the dog

im on third gallon and after running for a few minutes if i stop and try to start it again it doesnt have any compression. not enough to even prime the carb.then maybe a few minutes later it will all of a sudden be ok. any ideas?

snowbl!nd

This is a common problem with big-block engines. As the engine heats up, the cylinder expands and effectively reduces compression as the piston and liner are not as "tight" at TDC as when cold. The solution is to either apply some throttle when trying to restart the engine, or allow it to cool for a few minutes.

the dog

thanks for idea. yeah, thats what i figured.

the dog

hey snowblind, how much do you run in snow?

snowbl!nd

Erm, not much at the moment lol. But when it does i'll be out in it with my truck!

tmodlin

Are you using a rotostart or a pull start?

sledmanass

My Feedback: (2)

if you have the roto start, just turn the enigine over and use your other finger on the throttle trigger, and it should start.

Frost_

My Feedback: (1)

You're the guy that said his engine has NEVER been run when the outide temperature is ABOVE freezing. It is so difficult to get the engine up to operating temp that this usually leads the inexperienced to lean the engine out so that it seems to perform correctly.

My money says that your piston and sleeve are shot unless you have been doing some wrapping of the head, or something of that sort to help bring up the temp.

the dog

yeah thats me. your probably right frost. but i also wonder if the temp is getting up to temp because before i run it ill let it sit and idle for 5 min or so. ill reach down and feel the block and its hot enough that i jerk my hand away fairly quickly.
i also havent really messed with the hsn that much. ive only adjusted it about 1/2 turn more lean. the book said i could go 2.5 turns i think?
well ill just run it till summer, then if i have any issues ill by then want a new motor or ill buy a second truck. im already planning on getting that hellfire. i wouldnt mind a lst either.

i think im runnin still pretty rich.so then my sleeve and piston might still be good.
one odd thing. the more i run this motor the more power it seems to get every time i take it out.
any other ideas please let me know. thanks.

tmodlin

If you have a rotostart are you sure the one way isnt just slipping on the shaft. If you are runninr really rich and your exhaust gasket is leaking a bit or the backplate isnt sealed you will get nitro oil all over the shaft and the bearing will slip. It is easier to notice with a pull start compared to a rotostart. Take your rotostart off and clean out the one way with some brake cleaner and re assemble it. It probably needs it anyway and you can see if that is your problem. Even if you broke it in too cold you should still have enough compression to prime and start the engine, you just might not have the power due to the uneven fit between piston and cylinder.

Like I said, even if the one way isnt the problem it should still cleaned every so often to make sure it lasts.

the dog

ok it is the one way slipping. im guessing that the one way is the bearing inside the pull start shaft holder. i took off roto plate and then backplate and put the roto start on and i could hold the pullstart shaft holder very easy with one finger and it doesn't spin. so must be that bearing. any ideas?

tmodlin

If the bearing is not cracked and all of the rollers are there you should be able to clean it with brake clean and reinstall. I would recommend sealing the back plate since you already have it tore down, it could prevent some future problems. I am not really following your explanation of what you did when you took it apart but if you do what i said above you should be good to go.

the dog

ill spray with cleaner. are you saying seal like with a gasket sealer type stuff?

tmodlin

Yeah. I used Permatex Ultra Gray on mine and have had no problems. I only used it because I had some left over in the garage. Just make sure it says it is safe with fuel.

the dog

seemed to work good. i put all back together and seems to be great. ill try not to flood. thanks for advise.