Thread: 69 428 Gushing Oil After Rebuild-

Tweet

After rebuilding, boring 30 over, line honing, new pistons, shaving crank blah, blah,blah. My 428 is still leaking oil when under a load. Sitting in the shop it will never drip until you drive it and after 30 mins you have a nice 2: wide x 6" long oil puddle. I took everything out and out a new rear main in since that is the area where it was dripping. It was good for two days and now big puddle again??? Is the crank out of balance or internals off??? Please help

Is it oil wet in the bellhousing???? what did you use for side seals on the main cap?

is it a rope rear main seal if so it was not put in rigth or the rear seal is in the wrong way could be one 1/2 the upper or lower part or the hole thing

The bellhousing is wet. I didn't replace the seals myself. Too busy trying to pay the bills working. When we took the original rear main out and compared it to the new one the old one looked a bit smaller but even the new one is leaking badly. Do you think it has anything tho do with internals, balancing etc?

no i it is the seal or rear cam plug or galley plugs but i would think it is the rear seal in wrong

When we first put the motor in we had to resel all the plugs by the oil gallery because they were pumpming out. Is it better to use a rope style seal or is that the only kind they make. I didn't see what they put in.

there is some tricks to put a rope seal in the right way if that is what it has there are some new seals now that fit were the rope was and is a lip seal you will have to talk to the guy what they put in it if the lip seal is to the out side it will push oil out

Just a thought here. Any chance the "freeze plug" that goes in to the back of the block behind the cam installed correctly? If I recall correctly, that plug should be installed backwards (the dome facing out). I've seen a couple FE's leak oil because that plug was put in wrong.

i just did a 360 mopar and in the kit it used a moon plug on the cam. i allways use loctie 620 on all block plugs and then on all back plugs on the block get sealed with J B weld or lord high epoxy then it is a done deal. race engine all plugs get J B weld on them but the pipe plugs

I'll take it all apart on Monday and let you know what this mysterious leak is from.

Just wondering....you are running a PCV and vented breather aren't you, and how did you seal the front and rear ends of the intake?

If the block is really a 69 it should have threaded lifter oil galley plugs. Those started after 68 and limit the weeping to about nil correctly installed. Also the rear cam plug (besides being installed correctly like LA said) can use a bead of sealer around the outside edge. Also be sure the oil helix grooves -> ////// on the seal surface of the crank are present. If that area of the crank was worn, turned or touched for some odd reason the rear seal will leak. Also be sure the side seals were used installed correctly and tops filled with sealer. Rear main cap gaps sealed as well. Be sure the lip of the seal faces forward and also stagger the seal .250 so they seal gaps don't line up with the maincap gap.

Now... the oil was IN or ON the rear of bellhousing? If on the outside it can be the rear intake or a valve cover leaking. When it drips down can appear to be a rear seal leak.

Are you still selling the car?

THEM //////////////// help control oil if you look at a gm seal and other makes there on the seal and if you get a reverse rotation seal the are the other way and will wick the oil thru the seal lip in a standard rotation engine and you have to be careful not to polish the seal face on cranks with the hash marks on the crank

Do you have a good working PCV system???

Just a note. If the intake isn't even with the edge of the heads oil
will run down the bellhousing