Heymow - Lawnmower Racing Forum

Engine Help => Briggs OHV & Vanguard => Topic started by: nic_hayes on October 08, 2014, 09:14:52 pm

Title: EC Cam vs Cheetah
Post by: nic_hayes on October 08, 2014, 09:14:52 pm
Hey guys, I'm curious to here from someone that has ran a Precision Cheetah cam in a single briggs and then ran the EC billet cam, http://eccarburetors.com/store/en/precision-mower-accessories/mower-engines/model-28-ohv/model-28-ohv-performance/billet-cam.html that they have on there site now. I'm currently running the cheetah in my 33 ohv but I'm considering changing to the EC one. Any opinions?
Title: Re: EC Cam vs Cheetah
Post by: nip 19 on October 08, 2014, 09:35:15 pm
I've ran both in a 31. Both are great. Cheetah cam seemed to be a little quicker off the corner vs Ec cam came in later but seemed to pull longer.
Title: Re: EC Cam vs Cheetah
Post by: nic_hayes on October 08, 2014, 10:13:44 pm
My Cheetah pulls great off the corner but just seems to die out halfway down the straightaway.
Title: Re: EC Cam vs Cheetah
Post by: nip 19 on October 08, 2014, 10:33:02 pm
I prefer the cheetah over the Ec at our local track but I have ran some the Ec cam would have a benefit. If you have wide two or three groove corners the Ec cam might work better due to not lifting the throttle as much.
Title: Re: EC Cam vs Cheetah
Post by: nic_hayes on October 08, 2014, 10:43:59 pm
Thanks for the info. Will be thinking on this one.
Title: Re: EC Cam vs Cheetah
Post by: bimmerbaz on October 08, 2014, 11:28:44 pm
Hi Guys,

What sort of RPM do you expect the cheetah cam to start working?

Baz 8)
Title: Re: EC Cam vs Cheetah
Post by: Jeff McKelroy on October 13, 2014, 10:37:49 pm
ABSOLUTELY prefer the EC cam.
Title: Re: EC Cam vs Cheetah
Post by: nic_hayes on October 15, 2014, 07:25:12 pm
Hey Jeff, what do you like more on the EC cam over the cheetah?
Title: Re: EC Cam vs Cheetah
Post by: redline on October 15, 2014, 08:03:11 pm
Once upon a time, a long time ago, my brother in law ran a cheetah cam. Had about a 1200rpm window of doing anything other than just make noise. We then went to Isky. He has a real good grind for Briggs OhV's in fact..
Title: Re: EC Cam vs Cheetah
Post by: Jeff McKelroy on October 15, 2014, 08:17:34 pm
Hey Jeff, what do you like more on the EC cam over the cheetah?

Cheetah cams are like Crap-maros and Rust-angs -- too many people drive them. That's a big reason. But:

1. I have found solid increases in volumetric efficiency and dynamic compression ratio, even with stock compression and no head work.
2. 1-Piece billet construction over cast is good enough for me.  I do not know the metallurgy of EC's camshaft, but simply look at the O.D. of the two. That tells you something.
3. Billet construction also allows for more aggressive spring pressures (If that's your thing) and higher RPM without breakage, with either the stock steel or stainless flavors. Exotic metal valves would be a breeze for this little bump-stick.
4. Lightweight camshaft drive sprocket means less rotating weight.
6. I like the idea of having an unmolested cam lobe, not cut down the middle and welded.

IF you insist on stock rocker arms, keep the cheetah. You will bust stock rockers with an EC cam EVERY time, even when using only the outer spring.
 
Given unmodified rocker pedestal height and 2 stock steel pushrods, you may have to machine an additional .05" off the top of the exhaust valve guide, but double check with a light "checker spring" installed so you can measure retainer-to-guide clearance.

Really, a billet camshaft opens up lots of opportunities to the savvy engine builder.
Title: Re: EC Cam vs Cheetah
Post by: nic_hayes on October 15, 2014, 08:50:37 pm
Sounds good Jeff, I'm going to try one. I do have the ec roller rockers already.
Title: Re: EC Cam vs Cheetah
Post by: nic_hayes on November 13, 2014, 10:28:07 pm
I don't see the notch on the end of the cam for turning the oil pump. Does it not have them?
Title: Re: EC Cam vs Cheetah
Post by: George Herrin on November 13, 2014, 11:00:45 pm
When you order it tell them to cut it in. Most dont run the pump. Parsitic drag drains HP. They dont really do squat, if they did it would not have an oil slinger in them
Title: Re: EC Cam vs Cheetah
Post by: MIKE/PRECISIONCAMS on December 01, 2014, 12:17:43 am
I love this forum, its a big help to everyone building mowers.  I wish we had more time to post more.  I just wanted to clarify a few things and give some of my opinions.  We no longer grind our Cheetah profile for the single Briggs unless the customer asks for it specifically.  We have been grinding our 440 profile for around 3 years because it makes more power.  As far as Cast cam vs. Billet cam, I can tell you we have manufactured thousands of cast cams over the last 32 years with almost zero failures or problems.  In most cases I can get the weight of the cast the same as the billet, in some cases I have got it much lighter.  My cam grinder does not care, but I will say I have many more problems with Billet cams with lobe wear.  Almost all Billet cams have a hard facing weld down the center of the lobe to prevent this.  Almost all Billet cams will wear the lobes without the hard facing weld, which my not be visible with the eye.   
Title: Re: EC Cam vs Cheetah
Post by: George Herrin on December 01, 2014, 06:06:57 am
WHAT MIKE SAID
Title: Re: EC Cam vs Cheetah
Post by: nic_hayes on December 17, 2014, 08:46:48 pm
When you order it tell them to cut it in. Most dont run the pump. Parsitic drag drains HP. They dont really do squat, if they did it would not have an oil slinger in them


My engine is a 33 and has oil pressure to both crank journals and the rod, so I figured I better keep it that way.
I love this forum, its a big help to everyone building mowers.  I wish we had more time to post more.  I just wanted to clarify a few things and give some of my opinions.  We no longer grind our Cheetah profile for the single Briggs unless the customer asks for it specifically.  We have been grinding our 440 profile for around 3 years because it makes more power.  As far as Cast cam vs. Billet cam, I can tell you we have manufactured thousands of cast cams over the last 32 years with almost zero failures or problems.  In most cases I can get the weight of the cast the same as the billet, in some cases I have got it much lighter.  My cam grinder does not care, but I will say I have many more problems with Billet cams with lobe wear.  Almost all Billet cams have a hard facing weld down the center of the lobe to prevent this.  Almost all Billet cams will wear the lobes without the hard facing weld, which my not be visible with the eye.   

Thanks for the info Mike.
Title: Re: EC Cam vs Cheetah
Post by: George Herrin on December 18, 2014, 06:19:45 am
Its not pressure ;lubed Nick. if it was it would not have an oil slinger. Remove the oil slinger and see how long it runs.
Title: Re: EC Cam vs Cheetah
Post by: nic_hayes on December 18, 2014, 08:07:24 pm
Its not pressure ;lubed Nick. if it was it would not have an oil slinger. Remove the oil slinger and see how long it runs.

I don't mean the entire engine is pressure lubed, but it does build up to 20 psi and feeds oil to both crank journals and the rod through the crankshaft. I think it would be smart to keep that?