Tightening head bolts and exhaust bolts...

[RickDizzle]

Newb question here relative to gas rc engines.
Is it best to tighten my header to engine bolts and head bolts when the engine is cool, warm, or hot? I know things expand with the heat, so not sure when the proper time is to tighten these guys down?

 

[DougStar]

The few times iv done heads/rebuilds everything has been cold ?? so have to say cold coz iv never had an issue ??

 

[Haric]

I’ve done it cold with no issues??

 

[Seandonato73]

Torque is typically done cold.

 

[Z.hb71]

Cold, metal softens when it's hot so you have a greater chance of stripping (not sure how much more likely it is but I do cold just in case)

 

[RickDizzle]

Thanks guys! Now if I can just determine the correct torque specs. I cant find anything on this engine. Sean sent me a great torque sheet overview. Just wish I could get info specific to this engine. Wasn't able to secure a response from Primal this week yet.

 

[buzzkill]

IF U tighten it and it BREAKS its too tight !! rule of thumb #1

 

[RickDizzle]

Lol! I went through them all now and snugged up real snug. Not Hercules tight but for sure tight. Two of the head bolts were basicly finger tight when I checked them. Pretty sure that is where my oil was coming from at the head and why I was getting oil spray out. Also tightened my header to engine bolts...also pretty lose. Hopefully this will address and fix my top end tuning issue as well!

 

[buzzkill]

Lol! I went through them all now and snugged up real snug. Not Hercules tight but for sure tight. Two of the head bolts were basicly finger tight when I checked them. Pretty sure that is where my oil was coming from at the head and why I was getting oil spray out. Also tightened my header to engine bolts...also pretty lose. Hopefully this will address and fix my top end tuning issue as well!

if you had bolts that LOOSE YA remember the bottom end IS the air/fuel path ! ANY air leaks will fekk it up BAD

 

[Seandonato73]

Hopefully it didnt hurt the head gasket.

 

[buzzkill]

Hopefully it didnt hurt the head gasket.

probably blown ! I would change it in any case, besides that can cause a LEAN condition this can KILL ur Motor !

 

[DougStar]

Lol! I went through them all now and snugged up real snug. Not Hercules tight but for sure tight. Two of the head bolts were basicly finger tight when I checked them. Pretty sure that is where my oil was coming from at the head and why I was getting oil spray out. Also tightened my header to engine bolts...also pretty lose. Hopefully this will address and fix my top end tuning issue as well!

Id be ordering a new head gasket.? i had a lose head on a motor the time was all out .....torqued down the head but in the end blowing on the head the gasket was done? replaced it and it was golden kept a tune??

Hopefully it didnt hurt the head gasket.

+1??

 

[RickDizzle]

Dang you guys think? This engine was brand new from Primal. Only has about 1 and a half gallons on it. I was told it is a copper head gasket and that tightening it down should resolve the issue? By no means challenging you guys at all. Just trying to learn. How would that cause the head gasket to blow?

 

[DougStar]

If its a copper gasket I'm sure you'll be ? ok I was talking paper/graphite gaskets

 

[RickDizzle]

If its a copper gasket I'm sure you'll be ? ok I was talking paper/graphite gaskets

Thanks Doug. Yeah it is copper. Ill keep an eye on her when I run it in a bit. Thanks for helping me understand it all guys! Learning every day with the brap game!

 

[buzzkill]

If its a copper gasket I'm sure you'll be ? ok I was talking paper/graphite gaskets

Yep , on the bottom end it would be a blow out not a burn up like on a separate head motor , these things have integrated head/cylinders unlike most 2 strokes.

 

[DougStar]

Thanks Doug. Yeah it is copper. Ill keep an eye on her when I run it in a bit. Thanks for helping me understand it all guys! Learning every day with the brap game!

No worries bud ?? that why we all hang out here coz its the best place on the braaaaaap net?

 

[buzzkill]

Thanks Doug. Yeah it is copper. Ill keep an eye on her when I run it in a bit. Thanks for helping me understand it all guys! Learning every day with the brap game!

you might want to put some thread locker on them ! remember to torque the bolts in a pattern to get even torque on them ( lt/rt and around )

 

[RickDizzle]

Its four bolts so went corner to corner at each opposite corner diagonal.

 

[1Coopgt]

Cold, metal softens when it's hot so you have a greater chance of stripping (not sure how much more likely it is but I do cold just in case)

I don't think you can get the head of one of these engines hot enough to soften the metal. You would need a cutting torch .

Metal expands when it gets hot . You want to torque all the bolts to the motor while it's cold.