cylinder head valve guides

pcp20us

Member
hi all

Ok cleaning up the head this weekend. Upon removing the valves, there is movement of the values in the guides.

Specs for the inlet are 7.846 - 7.8232 mm. Mine are 8 mm
specs for outlet 7.8994-7.8740mm. mine are 8 to 8.1 mm.

Are have spot on guides needed on this engine or could i get away without doing these, asking as i have no experience with valves.

what are the consequences of valves with play in them.

Cheers
 
Excessive oil burning, increased wear, valve
breakage, damaged pistons, bent connecting rods,
holes in engine block, Your at step one, going into
two. Spin the wheel and see how long before three
shows up. Me? I would really like to know. I did my
valve job and the valves were worn far worse than
that.
 
I was looking back through your old posts, I
assume were still doing the in-tractor TEA20
overhaul?

Sounds like you're trying to avoid having the
head work done at a shop, which I don't blame you
for doing! That can add a lot of cost to a
project. If the seats are good, and you don't see
any cracks, you will probably be OK with lapping
the valves in and going with it.

The measurements you gave are slightly out of
spec, but not excessive. Have you checked the
valve stems for wear? If there is any wear, and
there probably is, replacing the valves would
tighten things up best as possible short of
replacing the guides.

The consequences of going back with loose guides
would be some oil consumption, but not really
excessive. (In an automotive application, loose
guides typically smoke under deceleration, which
a tractor engine never does, as it is always
pulling, not coasting.) Have you bought the
gasket set yet? Did it come with valve stem
seals, umbrellas? If not, you could check with a
shop that does valve work and find some seals
that would fit the stems and fit inside the
springs. (Be sure there is room between the top
of the stem and the bottom of the spring retainer
when the valve is open!)

Another factor is how will the tractor be used?
Is it destined for long hard labor, or will it be
occasionally started just to keep the battery up?
Also, if this is the in-tractor overhaul, you are
not doing a true-to-spec rebuild. There are many
more areas that are not within tolerance, so a
little guide wear is not a real concern. (My
opinion only! LOL)

But, it is your call, your tractor... I would
probably be OK with them as they are.
 

thanks guys.

You summed it up well Steve.
Yep its is the same tea20 in frame rebuild.

I have not bought parts yet, waiting to see what i need.

Thats the info i wanted re wear in the valve guides. good to hear that i can get some seals for the valves.

True everything will be worn so working out what i can leave and what i should do while i am here.

I basically want to get the the tractor going, without spending too much but looking at a rebuild kits.

It will be light occasional work for this tractor.

So work to do.
Head ( will do the grindin, but think i will replace the valves) .

Working out a way to remove the linears atm and reseat them with new seals. Looks like they can be tricky to get out. working on a diy puller for the job after lots of googling any hints appreciated.

Checking rings on 1 and 4 cylinder, replace 2 and 3 rings, new conrod bearings on 2 and 3 but will probably do all 4.

New water pump. ( can you dismantle and fix a water pump) as it is very very stiff?

Hopefully this should do the job
 
2 tenths of a millimeter??? That is how many/few ten thousanths of an inch? Again, this isn't rocket science here.
IF you can, find some nylon seals like Steve mentioned, and just try to get a careful valve facing/seating job.
Nay bloody worries mate, she'll be right....
 
Wear on the valve stems will account for almost half of the clearance , new valves will go a long way to sorting that out as Steve said .
Our mean temperatures are a lot warmer than the top half of the world , 20w50 oil in the engine will be its best friend .
Sometimes the liners on a Standard engine just fall out , it's a case of suck it and see.
 
I thought the same thing Charles, half the z's or Perkins I have rebuilt, only one, the MHF202, really needed the guides replaced... what a procedure eh? Since they are cast, they are shattered to bits, then new ones need to be pressed in carefully... you are not allowed any mistakes.
Super hard- but brittle cast iron, so yeah, they must indirectly wear the steel stems into an hourglass. So it seems the stems of the new valves- act? as if they were oversized, so that tighten things up by feel, not to specs... not free, but there's the second half of a lifetime. I don't think PCP needs to fret this one...
 

The bearings are no longer available for that water pump. If you can't revive them, the only solution is a new water pump (the replacements have different bearings).
 
Update on tea20.

Went to remove cylinder 3 sleeve on the weekend. Totally stripped the 1/2 inch bolt thread of my home made puller. theres that idea out the window!

Borrowed a metal wacker to knock out sleeves from the bottom and even used a jack on the wacker to lift out sleeve, it simply lifted the front of the tractor off the ground. Theres that idea out the window!!

Could not budge this sucker, it ended up cracking, so smashing it out, was the only option left.
I managed to get the top half removed with chisel and screwdriver. Back in there soon to remove the rest. There was some crud/ rust in there, suppose to be expected after 60 odd years...

Here's hoping the seat is OK... fun and games!!
 
Hi.

finally removed this stubborn sleeve with lots of banging. Here are pics of the sleeve seat, ( view is from the top looking down into the cylinder bore)

I am wondering if the seat is ok, there are a few bumps as you can see in the photos, at about 9 and 11 am.

I have read that you should not use copper sealant with these, will the new copper gaskets?? for the sleeves fill any imperfections between the sleeve and the seat.
 

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