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Besides clipping the valves for clearance, no one mentioned(or I missed it) anywhere about cutting the exhaust valve to 1.900. I agree with BG..old school cams should be set up the old school way. I run a Crane R290 in my 477 and it's clipped with 1.900 exh valves. It wouldn't work(clear) any other way even with moving the cam timing around.

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Besides clipping the valves for clearance, no one mentioned(or I missed it) anywhere about cutting the exhaust valve to 1.900. I agree with BG..old school cams should be set up the old school way. I run a Crane R290 in my 477 and it's clipped with 1.900 exh valves. It wouldn't work(clear) any other way even with moving the cam timing around.

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Hi,
I ran the old R290 (I still have it)years back also, I assembled the motor with out pistons and rods, with everything just the way it would run and checked it that way, I back cut the intakes and clipped the exh diameter till I had about .050 between the valves at full overlap.
Russ

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Besides clipping the valves for clearance, no one mentioned(or I missed it) anywhere about cutting the exhaust valve to 1.900. I agree with BG..old school cams should be set up the old school way. I run a Crane R290 in my 477 and it's clipped with 1.900 exh valves. It wouldn't work(clear) any other way even with moving the cam timing around.

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Hi,
I ran the old R290 (I still have it)years back also, I assembled the motor with out pistons and rods, with everything just the way it would run and checked it that way, I back cut the intakes and clipped the exh diameter till I had about .050 between the valves at full overlap.
Russ

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Yep
Thats what were are shooting for at least .040+ I know guys run them closer, I also know those guys service there engine a bunch more frequent also. I bet they dont go season, after season without refreshing the heads etc...Being a bracket engine, a few seasons with hundreds or runs..Guide clearance gets loose .003-.004 or so, and the bottom see's .008-.010 movement..kaboom. Its probably no big deal to those guys, if they kill a piston, or knock the head off a valve..they have deep pockets..I dont however..

The heads and valves are over to the machine shop now. He said the margins on these new valves were super thick and were +.080..He is going to gauge the clearance, then cut the margin down to about .040-.050 backcut the valve again, and see what he gained by doing this..If he gets a desent return he will do them all. I will then mock it back up and measure actual clearance between the valves during over lap.. We are looking for .040 minimal, or he will sink the exh valve some to achieve what I want...


The one cam I have is probably a 1970 Crane grind that has a narrow 104 LSA..I might try it in this long stroke engine just too see what and how it runs, just for experience. As for the .290-.300 I may not be able to get those margins, but I wished I had them. If it worked back then, it will work now..no matter how out dated it is. I have several intakes,cams, and I plan to just have fun, and test some parts out..

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Your astute wisdom reflects your age Gather all the information and make the best decision that will serve your purpose.

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i know its an old cam bob,, something for a 426 sized motor,, with a 3.75 stroke,, i know its totally the wrong cam for bob but i think he got it for free or something like that..


you DO NOT need that much overlap with a sroker motor due to the less dwell at tdc respective to stroke travel, more overlap helps to scavange intake charge while the piston is moving about tdc, higher rod ratios need more overlap due to more dwell time for their respective stroke. i dont know what your cam is,, i forgot but i though it had like 72-74 degrees of overlap at .050,,, you would be better with 60 or so,,, maybe even 55 with a 572

"it worked back then so it will work today",,, sure the engine will start and run,, will it be the best cam, or close to it,, not even close,, you will "waste" alot of charge out the exhaust due to overscavaging cause,,,,,,,,, drumroll please.... what cab said.... it has too much overlap,, and if you had less overlap, youd have more valve to valve and youd be fine,, if you had the appropriate cam for your combo...

i understand getting things for free, and wanting to learn yourself that when you do what people tell you to it runs faster,,, im sure it wont be much of a headacche to just clip the margins,, i would not face them,, airflow would be better if you clipped them

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So labor around here doesnt cost about $0.25 per/hour.

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Bob,
I never said I was going to work on your engine. (thats what my wage works out to be)
Brian

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I just dont think the cam is way off in left field for the engine..I wished it was about 5 deg smaller on both the intake and exh side as for as duration goes...I like the 112 LSA etc.

The cam is 290°@.050 on the intake and 300°@.050 on the exh looks like overlap is about 71 deg or so. I degree'd the cam in at 109.5-110 LSA which worked out to be exactly what the cams valve events written on the cam card. I liked the fact that the lift at the valve retainer was .775 for the intake and .755 for the exh.

I would love to know how much they can move this cam on a regrind. They probably couldnt tell me unless it was sent in and they knew things like hardness depth etc. Id say .010-.015 would be max they could move whats there including the base circle. Anyone know for sure or have any cam experience?
Looking at Comps Master Cam lobe library..I still would be looking at numbers in the mid 280's on the intake and low to mid 290's on the exh, with about the same LSA give or take a degree or so.

probably a DR or XR intake Lobe and a XCX or JX exh lobe.

Yep
Its a money thing now, buying parts twice is what has hurt me...Changing directions during the build, and not doing my home work has cost me time and money.
Things like Cam, lifters, valve springs,retainers, spring cups, cams, intakes, and even valve covers. But one way or another, the engine will be finished and running well. Even if things are optimal for my combo..They can be changed, I never cared to work on my stuff. I have even been known to take apart good engines for no apparent reason..just too have a look. So labor around here doesnt cost about $0.25 per/hour.

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I just dont think the cam is way off in left field for the engine..I wished it was about 5 deg smaller on both the intake and exh side as for as duration goes...I like the 112 LSA etc.

The cam is 290°@.050 on the intake and 300°@.050 on the exh looks like overlap is about 71 deg or so. I degree'd the cam in at 109.5-110 LSA which worked out to be exactly what the cams valve events written on the cam card. I liked the fact that the lift at the valve retainer was .775 for the intake and .755 for the exh.

I would love to know how much they can move this cam on a regrind. They probably couldnt tell me unless it was sent in and they knew things like hardness depth etc. Id say .010-.015 would be max they could move whats there including the base circle. Anyone know for sure or have any cam experience?
Looking at Comps Master Cam lobe library..I still would be looking at numbers in the mid 280's on the intake and low to mid 290's on the exh, with about the same LSA give or take a degree or so.

probably a DR or XR intake Lobe and a XCX or JX exh lobe.

Yep
Its a money thing now, buying parts twice is what has hurt me...Changing directions during the build, and not doing my home work has cost me time and money.
Things like Cam, lifters, valve springs,retainers, spring cups, cams, intakes, and even valve covers. But one way or another, the engine will be finished and running well. Even if things are optimal for my combo..They can be changed, I never cared to work on my stuff. I have even been known to take apart good engines for no apparent reason..just too have a look. So labor around here doesnt cost about $0.25 per/hour.

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Bob, I hear ya about money concerns. That being said, I'd really consider a new cam if I were you. It seems really strange that you'd use the wrong cam and go to a lot of trouble(and some $$) in a $20,000+ engine to save $300??

I wish you the best in whatever you decide to do. Love the car and look forward to seeing it make laps some day

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Bob, I know you like to go fast, BUT remember, this is a bracket motor not SS/AH. Approach the build as such. I need to get over and look at this baby soon.

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Exactly, Thank you..
I know how 10-20 HP will effect a time slip at this level of the game.....There is NO Magic Camshaft or cam selection Voodoo...people might want you to believe so but..If the cam is in the ballpark, how much power...or let me say how much of a diff E/T wise will one see on the time slip? And knowing 15-20HP hardly even changes the slip..well maybe .02-.03 tops

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Bob, hopefully this post has lost steam

I talked to Jack Moore(Moore&Moore) over the weekend at the Columbus swap met. He said, he actually ran as good if not better with an old profile cam(R296) in his 572incher.

ain't say'n no'mo

Fred

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You would be surprized at what those old cams will do if you are dead set on using them.I sent 3 to Bill Stiles a few years back when he was restoring his old P/S car.We had one 528"Hemi that we put in at 101/102 centerline and WOW!!!you think that i wheelstand now and not that my Hemi Dart is anthing close to the new SS/AH techonology nor even competetive,but for a untouched car that was raced last in 1984/85 when it ran the best of 9.97 and still today in it's 1985 old techonolgy with a similar old school cam can still rip of some respectable low 10s with the 30 year old sparkplugs.I respect Jeff's and others knowledge,but I also respect those who can't afford all the new and latest parts,and would be carefull of the advise or information that I gave them.As I have said before,no one is wrong here,just different schools of thought.Bob was given the specs on various cams and he posted them here for everyone's comments and with the information in hand,he made his choise,right or wrong.

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Bob, hopefully this post has lost steam

I talked to Jack Moore(Moore&Moore) over the weekend at the Columbus swap met. He said, he actually ran as good if not better with an old profile cam(R296) in his 572incher.

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I still run a 70's Crane it's been in my last 3 motors. I think maybe that the rate of lift in the older grinds was much more severe at lower lifts and could have caused the valve clearance problems.
my cam card

PART 66R000424 ENGINE TYPE: MECHANICAL ROLLER

SPECIAL

GRINDN R-288/4714-2S-10

ENGINE 1966-1971 PLYMOUTH-DODGE V8 HEMI 426 CU.IN.

(THREE BOLT GEAR)

VALVE SETTING: .026 EXHAUST .026 HOT

INTAKE @ CAM
4714 @
740 ROCKER ARM

INTAKE @ CAM
480 @
730 IN 1.57/EX 1.52 ROCKER ARM

LIFT: EXHAUST @ @

ALL LIFTS ARE BASED ON ZERO LASH AND THEORETICAL ROCKER RATIOS

CAM
OPENS
CLOSES
ADVERTISED

.0162 EXHAUS INTAKE 56.0 BTDC 92.0 ABDC 328 ° °



TAPPET LIFT EXHAUS
98.0 BBDC 54.0 ATDC 332 °

SPRING
RECOMMENDED RPM

RANGE WITH

TRIPLE DUAL OUTER MATCHING

PART
99877 MINIMUM RPM 4500

LOAD CLOSE
220 LBS 2.000 O 2" MAXIMUM RPM 9000

OPEN:
592 LBS 1.320 VALVE FLOAT 9600

CAM
OPENS
CLOSES
MAX LIFT
DURATIO

@ .050 INTAKE
37.0 BTDC 71.0 ABDC 105 ° ATDC 288 °

TAPPET LIFT EXHAUS
79.0 BBDC 33.0 ATDC 115 ° BTDC 292 °

IMPORTANT!
Crane Cams continuously improves and upgrades its cam designs. In some cases this may mean that two
Crane Cams with the same part number may actually be different grinds. You must check the GRIND
NUMBER stamped on the front of the camshaft and check it against the Grind Number near the top of the
Spec Card.

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