Volvo RWD 120-130 Forum

INDEX FOR 10/2025(CURRENT) INDEX FOR 4/2010 120-130 INDEX

[<<]  [>>]


THREADED THREADED EXPANDED FLAT PRINT ALL
MESSAGES IN THIS THREAD




  REPLY TO THIS MESSAGE    PRINT   SAVE 

Valve Spring Caps & Fine Sounding engine 120-130 1968

Since swapping heads and adjusting my valves using the "rock" technique, my engine has begin to sound like a quiet well-oiled sewing machine.

The idle is so smooth I can hardly believe it, and after my initial test-drive with the initially noisy replacement M40, the car seems to have settled down to a nice smooth purr on the road. The car starts up easily and shuts off without a hint of the dieseling I had previously experienced.

I'm hoping this will lead to a drastic improvement in fuel economy. I fueled up this morning, so we'll just wait and see (the last tank was again 13 mpg).

So... I know from my experience putting a B20E into my 67 wagon, that the little black plastic disk-caps on the top of the valves is not necessary. I noted that a few were missing when I put my original (but once-rebuilt) B18B cylinder head onto my 1968 B18B engine block.

After my commute today I found some oil leaking out from under the valve cover. I removed my valve cover and cleaned/scrapped the surface and re-glued my nitrile rubber valve cover gasket.

During clear up I found broken pieces of at least two of those bakelite-like caps lying on the top of the head. They were not there before, and I'm missing about four total now.

The engine still runs smoothly and I think I retrieved all the pieces, but these things breaking has me a little concerned.

Why did they break? Valve lash is still in spec, nothing else loose in there. Is this common or "normal"?

Should I remove the other caps? Seems like a bit of a hazard if I'm risking bits of black plastic circulating in my oil...













  REPLY TO THIS MESSAGE    PRINT   SAVE 

Valve Seals! 120-130 1968

RJ;

I'm happy to hear things are running well for you...

Those "black plastic disk-caps on the top of the valves" are actually the B18 style umbrella "valve seals" (which are known for not doing much in the way of sealing)...they are originally or pliable rubber (see any new B18 upper end gasket kit), pop into place in the last groove on the valve, and what they are know for is turning hard, often breaking into multiple pieces, and lying around on top of the head (where they perform the function of sealing what gets sucked down between the stems and guides about as well as they did before). Don't worry about them too much, just pop on some new ones...or not...if your guides are snug, there's not much getting past them anyway...

Cheers








  REPLY TO THIS MESSAGE    PRINT   SAVE 

B18 Valve Seals! 120-130 1968

If this is really an E (or F) head, then these valve stem seals are wrong - I don't even know if there is a top groove in the valve stem for these seals. E and F heads have valve seals which go under the retainer around the valve stem and on the top of the guide. Maybe it ain't an E head (can you see seals down inside the spring?) Or maybe some previous owner put the B18 seals on not knowing any better.








  REPLY TO THIS MESSAGE Replies to this message will be emailed.    PRINT   SAVE 

B18 Valve Seals! 120-130 1968

The B18 seals are 1/32" too big for B20 valves, which have 5/16" stems.
They wouldn't stay on anyway!
--
George Downs, Bartlesville, Heart of the USA!








  REPLY TO THIS MESSAGE    PRINT   SAVE 

This is a stock B18B 120-130 1968

Sorry this seems to cause so much confusion, but here's my engine and car breakdown.

1967 122S Wagon (220)
Had a rebuilt B18B with 500k miles when it was sold to me in Summer 2005. The distributor gear sheared and a ring snapped back in November 2006. I replaced it with a 1971 B20E/M41J combo from JohnMC's old 1800E. The B20E has plugged injector ports and carbs, but is otherwise stock.

1968 122S Sedan (130)
The *original* B18B died from oil starvation in 198x. It was replaced with another 1968 B18B and put in a barn for 20+ years by the original owner. Sold to me in Summer 2007


I put the 1967 Wagon's original B18B head on my 1968 Sedan's replacement B18B engine block. In retrospect this was probably not needed since poor valve adjustment seems to have been the problem all along.

To really add to the confusion, the 1968 Sedan's *original* B18B head was rebuilt before the original owner found another whole B18B replacement engine. So... I have the car's original cylinder head, which could be reinstalled if I find that my 1967-B18B Cylinder head has problems...

So, no B18/B20 parts mixing. I have had some rebuild experience with a B20E and a little with a B18B now.

The B20 lack the top seals, while the B18s have them... until they break up.









  REPLY TO THIS MESSAGE    PRINT   SAVE 

This is a stock B18B 120-130 1968

"The B20 lack the top seals, while the B18s have them... until they break up."

The mushroom caps fitted to the B18 only, are supposed to stop oil pooling around the collets. From there the oil drains down the valve stem and can get sucked down the valve guide by the inlet vacuum. The build up of that black crust behind the inlet valve head is due to this. Quick and easy to fit new ones.
The B20 has oil seals fitted to the top of the inlet valve guides. Volvo were trying to get up to date a bit here. The B20 valve guide is quite a bit shorter than the B18 one so a little wear can allow the valve to move sideways easier than with the same amount of wear in the B18. The extra valve stem wobble can allow the oil to pass the seal easier. These old seals harden and then break up. I believe there are some Ford seals with a better spec, silicone rubber I think and maybe with a spring around the top which can be fitted. The longer B18 guides can be grooved to allow fitment of these seals too.







<< < > >>



©Jarrod Stenberg 1997-2022. All material except where indicated.


All participants agree to these terms.

Brickboard.com is not affiliated with nor sponsored by AB Volvo, Volvo Car Corporation, Volvo Cars of North America, Inc. or Ford Motor Company. Brickboard.com is a Volvo owner/enthusiast site, similar to a club, and does not intend to pose as an official Volvo site. The official Volvo site can be found here.