Piston size
Posted: Mon Jul 05, 2021 9:50 pm
This is the top of my piston. I am reading this right that it is 10 thou???
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Re: Piston size
Posted: Mon Jul 05, 2021 11:18 pm
.001 would be one thou ????
Re: Piston size
Posted: Tue Jul 06, 2021 5:59 am
Hard to tell,
You would need to measure it with a set of vernier calipers.
Greg
You would need to measure it with a set of vernier calipers.
Greg
Re: Piston size
Posted: Tue Jul 06, 2021 7:24 am
Agree - vernier it.
The originals were stocked as standard, 1-thou oversized, 2-thou, 3-thou, 20-thou, 30-thou and 40-thou.
Cheers,
Harv
The originals were stocked as standard, 1-thou oversized, 2-thou, 3-thou, 20-thou, 30-thou and 40-thou.
Cheers,
Harv
Re: Piston size
Posted: Tue Jul 06, 2021 9:17 am
Ok thanks. This is the original engine out of my FJ. Just wondering if I should get it rebored or re-ring it.
Ive had the car 35 years and I have never rebored the motor so I would not be surprised if it is only 1thou
Thoughts
Jason
Ive had the car 35 years and I have never rebored the motor so I would not be surprised if it is only 1thou
Thoughts
Jason
Re: Piston size
Posted: Tue Jul 06, 2021 10:07 am
Jason,
The .001 here is the specified clearance between piston skirt and bore.
The oversize (if any) will be on the next couple of lines of text. I can just make out STD below. These are Repco (ACL) pistons, so the motor's already been rebored. My guess is that the pistons will be 3.0625", with an outside chance of 3.125". Measure across the bottom of the piston skirt.
Rob
The .001 here is the specified clearance between piston skirt and bore.
The oversize (if any) will be on the next couple of lines of text. I can just make out STD below. These are Repco (ACL) pistons, so the motor's already been rebored. My guess is that the pistons will be 3.0625", with an outside chance of 3.125". Measure across the bottom of the piston skirt.
Rob
Re: Piston size
Posted: Tue Jul 06, 2021 3:09 pm
I think it read 3 or 2 075 STD If that makes more sense
Re: Piston size
Posted: Tue Jul 06, 2021 3:15 pm
A quick measure with some calipers??
Re: Piston size
Posted: Tue Jul 06, 2021 5:33 pm
3" + two small divisions + about half a small division (vernier scale is affected by camera parallax), which is
3.000 + 0.050 + 0.0125 = 3.0625". This is standard bore size for a 138 grey.
The Repco part number for the pistons is RA2075.
How good are your gudgeon pins? Can you rock the big end back and forth (not side-to-side) at all? If there's any perceptible play, it's best to get new piston pins (Nornda aka JP in Adelaide), new small-end bushes, and have the bushes replaced and reamed to size.
Rob
3.000 + 0.050 + 0.0125 = 3.0625". This is standard bore size for a 138 grey.
The Repco part number for the pistons is RA2075.
How good are your gudgeon pins? Can you rock the big end back and forth (not side-to-side) at all? If there's any perceptible play, it's best to get new piston pins (Nornda aka JP in Adelaide), new small-end bushes, and have the bushes replaced and reamed to size.
Rob