This is topic Transmission bolt size, thread and length in forum Spec Miata Garage at Spec Miata Community.


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Posted by Gibscreen (Member # 2390) on :
 
Can anyone confirm that the thread size is M12x1.5?

Anyone have lengths for both the long and short bolts?

Thanks in advance.

The reason behind this question is the last few tranny bolts I got from MazdaComp all seem much more prone to stretching than the original bolts on the car (even when torquing to the lower end of the spec, and its not my torque wrench). So I'm going to get some Class 8.8 and 10.9 from McMaster to see if they work better.

Anyone else experience this with the newer bolts?
 
Posted by Qik Nip (Member # 1474) on :
 
Rob:
I've had the transmissions out of my 1.6 at least five times and I've never had a loose bolt, or a distorted thread. (Alternativly, I've never replaced the circa 1990 fasteners either.)

Are you saying that you are seeing stretched bolts? Given thier cross section mass and torque values, that seems very odd.
Rick
 
Posted by tony senese (Member # 3677) on :
 
You bought new bolts..... wow!

Seriously, I would give you dimensions, but I would have to take the bolts out and I have never had a loose bolt on the tranny, and I would say my torque wrench IS likely wrong!

Have you considered a junkyard tranny/motor?
 
Posted by Gibscreen (Member # 2390) on :
 
quote:
Originally posted by Qik Nip:
Rob:
I've had the transmissions out of my 1.6 at least five times and I've never had a loose bolt, or a distorted thread. (Alternativly, I've never replaced the circa 1990 fasteners either.)

Are you saying that you are seeing stretched bolts? Given thier cross section mass and torque values, that seems very odd.
Rick

The original bolts haven't stretched, but some of the new bolts have. So I'm not surprised that your original bolts haven't stretched.