99 TURBO EXHAUST VALVES

[BIRDIEMANGO]

HELLO CHAPS,

JUST A QUERY FOR A SUNDAY MORNING.....

I HAVE ANOTHER 99T 2DR AT THE MOMENT WHICH WAS RUNNING ON THREE CYLINDERS....COMPRESSION TEST REVEALED NO.3 WAS ''NO COMPRESSION'',SO I STRIPPED DOWN THE CYLINDER HEAD YESTERDAY,EXPECTING A BURNED OUT EXHAUST VALVE....

YES,INDEED....THE EXHAUST VALVE WAS THE CULPRIT

SO,ON REMOVAL THE PART NUMBER ON THE BURNT VALVE WAS 836440

I DELVED INTO THE DEPTHS OF MY OTHER 1978 3DR TURBO ,WHERE THE ENGINE IS IN BITS IN THE BOOT(AND HAS BEEN FOR TWENTY YEARS!) AND RETRIEVED AN EXHAUST VALVE PART NUMBER 930735.....

BUT,ON COMPARISON.......THE HEAD OF THE VALVE 99T 3DR IS MUCH THICKER?POSSIBLY 2MM...

BOTH HAVE THE SMALL DOT IN THE CENTRE TO INDICATE SODIUM COOLED VALVES......

I THINK POSSIBLY THE EXHAUST VALVE SET HAS BEEN REPLACED AT SOME TIME ON THE 2DR 99T? BUT FROM WHAT ENGINE DOES THE PART NUMBER 836440 COME FROM?

DOES ANYBODY HAVE ACCESS TO VALVE PART NUMBER CATALOGUE?

BIRDIE

[DeLorean]

from what I was told, 80-81 900-T's may have the larger valves? It may be that sometime in the past, the car already burnt a valve and it was updated?

[BIRDIEMANGO]

OK,AN UPDATE.........

I TRAVELLED DOWN TO WALES ON SUNDAY FOR A COFFEE WITH A FELLOW SAAB 'ANORAK'......AND TOOK THE VALVES WITH ME TO SHOW HIM.

HE HAS OWNED(AMONGST OTHERS) HIS 3DR 1978 TURBO NEARLY FROM NEW...

IN 2007 HE REMOVED THE ORIGINAL CYLINDER TO RENEW THE HEAD GASKET(AS A PRECAUTION) BEFORE DRIVING ACROSS EUROPE TO TROLLHATTAN FOR THE SAAB 50TH ANNIVERSARY FESTIVAL.

ON REMOVAL,THE CYLINDER HEAD WAS FOUND TO BE CRACKED LEADING FROM ONE OF THE VALVE SEATS.

SO A REPLACEMENT HEAD WAS FITTED........

BUT,MORE IMPORTANTLY THE 'OLD ORIGINAL' HEAD WAS STILL IN A CUPBOARD IN THE GARAGE......

SO WE REMOVED ONE OF THE VALVES...

GUESS WHAT?

IT HAS FOUR EXHAUST VALVES PART NO. 836440

NOW,THIS IS A NEW ONE ON ME.......?

BUT IT APPEARS THAT EARLY SAAB 3 DOOR 99T HAD THESE VALVES FITTED(836440),MAYBE THEY UPGRADED,AND SUPERCEDED WITH PART NO. 930735 WHICH HAS A MUCH THICKER DEEPER HEAD VALVE DEPTH?

THE 2DR TURBO I AM WORKING ON,HAS DONE HIGH MILEAGE,AND THREE OTHER VALVES 836440 ,SO IT IS POSSIBLE THE HEAD HAS BEEN REPLACED AT SOME TIME WITH AN EARLIER ONE.......

ANYWAY,IT LOOKS LIKE I CAN GET IT BACK ON THE ROAD,FOR NOW........

HERE IS THE CAR THE DONOR VALVE HAS COME FROM........WITH THE OLD CRACKED CYLINDER HEAD.

INCIDENTALLY I CONTACTED ALL THE SAAB 'ANORAKS' I KNOW WITH MICROFICHE AND ORIGINAL SAAB WORKSHOP MANUALS....

836440 DOES NOT APPEAR TO BE LISTED IN ANY OF THEM,ONLY 930735.........

BIRDIE

[BIRDIEMANGO]

FOUND OUT SOME MORE INFO....

836440 SODIUM COOLED VALVES WERE FITTED TO 'EMS' MODELS AND EARLY 3DR TURBO'S....

SUBSEQUENTLY I THINK MAYBE? SAAB HAD ISSUES WITH THE VALVES 'BURNING OUT' ON EARLY TURBO MODELS,SO THE SUPERCEDED 930735 VALVES HAD A MUCH THICKER 'HEAD',(SEE PREVIOUS PHOTO)PRESUMABLY TO ABSORB MORE HEAT......?

EITHER WAY, IN MY EXPERIENCE SO FAR,RUNNING A 99 TURBO ON UNLEADED,WITHOUT ADDITIVES CAUSES THE EXHAUST VALVE TO RECEDE INTO THE SEATS,OVER MILEAGE....

SEVERAL 99T ENGINES THAT I HAVE RECENTLY CHECKED VALVE CLEARANCES ON THE 'EXHAUST' VALVES,HAVE ALL 'CLOSED UP' AND REQUIRE RE-SHIMMING.....?

BIRDIE

[Crazyswede]

FOUND OUT SOME MORE INFO....

836440 SODIUM COOLED VALVES WERE FITTED TO 'EMS' MODELS AND EARLY 3DR TURBO'S....

SUBSEQUENTLY I THINK MAYBE? SAAB HAD ISSUES WITH THE VALVES 'BURNING OUT' ON EARLY TURBO MODELS,SO THE SUPERCEDED 930735 VALVES HAD A MUCH THICKER 'HEAD',(SEE PREVIOUS PHOTO)PRESUMABLY TO ABSORB MORE HEAT......?

EITHER WAY, IN MY EXPERIENCE SO FAR,RUNNING A 99 TURBO ON UNLEADED,WITHOUT ADDITIVES CAUSES THE EXHAUST VALVE TO RECEDE INTO THE SEATS,OVER MILEAGE....

SEVERAL 99T ENGINES THAT I HAVE RECENTLY CHECKED VALVE CLEARANCES ON THE 'EXHAUST' VALVES,HAVE ALL 'CLOSED UP' AND REQUIRE RE-SHIMMING.....?

BIRDIE

its my experience that in general the exhaust valves on machines tighten up...likely due to the lack of cooling that the intake valves get.