Performance cam in a governed engine.

[BigWes]

Just a question of curiosity. Has anyone out there ever put a performance cam in a governed engine?

Nothing radical or high lift or anything like that.

I was just curious. Actually I ordered the wrong one by mistake and was considering putting it in the kart I lend others to ride. It has a stage one but still governed. Bump the springs up and leave the rest along. I know it sounds stupid. It'll sound the part but just be rpm limited till I get around to building it the rest of the way up. Maybe a little more bottom end pull. Who knows. Or not. Haven't decided yet.

 

[Flyinhillbilly]

I only know of one sir fire way to find out.

 

[Brianator]

I have seen a thread here touching on exactly that! It was a "marine/winchboard" cam and because it's designed to work at lower rpms it apparently worked well!

I'm not making any promises but I'll try to find the thread, it was a couple months ago I came across it and dont know how old the thread itself was... wish me luck!

Either way I agree with FHB, it would be great to find more real world results!

 

[karl]

I did initially with my monster moto 212 lifan clone,

But a torque oriented marine grind cam. Went something like this
230-0211 NR Marine grind cam
10.8lb trick springs
4 degrees advance
Re-jet
Better flowing exhaust
Governor turned to 4500rpm

It was decent, then I took the motor off again and made it faster, then ya know how it works, I recently took the motor off yet again and have some fancy parts from NR racing on the way.

 

[BigWes]

Ok, I guess I'll give it a go then. I'm not gonna just throw the cam in there without making sure the valve train is up to par though.

.265 lift I/E. .226 I /.236E duration

No spring recommendation. But comparing to other profiles I think 22lb springs will be fine.

It's nothing excessive by any means. It's a non-hemi predator so coil bind and clearance shouldn't be an issue with stock rockers.

I suppose later I could do like Karl and build up.

I'll do it just for kicks.

 

[anickode]

Would definitely be interesting to see what kind of bottom end grunt you can squeeze out of a little engine. Everybody always builds for speed and top end power and then just gears down if they need more torque.

A longer intake runner could help some too, though you'd have to work out a new throttle rod to keep the governor intact.

 

[karl]

Would definitely be interesting to see what kind of bottom end grunt you can squeeze out of a little engine. Everybody always builds for speed and top end power and then just gears down if they need more torque.

I did something like this, with a Nr 252 rattlesnake cam, works well. Advertised to pull from 2000 to 6500rpm.

That with a flat top piston, milled gx200 head, ported, long runner intake , and gx340 carb, it pulls hard the second the clutch engages, punches like a bigger engine.

Increasing the compression ratio makes a huge difference in the " pull" , all 3 of my 212's are now above 12 to 1 compression.

 

[Brianator]

Increasing the compression ratio makes a huge difference in the " pull" , all 3 of my 212's are now above 12 to 1 compression.

Are you able to still run on (high octane) pump gas or no? I dont want to run special fuel and was concerned about going much higher than 10:1.

 

[mckutzy]

No kidding a difference of pull... as in might just pull your arm off...

 

[karl]

Are you able to still run on (high octane) pump gas or no? I dont want to run special fuel and was concerned about going much higher than 10:1.

With 10 to 1 , no worries on 93 octane, depending on your jetting/timing.

I run regular sunoco 93 , pump the first gallon or two in your car or separate can, then add a spash of a decent octane booster.

As far as starting, I casually start all of them, usally one handed while sitting down on the seat. Not difficult in the slightest.

Most starting difficulties/kickback are caused by improper pulling technique, just not pulling it swift enough, or an assembly error, like too loose valve lash.

 

[BigWes]

I have the camshaft and the piston rod on hand now but I don't have valve springs yet. This particular engine is a predator 212 non hemi.

It will retain the governor. So I haven't decided if I'm going to open it up and start working on it today or not. I do want to put at least 18 lb springs in it. But since it's governed I might could get by till they arrive in the middle of the week. I don't know what I'll do yet. I'm not young so my back can't handle the beating so I really only ride the things very seldom anyway.

Think I'll take a nap and think on it!

 

[anickode]

I would think the factory springs will get you by for now unless the cam profile is really steep.

 

[Whitetrashrocker]

If your gonna open it up for the rod and cam, why O why leave a grenade inside?

Make a throttle stop if you don't want full rpms.

 

[anickode]

If your gonna open it up for the rod and cam, why O why leave a grenade inside?

Make a throttle stop if you don't want full rpms.

The governor isn't a grenade if it's still functional... He's not disabling it and leaving it in, he's still planning to use it.

Throttle stop on an ungoverned engine only limits throttle, not rpms, so you lose acceleration and power.

 

[BigWes]

The governor isn't a grenade if it's still functional... He's not disabling it and leaving it in, he's still planning to use it.

Throttle stop on an ungoverned engine only limits throttle, not rpms, so you lose acceleration and power.

Exactly what Anickode has said. Top speed is not a concern presently with this kart anyway.

In its current gearing it will run 41 mph flat and level. And that is with whatever the factory governor setting is. Carb has a .038 jet and full stage 1. It sounds great and gets there faster. Actually in stock form I'm not sure that engine ever pulled into governor range on the big Murray Explorer.

This kart is stable on the road. It is easy to drive with no bad tendencies. This is currently the one
I loan out to new drivers. It gives a good driver experience. Nobody has gotten hurt or scared on it. That's a good thing don't you think?

As far as going into the engine is concerned it's no big deal to me. I just don't have a temperature controlled work space. It's 6pm and still 90 degrees outside.

What I've decided to do for now is this.

Pull engine from the frame. Take it apart. Clean and inspect while I have it apart. Remove the low oil sensor as I have it unplugged anyway. Might as well put that space to good use for oil. Tap and port the wire hole for later. Install the ARC billet rod. Install the HOT265 cam. Go back together with it. That being said. I do have a set of 18 pound springs I can take off my clone and use. May do that. I'm going in that engine as well.

Oh I also have one of those Auto lite racing plugs too.

When I get it all back together I'm gonna run it and report back on how it runs. If I don't like it well it's only a governor removal and a billet flywheel away from being a total different result.

Then I have to rethink letting kids drive it.

 

[BigWes]

I thought the thread would be better with at least one pic to get started. Today has went in a strange direction. Maybe tomorrow I can get something started.

 

[itsid]

I'm not aware of any cam that actually makes much sense to be used in a governed engine (i.e. below 4k rpms)
Never ehard of that "marine" cam karl mentioned earlier.. so maybe .. IDK

All cams I know shift the peak torque UP the powerband
and the "hotter" the cam, the further up it goes.
(and that means the torque in the lower rpm range drops by about the same amount)

if you can find a strict "duration" cam that's not altering the timing at all,
then it would serve you best I think;

Otherwise my best guess would be that increased compression (decked head, thin gasket..)
would serve you better than any cam since that increases the torque a bit.

So I think a custom ground cam (stock timing IMO is crucial for best governed performance)
with just a tad higher duration paired with a slightly higher compression ratio (maybe even a wild one with a GX160 markI head or so)
gives you the best bang for a buck at low rpms.

'sid

PS in my opinion such would outrun 95% of the modded engines on this forum...
the higher down low torque will accelerate you quite nastily and seeing how much revolutions are lost in insane setups (gearing and TC) you can likely pull all power from it and not loose 60% on the way to the wheel Maybe it won't reach insane 'on paper' top speeds but on the road it'll win I bet

 

[Brianator]

I'm not aware of any cam that actually makes much sense to be used in a governed engine (i.e. below 4k rpms)
Never ehard of that "marine" cam karl mentioned earlier.. so maybe .. IDK

It's a "winchboard" cam, designed for use with a governed engine and a CVT to pull boats up tracks (into a boathouse or building for winter storage) or onto a trailer. I came across them when researching a "low rpm/high torque" setup.

Never did find the post I mentioned earlier, Bob58o has a thread that started off that way because of the Kohler charging flywheel he was using. Quite the interesting (and time comsuming) thread to read! Lots of great info though.

 

[BigWes]

I'm not aware of any cam that actually makes much sense to be used in a governed engine (i.e. below 4k rpms)
Never ehard of that "marine" cam karl mentioned earlier.. so maybe .. IDK

All cams I know shift the peak torque UP the powerband
and the "hotter" the cam, the further up it goes.
(and that means the torque in the lower rpm range drops by about the same amount)

if you can find a strict "duration" cam that's not altering the timing at all,
then it would serve you best I think;

Otherwise my best guess would be that increased compression (decked head, thin gasket..)
would serve you better than any cam since that increases the torque a bit.

So I think a custom ground cam (stock timing IMO is crucial for best governed performance)
with just a tad higher duration paired with a slightly higher compression ratio (maybe even a wild one with a GX160 markI head or so)
gives you the best bang for a buck at low rpms.

'sid

PS in my opinion such would outrun 95% of the modded engines on this forum...
the higher down low torque will accelerate you quite nastily and seeing how much revolutions are lost in insane setups (gearing and TC) you can likely pull all power from it and not loose 60% on the way to the wheel Maybe it won't reach insane 'on paper' top speeds but on the road it'll win I bet

It may totally be a waste of time just as you say. Probably will be. I bought the wrong cam for another engine by mistake. I wasn't paying attention to what I was clicking on. But it fits the engine in my Murray so why not. Like I said it's only a flywheel and a governor removal away from full on anyway. It's not like it's going to hurt anything... and if it does it'll just be my stuff so that will give some of y'all something to hope for anyway. So on a positive note it's a win situation either way I go

 

[Brianator]

I don't see this experiment as a waste of time at all!