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Virtual Wrench
Virtual Wrench, Master Mechanic
Category: Car
Satisfied Customers: 14620
Experience:  35 years/Master Tech. Foreign and Domestic
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92 mazda miata: my water pump and timing belt..started right

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I just changed my water pump and timing belt on my 92 mazda miata. I marked everything and lined it all up, i started it up and it started right away but there is a terribly loud knocking sound that was not there before. What did I do wrong??


I'll try to help ya out,

Did the belt break while the engine was running?


Customer: replied 9 years ago.
no i needed a new water pump and since the belt had to come off and the car has 123,000 miles on it i changed it anyway


Do you think that maybe the timing marks may be off?

If so, i can shoot ya the alignment for them...

Customer: replied 9 years ago.
yes, but i put a compression tester on the number 1 to make sure that it was on the compression stroke when the timing marks lined up and the bottom v mark was straight up so i am not sure if or which one could be wrong. i had marked the old belt and then the new one and put it on the same was as the other, however, the cams moved slightly as i was putting it on cuz i had two cresent wrenches clamped together to hold everything in place and like i said it moved slightly, is that enough to throw the whole thing off?

Thanks for the details,,,

Yes,,if one or two cog's are "off" it will throw the timing way off...

Here is the procedure from our service manual,,,if you need more just holler..



Let me know if you need more info bro,,,

Virtual Wrench and 2 other Car Specialists are ready to help you
Customer: replied 9 years ago.
ok that is the way it looks now, and when i rotate it they line up again. i read somewhere that the tension spring could be causing the knock. what i really need to know is if it is knocking that loud is it going to kill the engine to drive it somewhere to have someone else look at it? the engine is a non interference engine so could i really wreck it?
Customer: replied 9 years ago.
i will accept your answer even though i already knew that stuff if you answer the one i just asked. can i wreck a non interence engine by driving it with a knock that sounds like i threw a rod?

I hear ya,,the knock can be of other reasons,

The 1.6 is a non-interferance vavle/piston relationship, but,,,,it depends upon the lower end relationship that creates the combustion,,,,so if the valves are not seating "completly" the cylinder wont seal completly.

A simple cylinder leak down test will confirm this. Its a matter of injecting air into a specified cylinder, while piston is at TDC and oth valves are closed,,,,if air escapes from the tail pipe,,,,an exaust valve is leaking,,,,if air is heard escaping from the intake manifold,,,an intake valve is leaking,,,

Most shops will charge you about $50 for a "cylinder leak down test".

This is the most accurate test that can be done,,,trust me..

If you have a compression gauge to where you can give me exact readings of each cylinder,,,,,we can REALLY narrow this down.

Let me know..

Thats cool,,ya ggot ahead of

You cant wreck a non interferance engine by driving it...providing rpm's wer not excesive :-) i have run those up to 9000 rpm's,,,,

Probably has a lower end issue,,,with the knock,,,,

If you need more info,,just give me a shout!


Customer: replied 9 years ago.
okay the thing is the car was running great. it was just the water pump was leaking and so it needed to be changed. i changed it and then the timing belt. there was no knock or anything wrong with the engine until i put it back together, so i guess what i really am wondering is what the knock really is and could i have bent a valve or done some really bad damage to that engine by the timing belt being off one tooth? it started right up. and lastly how the he?? can you tell if it is timed right. i have a light. will it mess it up to start it long enough to check it. and what do you move since there is no distributor if the timing comes up wrong? is the timing supposed to be right at tdc or is it 10 btdc. sorry to be such a pain, but someone gave me the car and i really like it and it was running great till i did the water pump. thanks
Customer: replied 9 years ago.
sorry i just read your answer. okay i will take it across the street the guys there can look at it. i thought i would save money by doing the pump myself. oh well. thanks again.
Your welcome, thanks for asking!