engine question

[Irishdude83]

been working on an old nitro boat. i acquired a losi mach 427 engine for the boat. anyway long story short, i got the engine bolted in and adapted everything to work. the engine i acquired is brand new never ran. i set the screws to factory settings and went to start the engine for the first time. I'm running vp 20% nitro. I've got a belt starter to start it and primed the engien pretty well. engine fired right up. i let it idle for 10-15 sec and revved it slightly then shut it down. let it completely cool, then started it one more time. i did notice that there was no smoke coming out of the exhaust. anyway a day later, spinning the engine over by hand, when the piston gets to tdc, its binds up and doesn't want to turn, i did pull the head and there appears to be minimal scratching on the cylinder walls but nothing that would cause it to bind up and basically stick at tdc. i havent taken the engine completely apart at this time. anyone have any ideas whats going on here based on what info I've given? i realize theres not a lot here to go off of. thanks

 

[Tunedfrog]

It's far too lean if you aren't getting any smoke. I would put a couple of drops of after run oil in the cylinder and see if it loosens up a bit.

 

[Irishdude83]

Definitely need some after run oil. I've read also that it's good to keep the piston at tdc to cool down. Yeah I'm totally aware that no smoke is very lean. I've since opened the screws up several turns to richen it up. I'm just hoping the piston and sleeve are not damaged because I doubt I'll be able to find a replacement.

 

[Tunedfrog]

When you say several turns, exactly how much? Only 1/16" to 1/8" increments should only be made at a time and ran between each adjustment.

 

[Irishdude83]

The manual said 2.5 turns out on both screws. I went to 4 out to start with while I break it in
I had it at 2.5 turns at first start up

 

[Tunedfrog]

Usually, to set it back close to factory settings the needles should be flush with the housing. Sounds like you just have it way too far out of tune to run.
I would lube it up with a couple of drops of after run oil, reset the needles and start over. When they get way out of adjustment, it's hard to get it tuned.
Don't get frustrated and give up on it, sometimes they can be a stubborn biotch.

 

[Chubaka]

Definitely need some after run oil. I've read also that it's good to keep the piston at tdc to cool down. Yeah I'm totally aware that no smoke is very lean. I've since opened the screws up several turns to richen it up. I'm just hoping the piston and sleeve are not damaged because I doubt I'll be able to find a replacement.

I've always heard keep it bottom desd center so the sleeve can cool, but also shrink down.

 

[Irishdude83]

I had it set to factory settings when I started it. I opened it up just to be safe for next time. Also worth noting that this engine is fir a car that i made work in a boat. I'm working on making a spacer so I can try out the water cooled head I have. I temporarily wrapped the air cooled head with some 3/16 aluminum tubing to try but havent taken to the water yet.

I've always heard keep it bottom desd center so the sleeve can cool, but also shrink down.

Makes sense maybe it was bdc that I read.

 

[Greywolf74]

The 454 came with 2 different carbs. One of the carbs matches the manual at 2.5 turns out on both needles. The other carb including the two 454s I had were the other carb and the manual settings do not work for that carb. That carb I believe needed about 3.5 - 4 turns out on the LSN and HSN should be set flush with the top of the brass tube. Try that, should get you squared away.

Store the piston at BDC. I make a mark with a paint pen on my fly wheel so I can have a visual indicator of when the piston is BDC.

 

[Irishdude83]

Sweet thanks. I set my collet up so the set screws are at tdc so it should be easy to store it that way.

 

[cbaker65]

Totally wrong ,if ye all listen to what he said ,you will understand that it is not too lean!

He said that it is new ,he set the engine to factory settings in which is rich!

Sir ,that engine is brand new ,the engine needs to go through a break-in process in which
you started it an shut it down ,the engine has to be heat soaked an 2 tanks of fuel ran through
it to lap the piston & sleeve together to get rid of the mechanical pinch ,that is why the piston gets
stuck!
Also ,you should have more wet fluid coming from the exhaust then smoke at this point ,also
it should have a pressure tube going to the muffler to the fuel tank to create fuel pressure!

You need a heat gun to heat the engine to about 200 to 220 degrees before you start it
it allows the sleeve to expand so it relieves some of the pinch & tension on the engine
on first start ups!

 

[Greywolf74]

I'm not wrong about that engine coming with 2 different carbs. Which one he has I can't say but that used to be an issue with the 454 and if you had a different carb from the one in the manual you will need different factory needle settings. Pretty sure storing it at BDC is also correct.

 

[WVNed]

There are 2 version of docs for this engine on the net
One says
We suggest the following settings for breaking in your engine:
High-Speed Needle: 4 turns out (counterclockwise) from closed
Low-Speed Needle: 2 turns out (counterclockwise) from closed.

the other

High-Speed Needle: 21 / 2 turns out (counterclockwise) from closed.
Low-Speed Needle: 21 / 2 turns out (counterclockwise) from closed.

Note none of them mention setting anything flush with anything.

I have never had an engine that would run with the high speed needle open 2 full turns from the break in setting so that tells me you have the engine that requires 4 turns open.

Do not leave the piston at top dead center as it cools. It can weld to the sleeve and then it is done. Once they are locked together there is no way to create a heat differential to get them apart again.

Here are copies of both docs
http://www.losi.com/ProdInfo/Files/LOSR1002_TL427_Manual_LoRes.pdf

https://www.horizonhobby.com/on/dem...r/default/Manuals/DYN0895_Mach_427_manual.pdf

 

[Irishdude83]

I'm just glad to hear my engine isnt messed up haha i was started to get pretty bummed as I've basically replaced every component on this boat and it still hasnt seen water yet. ill definitely try preheating the engine next time as well. i did read in the manual that one part of the manual said 2.5 turns out on both screws, another part says 4 turns out on the high side.

so question regarding cooling on this engine. think it would good enough to use some aluminum 3/16 od tubing to wrap the first couple slots on the air cooled head so i can run water through it? it was suggested by a few local guys to me. i do have a water cooled head for a novarossi engine that came with the boat that bolts up to the losi engine, however there is a gap where no contact is made to absorb the heat. i think if i get a spacer made to fill the air gap in the watercooled head, i think it will work

 

[WVNed]

I have no experience with water cooled engines but if you can get the coil to grip the head tightly and the boat people say it will work I would do it.
I would think copper tubing would be easier to form and have better heat transfer.

 

[Irishdude83]

the 3/16 tubing fits pretty tight on the fins and wrapped it 4 or so times. the water cooled head has just one ring for the water to pass and is sealed with an oring against the block.

 

[Greywolf74]

There are 2 version of docs for this engine on the net
One says
We suggest the following settings for breaking in your engine:
High-Speed Needle: 4 turns out (counterclockwise) from closed
Low-Speed Needle: 2 turns out (counterclockwise) from closed.

the other

High-Speed Needle: 21 / 2 turns out (counterclockwise) from closed.
Low-Speed Needle: 21 / 2 turns out (counterclockwise) from closed.

Note none of them mention setting anything flush with anything.

I have never had an engine that would run with the high speed needle open 2 full turns from the break in setting so that tells me you have the engine that requires 4 turns open.

Do not leave the piston at top dead center as it cools. It can weld to the sleeve and then it is done. Once they are locked together there is no way to create a heat differential to get them apart again.

Here are copies of both docs
http://www.losi.com/ProdInfo/Files/LOSR1002_TL427_Manual_LoRes.pdf

https://www.horizonhobby.com/on/dem...r/default/Manuals/DYN0895_Mach_427_manual.pdf

Thats the Losi Mach 427 engine bro. The OP has the Losi 454 and if hes got the alternate carb he needs to start with HSN flush and the LSN needs to be 2.5 to 3 turns out. I just went back and looked at a post from 2012 that I posted about this very subject to recheck my original numbers I stated above because I had the same issue with both of my 454s

 

[Irishdude83]

I have the 427 engine not the 454. Gonna get some after run oil and try to start it again. So I should just run the first tank at idle speed no load to help break it in? Obviously preheat the engine with a hear gun and monitor the head temp to keep around 200-220ish degrees? After the first start up I have since moved the screws I think I'm 4 turns on the low and 5 or 6 turns on high. I know this is extra rich which I want to to be just to be sure of a good break in and the fact it is going in a boat so the load on the engine will be different and I'm guessing harder load so I'm going more rich for that. Much easier to lean one out than to be replacing top ends Haha.

 

[Greywolf74]

I have the 427 engine not the 454. Gonna get some after run oil and try to start it again. So I should just run the first tank at idle speed no load to help break it in? Obviously preheat the engine with a hear gun and monitor the head temp to keep around 200-220ish degrees? After the first start up I have since moved the screws I think I'm 4 turns on the low and 5 or 6 turns on high. I know this is extra rich which I want to to be just to be sure of a good break in and the fact it is going in a boat so the load on the engine will be different and I'm guessing harder load so I'm going more rich for that. Much easier to lean one out than to be replacing top ends Haha.

Well now I feel like an idiot... My bad, not sure how I misread that. I'm very familar with both of those engines. I still run a 427 on one of my kits as well as one 454. Sorry for the confusion, must have started drinking to early today

 

[cbaker65]

I have the 427 engine not the 454. Gonna get some after run oil and try to start it again. So I should just run the first tank at idle speed no load to help break it in? Obviously preheat the engine with a hear gun and monitor the head temp to keep around 200-220ish degrees? After the first start up I have since moved the screws I think I'm 4 turns on the low and 5 or 6 turns on high. I know this is extra rich which I want to to be just to be sure of a good break in and the fact it is going in a boat so the load on the engine will be different and I'm guessing harder load so I'm going more rich for that. Much easier to lean one out than to be replacing top ends Haha.

We just been through this senerio on another thread ,here is a vid on a break-in ,it
will give you a better out look on how ,but you can do a little less fuel an not
a whole quart while actually running your boat ,but you want heat in the engine an
not a cooling device!...