Almost time for the machinist!

[Dartfreak75]

Its almost that time I'm getting excited as my project progresses. I have never took anything to a machine shop or had any work done before I have talked to the machinist a couple times and he has been very helpful I have a couple of questions I don't want to keep bothering him lol.
1) does the cleaning process remove paint? Do I need to remove all the paint before I take it to him?
2) this is the biggie. Me and the machinist talked some about the overbore and I told him I wanted to go enough to get it cleaned up. I want to go at least .030 because the piston weight for the .030 is almost Identical to the original pistons but .040 is only like 2 grams heavier. Here is the question. Is there any performance gained from a .010 overbore? I think it adds about 2 cubic inches or so and maybe a touch of scr. But is there gonna be a noticeable amount of gains between .030 and .040?
The reason I ask is I was gonna just wait and see if. 30 would be enough and if it is go with that. But I'm kinda thinking about just telling him to go .040 and be done with it so I can order my pistons and get a head start on fitting them to the rods while he has my block. I'm afraid if I order the. 030 piston and it's not enough to clean it then I just wasted time and money. I'm almost positive. 040 would be enough tho. Or would it be best to just wait and let him make the decision between. 030 and .040? Thanks guys/gals.

 

[318willrun]

Let him start with the block, hot tank and magna flux for cracks. Let him tell ya how much needs removed on the cylinders to clean it up. If .030 gets it clean, I wouldn't worry about the hp gains of .040.

 

[Dartfreak75]

Let him start with the block, hot tank and magna flux for cracks. Let him tell ya how much needs removed on the cylinders to clean it up. If .030 gets it clean, I wouldn't worry about the hp gains of .040.

Ok thanks that was the plan I was just thinking about getting a jump start on the piston

 

[Plymouth 65]

First thing, don't be in a hurry! Measure and record all the crankshaft mains and throw diameters. Buy the correct bearings based on the measurements. I like Clevite bearings with oil the groove. I recommend you get a service manual to make sure your clearances are correct. 65'

 

[Dartfreak75]

First thing, don't be in a hurry! Measure and record all the crankshaft mains and throw diameters. Buy the correct bearings based on the measurements. I like Clevite bearings with oil the groove. I recommend you get a service manual to make sure your clearances are correct. 65'

I'm buying a new crankshaft with bearings included.
When I say new its manufactured.

 

[Plymouth 65]

With a new crankshaft and pistons I recommend you have the rotating assembly balanced. 65'

 

[JBurch]

To answer your questions..........cleaning does remove paint.......blocks are baked in an oven to burn off grime and then shot blasted, when the block comes out of the shot blast cabinet it looks like a brand new piece of iron

Go with the least over bore as needed to clean up cylinders and piston availability; you can't overbore far enough to make any real difference in power as a result of displacement gained, vrs power lost to thin flexible cylinder bores, thick stable cylinder walls make power. A sonic check can/will tell you much. Buy your pistons before you bore the block so you have them on hand to measure and fit them to their respective cylinders......

Good luck

 

[toolmanmike]

What cha' buildin? Sometimes overbore depends on what pistons are available. A 318 may only have .030 and .06 over pistons available. The same goes with stroker kits. They may not have the more uncommon.020 or .040 over pistons available. Yes, the machine shop is a very exciting step in your engine rebuild.

 

[Demonic]

The other school of though is that a thicker cylinder wall is one that will make more power. If your block will clean up at .020 over, and there are pistons available that will meet your requirements, you might be better off.

 

[AJ/FormS]

I agree; smallest overbore possible. Maybe it leaves enough meat for next time.
Unless you have an early 318....... Some of those have been bored to 340 size.......... Then she can better use big-valve heads.

 

[Dartfreak75]

With a new crankshaft and pistons I recommend you have the rotating assembly balanced. 65'

I was under the impression that with the refurbished cranks the balance didn't change because it's a factory crank that has just had the journals cut and polished?

To answer your questions..........cleaning does remove paint.......blocks are baked in an oven to burn off grime and then shot blasted, when the block comes out of the shot blast cabinet it looks like a brand new piece of iron

Go with the least over bore as needed to clean up cylinders and piston availability; you can't overbore far enough to make any real difference in power as a result of displacement gained, vrs power lost to thin flexible cylinder bores, thick stable cylinder walls make power. A sonic check can/will tell you much. Buy your pistons before you bore the block so you have them on hand to measure and fit them to their respective cylinders......

Good luck

That makes sence but what if I get .030 over pistons (what I want) and it takes .040 to get the walls corrected? Then I gotta buy more pistons lol.

What cha' buildin? Sometimes overbore depends on what pistons are available. A 318 may only have .030 and .06 over pistons available. The same goes with stroker kits. They may not have the more uncommon.020 or .040 over pistons available. Yes, the machine shop is a very exciting step in your engine rebuild.

View attachment 1715304059

View attachment 1715304060

Building a 360 using speed pro h116cp pistons I'm gonna start a engine build thread soon I was kinda waiting till I get closer to final assembly. .030 is my goal because of the piston weight.

 

[Plymouth 65]

Incorrect, the refurbished crankshaft was factory balanced with a certain set of rods and pistons. You're charging all that so it requires balancing. Factory balance was also not the as precise as it will be done by a competent machinist. 65'

I was under the impression that with the refurbished cranks the balance didn't change because it's a factory crank that has just had the journals cut and polished?

That makes sence but what if I get .030 over pistons (what I want) and it takes .040 to get the walls corrected? Then I gotta buy more pistons lol.

Building a 360 using speed pro h116cp pistons I'm gonna start a engine build thread soon I was kinda waiting till I get closer to final assembly. .030 is my goal because of the piston weight.

 

[nm9stheham]

• Ignore any HP difference between .030 and .040 oversize; it is 100% trivial for what you are doing. I'd stay with .030" or .020" in case the cylinders had some core shift when cast. IMHO, you are not at a power level where .005-.010" extra wall thickness will make any difference either.
• Wait on the piston size decision. Take the block to have it cleaned and bored, etc., and ask that the bores be measured first, while you are there if possible so that can be settled.
• Make sure you agree upon the piston size upfront and order them pronto. Then take them right to the machinist; let him have them in-hand for final measurement when boring/honing.
• The crank balance changes from the under cut, BUT is then compensated with the extra material thickness in the undersized bearings. So that is a non-issue for balance per se.
• Make sure in your balance thinking that you include the pin weights. Ring weight will be a tad more with the oversize rings... a gram or 2 or 3....
• Cleaning rarely fails to remove all paint. Don't remove it yourself; just a waste of your time. Pull out the core plugs (freeeze plugs). 'Hot tanking' is the norm. If the inside of the block is very rusty, then 'rust tanking' is done at some shops as another step.
• Take the main caps with you to the shop and ask them what you need to leave with the machinist.
• Be prepared to clean out all threaded holes after you get the block back. That is more of an 'assembly detail'.

 

[Max1196]

And ask the shop if they could use a "torque plate" for the final hone.

 

[toolmanmike]

• Ignore any HP difference between .030 and .040 oversize; it is 100% trivial for what you are doing. I'd stay with .030" or .020" in case the cylinders had some core shift when cast. IMHO, you are not at a power level where .005-.010" extra wall thickness will make any difference either.
• Wait on the piston size decision. Take the block to have it cleaned and bored, etc., and ask that the bores be measured first, while you are there if possible so that can be settled.
• Make sure you agree upon the piston size upfront and order them pronto. Then take them right to the machinist; let him have them in-hand for final measurement when boring/honing.
• The crank balance changes from the under cut, BUT is then compensated with the extra material thickness in the undersized bearings. So that is a non-issue for balance per se.
• Make sure in your balance thinking that you include the pin weights. Ring weight will be a tad more with the oversize rings... a gram or 2 or 3....
• Cleaning rarely fails to remove all paint. Don't remove it yourself; just a waste of your time. Pull out the core plugs (freeeze plugs). 'Hot tanking' is the norm. If the inside of the block is very rusty, then 'rust tanking' is done at some shops as another step.
• Take the main caps with you to the shop and ask them what you need to leave with the machinist.
• Be prepared to clean out all threaded holes after you get the block back. That is more of an 'assembly detail'.

And clean all passages out before assembly even though the machine shop does it. And then clean them again. I cleaned mine twice and blew them out with compressed air and then fogged them with WD40 to prevent surface rust. I didn't know how long before I did the final assembly. I covered the block with a lawn and garden trash bag and tied the end ghut to keep moisture out. The coolant passages aren't as important as all the oil passages. Make sure you install the new oil galley plugs in the rear main bolt hole. THere is another one near the oil filter if I remember correctly. Someone will chime in I am sure if I can't find the thread about it.

 

[nm9stheham]

Incorrect, the refurbished crankshaft was factory balanced with a certain set of rods and pistons. You're charging all that so it requires balancing. Factory balance was also not the as precise as it will be done by a competent machinist. 65'

A production crank balance is done to a standard bobweight or some other standard to duplicate that. And in production, I don't know if they even actually attach bobweights or use some other, faster technique. The tolerance of standard crank balancing is pretty loose (something like +/- 15 or 20 grams as best I can tell), so even with the pistons and rods, etc. exactly at the nominal standard bobweight, there will be a variation on the resulting balance. I SERIOUSLY question if reman cranks get rebalanced at all.

If the OP is not changing component weights and not straying from the standard factory bobweight, then his resulting balance will be no different from a factory balance tolerance. Any subsequent balance work is just to tighten up the match of the crank balance to the actual rods, pistons, etc. But it is not by any means absolutely necessary for 'standard' builds IF the component weights are managed to stay near the standard weights. That is the point of using a piston like the H116CP at a .020-.030" oversize: it is very close to the stock 360 piston weight, and the pin weight is identical to stock.

 

[Dartfreak75]

• Ignore any HP difference between .030 and .040 oversize; it is 100% trivial for what you are doing. I'd stay with .030" or .020" in case the cylinders had some core shift when cast. IMHO, you are not at a power level where .005-.010" extra wall thickness will make any difference either.
• Wait on the piston size decision. Take the block to have it cleaned and bored, etc., and ask that the bores be measured first, while you are there if possible so that can be settled.
• Make sure you agree upon the piston size upfront and order them pronto. Then take them right to the machinist; let him have them in-hand for final measurement when boring/honing.
• The crank balance changes from the under cut, BUT is then compensated with the extra material thickness in the undersized bearings. So that is a non-issue for balance per se.
• Make sure in your balance thinking that you include the pin weights. Ring weight will be a tad more with the oversize rings... a gram or 2 or 3....
• Cleaning rarely fails to remove all paint. Don't remove it yourself; just a waste of your time. Pull out the core plugs (freeeze plugs). 'Hot tanking' is the norm. If the inside of the block is very rusty, then 'rust tanking' is done at some shops as another step.
• Take the main caps with you to the shop and ask them what you need to leave with the machinist.
• Be prepared to clean out all threaded holes after you get the block back. That is more of an 'assembly detail'.

He told me about caps to make sure I included them. I have the plugs already removed I just finished the oil plugs today I had to order a square socket.
The .030 over piston weight is 582 with a 154 pin.
The stock one is supposed to be 584 I'm not sure about the pin! I will weight one tomorrow.

 

[Dartfreak75]

And clean all passages out before assembly even though the machine shop does it. And then clean them again. I cleaned mine twice and blew them out with compressed air and then fogged them with WD40 to prevent surface rust. I didn't know how long before I did the final assembly. I covered the block with a lawn and garden trash bag and tied the end ghut to keep moisture out. The coolant passages aren't as important as all the oil passages. Make sure you install the new oil galley plugs in the rear main bolt hole. THere is another one near the oil filter if I remember correctly. Someone will chime in I am sure if I can't find the thread about it.View attachment 1715304102

I didn't remove the rear plug. I removed all the rest I was informed not to remove the rear main plug just to leave it.

 

[nm9stheham]

He told me about caps to make sure I included them. I have the plugs already removed I just finished the oil plugs today I had to order a square socket.
The .030 over piston weight is 582 with a 154 pin.
The stock one is supposed to be 584 I'm not sure about the pin! I will weight one tomorrow.

I just checked on the stock pin info that I have... 154 grams so you look to be good there. Checking one would not be a bad idea. With a few grams extra ring weight, you are as close as anyone can get IMHO. Good planning!

 

[TheGrateRonzini]

Also! Make sure you can get rings for the pistons. I ordered a stroker rotating assy for my 318-390 and mancini or I couldn’t find rings for .040 over bore. Luckily the motor didn’t need +.040 over. I just wanted to be able to use 392 emblems. I usually bring machinist a crusty block and have them clean it. They charged 500 for clean, mag, bore, hone parallel deck and cast blast. He will then take the pistons and hone to close I also go through with a die grinder and get any casting flash out of there and then 2 or 3 go rounds with the engine gun and mineral spirits. You should always have the bobweight balanced too, but also take into consideration that OG mopar was NOT within a few grams of each other but more likely ounces apart on factory balance

 

[toolmanmike]

I didn't remove the rear plug. I removed all the rest I was informed not to remove the rear main plug just to leave it.

If the block is boiled or baked the plug needs to be replaced from what I understand.

 

[Dartfreak75]

All I have left before I take it to the machinist is I have to finish my porting my heads they are almost done! Just some final polishing of the exhaust bowls and they are off! I love the look of fresh metal can't wait to get this thing back!

 

[Dartfreak75]

If the block is boiled or baked the plug needs to be replaced from what I understand.

Ok I will talk to the machinist I may go ahead and do it so i can do jabas oil mod.
I don't think that plug is included in the plug kit can you buy it separately?

 

[JBurch]

That makes sence but what if I get .030 over pistons (what I want) and it takes .040 to get the walls corrected? Then I gotta buy more pistons lol.

Building a 360 using speed pro h116cp pistons I'm gonna start a engine build thread soon I was kinda waiting till I get closer to final assembly. .030 is my goal because of the piston weight.

Once block is cleaned, you (actually your machinist ) should be able to tell real fast what the block will clean up at and therefore what size pistons to order up. Generally speaking .030 over will clean up just about any cylinder; I'll admit not always, rust pitting can be the death knell, myself almost got hit with that when I built my 360 years ago, had .030 over in hand and was worried it might take .040, he made a pass with his boring bar at less than .030 and we got a nice clean wall. Don't get too worried about piston weight, they are gonna weigh what they weigh, if anything look for lighter...........you have a balance job coming at you anyway so don't let that keep you up at night.

 

[nm9stheham]

you have a balance job coming at you anyway so don't let that keep you up at night.

Not sure I understand why...???? This is not a high revving, circle track engine.