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Old 10-24-2019, 04:09 AM
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Dave,

My thoughts: Dents on the closing ramp of cams can be caused by valve float but more likely by failure to keep up with lash adjustments.

Keep in mind that I've only worked on 82 and smaller saitos where max rpm is spec'd higher than the larger engines. Most of these smaller engines were pushed well beyond 11k by reviewers to obtain peak hp numbers so valve float was obviously not happening. The fa50 for instance made peak hp at 12,300. Had it been floating valves it would never have gotten there.

Online we read post after post about keeping these smaller saitos at less than 11k (10k on the ground) and generally speaking the tachometer readings posted by individuals online and setups I've seen at the field reflect that. It would take a small dia/large pitch prop and slick plane to unload a 4 stroke in flight to see 12000 rpm when starting with at 10,000 on the ground, a scenario reserved for speed planes.

I suspect the cam dent demon is valve lash procrastination.

Last edited by Glowgeek; 10-24-2019 at 04:12 AM.
Old 10-24-2019, 04:18 AM
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Yeah my 56 with a 11-7 APC I tune to 11500 on the ground. I havenít experienced the nose like I have on that 91. The 91 was new with a 14-6. APC. And only did that on a full throttle dive.
Old 10-24-2019, 04:27 AM
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Is your 56 supercharged? Surely you meant 10500?
Old 10-24-2019, 04:36 AM
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Nope seriously the 56 will will turn 11500
Old 10-24-2019, 04:41 AM
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What fuel are you running in that 56?
Old 10-24-2019, 04:45 AM
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Well that depends on the day right now I am running 35%
but I normally run 15%
and I canít give you numberís on a pic my tack is broke and itís been getting cold. If I can get a new tack here before it gets to cools I will run a 56 on a test stand and either prove myself wrong or show you that the 56 will turn 11500.

Last edited by Captcrunch44; 10-24-2019 at 04:49 AM.
Old 10-24-2019, 04:55 AM
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Well, that 35% is a real kick in the britches huh?

Your new 91 was probably just loading up on fuel in that shallow dive. The combination of a new engine running a little richer than normal, a forward tilted fuel tank and unloading the prop will do that. My experience anyway.
Old 10-24-2019, 05:20 AM
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Glowy
it sure helps my 72 get some power
Not really impressed with that engine the 65 with the big carb is proving to not so good unless youíre racing it doesnít like to idle vary well or fly at a low RPM. I did put a 15-6 on that it helped but now I donít have much high speed adjustment.
The 56 I ran on 15%. It will turn but like you say nobody runs those numbers there afraid of over revving. I was running a 11-6 on my new case 40 and it didnít seem to have much I put 10-6 on and that woke it up. I feel there is a point at where the size of the engine and the RPMís go done and you rely more on torque then revs.
Maldonado take the 180hc it will turn a 16-12 at 9800 and sounds great put a 18-6 on and get it down to 8700 and sounds like it needs help.
I wish I had more time like you and Dave and Gary to run these engineís and find out what really works for me. You Dave and Gary have been great for what should be but I always need a little more.
Old 10-24-2019, 05:41 AM
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Originally Posted by Glowgeek
Is your 56 supercharged? Surely you meant 10500?

My .56 isn't but my .53 is supercharged

Also, a pic of one of the degree wheels I made about 40 years ago. Made nicer ones since but people keep "borrowing" them. Nobody has borrowed the ugly one yet. The only reason I still have it.
Old 10-24-2019, 11:08 AM
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Crunchy, for the smaller 82 and under Saitos I've been propping for 9600-10600 on the ground depending on application. There's usually 3 or 4 prop sizes within that rpm range to match to the plane's characteristics. I'm not even that picky when propping aerobats or fun flyers. 3D and pattern ships are a different story, I'll usually try every prop I have that would fall within the desired rpm, speed or thrust for those planes.

Gary, nicer degree wheel than mine. I'm assuming that is a swappable hub for different shaft sizes.
Old 10-24-2019, 02:26 PM
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Originally Posted by Glowgeek
Crunchy, for the smaller 82 and under Saitos I've been propping for 9600-10600 on the ground depending on application. There's usually 3 or 4 prop sizes within that rpm range to match to the plane's characteristics. I'm not even that picky when propping aerobats or fun flyers. 3D and pattern ships are a different story, I'll usually try every prop I have that would fall within the desired rpm, speed or thrust for those planes.

Gary, nicer degree wheel than mine. I'm assuming that is a swappable hub for different shaft sizes.
Hmmmm
Old 10-24-2019, 03:19 PM
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Default Saito fA45 hair pulling exercise!

Ok Gary, you got me! Haw haw haw.

I'm just kidding, you probably didn't mean to but one of the 45's you sent had a 90T rear cam in it. That engine wouldn't idle below 3000 rpm for *$!# and I was pulling my hair out all morning trying to figure out why. Either the lobes are clocked differently on that 90T rear cam or the rear crank gear is clocked different? I don't understand how either would be true but saito does sell a front cam and a rear cam (the rear having the slash one tooth off from the dot.
Now that I think about it maybe the alignment/oil hole and the slash on that rear cam are where they are because the tappet bores in the cam housing are not symmetrically located. Just guessing though because this kind of stuff drives us lysdexics crazy.

I noticed the slash when I reassembled the motor and could not get the crank at perfect tdc with my cam tool in the cam oiling hole but blew it off as it just being my eyes. Shouldn't have but I was tired.

Anyways, anyone have an FA45 cam? Has to be the mild one, not the 45S cam.

Last edited by Glowgeek; 10-24-2019 at 03:50 PM.
Old 10-24-2019, 03:50 PM
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I didn't really pay much attention. The main elements were just a parts pile that wad given to me as a gratuity for some machine work. I tossed in a few parts I had on hand that I figured may be helpful. Please note, the early, open rocker cams had that same slash mark as well.

Last edited by Jesse Open; 10-24-2019 at 03:54 PM.
Old 10-24-2019, 03:56 PM
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I'll try timing the cam using the tdc exhaust stroke trick tomorrow.
Old 10-24-2019, 05:12 PM
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Originally Posted by Glowgeek
I'll try timing the cam using the tdc exhaust stroke trick tomorrow.
i bet you could run those backwards.
Old 10-24-2019, 05:13 PM
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Speaking of open rocker 30s there's a new one and a preowned on the bay.

There's a nib ys115ws there too.....just say'n. I really want one for my 46 strega but I can't afford nib and I'm scared to death to buy a preowned knowing what they're typically used for.
Old 10-24-2019, 05:19 PM
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Originally Posted by Captcrunch44


i bet you could run those backwards.
I'll bet your right, that is if the opening and closing ramps are symetrical.

Last edited by Glowgeek; 10-24-2019 at 05:22 PM.
Old 10-24-2019, 06:25 PM
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Dave
I got some mufflers today, there awesome!!! Thanks

Last edited by Captcrunch44; 10-24-2019 at 06:41 PM.
Old 10-24-2019, 06:42 PM
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Originally Posted by Glowgeek
I'll bet your right, that is if the opening and closing ramps are symetrical.
i think its a thing because the rear cam turns backwards
Old 10-24-2019, 07:25 PM
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Are we talking the 90T?
It has left and right cams. They are visibly different. The angle between lobes is different. The intake and exhaust roles are opposite from the left to the right cam assembly.
Old 10-25-2019, 01:56 AM
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Originally Posted by Jesse Open
Are we talking the 90T?
It has left and right cams. They are visibly different. The angle between lobes is different. The intake and exhaust roles are opposite from the left to the right cam assembly.
I thought we were talking about a front and tear cam. Not s left and right cam
Old 10-25-2019, 02:19 AM
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On a 90T?
Old 10-25-2019, 02:19 AM
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Originally Posted by Jesse Open
Are we talking the 90T?
It has left and right cams. They are visibly different. The angle between lobes is different. The intake and exhaust roles are opposite from the left to the right cam assembly.
Yes, still talking about using the 90T rear (right?) cam in a 45.

Seems strange.that the LSA would be different between the left/right cams on a 90T. I understand that the 90T is a odd firing twin, firing one cylinder and then the other 180į later but why the difference in valve overlap?

Last edited by Glowgeek; 10-25-2019 at 02:41 AM.
Old 10-25-2019, 02:25 AM
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Is the cam difference found in the 182 also?
Old 10-25-2019, 02:52 AM
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Originally Posted by Captcrunch44
Dave
I got some mufflers today, there awesome!!! Thanks
You're welcome, glad you like them.

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