how can i tell if the engine blowen or not?

[welchdennis63]

hello everybody how can i tell if my nitro engine is blowen or not? i have a friend trying to buy one of my old engines it ran fine when i took it out and we got it running the other day is sounded good so long story short he wanted it so he took it to the lhs to get a clutch and flywheel and so on but he comes back to gives me back my engine and say the lsh said it's no good it's blowen so i would like to know how you can tell or how they could tell it's blowen without pulling it apart? never blowen one so I'm not sure what I'm looking for

 

[Amoeba]

Usually this refers to an engine which has lost its pinch/compression.

If it's a pull start, when you pull on it it should lift the car if you're not holding car down. You can also check by turning the flywheel by hand. If it is easy to rotate with little force when the piston is going through TDC that's another indication. These are the checks you can do without taking anything apart.

Even when you lose most of your pinch the engine can still run but it'll be a pain to keep tuned and your performance will suck.

 

[sandiegan]

when my nitro engine lost its pinch, it wouldnt stay running. It would fire up, run really janky a few seconds, and die. Then when i would turn the crankshaft, it would spin all the way (past TDC) with zero resistance.

 

[welchdennis63]

thanks you guys it looks to me like the lhs is full of you know what beacuse this thing has tones of compression and i put it back in the truck it came out off and the things is pulling wheelies i think i may just keep the old os after all thanks again for the info

 

[Amoeba]

thanks you guys it looks to me like the lhs is full of you know what beacuse this thing has tones of compression and i put it back in the truck it came out off and the things is pulling wheelies i think i may just keep the old os after all thanks again for the info

It's possible they may be full of it but did they take the backplate off or inspect the inside? Your conrod/shaft bushing may be loose which can also be bad mojo. Engine will still run like that but eventually it'll fail.

 

[welchdennis63]

no my friend said they did nothing but pull the starter like 30 times with there fingers on the carb and exhaust port. i took it apart last night and it looks good to me. but i always seem to run my stuff a little on the rich side and always use after run. i think I'm going to look on ebay today for another kit for this engine