need valve guide advice

[mm]

so what the word on valve guide seals? I understand to decrease oil burning that better stem seals can be installed but then you get stem-guide wear. So should guide be reamed for bushings in order to use the seals. whats the cost to have a head worked on/

[ken wilhelm]

hello, you can knurl the guides and then ream them at a very cheap cost around 10.00 per guide this will get you through for some time or have the iron guides drilled and new guides pressed in, the guides are not expensive, and can be had at napa auto or the international dealer, the cost is not much higher, to install new and the machine shop will probably recommend new anyways ,might as well have the valves looked at too ,get them trued up or ground as some call it

[cdnsarguy]

If the guides show no/limited wear the newer seals will do fine.

[RLDSL]

The 6.9 came with positive seals on the intake valves and umbrela seals on the exhaust, which have a habit of letting a lot of splashed oil into the guides contributing to oil consumption, The 7.3 came with positive seals on both intake and exhaust,, it reduced oil consumption, but they found that the reduction in oil on the exhaust guides contributed to increased wear on the guides and stems, so they switched back to umbrella seals for the exhaust .
Right now, all of the valve stem seal sets sold for the IDI come with the umbrella seals. ( in case you're wondering, the intake valve stems get plenty of extra lube from the blowby oil vapour directed through the CDR back into the intake that passes over the intake valve stems )

When I had my engine apart, I opted to go with positive seals all around and went to Car Quest and ordered 2 sets of Reinz intake valve seals. Right after break in, I switched it over to Amsoil synthetic , so I'm not concerned about any valve guide or stem wear.
Had I left it on dino oil, I would have most likely stuck with the umbrella seals on th exhaust. As far as dino oil, the combination of the reduced oil flow and the new oil spec not being real friendly to situations like that where the guides could run dry occasionally and not enough zinc to protect the guides/stems when dry would most likely make the wear problem even worse than before they switched the seal type back

[schoelta]

I'm just curious. In a small block Chevy, people prefer the umbrella type seals since they don't wear out as fast or leak like the OE ones. Why then in our engines are the umbrella type seals not effective?

[chuckster57]

Originally Posted by schoelta

I'm just curious. In a small block Chevy, people prefer the umbrella type seals since they don't wear out as fast or leak like the OE ones. Why then in our engines are the umbrella type seals not effective?

For the last 10+ yrs. I have installed the viton positive seals and have had no problems or complaints. The "umbrella" type will "ride" on the valve stem.. thats why they don't wear out they get brittle from the heat and then the stem will "leak" past the seal. Positive seals have a spring like your front/rear main seal and they wear out becasue of the back and forth motion of the valve stem. I have yet to find a set of positive seals that have become brittle and failed...some after 200K+ miles. FEL PRO will include viton seals as standard on gasket sets, at least thats what I've been getting.

[arthurgoboom]

I know this probably doesn't apply and you guys might not care, but I work on alot of Onan 25hp industrial engines and they occasionally have valve guide problems as well. They're a horizontal opposed twin cylinder, so leaking down the exhaust guide isn't really a problem, but pulling oil into the intake port through the intake is a problem. The solution I use is to use the positive seal, but don't push it all the way down onto the valve guide. I push it up so that the taper inside the seal is touching the taper on the valve guide when the valve is fully open, then when the valve is closed it hangs away from the guide by about 1/4". This way when the vacuum in the intake is highest, the flow of oil is stopped, but then it allows some oil to splash on the stem during the valve's closed time.

I would think if you did this on the exhaust side of the IDI, the viton positive seal should never leak past the stem, but the stem would still get lubrication when the valve was closed. That's just my idea.

[icanfixall]

PEP in Las Vegas Nevada has the best material for valve guides. Go over to the oil burners site and ask Typ4 about his application he is using....

[mm]

have read bronze liners require less oil than cast guides. So if positive seals are installed, I am thinking that bronze guides installed.?