Thread: V8 Valve Guides

G`day ,

What was the fault with the stem seal in question ?

Has it gone hard or is it cranked or something else ?

From the shine on the valve stem it seems to have had a fairly good grip .

How did you ascertain that there is excess oil in #7 ?

I guess with that side off you have the top of the chamber off , have you put a camera down behind the valve head ?

How does the plug in that cylinder colour ?

Originally Posted by PLR

G`day ,

What was the fault with the stem seal in question ?

Has it gone hard or is it cranked or something else ?

From the shine on the valve stem it seems to have had a fairly good grip .

How did you ascertain that there is excess oil in #7 ?

I guess with that side off you have the top of the chamber off , have you put a camera down behind the valve head ?

How does the plug in that cylinder colour ?

The stem seal was pretty hard but looked ok

#7 plug was very oily, all other plugs were OK. Haven't used a borescope camera on it yet.

I discovered when I replaced the head gasket a few months ago This engine had a big sludge buildup in the top end and all the rocker gear had been starved for oil. It does not surprise me that the valve guides are also worn From what I understand there should not be any visible movement between the valves and the guides.

It seems that the aftermarket rockers can also let too much oil through which floods the valves with oil. One post I found said opening the drain holes in the head helped a lot as well

"The answer for me was to use a burr and a dremmel and open up the drain ways at either end of the head that allows oil to flow back into the engine/sump. At first I could hardly get my little finger nail into the hole. Afterwards I could fit my little finger through it."

So new sleeves sounds like the go, I'll talk to my local head guy on Tuesday

Thanks
Steve

The first time I had my heads done, they had bronze (K-line?) fitted.

When I had a full rebuild with tophats, etc. new standard guides were fitted (and the heads ported and port matched).

Originally Posted by TheTree

The stem seal was pretty hard but looked ok

#7 plug was very oily, all other plugs were OK. Haven't used a borescope camera on it yet.

I discovered when I replaced the head gasket a few months ago This engine had a big sludge buildup in the top end and all the rocker gear had been starved for oil. It does not surprise me that the valve guides are also worn From what I understand there should not be any visible movement between the valves and the guides.

It seems that the aftermarket rockers can also let too much oil through which floods the valves with oil. One post I found said opening the drain holes in the head helped a lot as well

"The answer for me was to use a burr and a dremmel and open up the drain ways at either end of the head that allows oil to flow back into the engine/sump. At first I could hardly get my little finger nail into the hole. Afterwards I could fit my little finger through it."

So new sleeves sounds like the go, I'll talk to my local head guy on Tuesday

Thanks
Steve

G`day ,

if it has excess oil in the cylinder it should blow smoke , blue .

In general.......... if it blows smoke all the time then the oil ring could be at fault . If it blows smoke after it is let idle for a while and the throttle is opened or when it is run at revs and the throttle is lifted , then the stem seal could be at fault .

If only one cylinder it may be hard to pick it up .

Between 0.025 and 0.066 mm clearance for inlet and the stem should be around 8.664 mm dia .

As indicated previously the valve stem doesn`t look like the seals been letting much past but if the seals hard it would give a similar look and your looking , i`m only guessing .

I`d imagine the post about the drains refers to the earlier heads the later ones are much tidier and to be a problem for the end cylinders they would need to be pretty much blocked off and if yours are not i doubt the post is applicable .

My opinion on kline guides is nothing special , i have a pair of heads that did alot of work with them fitted but also have heads that used std guides that have done similar but not over the same time period and neither have worn to any great extent and all were used with LPG and that was what the kline thing was about .

These kline guide heads were done over 20yrs ago , they are not currently on an engine bit were only replaced mid 2015 . They ran the umbrella type stem seals and oil burning was never a problem and as you`ve seen , the plugs soon tell when it is a problem . I should add over that time the exhaust valves were changed once but it was not a problem with the stems or guides .

so, if the oil level goes down,,
its either burning it or leaking it,
so no floor deposits means
smoke all the time or just off idle?


do valve stem seals require some oil just to survive?

Originally Posted by Pedro_The_Swift

so, if the oil level goes down,,
its either burning it or leaking it,
so no floor deposits means
smoke all the time or just off idle?


do valve stem seals require some oil just to survive?

It doesn't smoke much but it uses oil doing local driving, lots of iding and high intake vacuum; however when I do a trip on the freeway it uses virtually no oil. I believe if it was a problem with the rings, the opposite behaviour would be happening.

Not sure the seals need much oil to survive but I think the guides do need a little to stop excessive wear.

Originally Posted by PLR

G`day ,

Between 0.025 and 0.066 mm clearance for inlet and the stem should be around 8.664 mm dia .

As indicated previously the valve stem doesn`t look like the seals been letting much past but if the seals hard it would give a similar look and your looking , i`m only guessing .

My opinion on kline guides is nothing special , i have a pair of heads that did alot of work with them fitted but also have heads that used std guides that have done similar but not over the same time period and neither have worn to any great extent and all were used with LPG and that was what the kline thing was about .

These kline guide heads were done over 20yrs ago , they are not currently on an engine bit were only replaced mid 2015 . They ran the umbrella type stem seals and oil burning was never a problem and as you`ve seen , the plugs soon tell when it is a problem . I should add over that time the exhaust valves were changed once but it was not a problem with the stems or guides .

G'day mate,

I'll check the tolerances on the valve and guide, but given the amount I can wiggle the valve, I suspect they are way out of spec

Seems as if the best thing is to pull the heads off and send them out for new valve guide liners. If the valve stems themselves are worn new valves as well.

I fitted an ARP stud kit when I had the heads off so that makes it a little easier and cheaper to pull the heads

Steve

gee Steve,, what a great time to put some really huge inlet valves in, take 60thou off, change cams, change to MLS gaskets,, (someone stop me! )