Renewing V8 valve rubbers with the heads on ???

[Boothy]

When I rebuilt my V8 a couple of years ago, I had a bright idea of not fitting valve rubbers,

2 reasons being is they hardly do anything on a V8, as they are quite a dry head, and what bit is up there may help when things get a bit hot i.e. challenges.

No problems with this method for a couple of years until I filled the sump with Kirton gritwater this year, I immeadiately dropped the oil gave it a couple of good flushes refilled and heated it right up twice, and hey-ho its OK now, nearly.

But what is does do now is smoke at times, usually for a bit when its cold and usually just after a good revving session, none at all when working hard under load and none when accellerating hard, if its hot and left ticking over for ages and then revved it will give a good cloud out which will then clear, anyway oil pressure is good and no other problems are apparent, except it will sometimes missfire after its been smoking a bit, which can be expected.

Last Sunday on the Howlin Wolf it tipped quite a bit onto its drivers side (45* or more) and was there for a few minutes while we got it out the hole it had fell in, but at this point it smoked quite heavy, oily smoke, leading me to think that it had filled the right hand rocker box full of oil (or a lot more than usual) and then this had in turn had ran down the valve stem and been burned off.

Whenever I remove the plugs it never gives it away as to what cylinder is miss-behaving or oiling up which is proper annoying.

So this sort of proved to me a bit what I already suspected that its valve guide problems, more than likely not helped by Kirton and MAY be rectified slightly by having some stem rubbers/seals fitted, until closed season next winter when a good stripdown is planned.

So the question is, if I make a tool that will bolt in place where the rocker post was, and then fit over the valve top, and then when the piston is at the top of the bore if I push the said tool, will the valve hitting the top of the piston, stopping the valve from dropping any further give me enough to remove the collets and valve spring etc and also allow refitting in the same method??

Or is there already a tool in existance that is made for this job, that saves removing the head for a minor op, Ford had a similar tool for some engines if I remember correctly.

2nd question has anybody fitted other types of valve stem seal, and as previously mentioned Ford CVH type which fitted over the valve stem and then went on to fit under valve spring to complete the job, and provide an excellent seal, or will this be to much of a seal, i.e. run to dry if you know what I mean.

Any thoughts out there boys, all this just saves disturbing the head gaskets I know.

Thanks Guys

[Quagmire]

I have never tried this but have heard (and this was not v8 specific advice) you can keep valves from dropping by removing plugs, feeding string into the pot when at BTDC and then winding it by hand up to TDC.

The string will get compressed and hold the valves in place while you do the seals...

I guess you then rock the engine back a little to release the string and then pull it out. Job done. I can see how this would work on a straight 4 but not sure how the angle of the cylinders in the 8 will affect the string piling up.

[Steve 90]

Ive used the string method quite regularily a few years back when we went through a stage of fitting valve stem seals to the troublesome peugeot petrols and it works fine. Weve got a tool to compress the spring that just goes onto any stud in the head and bobs your uncle. A garage down the road was using compressed air via a cyl leakage tester to hold the valves in place which worked well but they once had an issue with an air line coupling coming apart and loosing a valve .

[RangeyRover]

Never done it so just an idea, but what about a (tough) balloon blown up via the spark plug hole?

[yella 90]

ive used both methods as steve has mentioned above at work, and both give good results, but i found string to be better and more effective

dan

[Boothy]

Hey I like this string idea, sounds like it should do the job, worst case senario is that it doesn't work and I have to take the head off, its not the end of the world I was just trying to save the effort.

Found out since that the post 94 stem seals are different, now I have got to find if they will fit pre 94 heads (cannot see why not) and make a tool that willl let them be fitted over the valve stem.

Thanks guys

[bushwhacker]

Hi

I used a tool from Sealy VS 168 to press down on the spring to allow the collets to come out on a couple of cylinders it worked great until one collet slipped and went down a push rod tube.

I do not know if the v8s are push rod but if they are this tool or a good diy one might be of help.

Make sure to plug any holes, I used a magnet to catch the collets when the spring was depressed. A second pair of hands might help some what.

I only done one at a time slow I know but I still managed a mishap.

There is away to hold the valves up with an airline with a connection screwed in to the plug hole.

Good luck

[pat_pending]

TBH from what you describe, I doubt sticking some seals on will make much difference.

I think the seals on the early engines were only a rubber washer stuck on the valve stem, and only on the inlets as well.

The v8 is not known for general valve stem/guide wear.

I'd leave it until you do a full strip.

[SteveRK]

"Last Sunday on the Howlin Wolf it tipped quite a bit onto its drivers side (45* or more) and was there for a few minutes while we got it out the hole it had fell in, but at this point it smoked quite heavy, oily smoke, leading me to think that it had filled the right hand rocker box full of oil (or a lot more than usual) and then this had in turn had ran down the valve stem and been burned off. "

As you mentioned the heads are pretty lightly oiled so where would this oil have come from?