Drop in pistons, to do or not to do “that’s the question”??
Mar 14, 2008, 02:52 PM
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Drop in pistons, to do or not to do “that’s the question”??
Ok guys, I really need serious opinion: there’s a real debate if to do a stock size piston and roads in a “drop in” without rebuilding the engine, obviously to save money and to save time, that’s the advantage of going this route, however the disadvantage is that you don’t balance the crank with the new pistons and roads etc., but guys that do it say it’s working…
Good vendors like Buschur Racing and TTP, say it is working good whit no problems!
I must say I’m tempted to try this route, but I’m concerned to do it.
I will like to hear your opinion: from guys that went this way and have good experience and guys that went this way and have no luck…
also it will be wonderful to hear the opinion of experience vendors like David Buschur, AMS and TTP, I know for you its more profitable to sell short block, but you also offer the drop in piston route, pleas open our eyes…
Good vendors like Buschur Racing and TTP, say it is working good whit no problems!
I must say I’m tempted to try this route, but I’m concerned to do it.
I will like to hear your opinion: from guys that went this way and have good experience and guys that went this way and have no luck…
also it will be wonderful to hear the opinion of experience vendors like David Buschur, AMS and TTP, I know for you its more profitable to sell short block, but you also offer the drop in piston route, pleas open our eyes…
Mar 14, 2008, 02:56 PM
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well just like anything it may work for some but not for all. If you take the easy way out it may pay off or it will just come back to bite you in the a@#. I'm doing a rebuild right now and have it all balanced.
Mar 14, 2008, 04:06 PM
#4
I debated this for months before doing it. I too was concerned about the balenecing of the assembly. After talking to many experts I began to understand how it is not as critical on an inline 4 cylinder compared to an engine with opposing pistons. I went as far as to remove the balance shafts as well. All with the engine in place. My recomendation is to go for unless you want to eliminate the balance shafts. In retrospect it would have been easier to just take the engine out. Mine worked out great and I feel zero difference with vibration. I turned down the front shaft on a lathe, but AMS sells one as well. Good luck.
Mar 14, 2008, 04:21 PM
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I debated this for months before doing it. I too was concerned about the balenecing of the assembly. After talking to many experts I began to understand how it is not as critical on an inline 4 cylinder compared to an engine with opposing pistons. I went as far as to remove the balance shafts as well. All with the engine in place. My recomendation is to go for unless you want to eliminate the balance shafts. In retrospect it would have been easier to just take the engine out. Mine worked out great and I feel zero difference with vibration. I turned down the front shaft on a lathe, but AMS sells one as well. Good luck.
Thanks for your feedback, good to hear it did work for you.
What kind of power are you doing? How long ago you did it? And what pistons and rods you got?
Mar 14, 2008, 05:02 PM
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Problems with the drop in method;
1.) Piston to wall clearance. Forged alloys have different expansion rates than cast pieces which the factory block is set up for. It's easy to end up with excess friction, scuffing and wear. This makes heat, pumps metal particles through the engine and costs you HP.
2.) Improper cylinder finish. This affects how the rings wear in and "seat". Aftermarket pistons rings are made from different materials than factory rings and most don't like the particular finish on the factory walls. Piston rings are designed to be used with very specific wall finishes, most of which wont work on the generally rough factory finish. Consequently you end up with less than ideal sealing. Can we say, "blowby"!!
3.) Inconsistent castings. Mass produced blocks are anything but perfect and many times the cylinders are out of round. This is why it's best to bore and plate hone the blocks. It brings the cylinders back into round and gives them the correct wall finish so the rings seat.
You can drop in standard bore pistons into a stock block, but you're sacrificing most of the benefits of an upgraded piston.
1.) Piston to wall clearance. Forged alloys have different expansion rates than cast pieces which the factory block is set up for. It's easy to end up with excess friction, scuffing and wear. This makes heat, pumps metal particles through the engine and costs you HP.
2.) Improper cylinder finish. This affects how the rings wear in and "seat". Aftermarket pistons rings are made from different materials than factory rings and most don't like the particular finish on the factory walls. Piston rings are designed to be used with very specific wall finishes, most of which wont work on the generally rough factory finish. Consequently you end up with less than ideal sealing. Can we say, "blowby"!!
3.) Inconsistent castings. Mass produced blocks are anything but perfect and many times the cylinders are out of round. This is why it's best to bore and plate hone the blocks. It brings the cylinders back into round and gives them the correct wall finish so the rings seat.
You can drop in standard bore pistons into a stock block, but you're sacrificing most of the benefits of an upgraded piston.
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Mar 14, 2008, 05:14 PM
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Problems with the drop in method;
1.) Piston to wall clearance. Forged alloys have different expansion rates than cast pieces which the factory block is set up for. It's easy to end up with excess friction, scuffing and wear. This makes heat, pumps metal particles through the engine and costs you HP.
2.) Improper cylinder finish. This affects how the rings wear in and "seat". Aftermarket pistons rings are made from different materials than factory rings and most don't like the particular finish on the factory walls. Piston rings are designed to be used with very specific wall finishes, most of which wont work on the generally rough factory finish. Consequently you end up with less than ideal sealing. Can we say, "blowby"!!
3.) Inconsistent castings. Mass produced blocks are anything but perfect and many times the cylinders are out of round. This is why it's best to bore and plate hone the blocks. It brings the cylinders back into round and gives them the correct wall finish so the rings seat.
You can drop in standard bore pistons into a stock block, but you're sacrificing most of the benefits of an upgraded piston.
1.) Piston to wall clearance. Forged alloys have different expansion rates than cast pieces which the factory block is set up for. It's easy to end up with excess friction, scuffing and wear. This makes heat, pumps metal particles through the engine and costs you HP.
2.) Improper cylinder finish. This affects how the rings wear in and "seat". Aftermarket pistons rings are made from different materials than factory rings and most don't like the particular finish on the factory walls. Piston rings are designed to be used with very specific wall finishes, most of which wont work on the generally rough factory finish. Consequently you end up with less than ideal sealing. Can we say, "blowby"!!
3.) Inconsistent castings. Mass produced blocks are anything but perfect and many times the cylinders are out of round. This is why it's best to bore and plate hone the blocks. It brings the cylinders back into round and gives them the correct wall finish so the rings seat.
You can drop in standard bore pistons into a stock block, but you're sacrificing most of the benefits of an upgraded piston.
Mar 14, 2008, 05:42 PM
#9
Our 10 second passes were accomplished on drop in wiseco pistons, eagle rods and clevite77 bearings. As long as you put a quick hone on the cylinders to break the glazing, file to fit the rings, remove and replace the oil squirters and keep everything clean, there is no reason why your drop in procedure would not be anything but sucessful.
In our local market 600+ whp has been demonstrated on a number of Evo's on drop in builds.
Good Luck!
TTP
In our local market 600+ whp has been demonstrated on a number of Evo's on drop in builds.
Good Luck!
TTP
Mar 14, 2008, 06:35 PM
#11
im running the drop in wiescos with manely rods, i took the engine out though because i was doing more than that. i have 1k on them now and no smoke or any bad vibrations. it definetly pulls harder but i dont know how much of that i can credit to the pistons. i also had the block honed before i put the pistons in. i went off the stock piston rings for measuring the clearence for the drop in ones.
Mar 14, 2008, 08:38 PM
#12
I made 500 WHP on a 50 trim. A quick and light hone before I installed CP pistons and eagle rods. Did it about 9 months ago and have had no problems. I definitly did not sacrifice HP. I don't know of too many 50 trims making more power and mine in a non-BB homemade turbo kit. No blowby problems. Very happy with CP rings.