273 302 318 340 build

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Thanks, yeah these were piston choices I had written down so far, Sealed Power 526AP, Sealed Power 285 AP and Silvolite 1266C. I agree with you on the 526AP
I checked out the links, thanks! Campbell is more expensive in this case(526AP30) by about $100??
Here is a link to the Summit site with my question posted about the weights of Silvolite1266C and answered at the bottom. Maybe your right with it being shipping weight LOL

I emailed thru Summit site to get the weights of the SP 526AP 30.
Thanks again!
nm9stheham said:
The 1266C has 4 valve reliefs; it is not a flat top. It crosses over to the Sealed Power 285. So you will add 6-8 cc's of valve relief volume in to the equation and go back downwards on CR.

Stick with the 526AP's, IMHO.

Silvolite catalog is here; look at the top of page 22 for the 1226 valve relief pattern:
https://www.uempistons.com/catalogs/silvolite_catalog.pdf

That weight range of 778-805 grams that you were given does not make sense...... Even adding 161 pin weight to 592 gives 753 grams... Typical ring pack weight would be around 58 grams and adding that in does make sense either. Maybe they are including the carton weight? LOL
Click to expand...

nm9stheham said:
BTW, check with Campbell Enterprises for another option on buying these pistons; their prices are generally a bit lower than Summit. This link will take you to the cast pistons, despite what the title of the link reads:

318 Pistons | Chrysler & Dodge & Mopar | Forged & Stroker Pistons
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Wow, yeah, a LOT cheaper at Summit. It pays to shop around. I see CE being cheaper (usually) for the KB's and such.
 
Ok had to call Federal Mogul tech support to get the weights of their Sealed Power 526AP 30.
He was able to pull a print for Std bore. 594.6 gms +/- 2 grams. BUT the weight goes up by 10 gms per .010" overbore. So in theory weight is 595 + 30=625 grams.
Is this ok to go without needing to rebalance?
Thanks
 
OK very good info. Seems like a lot for each .010"..... I was expecting maybe half of that???? You may find it is not all that much when you get them. But lemme plug in an extra 30 grams ..... and yes, the bobweight goes up from 2202 grams to 2232 grams, or about 1.4%. This is all assuming you have the later 318 bottom end with the heavier rods (same rod weight as the 360's).

For revving, yeah, I personally would re-balance. While typing this up, bingo... I remember this conversation with the machine shop over 40 years ago when overboring for my first performance build: "You really need to rebalance this engine with the new oversized pistons" Which I had them do, despite being a poor sailor making just over $450 per month....LOL!

BUT, IMHO this needs to be done by lightening the pistons and pins and small ends of the rods; doing it just at the crank will require ADDING weight on the crank counterweights.

Too bad you can't find a set of KB pins at 132 grams.....Diamond after-market ones are probably way too pricey. Or drill out the stock pins to get rid of most of the added piston weight and take the last bits out of the pistons.

BTW, all of the reciprocating weight part of the bobweight calculations ends up there in the pistons, rings, pins, pin locks (if any), and rod small end, so any of them can be lightened and have the same effect on balance.

One other (probably insane) idea: Confirm what the Sealed Power 814's come in at. They are Magnum 5.2 pistons. They have the same general overall weight listed as 761 grams for piston + pin, but a much lighter piston alone at 534 grams per the FM site, so the pins must be monstrously thick walled so they can be drilled out at will. These are hypereutectics (not regular eutetic cast) but oughta work fine. The one thing that I don't know is if the rod width area under the piston is as wide as in the 526AP's; the Magnum rod's small end is a bit narrower. Oops.. the 814's look pricier.....well, just throwing that out there.
 
When I was on the phone with FM, he couldnt tell me what the tolerances are for rebalancing. Machine shop is 45 min away and I don't want to bother him on the phone. I'll see him this week when I drop off.the 302 heads and ask then. I cant get a good seal on one head. Looks like I may be into a valve job. Haven't checked the other head yet but should do both anyway.
Thanks for the info/lesson! Lol
nm9stheham said:
OK very good info. Seems like a lot for each .010"..... I was expecting maybe half of that???? You may find it is not all that much when you get them. But lemme plug in an extra 30 grams ..... and yes, the bobweight goes up from 2202 grams to 2232 grams, or about 1.4%. This is all assuming you have the later 318 bottom end with the heavier rods (same rod weight as the 360's).

For revving, yeah, I personally would re-balance. While typing this up, bingo... I remember this conversation with the machine shop over 40 years ago when overboring for my first performance build: "You really need to rebalance this engine with the new oversized pistons" Which I had them do, despite being a poor sailor making just over $450 per month....LOL!

BUT, IMHO this needs to be done by lightening the pistons and pins and small ends of the rods; doing it just at the crank will require ADDING weight on the crank counterweights.

Too bad you can't find a set of KB pins at 132 grams.....Diamond after-market ones are probably way too pricey. Or drill out the stock pins to get rid of most of the added piston weight and take the last bits out of the pistons.

BTW, all of the reciprocating weight part of the bobweight calculations ends up there in the pistons, rings, pins, pin locks (if any), and rod small end, so any of them can be lightened and have the same effect on balance.

One other (probably insane) idea: Confirm what the Sealed Power 814's come in at. They are Magnum 5.2 pistons. They have the same general overall weight listed as 761 grams for piston + pin, but a much lighter piston alone at 534 grams per the FM site, so the pins must be monstrously thick walled so they can be drilled out at will. These are hypereutectics (not regular eutetic cast) but oughta work fine. The one thing that I don't know is if the rod width area under the piston is as wide as in the 526AP's; the Magnum rod's small end is a bit narrower. Oops.. the 814's look pricier.....well, just throwing that out there.
Click to expand...
 
So a little more info. Rods in 83 318 are 3418645 which books tell me stock and press fit.
70 318 con rods are 2406782 stock but not sure if press fit or floating I havent put it on stand yet.
I only have one engine stand so its a pain in the arse at this stage of the game.
Are the 83 rods better than the 70 rods? Should I pull the 83 ones before I put 70 on the stand?
Also pistons...the Sealed Power ones I was looking at are press fit. Can you convert floating to press fit?
Without major costs?
Thanks!
 
Got 302 heads dropped off to machine shop. Asked Al about the 2 "craters" in combustion chambers(see pics). Al thinks they are casting defects, but will take a closer look. I tried to get valves lapped on one head and couldnt get them sealed. So a valve job is in order. May as well do both heads. For now im going with factory sizes. 1.78 INT and 1.50 EX. This valve job is approx $200.
IF I went bigger to 1.88 & 1.60 its another $100. So potentially $300 in headwork.
For now no milling on block side or intake side. He can do it without having to remove any off the intake (he's done LOTS like this) but my compression might be good enough without milling.
I have a set of 1.88 & 1.60 valves in a nice clean set of heads (#3671587) that Mike/2darts gave me. THANKS AGAIN MIKE!
I got pistons removed from the 83 318. (See pics). Rods are #3418645 with press fit pins. Dammit the rods in 70 318 (#2406782) are full floating. So a mismatch! I haven't disassembled that engine to verify but can see enuf of conrod to get #. (Only one engine stand)
So with different pins I have to rethink my piston choices. Al told me if I find a piston with pin locks(floaters), you can use either style pin (assuming same od)
I had almost decided on Sealed Power 526AP 30 but those are press fit dammit.
If I go beefier rods with press pins (3418645) I have to take into acct the weight difference. Al told me balancing may be needed and the cost of that..... $650!!! So with piston choices muddled again, the piston price may go up, therefore I may need to do some cost saving (stick with stock valve job vs 1.88 & 1.60) "saves" me $100.
He can't start on the heads for a week so it gives me a chance to hunt pistons down as well as start tearing down the 70 shortblock for inspection.
After I removed the 83 pistons I put verniers on the crank journals. Not 100% accurate but gives me an idea anyway. I noticed on # 7/8 journal a very small mark that I could feel with my fingernail. Nothing drastic but thought I should note it(see pic its at approx 11 oclock 1/4" long). This block and crank more than likely wont be used anyway.
Pistons and conrods from 83 look good with bearings showing slight wear. Oh journals..
#1/2 2.1245"
#3/4 2.1250"
#5/6 2.1275"
#7/8 2.1270"
Specs in book are 2.1250 so my hokey measuring is off but it looks like a good forged crank.
Enough typing, time to watch hockey and hunt for pistons!
Thanks for checking in
Steve

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Let me understand something.... so you are going with the '70 crank? I assumed you were going with the '83 crank. The later rods should be the heavier ones and should be balanced with with the '83 crank. So why not go with the '83 crank in the '70 block? It should drop right in. Crank register should be the same and all else.....

Did you want to go with the forged '70 crank for a particular reason? Balancing the later rods with the earlier crank (that was originally balanced for the early lighter rods) would require adding weight to the crank and so the price he quotes is not all that surprising. The cheapest route is to go with the later cast crank and rods.

The pins will all interchange, but yes, your issue with the smaller rods is that the bushings in those rods need locks in the pistons as he said.

BTW, I am pulling for the Seantors......
 
My thinking was to go with earlier crank for the build. No particular reason than its forged. As mentioned I haven't disassembled 70 short block so not sure of condition( all journals and bearings). That's the beach of only having one engine stand lol) I did have 3 and sold 2 dammit.
I agree with dropping 83 crank and rods in the 70 block. Reason for buying the 70 block was for the forged crank.
It may be worth the $100 to buy another engine stand lol. I did stop today and buy a 2x12 to make an engine cradle to roll around.
Quick check on Summit site only shows the top dollar Icons or KB with floaters. $800/set lol.
Yep Im pulling for Sens too and Nashville in the other series. Pittsburgh were doing a buttload of whining/bitching last night.
I remember reading in another thread a member said an engine build is a "slippery slope"...I get that now lol
Thanks again!
nm9stheham said:
Let me understand something.... so you are going with the '70 crank? I assumed you were going with the '83 crank. The later rods should be the heavier ones and should be balanced with with the '83 crank. So why not go with the '83 crank in the '70 block? It should drop right in. Crank register should be the same and all else.....

Did you want to go with the forged '70 crank for a particular reason? Balancing the later rods with the earlier crank (that was originally balanced for the early lighter rods) would require adding weight to the crank and so the price he quotes is not all that surprising. The cheapest route is to go with the later cast crank and rods.

The pins will all interchange, but yes, your issue with the smaller rods is that the bushings in those rods need locks in the pistons as he said.

BTW, I am pulling for the Seantors......
Click to expand...
 
4spdragtop said:
I agree with dropping 83 crank and rods in the 70 block. Reason for buying the 70 block was for the forged crank.

Quick check on Summit site only shows the top dollar Icons or KB with floaters. $800/set lol.
Click to expand...
Yep, figgered that was what you would find. Campbell Enterprises often is lower than Summit and Jegs on KB's. But that is still are a LOT pricier than the 526AP's, and the lighter KB's means re-balance....although that would be cheaper to do that since it will require taking weight off of the crank, not adding it on. That is why I keep poking all that info at you about drilling out pins and such....so you can bypass the re-balance cost.

You are good with working on parts so there IS a way to get the re-balance cost waaaay down: you do the rods and pistons yourself, and compute the bobweight and hand that bobweight to the shop to just balance the crank to your bobweight. (I'd be happy to explain how that works.)

I would not be scared to use the '83 cast crank.... all I can find is that they are good for 400 HP or more and you won't be anywhere near there with the lower port flow of the 302's, even if you put in the larger valves.
 
nm9stheham said:
Yep, figgered that was what you would find. Campbell Enterprises often is lower than Summit and Jegs on KB's. But that is still are a LOT pricier than the 526AP's, and the lighter KB's means re-balance....although that would be cheaper to do that since it will require taking weight off of the crank, not adding it on. That is why I keep poking all that info at you about drilling out pins and such....so you can bypass the re-balance cost.

You are good with working on parts so there IS a way to get the re-balance cost waaaay down: you do the rods and pistons yourself, and compute the bobweight and hand that bobweight to the shop to just balance the crank to your bobweight. (I'd be happy to explain how that works.)

I would not be scared to use the '83 cast crank.... all I can find is that they are good for 400 HP or more and you won't be anywhere near there with the lower port flow of the 302's, even if you put in the larger valves.
Click to expand...
please,..carry on an explain!
 
Both my 69 FSM and 84 FSM have 318 rods weighing 726 grams. Nothing on the pin weights. Another difference I noticed is the piston pin bore dia on con rod. 69 ff is 1.027"-1.039" where the 84 pressfit is .9819"-.9834. I havent tore the 70 down yet to confirm. But the rod #'s on the 70 = FF style.
Im trying to wrap my head around the piston pin dliemna.
All the pistons that I can afford are the press fit style and 0.984" OD. SOOOO that means I cant use the 70 rods due to the diameter difference.
So now like "theham" mentioned that difference in conrod diameter and pin style has thrown a real wrench into things and is starting to confuse the **** outta me. I know there is a science to this and am starting to appreciate what goes into engine building BUT this was supposed to be a simple small block budget build and didnt think there would be this many hurdles to overcome on a 318 build.
Hope to teardown 70 318 in the next week.
2 318's later and a friggin stuffed garage, I got a call about a 340 shortblock that is apparently good to go. I have complete freshened x heads on the shelf and LD340, then definitely use 270S cam from the 273.
So unless I find 318 pistons within my budget, the 340 shortblock to purchase will be about the same as the 318 pistons, rings and machine work on 302 heads???
I wouldnt be stressed out if I had another 500 sq ft of garage space, but that aint the case. As it is now theres 3 engines in the shop im tripping over and seriously contemplating the 340 shortblock. I have a "rebuilt" 904 to go in the cuda, whether its 318 or 340.
Im still open to suggestions here, and "theham" I thank you for sharing your knowledge and time. When you can I would appreciate the "how to" on DIY balancing. Im not sure if I go that route, thus the title of this thread....covers a little bit of every sbm LOL
nm9stheham said:
Yep, figgered that was what you would find. Campbell Enterprises often is lower than Summit and Jegs on KB's. But that is still are a LOT pricier than the 526AP's, and the lighter KB's means re-balance....although that would be cheaper to do that since it will require taking weight off of the crank, not adding it on. That is why I keep poking all that info at you about drilling out pins and such....so you can bypass the re-balance cost.

You are good with working on parts so there IS a way to get the re-balance cost waaaay down: you do the rods and pistons yourself, and compute the bobweight and hand that bobweight to the shop to just balance the crank to your bobweight. (I'd be happy to explain how that works.)

I would not be scared to use the '83 cast crank.... all I can find is that they are good for 400 HP or more and you won't be anywhere near there with the lower port flow of the 302's, even if you put in the larger valves.
Click to expand...

dirty white boy said:
please,..carry on an explain!
Click to expand...
 
dirty white boy said:
sale off your 318s,..buy the 340,...youll love your self for it later on!!!
Click to expand...

LOL, Im definitely tempted. Forged crank turned 20/20. New rod bearings/main bearings/cam bearings, moly rings none installed. .030 over piston. Engine is completely apart for inspection. No pump no pan. As far as I know lol(so far) all I need to purchase is
oil pan
HV pump
gaskets
balancer(maybe)
Stall converter(recommendations??) I was told 2800 would be good with my 3:23 gears.
I have cam/lifters, X heads, LD340, carb and Hipo manifolds. And a rebuilt 904.

Now what I found out piston wise with 318. I spoke with both FM tech and Summit tech for piston options. FM tech (great guys!) stated the 285AP30 is the only option SO FAR!
Link
https://www.summitracing.com/int/parts/slp-285ap30/overview/make/dodge
1.72" comp height, so its stock, 9.2:1. Using 302's will raise it a bit. The 285's have 4 valve reliefs, so a loss there too. I havent crunched #'s on it yet. I looked on Summit site and it has the pistons listed as press fit.... WRONG, they are both, press or floaters.
I asked the machinist about using the smaller rods and bushing the small end. He said that he doesnt recommend it when you convert them to press fit. He said its fine if you go floating, but said to not do it for press fit.
He still said I could still go with cast crank(up to 400 hp) and heavier rods and not have to worry about balancing. That opens up a wider piston option, but in reality press fits were pretty much the same price, just wider selection(and bigger compression height).
I was hoping/trying to keep assemblies "matched" as once the engine is built I want to sell the other short block(tired of toe stubbin').
Decisions decisions..
 
I'll get to the balance stuff in a day or so...working looong days again. The homework assignment for that is to go on the Eagle site and look at the bobwieght computation card that they show; see here:
Eagle Specialty Products, Inc.


So what is it with the FM guy and the Summit guy and the 526AP's? Geez...... I suspect these guys is just reading out of a book! C'mon.... the specs are all there....The 526AP's are listed on the Campbell Enterprises site as available. Ahhhh it may be that the 526AP's and 814AP's are out of production.....that is why FM would not list them.

I agree with your machinist on the small ends. I can; timagine the bronze bushing holding a press-in pin; it is soft.

So what is the story behind the 340?
 
nm9stheham said:
I'll get to the balance stuff in a day or so...working looong days again. The homework assignment for that is to go on the Eagle site and look at the bobwieght computation card that they show; see here:
Eagle Specialty Products, Inc.


So what is it with the FM guy and the Summit guy and the 526AP's? Geez...... I suspect these guys is just reading out of a book! C'mon.... the specs are all there....The 526AP's are listed on the Campbell Enterprises site as available. Ahhhh it may be that the 526AP's and 814AP's are out of production.....that is why FM would not list them.

I agree with your machinist on the small ends. I can; timagine the bronze bushing holding a press-in pin; it is soft.

So what is the story behind the 340?
Click to expand...

LOL, yeah both tech guys were great on the phone. I figgered I would call FM tech first. 20 minutes on the phone with Hal and we had the 285 picked out. He had to look at prints etc. To determine float or press. I asked him to email print...he laughed. NOPE. He did give me all the info he had on the print though. I mentioned some above, but to add to it, piston weight 601.4 +/- 10 grams. Pin 154 +/- 10 grams, so 755.4 total. Piston pin bore diameter 0.98448 to 0.98468. 4 valve reliefs.
I had things to do so we left it at the 285 for now.

BUT when I talked to the Summit tech(good guy again) I mentioned that their website doesnt say floater, it simply says press fit, and that I am calling to confirm. I mentioned maybe someone could lay their hands on a piston to confirm. He laughed...(2/2) He said what they do is go to FM website and punch the part number in to get info....LOL. So here is what comes up for the 526 with press fit.

Sealed Power Cast Piston (Carton of 8)

Here is the link to the 285. These are actually a little cheaper. I think $270 pistons, moly rings, shipping taxes etc all in.
Sealed Power Cast Piston (Carton of 8)

Ring kit link
Sealed Power Premium Piston Ring Set

The 340....the owner was gathering all of them up he could in the 80's 90's etc. This is one he just simply doesnt need. Everything that comes with it has been refreshed a few years back and has sat. He mentioned its been decked, I forgot to ask how much, but he did say with stock X heads its around 10:1. Comes with all new bearings, cranks been turned 20/20. Pistons are used, but new moly rings and block hasnt been run since the .030 over bore.
It seems like just a simpler swap. It sucks that I have went and bought 2 318's and its a damned obstacle course in the garage right now. Altho the 1 318 came with the LD340 and Eddy 1405 so no loss there.
He is in no rush to sell the 340, and will "save" it for me. Need a 340 for the 69 ragtop so......
It is in the $1000 range....
I will do some number crunching on the 285 and see what compression turns out to be. Be a guessing game till I figger out whether I do the 302 heads or not.
Thanks, much appreciated.
OH, I will chk Eagle site out and NO RUSH on the how to. Im back at work(12 hr shifts) so eat sleep work lol

Foresee any issues with 68-70 hipo manifolds and power steering?
 
I don't know enough on the manifold and PS..sorry. Look at Cempbell Enterprises too; they list the 526AP's still so must have some stock. The 285AP's will drop a gob of compression, with their lower compression height AND eyebrows.

Does the 340 come with heads? You don't want to try to use the 302 heads with the 340 block and pistons.... CR would be out of sight!
 
No sweat on the PS and manifolds. I'll do some reading up on it.
I have a set of X heads that were given a valve job years ago and havent been used since. Basically for the 340 I need gaskets. I have everything else (I think)
I checked out the 526AP and they are press fit pins as.
I agree with losing compression with the eyebrows and compression height. Im still searching for piston options.
I told machinist to hold off on 302 heads for now until I decide which route I take.
Thanks for Eagle link, it was a good read!
Ive no way to get the seperate weights on the rods (big vs small ends) only a total.
Set of good scales and a press at work but no "special" scales. So not sure bout the bobweight...yet.
Thanks!

nm9stheham said:
I don't know enough on the manifold and PS..sorry. Look at Cempbell Enterprises too; they list the 526AP's still so must have some stock. The 285AP's will drop a gob of compression, with their lower compression height AND eyebrows.

Does the 340 come with heads? You don't want to try to use the 302 heads with the 340 block and pistons.... CR would be out of sight!
Click to expand...
 
Complete piston setup less conrod bearing weight removed from my 83 318 #3418645
Not cleaned or anything. 1564.6 grams

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4spdragtop said:
I will do some number crunching on the 285 and see what compression turns out to be. Be a guessing game till I figger out whether I do the 302 heads or not.
Click to expand...
FWIW, I ran numbers on the 526's vs 285's with your heads unmilled and a .028" thick head gasket and got 8.9 vs 7.8 Static CR. So the 285's drop over a point in CR..... and Dynamic CR with the 285's will be waaaay down with a 270 cam.
 
Thanks. Im wondering how you figure static vs dynamic compression ratio? I know static means "theoretical" and dynamic is the "actual" or working compression.
One of these 318 engines will be built whether its for the cuda or the truck.
Thanks again!
nm9stheham said:
FWIW, I ran numbers on the 526's vs 285's with your heads unmilled and a .028" thick head gasket and got 8.9 vs 7.8 Static CR. So the 285's drop over a point in CR..... and Dynamic CR with the 285's will be waaaay down with a 270 cam.
Click to expand...
 
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