question about my new motor

[tghoward1376]

ok  i have a 73 c-10 short step side.    me and my buddy pulled out the 250 six and put in my 355  in it today. my question is after we let it break in  we noticed that is started pushing oil out of just about every gasket,  oil pan at front , timing cover ,back of intake , and valve cover    you name it it started leaking    sems like its building up alot of pressure in the crank case.    what could be causing this.   the motor has diamond forged dome pistons, new heat treated steel crank, 488 ,488 lift   292, 300 cam 1.5 roller rockers 441 76cc heads does anybody have any idea?   thank you for any ideas

[Chevalade]

Did it leak at all during the break in? What was your process? Did you have steady oil pressure?

[tghoward1376]

yes it started leaking during break in       it has steady oil pressure 45lbs at idle hot    we let it run at 2200 rpms for 20 mins or so    has 7 quart oil pan   and 15w40 oil with lucas zinc additive added also

[VileZambonie]

What are you using for crankcase ventilation? If you remove the dipstick is there pressure while it's running with your finger over the tube? If you have no blowby problems and a good crankcase ventilation system then whoever rebuilt the engine didn't pay attention to detail and you'll be regasketing everything unfortunately.

[tghoward1376]

right now it just has breathers in the valve covers.    wonder if a pvc valve installed would help any   not sure about pressure at dipstick tube.  we used 1 piece blue oil pan gasket with the little metal rings so you cant over tighten same for valve cover gaskets we know that the intake has to be pulled back off as the sillicone didnt seal in corner.   when we primd the motor with a high speed drill last night it had 70 lbs oil pressure and no leaks  we pried it for 15 mins  while rotating the crank every couple mins.        so confused this ,  this sucks   lol

[HAULIN IT]

Tg, If you have breathers in both of the valve covers (not my first choice) you really can't have pressure "building up" unless there is a blow-by problem. Could be a number of things, like Vile said, it may just be not a good "sealing job"... scored balancer/cocked front seal, not enough goop, ect. on the end rails, "the intake didn't seal", a dab of pipe sealant on the oil sender treads, ect. At this point you know the intake is leaking & you don't want oil/water contamination, so fix that first, then look for the next highest leak. Sometimes fluids can be misleading...running down & around, then dripping off of an edge (maybe the intake leak is looking like multiple leaks?) someplace. Keep you head up! Lorne   

[tghoward1376]

thanks for the responses    intake will prob come off tommorow    trying to get truck ready to go to track    it has a th350 with 3000 converter and 12 bolt rear with 3.73 gears    once all the issues are dealt with then the nos kit will be going back on this motor  figured it would be a more interesting roject than the 88 camaro it came out of     lol

[Chevalade]

Another question, that may sound dumb, but are you using a good quality tq wrench? And proper torqing sequences.