jeff alder
Well-Known Member
I remember that hero. Your class was right next to my underwater welding clinicals and we kept catching your baskets on fire. Who was the genius behind that classroom arrangement?
273 Cylinder Bore .004 over spec
- Thread starter Bossanova5
- Start date
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Yes, we grew up poor. We would take a good, well taken care of engine and build a "throw together" engine, usually under .005 wear, clean up the block. Torque the mains to spec. Torque a honing plate with a used head gasket onto the block, and hone the cylinders till it would just start to "scratch? the wear at the top of the bore. Next file fit and stone the ring ends on a set of Speed Pro +.005 file to fit rings. New rod and main bearings, rod bolts, high pressure oil pump spring, windage tray, brass freeze plugs, cam, lifters, valve springs, double roller timing set, exhaust valves, gaskets and seals. Mill the heads, tighten up the exhaust guides and do a good valve job. As a matter of fact, that was the 383 engine in my 68 Formula S Barracuda. I did in the late 70's or early 80's. It came out of a 72 Newport along with the 727 transmission and 3.23 sure grip gear set from a Highway Patrol car. I'm just pulling it to put the original block back in this year. So what do you think is the problem? I can tell you it ran great, used very little oil and got good mpg for over 100,000 miles. How much money do you think I had in it?
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Scody21
Just send it
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Cus most here have not done it and don’t understand what it does. I’m not saying we send out every set of pistons.
Yup. I know if I could get people to understand what THAT coating does because EVERY piston should be coated with Line2Line.
Even new pistons benefit from THAT coating.
Jeremiah (jd)
Well-Known Member
Time out!
Lol
#1
What tool did we use to measure the bore?
Lol
#1
What tool did we use to measure the bore?
TT5.9mag
Two atmospheres are better than one
Post 39
Jeremiah (jd)
Well-Known Member
Ty sir : D
Jeremiah (jd)
Well-Known Member
The cylinder needs to be measured with a dial bore gauge using some type of setup fixture (anvil mic). Otherwise take it to a shop and have them measure it.
Shars makes an affordable (< $200) 19" dial bore gauge in .0005 resolution if a guy was interested in expandin his tool collection.
That said, if the holes are too big it will have to go to a machine shop anyway.
Shars makes an affordable (< $200) 19" dial bore gauge in .0005 resolution if a guy was interested in expandin his tool collection.
That said, if the holes are too big it will have to go to a machine shop anyway.
TT5.9mag
Two atmospheres are better than one
I don’t think there is any problem with throwing stuff together. I’ve done it. I’m saying in that case don’t measure anything because you aren’t going to fix what measuring tells you is wrong anyway. There seems to be a misunderstanding as well with regards to his numbers. He is .004 over the MAXIMUM allowable standard bore size. Now if he puts it together with new rings and the same pistons (without coating) it will be loose as a goose. I’ll say it again, it needs to go to the machine shop.
TT5.9mag
Two atmospheres are better than one
He seems to have made the decision NOT to go to the machine shop before measuring anything. And in my mind, measuring everything tells you wether or not you need to go to the machine shop.
Jeremiah (jd)
Well-Known Member
To each his own. Time to move on
I rebuilt a 360 that had 0.008" cylinder wear and it ran fine and didn't burn oil. I thought it was a bit much but after looking in the service manual as pointed out in post 52, I decided to send it and haven't had any problems. Back in my younger days still in high school, my brother was going to the local Community College for auto mechanic and they needed a block to do some training on the boring machine. I had bought a worn out 340 block and let him take it to the class who did a 0.020" overbore on it. I got it back home and put standard pistons in it with 0.020" over rings and it ran like a scalded dog. It just had a little piston skirt slap when you let off it. I don't remember it burning oil. It didn't smoke. I ran it hard for a couple of years until I couldn't stand that stock cam and was in better financial condition and decided to redo the whole engine going to 0.030" with new pistons and the works and of course a big cam.
Bossanova5
Well-Known Member
Measured the ring gap today on one of the cylinders.
Original ring gap was close to .085" (Bottom ring in picture)
New Chrysler OEM ring gap was .031 (Top ring at picture)
Manual allows .020" maximum ring gap.
Off too the machine shop for new pistons and a bore job.....
Original ring gap was close to .085" (Bottom ring in picture)
New Chrysler OEM ring gap was .031 (Top ring at picture)
Manual allows .020" maximum ring gap.
Off too the machine shop for new pistons and a bore job.....
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