g5067

I recently installed a pair of Dart SHP aluminum 64 cc heads on my 350 CI, 290 hp GM create engine. The engine only has 12,000 miles on it and has never burned any oil. Since I installed the Dart heads I am burning about 1 quart of oil every 500 miles. I thought maybe the intake manifold gasket may have broken and it was pulling oil from the engine galley since the number 5 and 7 plugs were oil crusted. Replaced the intake manifold gasket and I am still burning the same amount of oil. I called Dart tech people to ask if the heads had the old style umbrella type value seals. They indicated that they do not, so I am thinking that my next step should be to install them and see what happens. Has anyone else experienced the excessive burning of oil with these Dart heads?

dmaxx3500

did you tighten up the top end and now it needs rings?,did you do a comp test before,,,you could try a cyl leak-down test now and see it compression is going by the rings,before taking everything back apart

427Hotrod

If you're sucking that much oil through just two cylinders...the intake seal is still first place to look closely at again.

Did you see oil in the ports when you had intake off? Does it smoke?

Did you use any sort of abrasive wheel when cleaning the decks that could have got into cylinder and messed up walls/ring seal?

You can pop valvesprings off those intake valves and ck guide wear to make sure something bad hasn't happened to the guides.

JIM

derekderek

12k. Nothing wrong with rings or pistons. Tell Dart they owe you a set of heads and gasket set.

Taijutsu

Not being an engine builder or a person w/great experience. I can only pass on what happened to me. My 350 w/TFS heads was assembled by competent person. It burned too much oil, rings were shot.
Builder tried to say my carb washed out the rings and that weakened the valve springs. A person who knows told me valve grinding compound oif often left on valve stems and blows out seals. Cleaning and reassembling solves that problem!
After the rebuild, my engine is an animal! 280 RWHP 315 RWTQ

R

NeverTooOld

Pull the left valve cover off and see if there's something lodged in the rear oil drain-back hole OR see if that hole is even there. There is a remote possibility that hole never got drilled. As it's just the #5 and #7 spark plugs that are oil fouled it sounds like the oil is having to drain through the push rod holes; meaning the valve stems of those two cylinders are submerged in oil.

REELAV8R

I had the dart shp heads, pre assembled, and I had nothing but trouble with them.

pull the valve Springs on 5 and 7 and see if the seals have been dislodged. Mine liked to do that on a semi regular basis.

g5067

When I replaced the intake gasket the number 5 and 7 ports looked normal and the same as all of the other ports. The engine does not smoke at all even when I get into it there is no white smoke out the tailpipe. Just looking for possibilities that could account for that must oil loss in so little mileage.

JoeMinnesota

g5067

I also forgot to mention that before I changed the intake gasket I did run a compression check on all cylinders. All cylinders read between 145 and 150 psi. I guess the next check should be a leak down test to see what it shows. Still searching for possibilities.

427Hotrod

Any chance with the smaller chambers/added power etc we got into some detonation and hurt a couple of cylinders? As mentioned a leak down test would help. If oil was coming through intake it would have slime in the ports and be wet in those ports.

JIM

JoeMinnesota

Sucking oil thru PCV?

mikem350

YES, always a possibility...but in just two cylinders?
Any other changes to the intake, valve covers or PCV?

g5067

I have never changed the PCV, but it appears to be working okay. Just in case I will be buying a new one just to be sure. Still searching.

REELAV8R

Are you saying that Dart says there are no valve guide seals?

Mine were the roller cam heads and I can tell you that they absolutely do have valve guide seals.

Shine a flashlight into the valve spring, if you see blue in there that is the valve guide seal.

Problem was with mine was the installed height left the springs fairly uncompressed even at full lift of .600 and this led to too much spring surge which in turn would grab the valve guide seal and pop it off the guide. They also failed to leave adequate valve pocket depth for the spring to sit in after shimming and the spring walked around the pocket area.

g5067

Dart tech people said they do have valve seals, just not the old umbrella type. They were not very helpful. They would not even confirm that installing umbrella type seals would be okay. They referred everything regarding my problem to the engine builder, which is me. That is why I am asking forum members. Your discovery sounds interesting although my heads are for a flat tappet cam, not a roller, but that may not make any difference. The only other possibilities that comes to mind is that when I purchased the heads from Dart I did not install them until a year and half later. Could the valve seals have dried out over that period of time? Could it be that they cracked, fell off, and are laying at the bottom of the spring?

wabco40

I'm using Dart Pro1 aluminium heads and had a problem with oil fouling #5 spark plug. The other spark plugs at the rear where also oil stained but not as bad as #5.
The engine is a new build and a compression check was good. I suspected it was number 5 intake valve seal.
What I found was the intake rocker stud had no thread sealer on it. The rocker stud holes are tapped all the way through to the intake runner. As the stud tightens down onto a hardened guide plate it will not create a vacuum tight seal and requires thread sealer to do this. This stud had oil on all the threads and oil could be seen on the floor of the intake port. I checked all the other rocker studs and they had thread sealer on them. Looks like the builder forgot to put sealer on this stud.
This would explain why #5 spark plug fouled first, being right in the line of fire from where the oil was getting sucked in. The oil was then being distributed around the plenum to the other cylinders with the rear cylinders getting the most of it.
I re-sealed all the rocker studs and the problem was solved.

REELAV8R

My experience was the same. I won't buy Dart again at this point.

unlikely, there is one way to find out the state of the valve guide seals though.

I bought one of these when I was tired of using another valve spring compressor, well worth the money.