Topic: 600 mile "new" engine service?

[scondon]

      Aaaccckk! 1500 miles on the new "rocket" engine and oil is already pooling on the fins and blowing back on my nice clean rebuild. I went the extra mile on this engine to assure that it wouldn't hemmorhage. I did not, however, yank the engine at 600 miles to retorque the head. I really hate to have to pull this motor back out but it's gotta be done(sigh).

       Can anyone tell me the process of retorqing the head? Do you just tighten the nuts or do you back them all off and then re-tighten? 
   
       Also, once oil finds a path to leak will it be useless to retorque i.e. are new gaskets needed?

        Aside: MRieck, if you're reading this, check your PM


Oh yeah, Engine is CB750 with 836 pistons. '78 750F block with '78 750K head(milled).

[Sam Green Racing]

Sean ,

I have pulled a couple of topics up from way back on 836 power and oil leaks.
You will find them amongst the first few topics page 1..2  or 3.
Hope this may be of help.

Regards Sam.

[bryanj]

Honda do not specify a re-torque on any of their engies in the manuals after rebulid so unless you have a stud bad there should not be a need to redo it

[ChefJoe]

Sam,
Could you post a link to those searches?
Thanks,
Joe

[scondon]

Thanks for fishing out those topics Sam.

http://www.sohc4.us/forums/index.php?topic=1133.0

http://www.sohc4.us/forums/index.php?topic=1176.0

[Sam Green Racing]

Sean,

Just thought it might interest you re the pressure build up from the big bore pistons.

Sam.

[Terry in Australia]

G'Day Sean, sorry to hear about the "weep". I never remove the engine and retorque after 600 miles, but I DO torque it down, then leave it overnight on the bench and retorque the next day. I torque it to 20 ft lbs (yes I know that's a lot more than the manual recommends) leave it overnight, then the next day I loosen all the stud nuts and the 6mm screws a couple of turns until they turn freely by hand, (in the reverse of the torqeing order in the manual) then I retorque them to 20 ft lbs again, and mine don't leak! Cheers, Terry.  

[scondon]

I read that post, Terry. Sounded good to me so that's exactly how I torqued my engine. 20 ft. lbs, Yum! My guess is I'm leaking under the cam towers, but I'll have to pull the engine to be sure. Trouble is, I'm having too much damn fun riding this thing to pull it from service

    I'll try pulling the crankcase breather from the oil tank and see if that doesn't relieve some pressure. The valve breather is routed to my PC device which is basically open to the air(connected to nothing).

[Terry in Australia]

No worries Sean, as long as it's not making a farty blown gasket noise, it'll be fine, did you put a little adhesive around the edges of the round seals under your cam towers? Whassa "PC device"? Cheers, Terry.

[Bob Wessner]

PC = Polution Control, I think.

[MRieck]

Aftermarket studs work well as they torque to 22lbs. That graphite head gasket included in the 836 kit seals pretty well Sean though I use a very, very small amount of Hylomar around the oil return and feed holes on both the base and head gasket. Sealer around the cam cap rubbers is always a good idea. If oil is on the upper fins of the head that's probably your leak. If it's betwwen the head and cylinder that's different. I've read your PM Sean but have been busy this past weekend- I'll get to it tonight.

[scondon]

I didn't use any sealer on the head gasket, but I did put Gaskacinch on the base and a touch of silicon high-temp under the cam tower pucks.

     Took the bike on a 220 mile ride(race?) yesterday. Engine is very smooth all the way up to 9,000. Still working out the carb jetting, running lean on the mains. Still, very happy overall despite the "weeps".