My 1970 V8 has had an intermittent misfiring problem which is making the car undriveable. If I go for a drive, within seconds it will misfire. If I rerun home, and allow it to idle of a couple of minutes it clears and revs from idle very smoothly until I take it down the road again. When the misfire occurs, it is affecting cylinder 4 and 6. The usual hot and cold compression test has been done, mixture check, ignition checks done etc. The engine has recently had a top end rebuilt and was running a treat until yesterday. I decided to remove the carb that feeds the even numbered cylinders this morning to check that all was well. I peered down the hole in the inlet tower and saw a small pool of blue coolant in the bottom. The throttle butterfly on the carb also seems to have a few tiny coolant drops on it. Does this mean that there's an internal coolant leak on the manifold, causing my misfire? If so, is the manifold scrap? (I have a spare one). It's the original manifold with an 11/9/69 stamp on it.
Coolant in v8 inlet manifold
- Thread starter badrover
- Start date
Hmmm, there certainly shouldn't be coolant in an area that is designed only for fuel and air. It would certainly suggest that there is a leak within your manifold. It is good that you have a spare, as fitting that one will be the cure I suggest.
Ron.
Ron.
unstable load
Well-Known Member
It certainly sounds like your manifold has failed, first time I hear of that happening.
)
classicalgreen
Active Member
hopefully your misfire will get corrected soon. sounds as though a definite coolant leak but unless bad? ought not to interfere with cylinder firing though water spray ? can cause plug misfire. especially when cold engine.
mine always runs lumpy /misfiring when stone cold but pithing 2 mins starts to behave and ideals Ok when warm. having checked compressions wet and dry. new leads .plugs full electronic dizzy .timing .carb rebuild etc. no improvement until I added fuel 'improvement' pellets as advertised. now car starts on choke first time within seconds and runs lumpy but no heavy misfires . checked engine and it has the 9:25 ratio. not 10:1 . and has a four star emblem on. rear window. ( presumably can use unleaded) still oen does hope your problems get resolved and you can enjoy car for next summer.
mine always runs lumpy /misfiring when stone cold but pithing 2 mins starts to behave and ideals Ok when warm. having checked compressions wet and dry. new leads .plugs full electronic dizzy .timing .carb rebuild etc. no improvement until I added fuel 'improvement' pellets as advertised. now car starts on choke first time within seconds and runs lumpy but no heavy misfires . checked engine and it has the 9:25 ratio. not 10:1 . and has a four star emblem on. rear window. ( presumably can use unleaded) still oen does hope your problems get resolved and you can enjoy car for next summer.
I can't really see how the mating faces or a failed gasket can allow water into the manifold at 4 & 6? That's got to be a cracked manifold, possibly around the tower area somewhere, especially as the butterfly seems to have some water on it.
Richard