breaking in a fresh 350

[2square]

hey guys, ive got myself a fresh 350 bored out too 355, new pistons, new rings, new comp cam the works. bottom end done my a machinist top end by myself( ive done around 15 engines and never had this issue). i used the recommended comp cam break in oil with the zddp, and followed the instructions, running it at 2500 for a half hour. i instantly noticed that the driver side valve cover was 15 ish degrees hotter then the passenger, the temp gauge is reading 180 from the intake the cooling system is working as it should. now im also noticing blue smoke coming from the drivers side header, especially when i blip the throttle i cant see it being rings as this is all brand new done by well reputable builder. i have a funny feeling it has something to do with that side being hot. i plan on changing the rad to a 4 core this week to see if helps the cooling. what do you guys think could be causing these issues? the passenger side head i can hold my finger on all day and 0 blue smoke out of it? what do you guys think?

 

[1987 GMC Jimmy]

It’s either a cooling problem or a friction problem. If the water jacket in that head isn’t somehow blocked causing a localized cooling issue, your valve lash could be too tight, you could have a lifter issue (assuming hydraulic not solid), or the cam bearing could have been improperly clocked. I think that’s all I got. You need to pull the valve cover on that side and see how it’s oiling. I’d be more concerned about oiling or a lack thereof after a few moments of running instead of fretting about it not getting all the way up there immediately after turning the key. Oh, did the machinist hot tank the block and brush out the galleys, and do you know your startup and operating oil pressures?

I think it’s an oil problem, by the way. The smoke is odd to me. After you get this sorted out, you can do a wet/dry conpression test on it. It’s gotta be all related, but I don’t know what the missing link is.

 

[shiftpro]

I don't consider running in the cam time to count as seating the rings. I always make the engine work but keep temps under control. Honestly I hammer new engines. Don't overheat!

 

[73c20jim]

After cam break in, I find it's best to drive it, never holding at a single RPM.

Let the engine pull then let it cost to keep the loaded RPM varying.

 

[2square]

thanks for the replies guys, i found a nice 4 core rad to replace the stock one there is a lot more power here so i think my first step is getting that drivers side head to cool is my first step here, i think thats why those rings have not seated on that side. but you guys and some research makes me feel better never fun going trough a ground off restoration to find the motor f'd up right at the end. i think you guys are right ive just never had this issue usually i see blue smoke of the start but goes away fairly quick after breaking in the cam just like the passenger side, whatever is causing that heat must be part of the problem. im going to fix the cooling, do a leak test, and check under that valve cover, if that all goes well ill put some load on this thing and see what happens. keep the ideas rolling.