Valve adjustment in 740

I bought a 1991 740 wagon back in December.
It now has about 170K.
It is a good idea to have the valve clearance checked? Do any of you ever
see much variation in valve clearance at this mileage.
My mechanic(Volvo trained)seems to be of the opinion that they don't often
get out of adjustment and doesn't speak about it as being a good maintenance
item.
Any thought shall be appreciated.
The car runs well except for the problem I've stated in earlier post.
Doesn't use oil.
Thanks,
James

 

Only if the engine has started to sound "tappetty".

All the best, Peter.

700/900/90 Register Keeper,
Volvo Owners Club (UK).

 

As fate would have it, I am familiar with this.

Bought a '91 740 last year for the wife, about 165K.

There was a little valve tapping noise.

I checked all the valves, they were in spec except for one, which was
way out.

I corrected it using a different sized valve shim, it quieted right
down and has been a great car.

No idea what caused just one to go out of spec, but it is an
interesting DIY.

You'll need a special tool to compress the valvetrain, a feeler gauge,
and a selection of different sized shims.

There is math involved.

 

After 240K miles our '85 has never been adjusted.

Mike

 

My experience has been that the valves that wear lose about .05 mm
clearance per 90K miles. As the mating faces of the valve and the valve
seat wear the valve clearance decreases as the valve recesses deeper
into the head. If you hear a clackety sound then the valves are either
set way too loose or the rubber cushion that sits between the valve stem
and the bottom side of the tappet (bucket) has finally hardened and
broken away.

The factory service manual calls for checking valve clearances every 30K
miles and adjusting as necessary. Since the shims come metrically sized
you should measure the clearances and the shims with metric tools. The
checking spec is .30-.40 mm. I usually set them to .40mm cold.

Bob

 

It's the QUIET valves you need to worry about... those are the tight ones,
from Valve seat wear... and those are the ones that will burn.. and then,
engine damage.

loud valves are better than "hey... that's super super super quiet"... with
a burbling sound out the exhaust

 

Quiet valves are what you need to worry about. If a valve seat wears enough
to make the valve tight, well, then you've got issues. It will get too
tight and burn the exhaust valve.

I'd at least check them. It's easy, and the shims are readily available
everywhere... I've got a Fiat, and they're the same ones!!! (same with
Ferrari 2V 308s

 

for those running propane: Fiat do thinner shims than Volvo. Vauxhall
shims fitt too