Crankshaft woe
Discussion
I've had a MK1 VR-Ltd for about a month. It looks very tidy but judging by the state of the oil and lack of history I thought a service and cambelt was on the cards. The car went in to Freelance Mazda in Chatham today. They have reported that the keyway in the crank that locates the bottom pulley is badly worn and that someone has cobbled it up with Loctite. It runs OK bar a flat spot at 3,000 although I did mention that my sister's similar but scruffy 1.8 feels a bit sweeter to drive. Effectively the crankshaft is knackered and the timing is permanently retarded. A new one could be sourced but it would be cheaper to find a good used engine instead. I'll see them tomorrow and ask them to have a look at the back of their workshop! I'm going ahead with the cambelt anyway as I will continue to use the car until I come up with a plan.
If the engine is going in the bin if it can't be fixed have you thought of perhaps trying to bodge it with liquid metal? On that engine you don't need to remove the bottom pulley to change the cambelt so you'd never need to take the pulley off again anyway.
http://bbs.zuwharrie.com/content?topic=15988.0
http://forum.miata.net/vb/showpost.php?p=1185173&a...
http://bbs.zuwharrie.com/content?topic=15988.0
http://forum.miata.net/vb/showpost.php?p=1185173&a...
Got told my car should be slow (despite my protests that it wasn't) and that the engine was fit for the bin by Freelance.They also confused it with a short nose crank instead of the big nose that it is.As the car was cheap, I got my mates friend at his garage to do my cam belt and weld the pulley.Here I am, almost two years and numerous hard runs down the line later and the car is just as quick as it was when Freelance wanted £1000 of my hard earned.
They were correct that some of the fixes may not last though, hence they don't venture into those realms, but if your car was cheap to start with, what have you got to lose?
I did a lot of research re: the short and big nose pulley wobble issues and the end result was that if you have a big nose (8 slots in pulley), the chances are that any wobble will be down to poor maintenance and crank wear could be minimal.Short noses on the other hand can be a mixture of poor maintenance and bad design and if you are talking flat spots and pulley wobble on those, it may never have that zoom-zoom again regardless of what you do.
They were correct that some of the fixes may not last though, hence they don't venture into those realms, but if your car was cheap to start with, what have you got to lose?
I did a lot of research re: the short and big nose pulley wobble issues and the end result was that if you have a big nose (8 slots in pulley), the chances are that any wobble will be down to poor maintenance and crank wear could be minimal.Short noses on the other hand can be a mixture of poor maintenance and bad design and if you are talking flat spots and pulley wobble on those, it may never have that zoom-zoom again regardless of what you do.
I got a competent professional to strip the whole pulley system down to the bare crank. Place a new key in the splayed keyway using the "good" edge of the slot as a datum and fill the gap with liquid metal. Fit a good used pulley then the next part which acts as the outer guide for the belt (also good used). Finally the pulley which drives the auxilliary items - the original one which looked as if it was wobbly but was being thrown out by the looseness of the other parts behind. Fit a new bolt with Loctite.
Almost a day of labour with difficulty of pulling the rusty pulley, cleaning and degreasing.
Got a new water pump at the same time.
Feels like a new car with instant throttle response and lots of power. I should have been more critical of the symptoms when I test drove the car and experienced a definite step in power delivery around 3,000rpm as well as lumps and bumps below that. I paid too much attention to the bodywork assuming the engines were bullet proof and that a "tune-up" would sort it out. The timing must have been retarded by five degrees or more. Beware!
Almost a day of labour with difficulty of pulling the rusty pulley, cleaning and degreasing.
Got a new water pump at the same time.
Feels like a new car with instant throttle response and lots of power. I should have been more critical of the symptoms when I test drove the car and experienced a definite step in power delivery around 3,000rpm as well as lumps and bumps below that. I paid too much attention to the bodywork assuming the engines were bullet proof and that a "tune-up" would sort it out. The timing must have been retarded by five degrees or more. Beware!
Good to hear you have it fixed now.
I hate stories like these where garages condemn parts.
Down here in Hants there is a place that laser weld, it truly is fantastic and can put minute welded metal of any kind, they can even lay hard tool steel on aluminium!
I am a toolmaker and I have used them to repair complex gear shafts.
There is nothing wrong with good welding, it is the pigeon droppings that many garages manage that is unaceptable.
I hate stories like these where garages condemn parts.
Down here in Hants there is a place that laser weld, it truly is fantastic and can put minute welded metal of any kind, they can even lay hard tool steel on aluminium!
I am a toolmaker and I have used them to repair complex gear shafts.
There is nothing wrong with good welding, it is the pigeon droppings that many garages manage that is unaceptable.
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