Vavle seals or leaking intake gasket?

[ZZ4Blazer]

Im leaning more towards intake gasket leaking, since theres deposits on the head intake runners.





<hr width='200'><img src='images/jpg.gif'>: <a href="http://memimage.cardomain.com/member_images/7/web/259000-259999/259552_88_full.jpg" BORDER="0" target=_blank><font size="-2">image will open in new window</font></a><hr width='200'>






Most of the intake vavles look as bad. What else would cause this? Its gotta be killing flow and power.





<hr width='200'><img src='images/jpg.gif'>: <a href="http://memimage.cardomain.com/member_images/7/web/259000-259999/259552_94_full.jpg" BORDER="0" target=_blank><font size="-2">image will open in new window</font></a><hr width='200'>

[mzoomora]

Was it burning oil? I am having a similar problem now, but I\'m pretty sure mine is the guides. I am using some oil, but only right at startup, then a little after a few minutes of running- when the oil starts to seep down. I have the good viton seals, but if the guides are loose on the intake side it will suck the oil down past the guide and seal. Check to see if your guides are loose by trying to move the valve side to side with the spring off. I also thought mine was an intake gasket, but a lot of alloy and aftermarket heads run softer guides.

[ZZ4Blazer]

I never noticed it using oil. After switching to synthetic, I did develop a small oil leak, so oil did get low after a while. Nothing serious, maybe 1/2-3/4 of a quart after a month or so of driving. It seemed like the vavles were tight in the guides, I had a hard time trying to get the intake valves out.



IF it was the guides or seals, would there be dark deposits up the runners of the heads also? Theres some maybe 1/4-1/2\" up the runners of the intake manifold also.



It also seems like its worste on one side of the valve than the other.

[spacecadet]

I would say by looking at the second photo that it is oil deposit on the valve. If the valve stem guides are worn then, even with new seals they will leak because the valve is wobbling in the valve guide while the rocker pushes it up and down. That will allow the seal to \'egg-shape\' and leave a space open for leakage. The valve guides will wear if a rocker is it pushes on an angle. Roller rockers do a better job of elimnating or slowing this type of wear. If you had trouble getting the valves out my asumnption would be \'rub\' type rockers that wore or mushroomed the valve stem heads alittle.

[Satanklawz]

I had a problem with burning oil on startup for a long time and it was on a brand new engine, I had to replace all of the valve seals on the exhaust side and it cured it right up.

[ZZ4Blazer]

I\'ve never noticed anything on start up. Its only the intake side too.



I might just replace them for the hell of it. What is needed for me to replace them, and what do you guys recommend for replacement? I do not want to have any interference with anything

[spacecadet]

I\'d suggest the \'top-hat\' style. The o-rings by them selves don\'t work very well. What happens is while the engine is running the vac* sucks the oil past the seals.



This is what I was taught to help with removeing carbon deposits, on a running engine. Run engine till operating temp. Use a Windex spray bottle that is filled with soapy water. With the hot engine running, spray the water in to the intake. It will \'steam\' clean the valves and upper cylinders. This is the way the old timers used to clean the upper engine. Today, at most shops they use a machine to do the same thing. Like the Motorvac, I think it is made by Snap On.

[Scotty_S-15]

Regarding \"using\" oil and valve guides, it might seem odd, but an engine can puff smoke at startup, and even foul plugs because of bad guide seals, and hardly use any oil. I think it\'s a function of a tiny bit of oil going to the wrong places, at the wrong times.

..... Another thing that doesn\'t help the matter, is if an engine has a healthy amount of vacuum at idle, which is usually tied to the high initial timing numbers we with SBCs like to run. High vacuum likes to suck that oil right out of the heads.

....... BTW, Space, my Dad used to do the \"water-down-the-carb\" trick too. He also did the \"Marvel Mystery Oil\" thing too....

[mzoomora]

I used to just crank up the idle and feed the water (or sometimes water/transfluid 50/50) through a vacuum line. Just have to work to keep it running.

[ZZ4Blazer]

initial timing is set higher, I think I have it set at 14 or 16 degree\'s, cams not that big either, and has got good idle.



I think the swap to synthetic is what did me in. Just about everything started seeping some oil after I switched.

[Scotty_S-15]

On 2004-07-12 05:12, ZZ4Blazer wrote:

initial timing is set higher, I think I have it set at 14 or 16 degree\'s, cams not that big either, and has got good idle.



I think the swap to synthetic is what did me in. Just about everything started seeping some oil after I switched.



That\'s interesting..... maybe proves that the synthetic oil is more \"slippery\".... It slips right past your gaskets! http://www.s10v8.com/images/smilies/icon_razz.gif A buddy once had a 4 speed, and figured he\'d add some trans additive, supposed to make everything more slippery, help shifting, etc. Well, I\'d say it did it\'s job very well. Wasn\'t 2 days later during a power-shift that the trans handily slid right into 2 gears at once! Oh, the carnage. But I guess it was a linkage thing....

[Ced]

If you have \"screw in\" rocker studs and they weren\'t sealed when they were installed, it\'s possible oil could be getting sucked in around the rocker studs. Slow but sure.