The Dodge Challenger Message Board

Here are some closeup pictures of a cam i pulled out of a '71 340. It is in good condition, i was wondering if anyone recognises the symbol on it -looks like a brand name symbol. I did a Google search for the numbers, but nothing came up.

Its hydraulic

Looks definitely like a hairy spider to me.

thanks

Goldenblack440 wrote:Looks definitely like a hairy spider to me.

Makes me think of Edelbrock Tarantula. I have no idea if I am right or not though.

Thanks for reply Christer. Have you heard of Edelbrock making cams with names like that?

It could certainly be a Tarantula. Good leads like that i can search for, i will do an Edelbrock search tonight.

I thought the Edelbrock Tarantula was an intake not a cam?

I've seen that mark before and I am thinking it's Sig Erson Cam??

right u r Dave, just did a search, and its Tarantula intake they made.

as for Sig Erson, i'll have look there as well, thanks. hope so.

Goldenblack440 wrote:as for Sig Erson, i'll have look there as well, thanks. hope so.

Good luck with that because they went out of business years ago.

yeah i know, i think they were taken over by someone, i think Cam Dynamics rings a bell. They kept a listing of the part no,s of SErson for reference. I found that out because i installed an old skool Erson cam in this 360 and all the data was available. That doesn't mean i won't need luck looking for these numbers though.

They were bought by Mr Gasket I think and then sold on to someone else that makes stuff for chevys and fords only.

I think your best bet (if you have the equipment) is to stick a degree wheel and dial indicator on the cam and measure the spec yourself.

dave-r wrote:I thought the Edelbrock Tarantula was an intake not a cam?

That was also my first thought.
Nowadys they are doing "Performer"- or "Performer RPM"-kits, aren´t they? I had the idea that they maybe used to have a Tarantula series. Maybe I was wrong. It was a long-shot.

I think they named the intake that because it looked like an 8-legged spider type thing.

Had an Erson cam in mine when I bought it. Man it had a sweet lope to it. It was replaced long ago though, sorry no help here.

No problems, its all good discussion. Glad you liked your Erson as well. Yes my Erson cam i am very happy with. Its a 228/290 duration 484/484. I was worried about lack of torque from it initially, but with the other accommodating factors i used, it has turned into a really great all-rounder. Brakes are a bit on the limit due to lack of vacuum, so i have bought a vac cannister for extra stored vacuum to the booster. Installing that soon.

There is a place near here that regrinds cams, they have many data books. i will take the cam to them to see if they can match up the numbers, Surely it could not be that difficult. Hopefully someone with many years experience will recognise the symbol. This place can also spec up some of the dimensions of it, but that only tells a little of the story. They can't determine overlap or duration or ramp etc. with any accuracy. I'm surprised someone hasn't invented a machine where you can bolt in any cam and it can work all this out. If they can computer grind camshafts to close tolerances, surely they could engineer a system of rollers and sensors that can track the specifications of an uknown camshaft. But they reason it's probably easier to just throw it out and put in a new or known one. I just don't like throwing good stuff out!

I thought Tarantula Series was a good start. Edelbrock do things like that.

With a degree wheel and a dial gauge you can measure valve opening and closing times as well as duration and lift. In fact all the cam specs.

Done it myself once and I always check my cams that way to make sure they are ground correctly.

Umm, didn't know it could be done that accurately with manual equipment. Well that's good to know. I wouldn't have the skill to do it myself so i'll have to ask around. Ta!

How else would you measure a cam spec?

The whole point of "degreeing" a camshaft is to check it is in spec and to make sure all the opening and closing points are at exactly the right point of crankshaft rotation. Usually 3 degrees advance are built into the cam grind but you have to check for that.
There are lots of magazine articles about how to do this but if you think it would be handy for me to write or scan something on the subject here I will.

thanks Dave, no need yet, i will hunt around some magazines and the net and see what i come up with. I was under that impression because of what i was told by a camshaft regrinders years ago; i took in an unknown cam and for $50 they gave me an approximate estimation (about 85% accuracy) of its specs with their equipment. But they said they couldn't give a 100% accurate determination. Maybe they were too lazy to do it your way, i don't know. But they said a camshaft's unique characteristics is largely determined by the aggressiveness or otherwise, of the ramp, ie, how fast the valve opens, and for what amount during the opening phase, closing speed and at how long etc.

In any case, tonight i took some simple measurements and came up with weird readings. I took the BCD of a few lobes and got 3.25" +/- 0.01. Then i took the overall lift from top of lobe to base, and got 4.04 +/- 0.01, to give me a gross lift at the cam lobe of 0.79". Now, what do i do with this, do i halve that and multiply by the rocker ratio of 1.4? Or divide that by 1.4.? In all cases it comes up with a large value for a hydraulic cam, which came out of a cast pistoned standard bore 340 with an ancient 2 barrel on it and standard small valve J heads.

Thanks (BCD = Base Circle Diameter)

You would normally see about a 0.30" - 0.33" lobe lift on a performance street/strip cam.

But they said a camshaft's unique characteristics is largely determined by the aggressiveness or otherwise, of the ramp, ie, how fast the valve opens, and for what amount during the opening phase, closing speed and at how long etc

That is true. But when you look at cam specs they do not give you that information. All you can do is look at the amount of lift for the duration @ 0.050" lift and compare.
A higher lift for the same duration is going to be a faster rate of lift cam.

The faster the lift the better when it comes to performance.

Sorry, my mistake, i was hoping i could get back in time to edit that post... i was looking at cm on the vernier (under a magnifying glass)! I looked at inches this time. And got what you said, 1.59" - 1.279" = 0.311" of lobe lift. Also, i think the stock rockers are 1.5, not 1.4?. So this cam should give a valve lift of 0.467 at the valve. So that's a good start.

I see what you mean about rates now, you explained it so its easy to understand - one can get an idea of the rate of lifts by comparing the durations and lift in the specs.

Its looking good so far, might be a goer. The cam is in very good condition and i'm just doing a budget build for a streeter.

Stock rockers are supposed to be 1.5:1 but many fall a bit short of that.

Well, problem solved. I showed the symbol from this cam to a Mopar drag racer i had the fortune to bump into at the machine shop. He looked at it for a few seconds and said it was a Schneider cam. I didn't believe it at first as no matter how hard i looked i could not see a Maltese cross in that symbol. My brain kept telling me i was seeing a hairy spider.

Well, when 2 guys from the A body forum told me Schneider, i had another look and yes, it is a badly stamped maltese cross and the 'hair' is actually the "S" inside the cross. Only half the stamp is visible and the stamp has bounced so that a shadow was formed. So i have emailed Jerry at Sch cams and hopefully he can tell me the specs. Its great news.

Mystery solved then.

Yes, thankyou and Jerry emailed the specs and it is a perfect cam for what i want, in a 340 in a light A body. Very similar to the Erson cam i have in my 360, which i am VERY happy with. It is a 290 adv, 224 @50, 0.48" at valve, 105 centre line and 107 lobe separation. Although i am not really sure what lobe separation affects.

I'm going to experiment with some 1.6 ratio lifters i am getting off ebay, they seem reasonably priced copies of Comp Cams ones. That will give me a valve lift of around 0.497.

http://cgi.ebay.com/ebaymotors/ws/eBayI ... MEWAX%3AIT

wow, that was a quick response, thnks for the info and the website. Well mine is 107deg so definitely old skool there! But i'm, going to use it, i love recycling! -the car is a 4 speed and light. I have a 108 LSA 290 in my 360 and i am happy with the low speed torque and drivability, especially with the new 3.55 rear. But i suppose i did compromise the cam's upper rev range a little by using a simple old Edelbr Dual plane performer and small port heads. But these things help make it a good all-rounder i feel.

this should answer ALL your camshaft questions. http://www.webcamshafts.com/pages/cam_glossary.html The wider the LSA the better low speed street manners you will have. The narrower is useful for high RPM engine speed and is a little 'outdated' for todays modern grinds which both moderate lift and duration with wide LSA to help the bottom end. The Performer RPM,(AirGap), is a much better intake and will increase top end power, even though it's dual plane, it will outperform most single plane intakes that fit standart port small block heads. The wide LSA will also make carb tuning easier by having much more vacum at idle than a narrow LSA cam like yours.

Ed, good advice! I do have an AirGap sitting in my cupboard too! Yes, you're right about the vacuum, not much really. But in a $1000 340 standard bore engine (that's dirt cheap down here for that), complete with J heads, this Schneider cam in good condition was a gift from heaven.

It has been rebuilt previously but strange to see that it has 318 conrods. Same part number anyway. But still full floating.

Nice bit of forensic camshaft investigating there.

Keep us posted with the results using the 1:6 rockers, those look sweet, also the air gap intake. My old LD340 is about history. It would be nice to get rid of the heat riser too as it is counterproductive to the "cooler" intake designs nowadays.

Thanks Jon, I have continued this post into a new topic as it has moved into intakes now!