Topic: Crane Camshaft for cb750 - anyone ever run one?

[corky]

Hey guys,

So I am working on building a 970 motor, and have the following cam as an option to run in it.  Has anyone ran this cam, or seen it?  I am curious to hear opinions on it.  I am assuming it has 284 duration, and 400 lift.

Thanks,
Daniel

[MRieck]

That's a large cam. Do the valves ever close?

[gschuld]

And a pretty aggressive lobe profile compared to an old school big RC cam, the 454. The 454 cam has big rounded lobes, lowering valve train stress.  Yours is not only large lift, but opened up longer with a quicker transition on the backside on the lobe.  I'm thinking choose carefully with the springs, perhaps beehive springs?

I'd guess that cam, if indeed. 400 lift, was meant for very high compression and for a big bore race motor.

Is that your plan with this motor?

George

[dragracer]

Wow, the overlap on that thing is crazy.  Obviously this was a special grind for someone. Big cc's, big valves and big dollars went into that engine.

[BPellerine]

I have a crane cam stamped 284 ho,does not look that big,was in a stock engine and the pistons showed the valves were just kissing the pistons.bill

[corky]

Thanks for the input everyone.  I have another cam I will likely use.  By the sounds of it, this one may be a little aggressive!  I will look and see what info I have on it!

[BPellerine]

I cant seem to find info on crane cams.bill

[Jerry Rxman Griffin aka MuthaF'er]

Didn't Crane make the RC cams at least initially? 

[gschuld]

Ed Iskinderian (Isky cams) was just a few doors down from RC Engineering's first shop in Gardena California.  By all accounts, Russ worked directly with Ed to design and test cams for him.  Before 1973, RC recommended Isky cams, and they were called the Isky 315 and Isky 327 cams, sound familiar?

Around early 1973, these cams became RC cams in the catalog.  Presumably, Russ negotiated an exclusive for these cams, like he did with other suppliers (like Venolia, then Arias for pistons)

I assume that Isky supplied RC with cams going forward, but I really do not there know for sure.  There were certainly continual developments going on with cams, as at least one change in profile/specs was made across their cam list.

George

[754]

May have been Engle, i got a 315 with the other name on it .

[Jerry Rxman Griffin aka MuthaF'er]

That's it George. Thanks!

[Don R]

May have been Engle, i got a 315 with the other name on it .

 My 1124 welded stroker has an Engle cam.

[corky]

For comparison, here is another crane cam, next to a Norris R. I cannot find any info on these crane cams, and assume the 370-4, and the 400-8 is the grind number.

[gschuld]

Can you measure the lobe lift on intake and exhaust on both crane cams?  I'd be interested to know the specs.

George

[corky]

Just got the following info from Crane Cams.  Thought it was really interesting, and will be neat to compare to RC cams.

[corky]

cam #2 info

[gschuld]

I wasn't able to open them for some reason.

George

[BPellerine]

could you get info on the 284h0 cam that I have?bill

[Old Scrambler]

Note the recommended 5000 rpm minimum on the fat 400 unit

[BPellerine]

more info than most cam makers give.bill

[scottly]

The 284* duration is at .050" valve lift; the advertised duration is 320*!!!!

[754]

My 315 card says 310 degrees I think.. And they made two hotter cams than that model

[MRieck]

Note the recommended 5000 rpm minimum on the fat 400 unit

No sh!t......the valves never close. I wouldn't recommend that thing for the street (unless you start off with a ton of static compression).

[bwaller]

Note the recommended 5000 rpm minimum on the fat 400 unit

No sh!t......the valves never close. I wouldn't recommend that thing for the street (unless you start off with a ton of static compression).

Add some giant carbs though Mike & it'll be perfect.

[Camrector]

Note the recommended 5000 rpm minimum on the fat 400 unit

No sh!t......the valves never close. I wouldn't recommend that thing for the street (unless you start off with a ton of static compression).

Add some giant carbs though Mike & it'll be perfect.

Watch out Waller is saucy today!

[PeWe]

Note the recommended 5000 rpm minimum on the fat 400 unit

No sh!t......the valves never close. I wouldn't recommend that thing for the street (unless you start off with a ton of static compression).

min 5000 rpm, must be idle! Or when engine runs stable
for the strip, must be impossible to ride that cam on the streets.

[BPellerine]

salt flats maybe?bill

[dragracer]

Definitely a  cam for high rpm use only. The valve springs would need to be replaced quite often because they'd get beat to hell during every run.

[PeWe]

Win the race, it cost a few engines that sponsors gladly can provide when their visible names sells products. I understand that formula.

It would be nice with a chart where different cams are runned in same engine on dyno.
Different displacements and CR too.
To visualise the extra hp and torque the added amount of pain on engine and wallet will give except for less durability.

[corky]

Hey BPellerine,

i actually found the cam card for that crane cam you have.  Here it is.  Sorry for the late reply.

Thanks,
Daniel

[BPellerine]

thanks ,I never did know the specs on it,found in a stock motor,where the valves were just kissing the pistons.bill

[PeWe]

They made a lot of different cams for the CB750.
A very popular bike!

[Tracksnblades1]

thanks ,I never did know the specs on it,found in a stock motor,where the valves were just kissing the pistons.bill

Did you get to hear it run...?    🙏

[BPellerine]

no never heard it run,motor was apart.bill

[Tracksnblades1]

no never heard it run,motor was apart.bill

😩

That's to bad....

Once tore down a 350sbc, everything wrong by the accepted rule...
Big Crane .670 intake .625 exhaust...286@ .050 lift,  roller...1.5:1 crane roll rocks with double bar girdle
Stock cast iron Qjet intake with adapter to square 850 Holley DP...
Stock 8.5 cast pistons........
Stock 1.74 intake 1.50 exhaust 78cc cast iron heads bowl ported below valves w/ screw in studs and big 1.437 or 1.500 valve springs....
Unmatched header adaptors to Schoenfield 1 3/4 headers.....
Variable pitch stock th400 converter with manual body th400...

Ran like a screaming chicken....idled very decent @ 900....power brakes worked at stop sign...
Smoke the 3.73 posi street 60's anywhere anytime....
Still have the Crane Cam #...and still offered......

Do you want to sell it....?

[BPellerine]

don"t think I would sell it to anyone,looks to be some wear,might be ok might not be.bill