High Compression GX200 - Oil blowing out valve cover, gas blowing out the carb

[Denny]

You did shorten your cylinder head bolts after you decked the head and block, right?

 

[busted_blocks]

I didn't know about the crank shafts being so variable. Interesting.

Update from today, good news, the gasket stopped the oil spray, so that is one issue solved. I have a heat picture from the engine running. Unfortunately there is some bad news too, 2 exhausts cracked, so it's vibrating a lot and there is a significant amount of metal in the oil. I didn't have time to open it but there is likely an issue of some kind.

stay tuned...

 

[busted_blocks]

You did shorten your cylinder head bolts after you decked the head and block, right?

I switched to studs for the head and side cover which has the same effect. I have also now shortened the head dowel pins 1mm so there should be no length issues now. It's good thinking to ask. Thanks

 

[Denny]

If you’re cracking exhausts you need to add more supports. It’s vibrating too much. There is a lot of stress on the exhaust, your lucky your not pulling studs out of the head.

 

[BrownStainRacing]

I didn't know about the crank shafts being so variable. Interesting.

Update from today, good news, the gasket stopped the oil spray, so that is one issue solved. I have a heat picture from the engine running. Unfortunately there is some bad news too, 2 exhausts cracked, so it's vibrating a lot and there is a significant amount of metal in the oil. I didn't have time to open it but there is likely an issue of some kind.

stay tuned...

189.9 *c is 373 f* here.

I read from cylinder head temp,(CHT).

That's alot if it's running under NO LOAD.

373 *f would be a damn good tune during a race under a hard load, WOT for 15-20 laps.

I run 350-380 *f everyday under load, and comes down fast when I get off the throttle.
400 *f CHT is pushing it for my builds.

My temp alarm is set at 410 *f from the center on the head under the sparkplug, it never goes over 402 *f.

How's the spark plug look???

What's ignition timing??

What carb jets you got installed???

 

[busted_blocks]

189.9 *c is 373 f* here.

I read from cylinder head temp,(CHT).

That's alot if it's running under NO LOAD.

373 *f would be a damn good tune during a race under a hard load, WOT for 15-20 laps.

I run 350-380 *f everyday under load, and comes down fast when I get off the throttle.
400 *f CHT is pushing it for my builds.

My temp alarm is set at 410 *f from the center on the head under the sparkplug, it never goes over 402 *f.

How's the spark plug look???

What's ignition timing??

What carb jets you got installed???

That was running on the track. I did 2 and half break in sessions and then tried it under load. 15-20 laps sounds about right, but it's a very small track, only 600m, so 31s per lap more or less.

I was pressed for time when I left, so I haven't had a chance to take things apart. I'll go back today.

Timing was +7.5 over stock, but we don't know what stock timing is.

Carb is a PE22mm but have to check the jet. It runs OK for this engine but it's not very tunable and isn't a good carb. The PWK24 was lean and I didn't have time to tune the carb. I just wanted the cart to run for the day.

I did a quick test on the stand, and then put it on track. I had a friend visit from back home yesterday and let him drive the cart. I knew there was potential to damage the engine but I get visitors from back home less than once a year, if I'm lucky, so I figured what the heck. It's only an engine.

I'll take it apart today and see where the metal is coming from.

 

[BrownStainRacing]

That was running on the track. I did 2 and half break in sessions and then tried it under load. 15-20 laps sounds about right, but it's a very small track, only 600m, so 31s per lap more or less.

I was pressed for time when I left, so I haven't had a chance to take things apart. I'll go back today.

Timing was +7.5 over stock, but we don't know what stock timing is.

Carb is a PE22mm but have to check the jet. It runs OK for this engine but it's not very tunable and isn't a good carb. The PWK24 was lean and I didn't have time to tune the carb. I just wanted the cart to run for the day.

I did a quick test on the stand, and then put it on track. I had a friend visit from back home yesterday and let him drive the cart. I knew there was potential to damage the engine but I get visitors from back home less than once a year, if I'm lucky, so I figured what the heck. It's only an engine.

I'll take it apart today and see where the metal is coming from.

Good, I was hoping that was under load temperature.

I havnt looked at 600m, but I willl.

I love to see mph in a short distance. That means your $hit is "getting it in a hurry".

I don't believe in that 2 mile bs to get to 70 mph.

I'll leave them "wanna be's" scratching their "man-gina's" at the start line, wondering what the "f" jus happened in that 1st 100ft. sucka, you ain't never catching my 57 mph junk in 600ft,

I get wood most times, dont tell the ol' lady,

Yeap, we gotta let buddy's play with our toys.

It's jus a old "turd motor" anyways,

"Turd Motor Racing" ....foreverrrrrrr!!!!!!!

 

[busted_blocks]

Good, I was hoping that was under load temperature.

I havnt looked at 600m, but I willl.

I love to see mph in a short distance. That means your $hit is "getting it in a hurry".

I don't believe in that 2 mile bs to get to 70 mph.

I'll leave them "wanna be's" scratching their "man-gina's" at the start line, wondering what the "f" jus happened in that 1st 100ft. sucka, you ain't never catching my 57 mph junk in 600ft,

I get wood most times, dont tell the ol' lady,

Yeap, we gotta let buddy's play with our toys.

It's jus a old "turd motor" anyways,

"Turd Motor Racing" ....foreverrrrrrr!!!!!!!

Well, another "blown" motor. I'm lucky as the crank didn't explode and break another block, but the crank was seized to the connecting rod. Bolts were not tight on the connecting rod. This is how most of the engines have failed. Something is not happy. I measured the clearance from crank to connecting rod at 0.003" at 15Nm torque (11ft.lb) for the bolts which is even a little higher than recommended.

Spark plug rust colored. Main jet 115, pilot 36, needle all the way up (circlip in the lowest groove), PE22mm carb. I have pics attached of the whole mess. Piston skirt has some wear but hard to say that didn't occur due to the connecting rod issues.

When this engine was going it was a blast. Yeah this little engine costs almost nothing and is as much fun to me as the $10k rotax karts my friends drive on the longer track. I get thrown around in the corners and get tired out from the braking/accel/cornering in about 10 minutes and need a break. The engine is not long lived though, that's for sure. I'd feel pretty dumb if all of this was due to 15W40 oil....

I might have to try one of those sintered gear cranks as I don't have any more honda cranks, maybe one but it's used.

 

[Denny]

Never saw orange in a cylinder or on a plug before. 15w40 is too thick I would think for a splash lubricated engine. 10w30 or 40 would be better. You have an oiling problem it seems. Try using some works toilet bowl cleaner on those crank journals to remove the smeared bearings and see how they look. Just use baking soda and water to neutralize afterwards.

 

[BrownStainRacing]

Well, another "blown" motor. I'm lucky as the crank didn't explode and break another block, but the crank was seized to the connecting rod. Bolts were not tight on the connecting rod. This is how most of the engines have failed. Something is not happy. I measured the clearance from crank to connecting rod at 0.003" at 15Nm torque (11ft.lb) for the bolts which is even a little higher than recommended.

Spark plug rust colored. Main jet 115, pilot 36, needle all the way up (circlip in the lowest groove), PE22mm carb. I have pics attached of the whole mess. Piston skirt has some wear but hard to say that didn't occur due to the connecting rod issues.

When this engine was going it was a blast. Yeah this little engine costs almost nothing and is as much fun to me as the $10k rotax karts my friends drive on the longer track. I get thrown around in the corners and get tired out from the braking/accel/cornering in about 10 minutes and need a break. The engine is not long lived though, that's for sure. I'd feel pretty dumb if all of this was due to 15W40 oil....

I might have to try one of those sintered gear cranks as I don't have any more honda cranks, maybe one but it's used.

Thats unfortunate.

That orange color could be coming from that additive/booster stuff.

It's hard for me to get a good plug reading with any kinda of addictive, cleaner, or octane booster.

I dont believe in that octane booster stuff, it only bumps it .3-.7, not 3-7 FULL points as most claim.

You should be perfectly fine with that straight 92 octane.

IMHO, there is jus too much CR and rpm for that stock rod.

I think I would start from scratch with a complete new engine. Measure for CR from stock

Creep up on the CR, timing, and jetting, while testing.

Try to stay under 10.5:1CR, 32* of timing and 6000 rpm.

Stock cams can have a intake valve closing (ivc) point from 72*- 80* (crank degrees).

Customs Cams with Stock lifts can be as low as 66*, but they cost.

The lower the ivc, the more pressure is be put on that stock rod. Higher CR makes even more pressure.

Heres a CR calculator, open up advance mode and you can see dynamic compression ratio.

I keep DCR 7.7-8.1 with stock rod builds. The higher the DCR the more pressure is on that rod.

Good luck bud

Compression Ratio Calculator

The compression ratio calculator finds both the static and the dynamic compression ratio of your combustion engine.

www.omnicalculator.com

 

[BrownStainRacing]

@Darren

I would like to hear your comments, suggestions and opinions for this guys engines.

What do you see and what would you try or change???

 

[busted_blocks]

Thats unfortunate.

That orange color could be coming from that additive/booster stuff.

It's hard for me to get a good plug reading with any kinda of addictive, cleaner, or octane booster.

I dont believe in that octane booster stuff, it only bumps it .3-.7, not 3-7 FULL points as most claim.

You should be perfectly fine with that straight 92 octane.

IMHO, there is jus too much CR and rpm for that stock rod.

I think I would start from scratch with a complete new engine. Measure for CR from stock

Creep up on the CR, timing, and jetting, while testing.

Try to stay under 10.5:1CR, 32* of timing and 6000 rpm.

Stock cams can have a intake valve closing (ivc) point from 72*- 80* (crank degrees).

Customs Cams with Stock lifts can be as low as 66*, but they cost.

The lower the ivc, the more pressure is be put on that stock rod. Higher CR makes even more pressure.

Heres a CR calculator, open up advance mode and you can see dynamic compression ratio.

I keep DCR 7.7-8.1 with stock rod builds. The higher the DCR the more pressure is on that rod.

Good luck bud

Compression Ratio Calculator

The compression ratio calculator finds both the static and the dynamic compression ratio of your combustion engine.

www.omnicalculator.com

Yup, sounds like a good plan. Backup a few steps and start again.

I have been adding a bit of additive. Boostane professional. The reports on it seemed legit, but what do I know. I can certainly try without it. The motivation to start trying it was the detonation of the first engine with 89-90 octane. The rating system is a bit different here, we have 92,95 & 98 but the are the same 3 grades, just a different numbering system, not different gas. I switched to buying the 98 (US 92). On a side note, it's very hard to buy gas in a jerry can here.

1. Gas can needs to be metal, even if you can buy plenty of nice plastic ones, they won't fill them.
2. Need local ID card, so I can't buy it myself
3. Need to bring photocopy of ID
4. Must be registered as living in the city of the gas station
5. Only specific stations are authorized to sell gas in portable containers, about 1 per town
6. Fill out a form why you are buying gas, how much, the grade etc.
7. Do something on a phone app I can't read
8. Call the gas station to prove your phone number is the same one your wrote down.
Now you can go get them pump your gas.
There is an alternative, fill up a motorcycle and syphon it out, but those are illegal where I live so not so easy either.

I'll see what I can come up with for a simple starting build. The connecting rod for sure is a weak point. The exploded ones are easy to see it's not strong enough, but when it galls the aluminum it's lack of lubrication I assume. Though it might be loosening of the bolts which starts the issue. I'm limited in how tight I can make the bolts as the threads can strip but more importantly the end of the rod becomes oval. I did think of boring it out but it's so little metal to remove it's a complicated setup for me. I got a ball hone to try but haven't gotten around to it yet. I'll see what parts I have around and see what makes sense to put together for a new less ambitious build. Another good thing, the cam didn't seem to be damaged when the engine seized so that's another issue solved. It was likely do to previous damage to the valves and guides.

 

[Denny]

Yup, sounds like a good plan. Backup a few steps and start again.

I have been adding a bit of additive. Boostane professional. The reports on it seemed legit, but what do I know. I can certainly try without it. The motivation to start trying it was the detonation of the first engine with 89-90 octane. The rating system is a bit different here, we have 92,95 & 98 but the are the same 3 grades, just a different numbering system, not different gas. I switched to buying the 98 (US 92). On a side note, it's very hard to buy gas in a jerry can here.

1. Gas can needs to be metal, even if you can buy plenty of nice plastic ones, they won't fill them.
2. Need local ID card, so I can't buy it myself
3. Need to bring photocopy of ID
4. Must be registered as living in the city of the gas station
5. Only specific stations are authorized to sell gas in portable containers, about 1 per town
6. Fill out a form why you are buying gas, how much, the grade etc.
7. Do something on a phone app I can't read
8. Call the gas station to prove your phone number is the same one your wrote down.
Now you can go get them pump your gas.
There is an alternative, fill up a motorcycle and syphon it out, but those are illegal where I live so not so easy either.

I'll see what I can come up with for a simple starting build. The connecting rod for sure is a weak point. The exploded ones are easy to see it's not strong enough, but when it galls the aluminum it's lack of lubrication I assume. Though it might be loosening of the bolts which starts the issue. I'm limited in how tight I can make the bolts as the threads can strip but more importantly the end of the rod becomes oval. I did think of boring it out but it's so little metal to remove it's a complicated setup for me. I got a ball hone to try but haven't gotten around to it yet. I'll see what parts I have around and see what makes sense to put together for a new less ambitious build. Another good thing, the cam didn't seem to be damaged when the engine seized so that's another issue solved. It was likely do to previous damage to the valves and guides.

That seems like a real pain in the neck just to buy some gas! Definitely suffering from lack of lubrication with the aluminum smeared all over the crank like that.

 

[BrownStainRacing]

Our pump fuel is 87,89,91, and 93.

Before the local race track closed I was getting race fuel 108, and mixing it to get what I needed 95-108.

The closest track now is 40+ miles away and you need a $20 pit pass to buy race fuel.

It made more sense to me to jus keep the builds for 87 octane, 28*-30* of timing, and stay under 10.5:1 CR.

Builds with faster ramped cams, low ivc, needs less CR 9.5-10.1, they ALWAYS get a billet rod.

When I'm stuck using a stock rod, I keep the governor in and tune it for 5300 rpm max. They make big power with head work, the right cam, carb and exhaust.

Ducar has got a 224 with a stock rod and no governor, I've turned it 5700 a few times and let the grandson beat on it awhile, 30+ hrs. It seems to be fine and showing no signs of internal failure. Oil staying clean and no heavy metal build up on the magnetic drain plugs.

I've since tuned it to 5100 max rpm, but it's still way too fast for his buggy and this trail system.

I've pulled it off and put it on the shelf. When it warms back up, I'll find something to put it on.

224-1000 | Ducar 224cc Stock Engine

Ducar 224cc Stock Engine

www.dynocams.com

I made a short video of it after I jus installed a .675" bored stock appearing carb. It got nasty real fast.

Snappy quick, throttle response and accleration. Front tires off the ground coming outta corners. It got rolled over 3 times, then I decided to pull it off and put it on the shelf.

 

[busted_blocks]

Our pump fuel is 87,89,91, and 93.

Before the local race track closed I was getting race fuel 108, and mixing it to get what I needed 95-108.

The closest track now is 40+ miles away and you need a $20 pit pass to buy race fuel.

It made more sense to me to jus keep the builds for 87 octane, 28*-30* of timing, and stay under 10.5:1 CR.

Builds with faster ramped cams, low ivc, needs less CR 9.5-10.1, they ALWAYS get a billet rod.

When I'm stuck using a stock rod, I keep the governor in and tune it for 5300 rpm max. They make big power with head work, the right cam, carb and exhaust.

Ducar has got a 224 with a stock rod and no governor, I've turned it 5700 a few times and let the grandson beat on it awhile, 30+ hrs. It seems to be fine and showing no signs of internal failure. Oil staying clean and no heavy metal build up on the magnetic drain plugs.

I've since tuned it to 5100 max rpm, but it's still way too fast for his buggy and this trail system.

I've pulled it off and put it on the shelf. When it warms back up, I'll find something to put it on.

224-1000 | Ducar 224cc Stock Engine

Ducar 224cc Stock Engine

www.dynocams.com

I made a short video of it after I jus installed a .675" bored stock appearing carb. It got nasty real fast.

Snappy quick, throttle response and accleration. Front tires off the ground coming outta corners. It got rolled over 3 times, then I decided to pull it off and put it on the shelf.

Looks like a fun engine. I would like one of those

I'll try making something with less CR and a little head work and see how it does. My quest for high CR engine will have to wait. I'm trying to make the best engine I can with stock rod / stock cam and local parts. It means I can do just about anything to the head but I'm trying to not add CNC connecting rod and custom cam. I also don't have access to fancy ratio rockers or billet side covers etc.

I ordered some non flat pistons today and more head gaskets. I also ordered a 21mm PWK21 carb that I think will be better for the next engine.

I'll be back in a day or two with something new to try

I did get an exhaust done today. I tried to brace it at the far end this time. I also moved the bend farther away from the flange to make installation easier.

 

[Denny]

That is a good looking pipe. Any chance you could make the brace shorter but still attached at the end of the muffler like it is? Maybe attach it to the frame?

 

[busted_blocks]

That is a good looking pipe. Any chance you could make the brace shorter but still attached at the end of the muffler like it is? Maybe attach it to the frame?

Thanks, I hope it lasts this time. My pipe walls are 1.5mm thick (.060") which might be excessively heavy contributing to the vibrations.

The mounting points on the frame are limited and not so close by unfortunately. I was thinking I could triangulate with a second brace back to the head but that seems overkill. I've got some new parts for another pipe coming in a few days that will eliminate 2 weld joints. Many go kart pipes I see are short with no braces. Some are very long sections of pipe connected with springs. The excessive vibration is a concern and more bracing seems like a bandaid on the actual problem. Maybe not though, perhaps high CR engines vibrate more.

 

[Darren]

Single cylinder engines can only be balanced for a very small rev range window, I think the balance % for one of our engines is 56? If you change any of the moving masses, i.e. rod or piston, then you should adjust. Most of the time it's not worth the hassle.

 

[busted_blocks]

Single cylinder engines can only be balanced for a very small rev range window, I think the balance % for one of our engines is 56? If you change any of the moving masses, i.e. rod or piston, then you should adjust. Most of the time it's not worth the hassle.

I assume the principle is the same but I have only seen the balancing on 2 stroke cranks. I've been meaning to see what the balance looks like on the stock piston, odd bits and the crank...

 

[busted_blocks]

New Engine Build:
168F Case
GX200 Side cover (stiffer)
Standard crank (with sintered cam gear)
Standard GX200 dished piston
Aluminum cast flywheel (1.5kg)
0.052" head gasket
+.020" length connecting rod (stock type)
GX200 22cc head, very mildly ported, 27mm intake, 25mm exhaust (came with these valves installed)
Stock Springs
Stock Cam
Cylinder head studs 80mm
Side cover studs 50mm
PWK21mm carb
Custom free flow exhaust
Stock valve cover
Stock timing for first break-in
Crank side play .007", which is a bit low but I was already using my thickest side cover gasket.

I ran the engine 20 minutes from 2500-4500rpm, then 2500 to 4500 in 500rpm steps at 5minutes per step, then back down to 2500 the same way.
Changed the oil (5W30 this time), let it sit. I had a pressure gauge on the case, it showed zero.
After cooling, exhaust stud nuts were not as tight as previously, but not leaking.
There was so much less vibration that with my other builds, the exhaust pipe never got red and seemed very rigid.
The drained oil didn't seem to much metal in it and wasn't particularly black.
Spark plug was not showing signs of a rich mixture. But it's still rust colored as my gas has an octane booster in it, until I use up the tank.

I'm hopeful this engine will last. I'm very curious of the performance on the track. Next step is to repeat another break in session tomorrow. With any luck I'll be able to have an oxygen sensor on the exhaust for that testing as well. I'm waiting on a battery cable to run the sensor & meter.

I also changed my kart rear sprocket to limit max rpm to about 5500 at the end of the straight away. I can't be exactly sure, but it's the stock gear ratio for this kart with stock GX200.