Crankshaft problem....

[Life is Supra]

Hi there,I have a problem when I start engine there is a knocking sound in the bottom of the engine(I think it is a crankshaft failure because a pulley on the crankshaft have play or it is distorted)and that knocking sound last when I crank engine and stap on trottle,in neutral works fine.

[interested!]

Originally Posted by Life is Supra

Hi there,I have a problem when I start engine there is a knocking sound in the bottom of the engine(I think it is a crankshaft failure because a pulley on the crankshaft have play or it is distorted)and that knocking sound last when I crank engine and stap on trottle,in neutral works fine.

Hi! I posted a link about repairing this problem earlier this year in the MK3 FAQ. It is repairaible ! did mine 11 years ago -unbelieveablly parallel . .Put the car on ramps, basically, remove worn ( gone conical ) pulley and timing belt after setting crank to timing , file the crank to parallel using a spigotted tube as a guide -inner dimension to smallest crank diameter, Then ,make a sleeve to fit the crank ,not forgetting to set the timing mark THEN bore out pulley to fit seeve , all items to be a SLIDING FIT. Finally peg everything with a bolt shank through the pulley/sleeve/crank . this is to relieve shear on a damaged woodruff key/keyway . renew timing belt and crank seal as a minimum.

[Life is Supra]

Thanks a lot I hope we understand each other,by the way I must ask you can I drive it like that or must pull it to garage because I fear that can do some damage on the engine?

[interested!]

Originally Posted by Life is Supra

Thanks a lot I hope we understand each other,by the way I must ask you can I drive it like that or must pull it to garage because I fear that can do some damage on the engine?

Hi!, I would recommend repairing very soon , the longer it's left , the more the crank is being damaged by the " coning " action of a wobbling pulley. Create a tube and spigot , the tube inner diameter is the diameter of the crank at it's smallest , the spigot should be a sliding fit inside the CRANK thread and this is cut down as the crank is filed and the spigot bottoms out until the tube face reaches the timing belt gear. Check the face of gear and pulley for damage and replace the gear if any damage found .The spring is used to stop the tube jamming on the crank .

[cre]

If the shaft is fine and it's just the woodruff key and keyway that are damaged I'd recommend just getting the keyway and balancer cut for a slightly larger key. I don't know if welding is really something I'd care to try, I'd leave that question for a good machinist. I would be much more inclined to just replace the crankshaft than have it sleeved... a crank is very easy to find, especially from a GE Supra or Cressida.

[interested!]

Originally Posted by cre

If the shaft is fine and it's just the woodruff key and keyway that are damaged I'd recommend just getting the keyway and balancer cut for a slightly larger key. I don't know if welding is really something I'd care to try, I'd leave that question for a good machinist. I would be much more inclined to just replace the crankshaft than have it sleeved... a crank is very easy to find, especially from a GE Supra or Cressida.

Hi!, The pictures are of the tool I made to repair my crank in situ, My crank had coned by about 0.006 inch,the pulley was worse and had only been rattling for a week , the key was found at 45 degrees to vertical and the keyway looked more like a " D " than a slot. All done with some patience and a very small price. I did mine 11 years ago, still solid and true . Ensure the spigot is centralised in the tube as this is essential and weld that if required.