I have a 1990 RV with a 460 in it and just recently it has started to use oil to the extent of a quart in 200 miles. I doesn't show any smoke out of the tailpipe when accellerating or decellerating. I expect that it is the valve stem umbrella seals and am wondering if anyone has discovered anything better than the stock seals that it came with in 1990. As I am the original owner and know that it only has 43,000 miles on it, I don't expect the rings to be gone yet but will do a leak-down test to ascertain that. I did experience a drop in oil pressure about 2 years ago and dropped the pan to take a look inside and found the oil pump pickup tube to be fractured right at the flange where it bolts to the pump. I changed the rod and main bearings and put a new Mellings high volume oil pump and new pickup tube in it at that time. None of the bearings I removed showed any signs of wear or scoring so I am sure that the drop in oil pressure (from 80psi to 60psi) did not harm anything and is was only driven about 7 miles after I noticed the change. Other than that, its as it was when new. So, does anyone know of a better valve stem sealing method other than the stock umbrella seal that it came with 20 years ago? Surely someone has made an improvement on this. Maybe the PC teflon seals that grip to the outside of the guide or the metal shields that GM uses on the 454's under the spring retainers? Just want to do it right this time and never have to worry about it again.

 

Another thing to look at is the PCV system. If the engine has a catalytic converter, it can take care of any blue smoke you'd see before you see it

Positive-lock valve stem seals require head machining, so they'd have to come off to have the job done. Depending how much room you have under the hood, it might be worthwhile just to put new umbrellas back on, but ...

Are you finding pieces of the seals in the oil pan yet?

 

Thanks for the info. I have replaced the PCV valve and the first one I replaced was like there was no spring left in it as the valve was about 1/8" off the seat when you held the valve in the upside-down position. Now I change them when I change the oil, around 2500 miles. I am confused about what type of seals I am going to find if and when I get the springs off due to conflicting information found in Ford Truck Shop Manuals. The 1990 Econoline, F-Series, Bronco Truck Shop Manual says that the factory installed valve stem seals are "Unique exhaust and intake guide mounted valve stem seals are required and care should be used to install the correct seal in the appropriate location. The seals are identified on one end with IN for intake and EX for exhaust. The pictures depict a spring type assembly that slides over the outside of the valve guide like a Perfect Circle type seal and shows in three steps how to install it on the guide, but the parts list calls out a umbrella seal that merely slides over the guide when the valve moves up and down and is not attached to the guide. I am hesitant to take this thing apart at this moment due to conflicting information in what I used to believe was a Bible! Any thoughts?

 

Sorry, forgot to answer your question: No, no sign of any parts in the oil when I do my oil changes, thank goodness.

 

It fixing yes the engine isn't advanced?

And vending white smoke?

 

I'm sorry, I don't understand your post.

 

I pulled the passenger side valve cover today and found that this engine does indeed have the guide mounted (PC style) valve stem seals factory installed on it. I went to the local Ford dealership and asked for a set of intake and exhaust seals and he argued that the umbrella seals were the only thing he showed for my application. I showed him my Ford shop manual and he called a mechanic to come up and the mechanic said he had never seen them from the factory as stock items and the Ford parts search only turned up the umbrella seals. I do notice that Napa auto parts shows a replacement seal very similar to what I need and am going there next to take a look at what they have. The beat goes on.....

 

is fixed if the engine are is advanced?

Check the oil pump, okay, 80psi (engine cool) AND 60psi (engine hot) is normal...

 

As I stated in the original post, it has a new Mellings high volume oil pump and pickup in it. It pumps a constant 80 psi when warming up and drops to around 70 psi when driving. I don't envision the oil pressure as a problem but am having second thoughts about the high volume oil pump putting too much oil on the rockers, causing the PCV valve to be pulling more oil-laden air from the engine, maybe causing some of this oil usage. The factory installed oil shield in the right hand valve cover under the PCV valve is intact and not loose. I was able to procure the Napa intake and exhaust spring clip stem seals today so that will be my next project to install those. The cylinder leak-down test showed no problems in that area either. Given that the compression was: #1-170psi, #2-170psi, #3-165psi, #4-170psi, #5-175psi, #6-170psi, #7-170psi, #8-175psi, and that the engine only has 43,000 miles on it, I really didn't expect find a problem there. Doesn't leave much else to fix.

 

Stop... You are mixing the oil precion, with the psi of the nozzles can be?

His van has injectors?

 

I gonna have to pass on this! Thanks for your help.
Les

 

Gianni is not from this country, so his English is not all it can be

Les, let us know how the stem seals work out for you. Also, make sure the head drains are not clogged. Even though it's low mileage, who knows.

 

Thanks Krewat,

Reviewed the oil filter is clogged capable.

 

Today I had a friend of mine who was the manager of the Automotive Engineering shop in Oakland, Ca. help me do a cylinder leak-down test and he and I don't really believe the results but his tester is brand new (doesn't mean it couldn't be faulty though) and all 8 cylinders were less than 5% on the leak-down gauge. So, I applied 140psi directly into a couple of cylinders just to listen for leaks and I could hear a little noise within the engine, but no big hissing or blowing anywhere. Being as how I already had removed the right side valve cover I thought I would hear a little more noise, but didn't really. Maybe I just need to replace the valve stem seals and call it good. I almost wish I had found something because I have this nagging feeling that I am missing something and I am never lucky enough to have something this minor go wrong. Also, I hadn't mentioned before that I have 51 years as a Ford mechanic myself so I have seen some strange things in my years of twisting wrenches. Stay tuned, my seals will be here in the morning.

 

5% is good and you are probably right on the money about it being the valve stem seals. Check into Felpro or some other aftermarket maker of seals to find the ones that fit on the valve guides, Autozone, Advance, NAPA etc.

Perry