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QuoteReplyTopic: hi comp pistons Posted: 26 Jun 2013 at 8:32pm
Does anyone out there know if you can install ap46 M&W pistons in a series four d-17 without any cutting? Next what are some experiencies with rear wheel weights versus liquid ballast?
Those pistons should be a 2.94" compression height, meaning from the center of the wrist pin to the top of the piston measures 2.940". They have a 70CC dish in them.
Now do the math for those specs and that piston in it's intended 4" stroke engine was right near 8 : 1 (7.85 : 1 to be exact) compression ratio. Put it in a 4.5" stroke engine and figure the compression ratio... and you'll be in the 12.5 : 1 by simply trimming the tops enough to miss the head. But you'll need a little valve relief, or trim the pistons more all around for clearance.
I put a set in like you wish to do, I trimmed about .050" off going from memory. There is a direction arrow cast in the top of the pistons, some of it is still visable after I trimmed them. I measured them, did the math and cut the appropriate amount to have some piston protrusion from the block deck to have them come up close to the head for a quench. Then I cut the bowls out to allow for a compression reduction and cut valve reliefs in them. I was aiming for a 11.25 : 1 compression ratio when I built it. I just degreed the stock cam in at a 105* intake centerline.
There's a few varoius threads where I explained things, put some pictures up but you'll find nothing usefull other than a rant from our village idiot on how this or that is wrong, how it's impossiable to do in the first place....etc.
Point is it's easy to do, weather you want to trim all the relief off the top, or trim and build a quench engine, it's going to take some simple machine work to put them in your engine. Or a thick custom copper head gasket and no machine work.
"see what happens when you have no practical experience doing something...... you end up playing with calculators and looking stupid on the internet"
I really haven't ever figured out why anyone would want to reuse a piston that has been ran 50 years let alone push the compression ratio up several points on them unless they have some and are trying to push on someone for a quick buck especially when a set of 4 forged pistons at any comp. height can be purchased new with pins for around 450. Not to mention large crevice volumes are bad only thing good from them is flames out the exhaust from the not burned trapped fuel . It makes a show that will get a wow from uneducated spectators .Crevice volume is figured at distance of top ring groove to deck of piston on this calc. http://www.rosspistons.com/products/calculator.html
What's amazing is that pistons cost $650 in March in your ad with no rings but are $450 now after getting busted up haveing to get Ray to do your dirty work.
It's smarter to use 50 yr old pistons that work than it is to use 50 yr old rods that don't work when good ones are available for purchase from a reputable forum member and other suppliers.
Hey Guys No one has addressed the question of liquid ballast in the tires verses external wheel weights, must be this question is either too simple or to hard to answer. NNYACAL
I really haven't ever figured out why anyone would want to reuse a piston that has been ran 50 years let alone push the compression ratio up several points on them
Hey spanky, where did you get the idea he wanted to use USED pistons? I see NOS stuff sell almost every day. Oh ya, NOS means New Old Stock.
http://www.ae-ta.com Lena 1935 WC12xxx, Willie 1951 CA6xx Dad bought new, 1954WD45 PS, 1960 D17 NF
I don't care which side you are on. Language and adult themes will not be tolerated. Consider yourselves warned. Another offense like that and your gone. If you wonder who is involved, here's a clue... If I deleted your post, you are involved.
I'll tackle the liquid vs cast weight thing. If you never plan on changing weight classes then liquid is probably ok. If you want to roll in as light as possible and starting pulling every weight class from there up, then you need the cast stuff to throw on. I get to one antique pull a year and see guys run in the 3,500 lb class and throw weight at 250 or 500 lb increments all the way to the 5 or 6,000 classes. Watch the same tractor about 5 or 6 times weighing more each time. Need cast for that. AaronSEIA
I don't care which side you are on. Language and adult themes will not be tolerated. Consider yourselves warned. Another offense like that and your gone. If you wonder who is involved, here's a clue... If I deleted your post, you are involved.
Those pistons should be a 2.94" compression height, meaning from the center of the wrist pin to the top of the piston measures 2.940". They have a 70CC dish in them.
Now do the math for those specs and that piston in it's intended 4" stroke engine was right near 8 : 1 (7.85 : 1 to be exact) compression ratio. Put it in a 4.5" stroke engine and figure the compression ratio... and you'll be in the 12.5 : 1 by simply trimming the tops enough to miss the head. But you'll need a little valve relief, or trim the pistons more all around for clearance.
I put a set in like you wish to do, I trimmed about .050" off going from memory. There is a direction arrow cast in the top of the pistons, some of it is still visable after I trimmed them. I measured them, did the math and cut the appropriate amount to have some piston protrusion from the block deck to have them come up close to the head for a quench. Then I cut the bowls out to allow for a compression reduction and cut valve reliefs in them. I was aiming for a 11.25 : 1 compression ratio when I built it. I just degreed the stock cam in at a 105* intake centerline.
There's a few varoius threads where I explained things, put some pictures up but you'll find nothing usefull other than a rant from our village idiot on how this or that is wrong, how it's impossiable to do in the first place....etc.
Point is it's easy to do, weather you want to trim all the relief off the top, or trim and build a quench engine, it's going to take some simple machine work
illionois nazi says he seen a 11.25.1 compression ratio tractor rake hay . This means one of two things with the cam degee in at 105 advance the dynamic compression ratio should be as about equal to the static compression ratio as one can get. That means the motor octane a demand would be for high quality octane fuels . Unless the crevice volume wasn't taken into consideration when static compression was calculated which would in turn lower the static compression ratio lower than what was originally calculated . At the minimum 93 octane would have to be used injunction with low timing and cold plugs and the fuel consumption of a compression engine would not make a engine with a compression ratio in double digits economical to rake hay with. A stock cam not degree in on 105 advanced and installed straight up or retarded would blow of some cylinder pressure lowering the dynamic compression ratio considerably lower than the calculated static compression ratio wither it was calculated correctly or incorrectly taking in all details or overlooking small details .
illionois nazi says he seen a 11.25.1 compression ratio tractor rake hay . This means one of two things with the cam degee in at 105 advance the dynamic compression ratio should be as about equal to the static compression ratio as one can get. That means the motor octane a demand would be for high quality octane fuels . Unless the crevice volume wasn't taken into consideration when static compression was calculated which would in turn lower the static compression ratio lower than what was originally calculated . At the minimum 93 octane would have to be used injunction with low timing and cold plugs and the fuel consumption of a compression engine would not make a engine with a compression ratio in double digits economical to rake hay with. A stock cam not degree in on 105 advanced and installed straight up or retarded would blow of some cylinder pressure lowering the dynamic compression ratio considerably lower than the calculated static compression ratio wither it was calculated correctly or incorrectly taking in all details or overlooking small details .
How about a third thing Mitch, they were raking with a diesel
http://www.ae-ta.com Lena 1935 WC12xxx, Willie 1951 CA6xx Dad bought new, 1954WD45 PS, 1960 D17 NF
I guess I can't think of any manufacturer that ever made a true compression ignition (diesel) engine at 11.25 to 1 compression, so I guess they were not raking ray with a diesel.
illionois nazi says he seen a 11.25.1 compression ratio tractor rake hay . This means one of two things with the cam degee in at 105 advance the dynamic compression ratio should be as about equal to the static compression ratio as one can get. That means the motor octane a demand would be for high quality octane fuels . Unless the crevice volume wasn't taken into consideration when static compression was calculated which would in turn lower the static compression ratio lower than what was originally calculated . At the minimum 93 octane would have to be used injunction with low timing and cold plugs and the fuel consumption of a compression engine would not make a engine with a compression ratio in double digits economical to rake hay with. A stock cam not degree in on 105 advanced and installed straight up or retarded would blow of some cylinder pressure lowering the dynamic compression ratio considerably lower than the calculated static compression ratio wither it was calculated correctly or incorrectly taking in all details or overlooking small details .
How about a third thing Mitch, they were raking with a diesel
he says he saw the tractor wi was talking about a 11.25.1 rake hay at the end of a day
What's amazing is that pistons cost $650 in March in your ad with no rings but are $450 now after getting busted up haveing to get Ray to do your dirty work.
It's smarter to use 50 yr old pistons that work than it is to use 50 yr old rods that don't work when good ones are available for purchase from a reputable forum member and other suppliers.
Rod would you put that much compression on a M&W piston manufactured 50 years ago? I remember you saying you wouldn't put that much compression on a new manufactured 413 chrysler cast piston.
For the average guy pulling on a budget , used pistons could be very welcome. If the clearence was a bit much they could be knurled and hand fitted. I I R C , knurling pistons used to be a fairly common fix for taking up a little slop and benifitted a pistons ability to keep an oil film between its self and the cylinder wall.
For the average guy pulling on a budget , used pistons could be very welcome. If the clearence was a bit much they could be knurled and hand fitted. I I R C , knurling pistons used to be a fairly common fix for taking up a little slop and benifitted a pistons ability to keep an oil film between its self and the cylinder wall.
knurling tools sell around $200.00. ceramic coatings is another way to get about .002 . both remove any economics of utilizing 50 year old pistons. not to mention most want one on here to last 20 years to be considered reliable
For the average guy pulling on a budget , used pistons could be very welcome. If the clearence was a bit much they could be knurled and hand fitted. I I R C , knurling pistons used to be a fairly common fix for taking up a little slop and benifitted a pistons ability to keep an oil film between its self and the cylinder wall.
knurling tools sell around $200.00. ceramic coatings is another way to get about .002 . both remove any economics of utilizing 50 year old pistons. not to mention most want one on here to last 20 years to be considered reliable
I had 4 pistons knurled several years ago, for the cost of a 12 pack, but then I didn't tell the guy how to do it or try to impress him with what I knew, or dazzle him with BS. Knurling pistons is probably one of the least expensive operations in an auto machine shop. Fitting them to the cylinders is time consuming tho, that part of it I did myself.. Your could benifit by forgetting what you think you know , and find a good machine shop in your area,and let an expert build your engines.
I had 4 pistons knurled several years ago, for the cost of a 12 pack, but then I didn't tell the guy how to do it or try to impress him with what I knew, or dazzle him with BS. Knurling pistons is probably one of the least expensive operations in an auto machine shop. Fitting them to the cylinders is time consuming tho, that part of it I did myself.. Your could benifit by forgetting what you think you know , and find a good machine shop in your area,and let an expert build your engines.
Probably had half a dozen different knurling tools at the shop I worked. I used them off and on and it seems they will work over and over again without any maintenance. They come in REAL handy for a lot of things other than pistons and if a shop doesn't have one, they can't economically fix a LOT of things like the undersize front spindles in my 79 F150 4x4.
http://www.ae-ta.com Lena 1935 WC12xxx, Willie 1951 CA6xx Dad bought new, 1954WD45 PS, 1960 D17 NF
Not to many on here own a shop or a knurling tool .For some of us that do a knurling tool is handy . Yes the shop will knurl them for you that's one way to recover the expense of the tool. If a piston needs knurled most of the time a closer look would find something else worn on it as well ,examples like ring lands wrist pin bore etc. Expert machine shops usually try to steer the customer away from using 50 year old parts when new parts are easy to obtain. Then they are the customers like some that has expert shop looking for a piston ring that's none existing remember the shop looking for the ring longer than .005 file fit cause the customers read something on here where someone promotes the use of using worn out parts . Piston technology and materials have definitely made progress in the last 50 years making a new old stock fifty year old piston obsolete to today's piston manufacturing standards.
Not to mention the same guys promoting use of a 50 year old m&w piston with a 2.9 comp. height also argues for use of long rods and pistons with short compression height . It kind of makes one wonder if they really believe what they argue or just argue.
Yes the shop will knurl them for you that's one way to recover the expense of the tool. Then they are the customers like some that has expert shop looking for a piston ring that's none existing remember the shop looking for the ring longer than .005 file fit cause the customers read something on here where someone promotes the use of using worn out parts .
ANY shop worth having will not knurl a piston with bad ring lands unless they are capable of re-cutting the lands and fitting a wider ring or making a back-up ring. 50 year old aluminum pistons will always have the ring groove stretched out beyond acceptable working tolerance.
http://www.ae-ta.com Lena 1935 WC12xxx, Willie 1951 CA6xx Dad bought new, 1954WD45 PS, 1960 D17 NF
Yes the shop will knurl them for you that's one way to recover the expense of the tool. Then they are the customers like some that has expert shop looking for a piston ring that's none existing remember the shop looking for the ring longer than .005 file fit cause the customers read something on here where someone promotes the use of using worn out parts .
ANY shop worth having will not knurl a piston with bad ring lands unless they are capable of re-cutting the lands and fitting a wider ring or making a back-up ring. 50 year old aluminum pistons will always have the ring groove stretched out beyond acceptable working tolerance.
So your just arguing . Cause you are in a agreement with me that a fifty year old piston if new pistons can be obtain even if its custom that the 50 year old pistons belong in scrap bin . cause knurling re working ring lands opening pin bore to next size etc costs time and time costs money. where do you draw the line in piston repairs. Ps when you quote me quote it all this picking sentence and not showing the complete context is getting old and has always been inmature
It goes without sayin that only a piston that is sound would be re used. As for argueing, That is your only area of expertise., and no one here could argue with that.
A piston requiring work other than sanding down the casting lines that could create hot spots and cutting valve reliefs isn't sound in my opinion. by the sound of it your definition of sound isn't as critical in some areas as mine. As for arguing I don't argue I express my opinions so others can adopt them for their own
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Probably had half a dozen different knurling tools at the shop I worked. I used them off and on and it seems they will work over and over again without any maintenance. They come in REAL handy for a lot of things other than pistons and if a shop doesn't have one, they can't economically fix a LOT of things like the undersize front spindles in my 79 F150 4x4. 