Phreakish
Well-Known Member
Vegas is in CA!?!
NV luckily has a rolling smog exemption. I forget what the age is, but it goes with the car and not the engine (at least 3 years ago when I was there..) and my 72 was definitely exempt at the time.
Blueprinting... Educate the uneducated
- Thread starter DentalDart
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Vegas is in CA!?!
NV luckily has a rolling smog exemption. I forget what the age is, but it goes with the car and not the engine (at least 3 years ago when I was there..) and my 72 was definitely exempt at the time.
Phreakish
Well-Known Member
Here's a good video that gives an idea of what the various operations are and what they kinda look like. The actual machines vary slightly and the level of computer involvement varies substantially by facility. But you can maybe get an idea of the various tools, equipment, and need for various fixtures that are unique to particular engines.
There's lots more to know and understand, but this is a good overview of quite a few common operations.
There's lots more to know and understand, but this is a good overview of quite a few common operations.
pishta
I know I'm right....
I think the only way Mopar could get '10.5:1' pistons in a 65 Commando 273/4 was to get their head combustion chamber down to the "blueprint" 57cc, and that never happened.
We don't kick anyone out of California- all the weirdo's live here.
Vegas is in CA!?!
NV luckily has a rolling smog exemption. I forget what the age is, but it goes with the car and not the engine (at least 3 years ago when I was there..) and my 72 was definitely exempt at the time.
Yes my 69 is smog exempt as long as I dont drive more than 3k miles in a year.
This was cool! Funny we use a sonic cleaner for cleaning dentures
69_340_GTS
Well-Known Member
When a 408, 416, or even bigger small block can be quite easily built with off the shelf parts, I can see no reason for wanting to put a big block in an A-Body. Not from a cost vs reward aspect anyways. Yes, the big block will look cool, and all that. And of course you'll need a big block if you want something way over 400 cu. in.
Stroker kits are $$$ but seems like stroker 340s and people who have them really enjoy them and say they are very driveable
Vegas is in CA!?!
My tired old brain said Doc was in San Diego area of CA. Thanks for the poke!
Blueprinting an engine, simply means that the critical dimensions have been met. When you do this you would be crazy not to have recorded and kept the measurements. You do not have to change cylinder bore centers or angles. Your decks should be the same hight, and perpendicular to each other, rods, very close to the same lengths, position of the piston tops to the deck, bearing bores within specifications, Chamber size, rocker arm ratio, True TDC, degreeing the cam, Center the bell housing on the block, and a lot of other dimensions that all add up to big gains.
Big blocks, in stock form are stronger, and breath better giving them a performance edge, but they require different and rarer pieces to fit in an "A" body. I too have a 68 Formula S 383 Auto Trans car and love it!
Big blocks, in stock form are stronger, and breath better giving them a performance edge, but they require different and rarer pieces to fit in an "A" body. I too have a 68 Formula S 383 Auto Trans car and love it!
Here ya go doc. Four minutes and your an expert! Lol
Vegas is in CA!?!
NV luckily has a rolling smog exemption. I forget what the age is, but it goes with the car and not the engine (at least 3 years ago when I was there..) and my 72 was definitely exempt at the time.
I belive it is 25 yrs.....my 1994 Dodge ram 2500 is now able to be smog exempt....and as a Classic Vehicle you are allowed 5k miles an year and the DMV does not check your odometer.....you just sign a form to say how many miles you have driven it.
pishta
I know I'm right....
All this hype on cast/forged rockers having ratios all over the place seems very suspicious...take a factory or an aluminum rocker that has been determined to be "out of spec" for ratio and change the adjuster length, it will change the ratio! as modern (even 60's) manufacturing process' would not send out a product as simple as a rocker (2 precision processes: shaft bore and adjuster thread boss and potentially the tip face height but not really as even that is highly controlled) that varies much as the jigs used to drill these are rigid. With everyone knowing the decks of these blocks are not square, that changes the relationship between the rocker shaft and the camshaft axis. Even the truest rockers (T&D, HS, etc) are going to show a slight variation in rocker ratio if measures on the non squared up block. I guess the only way test this would be to get some 'out of spec' rockers and accurately measure the distance from the center of the shaft bore to the tip of the adjuster, equalize this across a few and then test them against each other. Post your results if they are still wonky. Should have been a covid incubation project for me.....
"...A unique feature with the shaft mounted rocker arms such as those found on the ...(Mopar LA)... engines is that the solid lifter or lash adjusting versions can be measurably variable in the rocker arm ratio depending upon where the lash adjusting screw is positioned within its range of travel. Where changing the pushrod length on the stud mounted or trunion type of rocker arm affects the geometry of the rocker and not the rocker arm ratio, changing the pushrod length on the shaft mounted (LA) rocker allows for some deviation from the advertised amount of rocker arm ratio. .... What makes this possible is that the contact point for the pushrod at the bottom of the adjustment screw changes in relationship to the center of the pivot point (shaft) as the adjusting screw is moved up or down. (see illustration)..."
"...A unique feature with the shaft mounted rocker arms such as those found on the ...(Mopar LA)... engines is that the solid lifter or lash adjusting versions can be measurably variable in the rocker arm ratio depending upon where the lash adjusting screw is positioned within its range of travel. Where changing the pushrod length on the stud mounted or trunion type of rocker arm affects the geometry of the rocker and not the rocker arm ratio, changing the pushrod length on the shaft mounted (LA) rocker allows for some deviation from the advertised amount of rocker arm ratio. .... What makes this possible is that the contact point for the pushrod at the bottom of the adjustment screw changes in relationship to the center of the pivot point (shaft) as the adjusting screw is moved up or down. (see illustration)..."
1 thread showing is good. 2 threads showing is OK. 3 threads showing is too much, check your pushrod length.
MopaR&D
Nerd Member
I deal with related stuff at work. Any part you design and then send off to a vendor/contractor to be fabricated must have drawings that show target dimensions and EACH ONE needs a tolerance, + or - a certain amount. The wider your tolerances, the less "careful" they need to be when making the part. Some things can be "loose", other parts need to be right on or they won't work properly.
Chrysler was terrible with their manufacturing tolerances. I saw a post somewhere that the allowable range of compression ratios due to "tolerance stacking" (tolerances of various parts adding up once they're assembled together) for a 1968 HP 440 was 9.2-10.1!!! That's atrocious and explains why there was so much variation in performance from the same cars with the same engines. You've heard the stories where one guy's 383 Road Runner stomped everything in town and ran high 13s in the 1/4, then another guy with the exact same car could barely get into the 14s and it ran like garbage. If one had a true compression of 9:1 and the other had 10:1 you can bet it's not gonna perform the same.
I recently had my 440 block bored, honed and decked but not really "blueprinted". To really do that would have required square-decking which is much more expensive and time-consuming. The Icon pistons I got for it all weigh within 2 grams of each other straight out of the box, far better than factory. Haven't checked my 440Source rods yet but they're probably just as good. I also had the crankshaft balanced to the lighter pistons and I'm willing to bet that balance job is now better than it was before with stock-weight pistons. Casting, block machining and rotating assembly balancing were not taken very seriously by Chrysler. By comparison, Buick might have well been Japanese with how much tighter their tolerances were (I'm a closet Buick fanatic lol).
Chrysler was terrible with their manufacturing tolerances. I saw a post somewhere that the allowable range of compression ratios due to "tolerance stacking" (tolerances of various parts adding up once they're assembled together) for a 1968 HP 440 was 9.2-10.1!!! That's atrocious and explains why there was so much variation in performance from the same cars with the same engines. You've heard the stories where one guy's 383 Road Runner stomped everything in town and ran high 13s in the 1/4, then another guy with the exact same car could barely get into the 14s and it ran like garbage. If one had a true compression of 9:1 and the other had 10:1 you can bet it's not gonna perform the same.
I recently had my 440 block bored, honed and decked but not really "blueprinted". To really do that would have required square-decking which is much more expensive and time-consuming. The Icon pistons I got for it all weigh within 2 grams of each other straight out of the box, far better than factory. Haven't checked my 440Source rods yet but they're probably just as good. I also had the crankshaft balanced to the lighter pistons and I'm willing to bet that balance job is now better than it was before with stock-weight pistons. Casting, block machining and rotating assembly balancing were not taken very seriously by Chrysler. By comparison, Buick might have well been Japanese with how much tighter their tolerances were (I'm a closet Buick fanatic lol).
MOPAROFFICIAL
If it has tits, it's a liabilititty.
Blueprint. Same definition whether house or engine.
Be it clearances, stroke,compression,etc.
Everything is intentional.
Be it clearances, stroke,compression,etc.
Everything is intentional.
Question
Within spec = blueprinted?
Within spec = blueprinted?
MOPAROFFICIAL
If it has tits, it's a liabilititty.
Folks will call a motor rebuilt to stock specs blueprinted. It's used loosely imo.
Balanced and blueprinted, crane blueprint cams, etc. To spec, their spec, within spec, I think its interpreted more than one way.
Is there a sheet of all m/r oil clearances stroke,rod length, bore, chamber, port cc, flow.. many times the 'blueprints' for such "blueprinted motor" are non existant.
Rat Bastid
Dunamis Metron
NHRA Stock and Super Stock have blue print data per class. It gives minimum and maximum data.
If you aren’t building to a class, blue printing is making everything equal. As in volumes, deck heights, stroke lengths (many cranks are off on stroke length) and such.
If you aren’t building to a class, blue printing is making everything equal. As in volumes, deck heights, stroke lengths (many cranks are off on stroke length) and such.
I think that's an acceptable definition. Making all the specs on the engine fall in line with what the factory tolerances are. To me that makes the most sense. Just keep in mind, the factory specs "may not" be the only ones taken into consideration. In other words, if someone wants to blueprint to their own specs, there's "THAT". lol
I "guess" the reason for that is because the factory specs might not be "good enough" for certain situations as in serious racing and the like.
Just another example that there are "MANY" specs to blueprint "TO".
...and IMO that is completely correct, IF said person went through every single measured spec and brought those that were out of spec, into spec. We all know deck heights and chamber volumes were all over the map, just to give one example. Aligning "all that" with what it should be, is blueprinting to Chrysler specs. But just slinging one together......not so much. lol
To me it means you checked everything, and wrote it all down, so 30 years you know what you did. It is also helpful diagnose problems.
Pishta,
Agree with your comments in post #37. However, part of the quoted section is incorrect, with some strange claims. In terms of how the rocker pivots, whether it is a stud/trunnion type or Mopar shaft type, what is different in the rocker action? Nothing! Nothing other than how the rocker is held in place & operates through it's cycle. Another way to view it : the Mopar rocker pivots on a shaft of 7/8"? diam. The stud rocker also pivots on a shaft, diam is the trunnion brg OD. The point is they are both pivoting around a centre. So moving the adj up or down with either type will have identical lift, ratio etc & the claim that the ratio does not change for the stud type is incorrect. It will change as per the diagram.
Agree with your comments in post #37. However, part of the quoted section is incorrect, with some strange claims. In terms of how the rocker pivots, whether it is a stud/trunnion type or Mopar shaft type, what is different in the rocker action? Nothing! Nothing other than how the rocker is held in place & operates through it's cycle. Another way to view it : the Mopar rocker pivots on a shaft of 7/8"? diam. The stud rocker also pivots on a shaft, diam is the trunnion brg OD. The point is they are both pivoting around a centre. So moving the adj up or down with either type will have identical lift, ratio etc & the claim that the ratio does not change for the stud type is incorrect. It will change as per the diagram.
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