compression issues.

[StarLordMadCap]

Whats up everyone. I had the Savage out yesterday and it was running great when all of the sudden it stalled. When I tried to restart it, it felt like there wasn't any compression at all. I checked the plug and was tight, as were the allen screws that hold the head on. It felt kind of like when you pull on the starter without a plug in it. I have a wasp .26 with about 2 gallons through it. I run slightly rich for longevity and I have a nova cooling head. My temps run between 210-240, which would be around 240-270 with the stock head. Anyways, I was able to get it started after it cooled down, it felt normal at this point. I ran it for a while and after temps got up and stayed there for a while, I killed it to see if it would start. It started right up, felt normal when I pulled on the starter. So, I continued to play for a couple more hours when it stalled and had the same problem again. When the engine is running, it runs great, with no signs of needing to be rebuilt. Even when running rich and with a 17/49 it will pull wheelies and I am constantly checking my temps. They never peak over 250 (and it seldom hits 250). When I got home, I tore down the engine and there are no signs of any type of damage to the sleeve or piston. My first thoughts are that it is in need of a rebuild but I am hoping that is not the case. Anyways, does anyone have any suggestions as to what could be causing this loss of compression. Thanks and sorry for the long post.

 

[hb1111]

it happened to me also to a new fantom .27 and after it cooled down it was fine and has been fine ever since i have to think that it may just have got to hot,and when aluminum gets hot it expands so i was stumped and thought the same as you so i wouldnt worry about it!!!

 

[StarLordMadCap]

Ok, I was hoping it was something to that effect. Maybe I should recalibrate my temp gauge. Thanks for the reply.

 

[petal2thametal]

you can messure the compression when the engine is cold. when an engine gets hot the compression goes down. cause the sleeve expands. this is normal.
when there is no compression when the engine is cold, then you gotta worry .

and maybe it stalled because you were running a little lean?
i had the same prob. was running to lean and the engine staled. dont have these probs now with a correct tuned engine.

Blimp the throttle few time when the engine doesn't start.

 

[aussiexl59]

I've had that problem with my 5.9.now it wont start coz there not enuff compression to start it.i dont no wot the problem is.how hard is it to tear motor apart and put back together?i hell new at this.I'm scared I've burnt a hole in the piston.

 

[hpiracing1123]

let me guess u were using odonnels?

 

[aussiexl59]

i was using extreme blend 2 "black magic" 25% nitro,8%oil and 7%methyl alcohol.