Hi,

the starter bracket finally arrived, so now I need the bolt to bolt it to the block. It seemed to be an 8mm bolt, so I got one, but the diameter seems to be a bit too large.

I have the same problem with the bolts for the flywheel cover on the 700R4. I`m missing some, but 10x1.25x30mm and 10x1.50x30mm don`t seem to fit. The diameter seems to be fine, but I can`t tell if it`s the right thread, or if I need standard bolts.

The problem is I`m used to the metric system. Metric bolts usually have all the same threads (1.25mm afaik) --- and nobody cares about it because if you get a bolt with the right diameter, it will just fit. Now I can get metric bolts here with 1.00, 1.25 and 1.50mm thread, and I can`t tell what kind of thread I have by looking at it.

All this makes it very difficult to find a bolt that would fit. I could try like 20 different bolts before I might find the right one. Is there some kind of system with standard bolts that would allow you to easily tell if, for example, a 9/16 bolt has a larger or smaller diameter than a 5/8 one? Are there particular fractions of inches that are usually used, like 9/16, 5/8, 3/4, 1/2 so that I could just memorize them in ascending or descending order? How do I know if I need a standard bolt or a metric one?

And does anyone know what size bolts I need for the starter bracket and for the flywheel cover?

Is there some kind of system with standard bolts that would allow you to easily tell if, for example, a 9/16 bolt has a larger or smaller diameter than a 5/8 one? Are there particular fractions of inches that are usually used, like 9/16, 5/8, 3/4, 1/2 so that I could just memorize them in ascending or descending order? How do I know if I need a standard bolt or a metric one?



uh, common standard sizes are by the sixteenth of an inch. 5/8 = 10/16, so it follows that a 5/8" anything, nut, bolt, widget,etc. is larger than a 9/16" whatever, by exactly one sixteenth of an inch.

however, you may find yourself getting into 32nds of an inch, or 64ths. although i seriously doubt it for this particular application.

there are different threads, also. coarse, fine, automotive, even a type called 'acme'

Hi,

the starter bracket finally arrived, so now I need the bolt to bolt it to the block. It seemed to be an 8mm bolt, so I got one, but the diameter seems to be a bit too large.

I have the same problem with the bolts for the flywheel cover on the 700R4. I`m missing some, but 10x1.25x30mm and 10x1.50x30mm don`t seem to fit. The diameter seems to be fine, but I can`t tell if it`s the right thread, or if I need standard bolts.

The problem is I`m used to the metric system. Metric bolts usually have all the same threads (1.25mm afaik) --- and nobody cares about it because if you get a bolt with the right diameter, it will just fit. Now I can get metric bolts here with 1.00, 1.25 and 1.50mm thread, and I can`t tell what kind of thread I have by looking at it.

All this makes it very difficult to find a bolt that would fit. I could try like 20 different bolts before I might find the right one. Is there some kind of system with standard bolts that would allow you to easily tell if, for example, a 9/16 bolt has a larger or smaller diameter than a 5/8 one? Are there particular fractions of inches that are usually used, like 9/16, 5/8, 3/4, 1/2 so that I could just memorize them in ascending or descending order? How do I know if I need a standard bolt or a metric one?

And does anyone know what size bolts I need for the starter bracket and for the flywheel cover?

american standard bolts go larger starting at 1/4 by 1/16. 1/4,5/16,/3/8,etc.the threads per inch dictate either fine or coarse.a 3/8-16 coarse bolt would be 3/8 in diameter and have 16 threads
per inch.a 3/8-24 fine thread bolt would be 3/8 in diameter and have 24 threads per inch.

metric bolts are a little different.the body diameter is measured in milimeters.examples are
10mm,12mm,14mm.coarse and fine are determined by thread pitch.m10x1.5 would be coarse thread and m10x1.25 would be fine thread.the 1.5 and the 1.25 is the distance between threads measured in millmeters.

as far as i know all the bolts on a 6.2 are metric except the bell housing mounting bolts.
any g.m.truck parts guys can supply you with the info for the size bolts you need.get the size and go to the hardware store.

hope this helps

the bracket to starter is m6x 1.25 x 15mm long. or 1/4" unc x 3/4"
bracket to block is m8 x 1.25x20mm long.

Hope this helps

Thanks a lot for the info! I`ll try to get these bolts tomorrow.

And yes, almost all bolts/threads are metric. It`s the exceptions like the bellhousing, (front) shock mounts and grease nipples that make you wonder what you might need when you don`t know.

Oh, and I`ll make a list of standard bolt sizes, like you said in increments of 1/16. That`ll make it easier :)


Hm, does this sound about right?

1/4, 5/16, 3/8, 7/16, 1/2, 9/16, 5/8, 11/16, 3/4, 13/16, 7/8, 15/16, 1 inch? Looks really crazy, but makes sense.

Thanks a lot for the info! I`ll try to get these bolts tomorrow.

And yes, almost all bolts/threads are metric. It`s the exceptions like the bellhousing, (front) shock mounts and grease nipples that make you wonder what you might need when you don`t know.

Oh, and I`ll make a list of standard bolt sizes, like you said in increments of 1/16. That`ll make it easier :)


Hm, does this sound about right?

1/4, 5/16, 3/8, 7/16, 1/2, 9/16, 5/8, 11/16, 3/4, 13/16, 7/8, 15/16, 1 inch? Looks really crazy, but makes sense.

go to your local industrial supply house and ask for a decimal equilivant chart.this chart will give you all the fractions,decimals,letter drill size,number drill size,all american tap sizes and their correct drill size,also all the metric tap sizes and their tap drills.once you get the chart i can walk you through it.its good info.

Cool, I`ll look out for one :) Some sizes don`t seem to exist, like 7/16 --- or at least they didn`t have them.

Today, I finally got the bracket installed and also put in the missing bolts on the flywheel cover. This bracket has been a real blocker.

The bolts for the flywheel cover are 3/8x1", the bolt starter bracket to block is 8x1.25x20mm, and the nut for the bolt on the starter is not metric but standard, 1/4". That`s a cute mixture ;)

I installed it right away on the parking lot at home depot and had to go back in three or four times to get it all together, lol.

Cool, I`ll look out for one :) Some sizes don`t seem to exist, like 7/16 --- or at least they didn`t have them.

Today, I finally got the bracket installed and also put in the missing bolts on the flywheel cover. This bracket has been a real blocker.

The bolts for the flywheel cover are 3/8x1", the bolt starter bracket to block is 8x1.25x20mm, and the nut for the bolt on the starter is not metric but standard, 1/4". That`s a cute mixture ;)

I installed it right away on the parking lot at home depot and had to go back in three or four times to get it all together, lol.

go back 3 or 4 times.that sounds like me under a truck at the highway garage going back and forth to the tool box to find the the wrench or socket i thought was the right one!!!!!!!!!!!!!!!!!!

Sometimes you are better off with a whole store in reach ;) Besides the bolts and nuts, I actually decided to get a set of deep sockets and a 1/4" wrench since I didn`t have these and they were extremely useful for this.

It`s amazing though that metric sockets fit even on standard bolts most of the time: I got the set before I found out that the stud on the starter is standard :)

Sometimes you are better off with a whole store in reach ;) Besides the bolts and nuts, I actually decided to get a set of deep sockets and a 1/4" wrench since I didn`t have these and they were extremely useful for this.

It`s amazing though that metric sockets fit even on standard bolts most of the time: I got the set before I found out that the stud on the starter is standard :)Told you so,:eek: 6mm or 1/4"