Bent valve remove and replace

I have inherited a 1989 240 station wagon with a bent valve. I would
not hesitate to have it fixed professionally if the underbody was not
rusted out from too many upstate NY winters. Two questions: 1.) Can
anyone suggest a test for what is 'too rusted'? 2.) What, besides
removing the head, which I am pretty sure that I could do, would be
involved in replacing a bent valve. I have removed and replaced a
head on a Triumph TR3a so the R and R I am pretty confident about. I
have not replaced a bent valve. Is it pointless to remove a head to
replace one bent valve? I see that gasket kits cost about $50 which
would be worth the experience of doing the job from my point of view
as I have another fine running 240 of the same vintage and plan to
have other 240/740's in the future. I just don't think I would want
to spend much more than that because of the amount of rust on the car.

All thoughts most appreciated.

Thanks very much,
Jim Lee

1989 240 Wagon
1988 240 sedan

 

LOL Jim
Being from Upstate NY myself , if your not falling thru the
floor there then its not to much.
if the fuel tank is falling off or the fuel pump and lines
(fuel&brake) arn't rusting away you should be fine.
As far as the bent valve, you should remove the head first and see if
that is the problem. it could just require a replacement valve and
lapping compond.

I would suggest removing the head yourself but sending it to a machine
shop to be checked for cracks and warpness.

All this can be fixed for less then a few hundread and being a wagon
(wish mine was) is more then worth fixing.

good luck with it

 

How did you bend a valve in a 240? I've replaced a few broken timing
belts on those and never ran into a bent valve, practical experience
says they're non-interference engines. You could have a burned valve
though or some other problem.

Pull the head, that's all you can do. There isn't any shortcut to it,
and it's not a particularly difficult job. As far as modern engines go,
the B230 is one of the simplest to work on I've encountered. Replace all
the seals while you've got the head off and inspect the rest of the valves.

As for rust, any rusted out parts in the unibody are deal breakers for
me, but then about the only time we see rusted cars here in the
northwest is when they've been brought in from some place where they use
that awful salt on the roads.

 

Over rev it, maybe..? have to wind it pretty tight to float a valve and
tag a piston. I'm not sure the old B23 can even breath well enough to
rev that high.

Seals and inspection for sure. Doing all the valves (valve job) might
seem like a good idea once you have the head off but fresh valves over
old rings can be a bad thing. Valves and rings are good for several
hundred thousand miles and get along better when they grow old together.
A nice tight head and old rings could cause blow by, pressurize the
block and push out the seals.
....or not.
ymmv.

 

The B21/23/230 can rev pretty high. Back before I installed Megasquirt
(which has a rev limiter) on my 240T, I once looked down to see the tach
needle coming down from up past 7K somewhere, I'd been watching the
boost gauge and not the tach, then the wheel spun and it revved way past
where I meant to. Still no damage though.

 

And we know this because . . .?

What - someone said so when he gave you the car?

Start with a simple compression check. If you have little or no
compression on a cylinder, then you know you need to investigate
further.

If the body's too rusted to repair, at least you'll know if you have
parts to offer for sale.

 

I do not know for sure that the problem is a bent valve. That is what
a pro mechanic who knows Volvos said after hearing it. Your point is
well taken though. I will never know for sure what is going on until
I pull the head. Which I have decided to do since at the very least
it will be a good learning experience I have removed and replaced a
head before but it was on a 1959 Triumph TR3a which is about as simple
as you get.

The car was being driven by my brother and this problem happened
without any unusual circumstance that he knows of. It was running
great one moment and then the next it was running really rough.
The only symptom other than running rough (I believe the mechanice did
a compression test and the #2 cylinder had little or no compression)
was a distinct metallic sound in the enigne. He was able to get home
with it. I was able to drive the short distance to my mechanics but
it was not fun. Sounded like crap with the sharp metallic sound in
sync with the rpm.

So it sounds like it is possible to
1 - Remove the head.
2 - See what is really going on.
3 - Replace whatever mechanical parts need replacing
4 - putting the head back on with a new gasket set.

So it is possible it could be just the cost of the head gasket set
(about $50) and a valve or whatever is messed up?
When the mechanic said it was not worth fixing because of the rust he
was assuming that he would be doing the work and one thing leads to
another when you remove a head and my cost would quickly exceed the
value of the car. I has about 190k miles.

Are there any online guides to removing and replacing the head on this
car or one similiar. I have three Volvo manuals but I am wanting to
get all the help that I can.

Thanks very much,
Jim Lee

 

There's a number of other possibilities, bent valve, burned valve,
broken valve, burned or cracked piston, or a broken connecting rod,
though the last one will usually have much more severe consequences.
Pull the head off and see what you have to work with, only then can you
really determine what parts you need or if the job is worth doing.

I recommend picking up either a Haynes or Bentley manual, the latter is
much better, but also more expensive and either will be adequate for
this job. Taking it apart is easy, putting it back together is where
some more information is handy.

In a nutshell, going from memory:

Disconnect the negative battery cable (I've found out the hard way why
this is a wise thing to do)

Drain the oil

Drain the coolant

Remove the accessory belts

Remove the timing belt cover

Remove the crank pulley

Remove the timing belt

Remove the timing belt pulley

Remove intake plumbing and disconnect wiring from intake manifold

Remove intake manifold, you can set it aside with the fuel system still
intact if you choose

Disconnect wiring from head mounted coolant sensor(s)

Remove exhaust manifold nuts, heat from a torch and P'Blaster soak is
helpful, be really careful to avoid snapping off studs, if you break any
of those, you've got another project but at least with the head off
that's the time to do it.

Pull the exhaust manifold to the side or unbolt it from the downpipe and
remove it entirely

Remove the valve cover

Remove the head bolts

Lift off the head and survey the damage

Report back here and let us know what you found

 

A bent valve is simple to diagnose. Pull the valve cover and check the
valve clearances. The bent one(s) will have excessive lash. That's where
all the rattling comes from.

 

The T does breathe better than the normally aspirated ones. *g*
An ohc four banger valve train will spin 7 grand all day long. Probably
need 9-10k to get the valves to float enough to bang a piston.
I used to race a hydroplane that ran a stock 2L Ford Pinto (122 c.i.
German block.) At speed the motor is pretty much freewheeling, turning
7200-7400... higher when the prop unhooks on a bump.
Now, if the OP has a busted valve spring..? Don't know what the failure
rate is for springs on the B motor. I'm guessing they're as bullet proof
as the rest of the motor. A flat cam lobe will make lots of racket too.
Probably another thing that never happens on a Volvo, that bullet proof
thing again...
The Pinto used to eat cams.

 

Well all this stuff is very uncommon, but even the rare faults do happen
once in a while.

 

I have both the Haynes and the Bentley manuals but I am confused here:

Exhaust manilfold was not a problem at all. Intake side is puzzling
me. I will be removing the intake manifold and leaving it right? Why
do I disconnect the wiring from the intake manifold then?
I have all 8 nuts off the intake manifold and there was one extra one
hiding down low attached to some sort of support bracket. I still
cannot detach the intake manifold. There is some nut somewhere that I
cannnot see that is keeping it attached to the head. Is there
another bracket with a stud or bolt attached that is hidden underneath
the intake stuff? I probably just need to see a parts diagram of the
intake manifold and see where all the attach points are.

Also, why do I have to remove the fan and both the crank and cam
pulleys? I could pull the head out with the cam shaft and cam pulley
still attached right?

Thanks very much,
Jim Lee

 

Well remember that I'm going by memory here. Intake manifold has the 8
bolts that hold it to the head, and the bracket that holds the idle
control motor, I don't recall anything else. Are you sure it's still
bolted or is it just stuck by the gasket?

The wiring runs down underneath and snakes off to other things. I
suppose you could probably get the manifold out of the way without
disconnecting it but it's a lot easier when you do. It's a good time to
inspect the harness while you're in there, if the car is pre-'89 and has
the original harness, it will need to be replaced or rebuilt because the
insulation will be crumbling off the wires down inside the sheath.

Yes you could get the head off without removing that stuff, the issue is
putting it back on. You will want to change the timing belt while you
have it apart unless the belt has been recently changed, in which case
you could get away without doing that. The tensioner is attached to the
head, just loosen the bolt in it so you can push it in and slip the belt
off.

 

I would verify that it is a bent valve or valve related before pulling
the head. A compression check would be a start and maybe a leakdown
test. Pull the valve cover and do a visual and a lash check. As
suggested, it could be just a broken or weak valve spring or similar,
or maybe just a broken valve shim and it might just need a valve
adjustment.. If the valve bent and did piston damage, it could be a
lot bigger of a job than just a valve job...

__ __
Randy & \ \/ /alerie's
\__/olvos
'90 245 Estate - '93 965 Estate
"Shelby" & "Kate"