Has anyone done any mods to an os18 cvr?

[Certified Mike]

I have to take apart an os18 cvr for cleaning, inspection etc... I have read about mods that include roughing up the carb before and after the rotating assembly for better fuel atomization. Cutting lines in the head for better fuel economy, rounding the bottom of the sleeve, matching the exhaust (seems like a no brainer on this one)
So has anyone tried any of these or others with any success?
The motor has good compression but Sat for a long time with a pretty blue gel in the fuel system. I did have to drop in some cleaner to get it to even turn over so I am Def pulling it apart to do the bearings and clean out the crank area. Carb is coming apart too. It wouldn't move When I got the car.
Any thoughts or working mods would be appreciated. Thanks!!!

 

[cbaker65]

I have to take apart an os18 cvr for cleaning, inspection etc... I have read about mods that include roughing up the carb before and after the rotating assembly for better fuel atomization. Cutting lines in the head for better fuel economy, rounding the bottom of the sleeve, matching the exhaust (seems like a no brainer on this one)
So has anyone tried any of these or others with any success?
The motor has good compression but Sat for a long time with a pretty blue gel in the fuel system. I did have to drop in some cleaner to get it to even turn over so I am Def pulling it apart to do the bearings and clean out the crank area. Carb is coming apart too. It wouldn't move When I got the car.
Any thoughts or working mods would be appreciated. Thanks!!!

I've seen folks do it in detailed pics years ago ,but never done it myself.
I personally don't think that it really does any high performance change an really isn't worth the time
an chance of damaging the engine.
However ,roughing up the carb throat for better oxygen atomizing will probably help ,an smoothing
or polishing the exhaust port an taking the eccess material out of the header entrance may enhance
the performance.
But I wouldn't channel the sleeve for better fuel economy on a small block!...

 

[Certified Mike]

The rounding of the sleeve is just to round the very bottom of the edge, instead of it being a 90° angle, it is just rounded off. It said to be careful NOT to cut into the edge of the sleeve itself... I am not sure if that's what you mean by channelling, I just wanted to clarify. I don't have the knowledge and frankly no interest in learning how to time it differently with cutting the ports etc... I am good with a dremel and after polishing a TON of Harley parts, I can polish damned near anything to a pretty mirror finish...
So yeah, I am looking for mods like that... Unless someone has a pre-made templet I can wrap around the sleeve that shows where to cut and all that, I wouldn't have the interest to learn the skills, not right now Anyways,
Thank you for your input. I think the carb cutting will work (wish i had the equipment to swirl cut it!!!) . The exhaust port and polish is gonna be done unless I hear horror stories about it... Have only heard/read good things so far tho. Just not to cut too close, I can handle that.

 

[cbaker65]

The rounding of the sleeve is just to round the very bottom of the edge, instead of it being a 90° angle, it is just rounded off. It said to be careful NOT to cut into the edge of the sleeve itself... I am not sure if that's what you mean by channelling, I just wanted to clarify. I don't have the knowledge and frankly no interest in learning how to time it differently with cutting the ports etc... I am good with a dremel and after polishing a TON of Harley parts, I can polish damned near anything to a pretty mirror finish...
So yeah, I am looking for mods like that... Unless someone has a pre-made templet I can wrap around the sleeve that shows where to cut and all that, I wouldn't have the interest to learn the skills, not right now Anyways,
Thank you for your input. I think the carb cutting will work (wish i had the equipment to swirl cut it!!!) . The exhaust port and polish is gonna be done unless I hear horror stories about it... Have only heard/read good things so far tho. Just not to cut too close, I can handle that.

The channeling would be on the outside of the sleeve wall at the exhaust port hole an down towards the bottom of the
sleeve ,its to scruff up xtra fuel.
I've seen manufactures started to add those features in recent engine designs!

 

[Certified Mike]

Ah, ok. Yeah, I saw something about that and about cutting the crank too... I was a little concerned about doing that, like I might loose propper engine lube if more fuel was being scavenged like that. Like if I cut the wrong place fuel would just blow in and right back out.
No good for a small block tho, huh?

 

[cbaker65]

Ah, ok. Yeah, I saw something about that and about cutting the crank too... I was a little concerned about doing that, like I might loose propper engine lube if more fuel was being scavenged like that. Like if I cut the wrong place fuel would just blow in and right back out.
No good for a small block tho, huh?

I've channeled the crank & sharpened the rod on a 28 before ,but the 28 was wore out an didn't get
to tell the difference in performance.
I'm not sure if cutting the crank throws it off balance though ,that would be one of my concerns!
I had forgot about those mods ,chanelling the crank help bounce the fuel around as well!...

 

[Certified Mike]

I don't think the balance on a single piston is all that precise anyways... I would think the crank would have to have lobes and they would still have to be custom cut per motor for precision.... But perhaps I am mistaken about that too. I am trying to apply 1:1 car/truck crank logic to this... Either way, there has to be some kind of balance going on in there.
Yeah, the cuts on the crank are (according to one source) almost unlimited modding. Like you can cut to your hearts content... I find that difficult to believe tho... THAT would likely turn the motor into a vibrator!

 

[cbaker65]

I think you might want to check head shims for more torq. timing.

 

[Certified Mike]

I plan to play around with the shims and the different length plugs etc...that will all come after re-assemble tho. I should have mentioned that in my list of found research. Yeah, the different depths of the plug and height of the head (similar ideas really)are going to change when the fuel reaches the plug to ignite... Delaying fire or increasing and the effects accordingly.
This engine will be dismantled and reassembled quite a few times... So I can see how each mod changes things.
I just hope I don't run into something that's real bad and can't be undone!
I have a steady hand and have the patience to go slow and easy so I'm thinking unless something grabs my wheel and throws my cut REALLY bad, everything will be intentional. So if and when other ppl chime in with ideas, I will research them and make my decisions from there.
I found an article posted in a different site (one you posted pics of your GT on a couple years back actually) that has a list of mods and what they do, why etc... But none are specific to the .18. I don't believe that every motor will react the same with every mod listed... This is why I'm hoping to see what other ppl may have had specific success with. But any ideas for cutting pretty much anything but the ports in open to checking out and discussing. There are lots of very smart ppl here. I'm sure there will be a lot more good ideas coming soon.

Btw, what are you using for the steering on your gt? The stock servo saver set up seems a poor set up. It is Def messed up on this car, but then again, so is everything else! )

 

[cbaker65]

I plan to play around with the shims and the different length plugs etc...that will all come after re-assemble tho. I should have mentioned that in my list of found research. Yeah, the different depths of the plug and height of the head (similar ideas really)are going to change when the fuel reaches the plug to ignite... Delaying fire or increasing and the effects accordingly.
This engine will be dismantled and reassembled quite a few times... So I can see how each mod changes things.
I just hope I don't run into something that's real bad and can't be undone!
I have a steady hand and have the patience to go slow and easy so I'm thinking unless something grabs my wheel and throws my cut REALLY bad, everything will be intentional. So if and when other ppl chime in with ideas, I will research them and make my decisions from there.
I found an article posted in a different site (one you posted pics of your GT on a couple years back actually) that has a list of mods and what they do, why etc... But none are specific to the .18. I don't believe that every motor will react the same with every mod listed... This is why I'm hoping to see what other ppl may have had specific success with. But any ideas for cutting pretty much anything but the ports in open to checking out and discussing. There are lots of very smart ppl here. I'm sure there will be a lot more good ideas coming soon.

Btw, what are you using for the steering on your gt? The stock servo saver set up seems a poor set up. It is Def messed up on this car, but then again, so is everything else! )

You don't Harley see threads on engine mods. anymore , it is very controversial an ends up in heated battles!...lol
The 2 stroke engine is a fixed port engine an is very hard to manipulate it for more power!

Sure ,you can do things to gain more torq.in these small engines ,but you can only do so much to them because
of what they are an so little of what they can handle!
But a combination of mods may make it perform better !

Its like a domino effect ,if you change one thing ,it may create another problem ,like gaining torq but losing top end
with out grenading or over heating an engine...You will have to think about other factors like heat transfer ,oil content ,
a larger head ,proper tuned pipe to match!

 

[Certified Mike]

Agreed 100%. I am actually looking to increase the top end at the cost of some torque. This engine is going on an associated rc10gt. This engine and kit combo, even with gearing mods etc is almost impossible to keep the front end on the ground. This is how I got the car and am going to restore it... I have a soft spot in my head for associated kits.
As I mentioned, I am planning on doing 1 thing at a time and checking and recording the results. Certainly finding the best pipe, perhaps changing the oil content, plug changes etc...
I really hope this doesn't turn into heated drama, I'm just looking for input from ppl who have done a mod, preferably in the .18 specifically and to be able to discuss what the mod did for them etc.
Whatever the mod, I do not want nor expect any super high torque or rpm changes. The stock specs are impressive. I would like to get anything done that I can while I'm building the car, before I make it pretty etc...

 

[cbaker65]

Agreed 100%. I am actually looking to increase the top end at the cost of some torque. This engine is going on an associated rc10gt. This engine and kit combo, even with gearing mods etc is almost impossible to keep the front end on the ground. This is how I got the car and am going to restore it... I have a soft spot in my head for associated kits.
As I mentioned, I am planning on doing 1 thing at a time and checking and recording the results. Certainly finding the best pipe, perhaps changing the oil content, plug changes etc...
I really hope this doesn't turn into heated drama, I'm just looking for input from ppl who have done a mod, preferably in the .18 specifically and to be able to discuss what the mod did for them etc.
Whatever the mod, I do not want nor expect any super high torque or rpm changes. The stock specs are impressive. I would like to get anything done that I can while I'm building the car, before I make it pretty etc...

I've always wanted to experiment but didn't really have the time to stay focused!
I am a small engine repair man an understand the machanics of these engines!

 

[Certified Mike]

Understood. I have been working on car engines for a LONG time! They are certainly different although the basics apply. When timing comes from the sleeve etc, it became a new world... Just not something I want to learn right now. The simple stuff, that's all I want for now Anyways... If I get sucked into the science somehow.... Its a different story. I have also been into electronics for quite some time.

 

[cbaker65]

Understood. I have been working on car engines for a LONG time! They are certainly different although the basics apply. When timing comes from the sleeve etc, it became a new world... Just not something I want to learn right now. The simple stuff, that's all I want for now Anyways... If I get sucked into the science somehow.... Its a different story. I have also been into electronics for quite some time.

Me an you both know that any engine or a fire cracker rely's on a tight sealed chamber on where the explosion takes place ,an
the key is to find the right time to release that energy ,on a 1.1 engine ,we have that at are exposal ,but on a 2 stroke with fixed
porting ,you don't have many options!....But people still try to pull a wabbit out of their a$$!......

You can't blame a person on trying to get the most performance out of their engine!
Even I would try!...

What I would like to see is for someone to totally scratch the old school off an start a new design ,but sense it is
a hobby ,people wont waist their time!

I think maybe the 4 cycle maybe a start with the valves!...

 

[Certified Mike]

Have you seen these? www.moyermade.com/chevyv8.html
There are a bunch of them out there... I think they're VERY cool! I'm not sure I have it in me to do a valve job on one of these tho.
Little tiny parts and I have big hands and fingers... Not a great mix as my experience has proven. Lol!
Trying to pull the rabbit out... That's why I'm hoping for an answer from someone who has done, or tried to do some of the mods that we've talked about... So I don't try for the rabbit and pull out a porcupine!!!

 

[cbaker65]

Have you seen these? www.moyermade.com/chevyv8.html
There are a bunch of them out there... I think they're VERY cool! I'm not sure I have it in me to do a valve job on one of these tho.
Little tiny parts and I have big hands and fingers... Not a great mix as my experience has proven. Lol!
Trying to pull the rabbit out... That's why I'm hoping for an answer from someone who has done, or tried to do some of the mods that we've talked about... So I don't try for the rabbit and pull out a porcupine!!!

LOL....That's too intricate for me!

But getting back to your engine ,I think finding the right things to do in each mod may enhance
the engines performance together ,but you do have to keep in mind of the fixed port timing ,in
which I have no knowledge of!

 

[Certified Mike]

Yeah, I am not planning on messing with the sleeve port timing... Like I said, unless someone has a template I can cut out and has been a totally proven mod... Not holding my breath on that one!

 

[cbaker65]

Yeah, I am not planning on messing with the sleeve port timing... Like I said, unless someone has a template I can cut out and has been a totally proven mod... Not holding my breath on that one!

There is folks out there that's done mods & actual dyno testing or some type of RPM test!
I've been involved with a bunch of rc forums for 15 years.
The person that comes to mind....I would have to PM his address to you about the matter ,hes
been doing a lot of research an including dyno testing on the nitro engines....

 

[Certified Mike]

Oh yeah, I know there are ppl out there doing mods, it's just that they are usually doing mods for profit when they get to that level. If he wouldn't mind talking, I'd Def like the info and whatever he can teach me.

 

[ninnon]

It's called porting and polishing, you can pay to have it done. It involves most of the things you mentioned- however with the polishing of the crank inlet, I doubt it makes a difference. The extra speed will cancel out the worse atomization from what I've heard.