E85 Predator 212cc build

Lykkan

Member
I get the same compression ratio in my spreadsheet, but I was wondering, with that gasket thickness and that deck height, isn't that a little thin?
I checked clearances and I had plenty of room still o_O I was expecting to have to use a thicker head gasket, but remember I'm still on stock cam but with my homemade ratio rockers 1.27 intake 1.24 exhaust. So .283 lift on intake, .286 exhaust. I should pull the head and verify everything again but like I said I still had plenty of room when I checked before. I know some people throw 14cc heads on and probably a longer rod, and definetly need to fly cut the pistons for good valve spacing. I fly cut mine just to be safe.
 

Kart43

Member
Brake clean, I don't know about brake fluid I am sure there is danger with brake fluid also. But there are many that are spraying everything including the BBQ with brake clean they are ill informed.
 

Lykkan

Member
Started up the engine, waiting on throttle cable still... and resonator to quiet it down a bit.. oh and for me to finish my kart frame :rolleyes: lol
VM22 starter jet was .040mm stock, I drilled it to .055mm. Main jet was 1mm stock, I drilled it to 1.58mm. Preferred would have been 1.3mm but I didn't have a closer drill bit. The VM22 also offers needle height adjustment so you can get the higher rpm's fuel well balanced. This is for the 30% increase in fuel requirement with e85 over gasoline.
This is not the final fuel adjustment of course, this was just to get it up and running so I can heat it up and tune it appropriately without worrying of running too lean. I'll post my final jet sizes when I get to that point after tuning.
 
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Lykkan

Member
still tuning idle circuit. Settings are on a chinese VM22 clone, stock pilot jet was .40mm, drilled out to .75mm but I believe about .65mm to be near where I need to be. Waiting on new jet. Need the idle of the carb perfect before I can tune the other rpm ranges accurately. Main jet is still 1.58mm but I think that's pretty close to where it needs to be.

 

flattop1

Dawg 89
Started up the engine, waiting on throttle cable still... and resonator to quiet it down a bit.. oh and for me to finish my kart frame :rolleyes: lol
VM22 starter jet was .040mm stock, I drilled it to .055mm. Main jet was 1mm stock, I drilled it to 1.58mm. Preferred would have been 1.3mm but I didn't have a closer drill bit. The VM22 also offers needle height adjustment so you can get the higher rpm's fuel well balanced. This is for the 30% increase in fuel requirement with e85 over gasoline.
This is not the final fuel adjustment of course, this was just to get it up and running so I can heat it up and tune it appropriately without worrying of running too lean. I'll post my final jet sizes when I get to that point after tuning.
LoL. Must be a long lost cousin .
I used a shoe string for throttle cable on a mini bike . just before i crashed into a rock promptley breaking my collar bone 🙄
 

Lykkan

Member
LoL. Must be a long lost cousin .
I used a shoe string for throttle cable on a mini bike . just before i crashed into a rock promptley breaking my collar bone 🙄
lmao damn. Hey gotta be resourceful when you gotta get **** done, can't always wait for china mail, or for the people with the checkbooks to approve everything you need lol.
 

Lykkan

Member
Got some goodies today. Waiting on a round collector so I can mount the muffler so it can be easily removed and not put pressure on the head if it's bumped.
photo_2019-10-02_16-48-55.jpg
 

Kart43

Member
If you are not using it in racing what differntial will you use on the rear axle? or is it 1 wheel drive?
 

Lykkan

Member
If you are not using it in racing what differntial will you use on the rear axle? or is it 1 wheel drive?
Using 1 1/4 axle. I want to gear it for just ******* around and drifting a bit, thus I want a lot of power for doing so
 

Jim46

Member
Are you going to be using E85 from the pump, I've been told is very inconsistent for a carb. , great with EFI ,
when welding galvanized- drink milk , that's what the old welders did
 

Lykkan

Member
Are you going to be using E85 from the pump, I've been told is very inconsistent for a carb. , great with EFI ,
when welding galvanized- drink milk , that's what the old welders did
yeah, and the octane rating does change, but I'm only at 12:1 compression. 14:1 is more of a preference with it so I should be fine with any fluctuations of the octane that e85 varies through
 

Lykkan

Member
About got her dialed in, chinese vm22, 57.5 pilot jet, 140 main jet. I think I'm hitting valve float at about 7200 rpm with the 18# springs, need to upgrade to the 26's but I'll do that when I switch to stainless valves, and need non-oem cam to tolerate the ratio rockers + stronger springs
 

Kart43

Member
You will not know what tune that engine has until a load is put on it, I did not see anything there that would indicate valve float.
 

Lykkan

Member
You will not know what tune that engine has until a load is put on it, I did not see anything there that would indicate valve float.
I went WOT until I hit an RPM wall and I let off the throttle. According to member "ole4" the chinese vm22 can flow 88cfm, and according to math (bore, stroke) my engine only needs 28cfm (assuming 110% volumetric effiency) @ 7500 rpm. My heads are heavily ported on intake and exhaust, gasket size matched to port shape as well as exhaust flange, exhaust pipe is 1" ID going into 2" ID thru-resonator. Without a wideband it's hard to tell but it is possible I'm leaning out on WOT. I tried a 145 jet but was experiencing rich condition in all RPM ranges so I went back to 140. What do you think it could be if it's not valve float? I'm on 18 lbs valve springs which are known to only be good til about 6500 rpm I believe...

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Being a spreadsheet junkie, I love numbers. Just a friendly piece of advice, watch your decimal point placement. Throwing in a "mm" & " here and there could help. Very much enjoyed reading all your posts on your efforts to build your engine.
I don't know anything about your engine, or for that matter, not much about 4 cycles, but having followed Bob's for 6 years, I read a lot about jetting for various fuels. Alcohol burns at about a 6 – 1 ratio, and the information I have read here on Bob says, generally, that a .052" main jet is about right, give or take. Running a .062" with E 85 would seem a little big, maybe?
Mixture ratios of E 85, as was mentioned, would have more of an effect on jetting than any concerns you might have about octane rating. EFI can handle those varying mixture ratios, fixed jets can't.
Another concern; what do you suppose the octane rating is of the gas they mix with alcohol to make E 85. Would that gas retain its original octane rating? Knowing that you can't run regular gas with a compression ratio like yours, what would be the effect with the E 85? Would the gas still be detonating?
 

Lykkan

Member
Being a spreadsheet junkie, I love numbers. Just a friendly piece of advice, watch your decimal point placement. Throwing in a "mm" & " here and there could help. Very much enjoyed reading all your posts on your efforts to build your engine.
I don't know anything about your engine, or for that matter, not much about 4 cycles, but having followed Bob's for 6 years, I read a lot about jetting for various fuels. Alcohol burns at about a 6 – 1 ratio, and the information I have read here on Bob says, generally, that a .052" main jet is about right, give or take. Running a .062" with E 85 would seem a little big, maybe?
Mixture ratios of E 85, as was mentioned, would have more of an effect on jetting than any concerns you might have about octane rating. EFI can handle those varying mixture ratios, fixed jets can't.
Another concern; what do you suppose the octane rating is of the gas they mix with alcohol to make E 85. Would that gas retain its original octane rating? Knowing that you can't run regular gas with a compression ratio like yours, what would be the effect with the E 85? Would the gas still be detonating?
The only advantage of higher octane is lower chance of detonation. If the alcohol content is higher, they can add lower octane gasoline to offset the difference. At the end of the day it's still working in the e85 safe area which is a range of 100-105 octane. [https://en.wikipedia.org/wiki/E85#Octane_rating]
Running higher octane GASOLINE than you need is bad as it creates additional carbon buildup on your engine internals. A nice thing about e85 is it burns so clean you have MUCH less carbon buildup from it. My only mentions of octane rating previously were of what people were asking about it.
Also, I mentioned inches with the jetting size, as I used a drill to assist me in drilling for finding the proper jet sizes.
I switched to the 145 main jet a bit ago, and let her run for about 20 minutes, she pulls hard, but I'm gonna have to tune for a wandering idle issue. I don't mind, it's fun for me to tinker with hsit to get the best performance I can
 
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