Another Fix? Swaintech coated pistons

milehighassassin · Apr 1, 2011

I found myself on the Swaintech website and saw that they can tighten up piston skirt clearances with their coatings.

They can make up 0.004" of difference. It seems to me that this might be a pretty cheap and easy fix. Seems that this would be enough to tighten up the OEM pistons.

Cost: $24 per piston for side only or for $44 per piston you can have the piston dome coated with a different coating and have the side piston done as well.

On a used piston there would be a cleaning fee, which I imagine wouldn't be much. Probably $100 total?

http://www.swaintech.com/store.asp?pid=10972

Thoughts?

2XM3 · Apr 1, 2011

I have used swain for years, really nice coating, very good idea. And even better is that the coating will wear off in areas you have tight spots, thus actually making things more "round" as the crappy cylinder distorts.
It would be interesting to take that baby to .003 clearance and see if it would stick or not (i'm not going to go that tight tho...lol)

skibreeze · Apr 1, 2011

I had my pistons done by Swain tech last year. I did it to tighten up the clearance as well as to reduce heat transfer through the piston. This gives it a little insurance with a lean fuel map. I also added a PCV and now have 800 miles on those pistons with no scoring.

If going through all the work and expense to do this, I would just use new pistons.

augerin · Apr 1, 2011

Your still going to have high side loading due to the high pin location on the stock piston and that kinda bothers me. Especially after all the broken cylinder skirts we are seeing(me included). I like the idea but am still leaning to the Fix.

skibreeze · Apr 1, 2011

Agreed. Although it seems that loose case to block clearances can be the blame for those failures also.

Angermangement890 · Apr 1, 2011

augerin said:
Your still going to have high side loading due to the high pin location on the stock piston and that kinda bothers me. Especially after all the broken cylinder skirts we are seeing(me included). I like the idea but am still leaning to the Fix.

How about using a 136mm rod a 4mm increase from the stock 132mm rod? The older BB 800 used a 136mm rod with great success, no funky side loading on that engine. Hot Rods sells the 800 BB connecting rod for $100 ish. You would have some machining to achieve the proper lower rod pin size.

modjunkie · Apr 1, 2011

Angermangement890 said:
How about using a 136mm rod a 4mm increase from the stock 132mm rod? The older BB 800 used a 136mm rod with great success, no funky side loading on that engine. Hot Rods sells the 800 BB connecting rod for $100 ish. You would have some machining to achieve the proper lower rod pin size.

Wouldn't you have problems with port timing if you increased the stroke without changing where the piston sits in the clylinder, or am i not thinking about that right.

I think that the coating might work on some pistons. My stock pistons were alot further out the .004 i think this fix would only work on some sleds.

Angermangement890 · Apr 1, 2011

modjunkie said:
Wouldn't you have problems with port timing if you increased the stroke without changing where the piston sits in the clylinder, or am i not thinking about that right.

I think that the coating might work on some pistons. My stock pistons were alot further out the .004 i think this fix would only work on some sleds.

Changing the rod length does not affect the stroke. The lower rod pin would still be in the same place, only the length of the rod would change. The port timing would remain the same as long as a spacer equal to the rod length change was placed under the cyl. Longer rods would reduce the side loading presently found in this engine and as a side benefit the longer rod with a spacer would increase the case volume of the engine.

skibreeze · Apr 1, 2011

I prefer the taller piston fix vs a longer rod. Less rocking in the bore.

Angermangement890 · Apr 1, 2011

skibreeze said:
I prefer the taller piston fix vs a longer rod. Less rocking in the bore.

Its kinda 6 of 1 and a half dozen of the other. Both fixes achieve the same result, less side loading of the piston and less piston rocking. The "Fix" does not address the poor rod ratio on the current engine, it only masks it with the taller piston. The stock rod is 132mm with a 70mm stroke that gets you a rod ratio of 1.88, a 136mm rod with the 70mm stroke gets a rod ratio of 1.94.

This rod ratio has been an issue with the small block based 800 engines since 02 when Polaris had the 797, that was 128mm rod with a 70mm stroke and a 1.82 rod ratio. That engine was know for beating the heck out of the piston on the exhaust side and occasionaly breaking the rod in the middle of the beam. The problem started there and Polaris evolved the combo, thus the move to the 132mm rod 70mm stroked engines. I still think the rod is too short at 132mm. Longer rods have been proven to make more HP and TQ in countless engine applications.

Combine the 2 fixes and I think you have a real winner.

milehighassassin · Apr 1, 2011

Can longer rods be added without taking apart the bottom end?

milehighassassin · Apr 1, 2011

I think I might yank my pistons and measure clearance. If I can get them closer I will do this.

I have had a set of regular Wiseco drop-ins on order for over 3 weeks, frustrated that I have not received them. Every time I call they say they are on the way.... :-(

Angermangement890 · Apr 1, 2011

milehighassassin said:
Can longer rods be added without taking apart the bottom end?

No, the bottom end must be split, but if your going to attempt a few of the ideas to tighten up the case/cyl clearance, its a non issue.

2XM3 · Apr 2, 2011

But the biggest issue for most people would be pressing the crank apart and then back togeather to change the rods, it requires the assembly be sent to the crankshop,indydan or others to do. So between rods,freight,pressing,balance ect it adds up, BUT I agree 100% that a rod ratio increase as well as a longer piston would help the problem greatly.

at some point it is actually more cost effective to $hit can the motor and or the sled for another. I can think of many examples of my old racer customers who just flogged and flogged a poor combination while gettin spanked by there oponents while just stuffing money in the garbage can, no matter how hard I told them peoples ego just gets in the way of taking there losses and moving on...sucks this happens in a stock low stress production engine ment to be pull and go....should be a recall of all these motors.... :deadhorse:

::

Angermangement890 · Apr 2, 2011

2XM3 said:
But the biggest issue for most people would be pressing the crank apart and then back togeather to change the rods, it requires the assembly be sent to the crankshop,indydan or others to do. So between rods,freight,pressing,balance ect it adds up, BUT I agree 100% that a rod ratio increase as well as a longer piston would help the problem greatly.

at some point it is actually more cost effective to $hit can the motor and or the sled for another. I can think of many examples of my old racer customers who just flogged and flogged a poor combination while gettin spanked by there oponents while just stuffing money in the garbage can, no matter how hard I told them peoples ego just gets in the way of taking there losses and moving on...sucks this happens in a stock low stress production engine ment to be pull and go....should be a recall of all these motors....::

The crank can be split, and new rods installed for $300-400 in my area and that includes the rods.

I agree with you though, at some point you need to just walk away. At times I get really tired of the squishy sound my brain makes when I bang my head against a wall for a while so I stop. Although its tough to do when the chassis is so much fun to ride.

I think the engine needs to be addressed from the standpoint of a total build where all clearances are measured and set by the builder to appropriate tolerances for the engines intended use. I personally think its crazy that all this work has to go into making a stock engine live. And I'm blown away by how far out of tolerance these engines and engine parts are. Have you measured a 2010 or 2011 cyl to check and see if they corrected the issue on the later years, I know the casting changed companies for 08-09 and 10-11.

2XM3 · Apr 2, 2011

on the 2010 the cylinder skirt is 2mm thicker on each side, thus giving (or getting very close to depending on case) the correct zero clearance fit. The skirt is also a bit longer and the 08-09 case must be bored deeper to allow the 2010 cyl to be fit. As far as I can tell so far the bore size is the same on the 2010. Polaris lists the same part number for the 2009 and 2010 replacement piston, the 2011 takes a different part number as well as a totally different cylinder. I have not had a 2011 apart and measured it.

I do not know if the webbing on the 2010 case was changed to help with bore distortion issues, but from the piston size listed I would suspect that it is still set at the .009 area as if they tightened it with the same distorted cyl in some cases there would be the sticking problem again... IMHO I would NOT set the piston any tighter than .006 in a 2008-2010 case that was correctly honed..yes .004 would be great but would kind of scare me due to the egg shaped cyl I have seen. And I really think that a motor at .006 with the zero to press fit cyl to case should live...maybe..kind of..perhaps..chances are.... :loco:

2XM3 · Apr 2, 2011

Oh on a side note fyi deal, in the past (maybe 20 years) it became the vogue to build big block chevys with a short deck bowtie (4.5 bore) block but still make a 540 inch motor by stuffing in a 4.250 crank using a stock 6.135 rod and a custom piston...wellllllll...this gave a horrendous rod ratio of around 1.4, these motors had a very short life,broke pistons,insane high oil temps due to side load, bad power due to drag,cracked skirts ect ect...just going to the 6.385 rod in tall deck ...all issues solved. I like rod ratio of 2/1 or better in any endurance engine.

augerin · Apr 2, 2011

Does anyone know if the piston ratio was addressed in the Carls Cycle 860 kit? These engines seem to work good and last. So what I am getting is install the BB rod and the Fix kit with an additional spacer, run the pistons at .006 clearance, and have the block fitted to the cylinders properly and I will have a realiable engine. Would there be any concern that with the additional spacers I might get a little more flex between the bottom and top end?
This is a great thread with some great info. I get the feeling that there are more and more of these failures popping up now that most of these sleds are getting to the end of there fuses. I havent seen many that have made it to 1k on the update.

Angermangement890 · Apr 2, 2011

augerin said:
Does anyone know if the piston ratio was addressed in the Carls Cycle 860 kit? These engines seem to work good and last. So what I am getting is install the BB rod and the Fix kit with an additional spacer, run the pistons at .006 clearance, and have the block fitted to the cylinders properly and I will have a realiable engine. Would there be any concern that with the additional spacers I might get a little more flex between the bottom and top end?
This is a great thread with some great info. I get the feeling that there are more and more of these failures popping up now that most of these sleds are getting to the end of there fuses. I havent seen many that have made it to 1k on the update.

The rod ratio has not been changed on the 860 kit, it still uses the 70mm stroke/132mm rod. My opinion is they are having better luck with longevity of the 860 as their cylinders/pistons may be get this novel idea......... round at operting temp. Weird.

I think the higher assembly tolerances they hold their engines to and the likely lower mass of the Wiseco piston they are using vs the cast stockers is probably not hurting things either.

I would not be overly concerned with case flex. I would have cometic make 1 spacer out of aluminum/steel and custom make metal base gaskets in the right thickness. I would take the thickness of the "fix" spacer and add the 4mm/0.1576" of rod change to it to arrive at the new spacer thickness. Cometic can make Viton coated Steel gaskets out of .010/.014/.020 thicknesses. They can do paper and foam coated aluminum in a variety of thicknesses up to .060" IIRC. I had lots of gaskets made at Cometic over the past 4 months to address the rod issues present on my 797's.

If my memory serves me right, in a conversation with IndyDan he mentioned having longer rods made for the 800 CFI. Might be worth a call to see where he is at.

Angermangement890 · Apr 2, 2011

2XM3 said:
Oh on a side note fyi deal, in the past (maybe 20 years) it became the vogue to build big block chevys with a short deck bowtie (4.5 bore) block but still make a 540 inch motor by stuffing in a 4.250 crank using a stock 6.135 rod and a custom piston...wellllllll...this gave a horrendous rod ratio of around 1.4, these motors had a very short life,broke pistons,insane high oil temps due to side load, bad power due to drag,cracked skirts ect ect...just going to the 6.385 rod in tall deck ...all issues solved. I like rod ratio of 2/1 or better in any endurance engine.[/QUOTE]

+1

Longer rods have proven to make more power and be easier on engine components, its been proven over and over in all forms of motorsports from Big Block V-8's to 4 cyls, to motorcycles and sleds.

I just can't figure out how Polaris had a good rod/stroke combo in the 800 BB for years, but had issues with crank durability. For the 800 CFi they addressed the crank durability issues but they invited an unproven rod/stroke combo to the party which is causing more havoc than the cranks of the 800 BB did. You think they would have shied away from anything that wasn't a proven winner after the 900 fiasco.

Just proves if you don't learn from history you are bound to repeat it.

Another Fix? Swaintech coated pistons

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