Heymow - Lawnmower Racing Forum
Engine Help => Briggs OHV & Vanguard => Topic started by: nic_hayes on October 08, 2014, 09:14:52 pm
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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?
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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.
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My Cheetah pulls great off the corner but just seems to die out halfway down the straightaway.
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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.
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Thanks for the info. Will be thinking on this one.
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Hi Guys,
What sort of RPM do you expect the cheetah cam to start working?
Baz 8)
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ABSOLUTELY prefer the EC cam.
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Hey Jeff, what do you like more on the EC cam over the cheetah?
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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..
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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.
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Sounds good Jeff, I'm going to try one. I do have the ec roller rockers already.
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I don't see the notch on the end of the cam for turning the oil pump. Does it not have them?
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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
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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.
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WHAT MIKE SAID
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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.
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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.
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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?