
I was at the machine shop after work today, dropped off 2 heads that I ported as far as I dared. I admit to not being a porting "expert", not by a long shot. these were my 1st 2 serious attempts at it. IDK if I wrecked the heads or not. I'll find out soon. But, as I told him what I wanted done to (one of) those heads-- if it survived my butchery attempts--- and my goals for this engine, he looked at the sheet I gave him that came back with "Wow-- that's stout..... for one of THOSE engines anyway"...
 
volaredon said:
I was at the machine shop after work today, dropped off 2 heads that I ported as far as I dared. I admit to not being a porting "expert", not by a long shot. these were my 1st 2 serious attempts at it. IDK if I wrecked the heads or not. I'll find out soon. But, as I told him what I wanted done to (one of) those heads-- if it survived my butchery attempts--- and my goals for this engine, he looked at the sheet I gave him that came back with "Wow-- that's stout..... for one of THOSE engines anyway"...
Click to expand...

What did he consider stout?
 
volaredon said:
I was at the machine shop after work today, dropped off 2 heads that I ported as far as I dared. I admit to not being a porting "expert", not by a long shot. these were my 1st 2 serious attempts at it. IDK if I wrecked the heads or not. I'll find out soon. But, as I told him what I wanted done to (one of) those heads-- if it survived my butchery attempts--- and my goals for this engine, he looked at the sheet I gave him that came back with "Wow-- that's stout..... for one of THOSE engines anyway"...
Click to expand...
Don, did you leave the valves that you intend to use with the heads at the machine shop. They will need the valves to get the seat diameters right.
It’s always a good idea to also have the shop check and if necessary replace the valve guides.
 
my68barracuda said:
Don, did you leave the valves that you intend to use with the heads at the machine shop. They will need the valves to get the seat diameters right.
It’s always a good idea to also have the shop check and if necessary replace the valve guides.
Click to expand...
Yup. They have the valves and all hardware.only thing I forgot to take was the stem seals.

The owner looked at the 1st head and said "oh my God, what happened to the bowls"? So I hope that isn't a bad sign. I took them 2 heads one hacked on more than the other, and I told him that I have 1 more at home, (still assembled and untouched) need 1 good head of the bunch.
I also took the old valves and hardware out of the 1 head that came to me loaded. Mainly to compare to my new stuff. I explained that I had OS valves to be put in, and gave them to them.
I didn't get to tell him everything, like I want the tops of the guides trimmed a bit shorter, I'm figuring on at least new exhaust seats and whatever the guides need. I know I slipped down a couple of the guides (oops) with the burrs.
 
Last edited:
another related Q about cams.... at what lift do I have to have the tops of the guides machined so the keepers don't crash the guide seals and the tops of the guides?
 
volaredon said:
another related Q about cams.... at what lift do I have to have the tops of the guides machined so the keepers don't crash the guide seals and the tops of the guides?
Click to expand...
When I was playing the / game ..with my '71 head..the retainers interfered with the seals around .460 lift.
If you cut the guides for a positive seal...that won't be an issue.
 
All of the heads I have look like they had never been touched, and look like they could take a positive type of seal. I took both positive and umbrella seals to the machine shop with the heads we'll see which ones they use.
 
Princess Valiant said:
I am rebuilding my slant ....its a 1970 Slant six.

I want a new cam and lifter set but I do not understand cam numbers so good so what do you guys out there run and what is a good one to get.

the engine .....1970 slant six with a shaved .070 head and a decked block, bored .030 over and has a Clifford intake and header (4bbl.)

Transmission is a 4 speed from a 65 Barracuda

The car is a 1963 Plymouth valiant wagon and I plan to use some low gears ....either 3.55 or 3.91. Definitely not a race car, will be used on the streets, possibly tow a small pop up trailer and,/or a lawn mower trailer.

I don't care gas mileage and the 4 speed says the idle can be rough if need be, No power brakes or any kind of vacuum accessories at all

what is a good cam and where can I order one today .....GO!!! :)

I had suggestions before but nothing I could real world find and order today.

other question is if the head has been milled and block decked and all that good stuff, will I need custom pushrods or is there enough adjustment in the stock pushrods and rocker arms ??

I need new pushrods because I do not currently have any.....so any help on where to order today ....GO!!! :)
Click to expand...
If you really want to know contact Randy McDowell Power Tech Racing Engines. Just friend him on FB and message him or call. He will know exactly what you need! check mine out!
 
talk about reviving an old thread..... this comes up often/ could it become a sticky?
 
You must log in or register to reply here.
-

Back
Top