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Old 11-24-2019, 08:53 AM
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Default Compression Release Question

What do y'all think of this here video:


He recommends grinding down the valve stem to counteract compression release. But doesn't compression release only affect the engine at very low speed?
It just seems wrong to me to grind down the valve stem.
And either way, would it even really help with power?

On the same topic: On my HiPo flathead, I've got the #691164 camshaft. It does not have the mechanism on the cam gear to release compression. Is the compression release built into the lobes? My tiller has Easy-Spin on it, and it's the same camshaft number.
EDIT - My Clymer manual from the library just answered most of this paragraph: Easy Spin is built into the lobes, and Easy-Spin camshafts can be identified by two holes drilled into the web of the cam gear. The HiPo cam gear only has one hole in it.

So my HiPo does NOT have a compression release! That's interesting! It might be a bane to start if I put a billet flywheel on....
That explains why I can so distinctly feel the compression, even turning it over by hand.
EDIT - See post# 6
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Old 11-25-2019, 06:32 AM
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I think that some of the older engines had compression releases built into the camshaft, like the one on your tiller. That style compression release does affect the engine all the time, not just at low speed. Personally I'd of pulled the cam, filed off the compression release and polished it, rather than opening up the valve clearance. He's being counter productive in my opinion. He is getting rid of the compression release (more power), but he's taking some of the lift out of the valve (less power).
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Old 11-26-2019, 02:25 PM
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Contacted B&S, didn't have much useful info. But they did point out that the parts manual says that the camshaft is part# 212733, and the illustration shows two holes drilled in the cam gear, indicating an Easy-Spin camshaft.
BUT, the Outdoor Power Direct parts lookup says part# 691164. Looking it up on Ebay, I see camshafts part# 691164 with only one hole in the gear, matching mine.
So there REALLY is NO compression release on my engine! Huh, interesting...
So if you want the "good" cam for a flattie, get #691164! EDIT - See post# 6
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Old 11-26-2019, 09:35 PM
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I thought the compression release on those older engines was a tiny, barely noticeable bump on the exhaust cam located 180 from the lobe.
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Old 11-27-2019, 08:06 AM
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Most engines have that, but some also have a spring actuated compression release.
I'm almost certain my tiller has the lobe release, since it feels too easy to spin over, even compared to my 3 HP, but hey, it runs. *shrug*
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Old 12-07-2019, 12:03 PM
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Oh, oops.
I was mistaken.
Since I had my HiPo open, I checked for the Easy-Spin compression release, and it does have it, despite only having 1 hole.
So #691164 still has the compression release.
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