Will A Performace A8 or A14 Cam Work On A Stock 150cc GY6 Head?


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Posted

It can not be a 157QMJ if it has factory installed external oil cooling....

1 = 1 cylinder

57 = Diameter of piston 

Q = Cooling type

M = Motorcycle (application type

J = 150cc (cc's affix)

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Here's a nice little chart I snatched off the web

 

Engine_Stamp.JPG

You've gotta be kidding me.

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Posted

Well, in that case, mine is a 157YMJ. I read through the Hammerhead article again and found they were talking about their non-oil-cooled engine. I guess they come in both forms.

Either way, that wouldn't affect the head, would it? I know for sure I don't have the P-type tall head.

What are my options?

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Posted

I can also measure and take pictures of anything you need.

By chance can you take some real good and clear pictures of your engine gear box? Actually, a bunch of pictures of the whole motor would be great as well.. I need some reference photos of different buggy motors for stuff I have going on around here.....  :thanks:  

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Posted

 

What are my options?

I can't say without knowing what you have. 

My advice really is still the same..... Add the A8 to your art shelf for later :rofl2: 

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Posted

I have done some very questionable things in my past, and I dont have a machine shop. I've shortened valves and recut locks using a HILTI drill and a dremel. This was for a gx160 though so the rpm's are limited. I've also cut a drill bit and hand made a flat faced milling bit (whatever the proper term is) and relieved valve seats to run a stronger spring that was getting coil bind. I even cut too much and punched straight through and had to weld it back up using a DC stick welder. 

The engine ran great pulled about 7000rpm using a cam I welded up with a cast iron electrode and regound to my own profile using a small lathe a printed degree wheel and bench grinder. I tilted the lathe by hand.

All madness aside, I've used the A8 cam in my scoot, runs great I starved the engine of oil and destroyed the cam bearibngs, I also tried the Nibbi cam, that one will let you push your rpm way past what you should, (I tried it), and I'm testing out the A10 cam right now, it is tricky to dial in, I have to do some rejetting but it has good power up top.

So far I think my favorite will be between the A8 and the Nibbi, but the Nibbican get you into a lot of trouble.

If you can get the info for Dan he can point you in a good direction for a good head, I'm currently using one of his Taida heads and it is awesome.

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Posted (edited)

I have done some very questionable things in my past, and I dont have a machine shop. I've shortened valves and recut locks using a HILTI drill and a dremel. This was for a gx160 though so the rpm's are limited. I've also cut a drill bit and hand made a flat faced milling bit (whatever the proper term is) and relieved valve seats to run a stronger spring that was getting coil bind. I even cut too much and punched straight through and had to weld it back up using a DC stick welder. 

The engine ran great pulled about 7000rpm using a cam I welded up with a cast iron electrode and regound to my own profile using a small lathe a printed degree wheel and bench grinder. I tilted the lathe by hand.

All madness aside, I've used the A8 cam in my scoot, runs great I starved the engine of oil and destroyed the cam bearibngs, I also tried the Nibbi cam, that one will let you push your rpm way past what you should, (I tried it), and I'm testing out the A10 cam right now, it is tricky to dial in, I have to do some rejetting but it has good power up top.

So far I think my favorite will be between the A8 and the Nibbi, but the Nibbican get you into a lot of trouble.

If you can get the info for Dan he can point you in a good direction for a good head, I'm currently using one of his Taida heads and it is awesome.

That is some true rigging right there. I like the idea putting the cam in a lathe to grind the lobes. I bow to you. :notworthy:

What engine do you have? Is it a scooter or buggy?

I'm thinking the A10 you have is a Hoca being it has power up top. Am I right?

By chance can you take some real good and clear pictures of your engine gear box? Actually, a bunch of pictures of the whole motor would be great as well.. I need some reference photos of different buggy motors for stuff I have going on around here.....  :thanks:  

I will take some pictures on the weekend.:photo:

Warning: the head will look like sh*t. That's just because it is. I stripped out the spark plug, "tried" porting, and somehow managed to strip out the exhaust studs. I know I need a new one.

And BTW, this forum has the absolute best yellow face thingies. They really satisfy my inner 12 year old.:786_toilet_grabbing_smiley::nutkick::moon:

Edited by TheDullCarbide

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Posted (edited)

The engine is a 1P52QMI on a scooter, I'm not too sure of the brand of cam the A10 is, I got it from Dan, he may know the brand. It works really well though. 

I had a lot of fun in the old days, I wouldn't try doing the cam work for my scoot though, cams are too cheap. I spun the bearings on the A8 cam I had so I got some replacement bearings to put on, I enjoyed the lower end torque of the A8, it gives me a more useable torque curve for my riding 

Yes you are very right, the A10 has the power up top, then I end up in problems at high rpm with vibration, same thing for the Nibbi cam

Edited by bcyprian25

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Posted

The engine is a 1P52QMI on a scooter, I'm not too sure of the brand of cam the A10 is, I got it from Dan, he may know the brand. It works really well though. 

I had a lot of fun in the old days, I wouldn't try doing the cam work for my scoot though, cams are too cheap. I spun the bearings on the A8 cam I had so I got some replacement bearings to put on, I enjoyed the lower end torque of the A8, it gives me a more useable torque curve for my riding 

Yes you are very right, the A10 has the power up top, then I end up in problems at high rpm with vibration, same thing for the Nibbi cam

A8 is a low end cam? That can't be a Hoca.

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Posted

A8 is a low end cam? That can't be a Hoca.

I dont want to give any wrong info here, but for my setup, with the 4 cams I've used (1. Stock,  2.A8,  3.Nibbi and 4.A10) the A8 has given me the most grunt down low. I know for a fact that the A10 has more overlap than the A8 and Nibbi cam so of course I expect it to make its power higher in the rev range. The Nibbi cam is between the A8 and A10 for my setup. 

Stock cam is just dead in my case. The lack of lift is blahhhhh.

I wish a reputable cam company would do some proper grinds with some proper figures. I know you can send a cam to ISKY and they will hook you up I know they do alot of small engine cams. 

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Posted

I dont want to give any wrong info here, but for my setup, with the 4 cams I've used (1. Stock,  2.A8,  3.Nibbi and 4.A10) the A8 has given me the most grunt down low. I know for a fact that the A10 has more overlap than the A8 and Nibbi cam so of course I expect it to make its power higher in the rev range. The Nibbi cam is between the A8 and A10 for my setup. 

Stock cam is just dead in my case. The lack of lift is blahhhhh.

I wish a reputable cam company would do some proper grinds with some proper figures. I know you can send a cam to ISKY and they will hook you up I know they do alot of small engine cams. 

I've only had a stock and my A8. My A8 has crazy overlap and pretty high lift. Most people who get the Hoca A8 say it's not too different than stock. I could spend an afternoon degreeing both my cams, but I have other things to do to my engine for now. Not to mention COIL BIND!!!

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Posted

It seems as though you may have gotten your hands on a mis-stamped A9 cam. It may be possible. Unless the head for your engine is so restrictive in all ways even down to the length of the valves and valve springs something is off. We will figure out this problem sooner or later. I'll try to get some measurements off of my A8 cam when I reach home, will let you know the specs.

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Posted

It seems as though you may have gotten your hands on a mis-stamped A9 cam. It may be possible. Unless the head for your engine is so restrictive in all ways even down to the length of the valves and valve springs something is off. We will figure out this problem sooner or later. I'll try to get some measurements off of my A8 cam when I reach home, will let you know the specs.

Important to note my cam is an eHaze brand, not Hoca. My cam matches all the specs the seller provided (to my surprise and delight). It has a 6.4mm lift on the intake and 6.6mm lift on the exhaust. I have confirmed this with a caliper.

Also, the bearings are so-so, but they'll work fine.

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Posted (edited)

Important to note my cam is an eHaze brand, not Hoca. My cam matches all the specs the seller provided (to my surprise and delight). It has a 6.4mm lift on the intake and 6.6mm lift on the exhaust. I have confirmed this with a caliper.

Also, the bearings are so-so, but they'll work fine.

I still am highly suspect that you have a "P" head or it's proprietary to Tong Jian......

I had to look some of this stuff up, and it may still be wrong so don't hold me to it yet.... But both valves may have the same length and diameter, but be angled differently... It explains why the P has the cam cradle at a different height.  What I don't yet know is if the cams and rocker arm ratios are the same.... It has me in a quandry.... I have this stuff in stock and when I buy an OEM camshaft, it usually is just labeled GY6 125/150cc camshaft and doesn't specify if it's a P or not.... Same-thing with the rocker arms.....

:thinking:   This is actually turning into a side project for me. I have to make sure my inventory is correct..... :compsmash: 

 

BTW, If anyone can find some mechanical drawings / cad / wire-frames of these two different heads, I would be in your debt. 

Edited by DMartin95

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Posted

I still am highly suspect that you have a "P" head or it's proprietary to Tong Jian......

I had to look some of this stuff up, and it may still be wrong so don't hold me to it yet.... But both valves may have the same length and diameter, but be angled differently... It explains why the P has the cam cradle at a different height.  What I don't yet know is if the cams and rocker arm ratios are the same.... It has me in a quandry.... I have this stuff in stock and when I buy an OEM camshaft, it usually is just labeled GY6 125/150cc camshaft and doesn't specify if it's a P or not.... Same-thing with the rocker arms.....

:thinking:   This is actually turning into a side project for me. I have to make sure my inventory is correct..... :compsmash: 

 

BTW, If anyone can find some mechanical drawings / cad / wire-frames of these two different heads, I would be in your debt. 

I can take measurements of rocker ratio, valve angle, and the cam lobes.shr

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Posted

I've only had a stock and my A8. My A8 has crazy overlap and pretty high lift. Most people who get the Hoca A8 say it's not too different than stock. I could spend an afternoon degreeing both my cams, but I have other things to do to my engine for now. Not to mention COIL BIND!!!

"carzy overlap" cool since none of these numbers are published and you must have compared to stock and other cams how bout posting up those crazy overlap numbers?

Curious, since none of these over the counter cams have adjustable timing gears to be able to degree the cam how are you decreeing your cam?

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Posted (edited)

Wow, realizing what a thick-skulled millennial I am. I put the stock cam back in for now to practice a few donuts.

You've stated the head is off with butchered porting stripped out spark plug hole has stripped out exhaust stud and you need a new head so how did you slap this back on to practice a few donuts?

And how did you get a degree wheel and dial indicator up in that buggy?

Ive bloodied enough knuckles in the day to see that Buggy motor aint been touched, and btw Fix the Cracked frame.

 

Edited by pistonguy

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Posted (edited)

You've stated the head is off with butchered porting stripped out spark plug hole has stripped out exhaust stud and you need a new head so how did you slap this back on to practice a few donuts?

And how did you get a degree wheel and dial indicator up in that buggy?

Ive bloodied enough knuckles in the day to see that Buggy motor aint been touched, and btw Fix the Cracked frame.

 

Yup, I stripped the spark plug hole and exhaust studs. I own that one...

I used an insert (not the heli-coil type) and tapped the inside of it to the spark plug head. I also used 5/16-18 studs for the exhaust. It ain't pretty, but it works. I know I could use a new head. But there's other things before that, like the cracked frame. And heck, it's not like I can keep this thing spotless for 2 years straight like a scoot driven on a road. It's a buggy!

I can degree the cam. I haven't done this one yet, but I did on my other gokart that has a GX200. I have indicators and printed-out degree wheels. I will do this in my Tong Jian vs Scoot thread when I get the chance.

Edited by TheDullCarbide

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Posted

Do these engine specs help?

9.2:1 compression ratio

9.9HP @ 7500rpm

13ft/lb @ 5500rpm

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