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Predator, Wiseco Piston Issues.

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PoPgetbizi

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Has anyone successfully installed and ran a Wiseco 2.756 piston in any
Predator Engine. I have tried two separate pistons in tow separate Hemi
engines with file fitted rings and it still pumps oil. Both blocks were Honed
before the pistons were installed. I can't figure out what I am not doing
right.
 
what is the piston clearance? on the two I have the 2.756 piston is a drop in deal, if you try to straighten the bore and use the 2.756 piston then you will have to much piston to cylinder clearance, the last one I used the 2.776 piston haven't had any oil issues with mine
 
Like this guy said above, the 2.756 wiseco should be a direct fit for the stock hemi predator. When you say it still pumps oil, do you mean your getting oil past the rings and into the combustion chamber, causing the engine to smoke excessively? If so, you may have too much gap on the bottom oil rings or 2nd ring, what did you set the ring gaps at?
 
Yes the Oil is getting into the combustion. The Wiseco only has two ring lands, Where the Stock Piston have Three, first, second, then the oil.
I filed the rings to .011 for the top ring, and .014 for the oil rings. the oil rings were clocked 180 degrees. My first setup was on an engine that had already
been ran. I purchased a Brand New one. Set it up and had the same results. The Piston clearance is .004 on the skirts. That Wiseco Piston is a direct fit
but there is still a slight side to side movement of it in the Cylinder. I used SAE Non Detergent 30 oil for the break-in and each time it ran for about 8 min
and then started smoking excessively. The Rings that come with NR's kit are .018 top ring and .020 for the oil rings so I got some .020 over @ 2.776 and
filed them to .011 and .014 respectfully.
 
Are you sure it's coming from the rings? Sounds like you did everything correctly. Worn guides??
 
There is a limit on how big of a oversize can be cut to fit a smaller bore, as it makes the ring "egg shapped". I don't know what than number would be on one of these though. I have used the wiseco, with the rings that came with it..with no issues.
 
I took the Cylinder head off the engine this morning and found a broken valve spring (intake). Also the exhaust port is obviously
black from the oil burning in the cylinder. The Head was Milled .035 when I built the motor. I'm gonna take it and have it checked
for cracks. I originally used one .010 head gasket and it ran fine with the stock piston. I didn't have any problems until I changed
the piston.
 
Did the head gasket show any signs of blowing? Black along the edges of the gasket is a normal sign of a blown gasket, but even with a blown head gasket you shouldn't be seeing excessive smoke unless its pretty bad. I believe you may have started with too big oversized rings and they are not sealing in the cylender, they could be egg shaped like Barry said above. Try the stock predator rings and see if that fixes it
 
Let me state what initially prompted me to go with the Wiseco. Everytime I ran my bike, afterwards I would change or at least check my oil. It was always black.
Good Oil I'm using. (Amsoil) I pulled the piston and checked the clearances, then the rings. Remind you that the engine ran okay. When I checked the ring gaps
they were .018 top ring, .020-.022 second ring, and over .025 on the oil rings. Okay So the Predator engines are manufactured with there tolerances all over the
place. I decided to go with the aftermarket piston from Wiseco because seemingly No One else makes one. When I checked the Rings that came with the kit they
were the same as the Predator stock ones. Local Builders are going .006 on the top ring, .008 on the second ring, and .012 for the oil rings. Well Wiseco Pistons
only have Ring Two Ring Lands. So I brought some .020 over @ 2.776 and filed them to Wiseco's recommended sizing .004 x cylinder bore which gave me .011
top ring and .015 for the oils. That's where I'm at. Engine still not running. Still have to get the head tested.
 
These engines tolerate loose rings, big end gaps etc. very well. The most common excessive oil consumption problem comes from the head gasket. It leaks between the cylinder and oil passage, this will force combustion gasses into the crankcase, (black oil) it will also draw oil from the crankcase on the intake stroke. Flooding the cylinder. Investigate why the valve spring would break that is not typical.
 
It obviously was Coil bind. The springs were 37lb, but they were used. I have some new ones now and they are 37lb also, but they have the appearance of being about
.040 taller than the previous ones. I'm just not certain if that caused oil getting into the combustion chamber. I intend to rework the Head if it proves to be usable. I was
able to nicely port the head and it made decent power. I weigh almost 300lb and I clocked myself at 63mph before the 1/8 mile. Most builders in my area don't believe
Predator's are a good platform to start with. Now I KNOW WHAT TO CHECK. I've built small block chevy's so I have been trying to apply my skill set to the small engine.
I came on this Forum to share my experience and get a little help from the experienced.
 
PoPgetbizi said:
Has anyone successfully installed and ran a Wiseco 2.756 piston in any
Predator Engine. I have tried two separate pistons in tow separate Hemi
engines with file fitted rings and it still pumps oil. Both blocks were Honed
before the pistons were installed. I can't figure out what I am not doing
right.
Click to expand...

Guides?
 
Through trial and error I've come full circle to re-installing the stock Piston back into my engine, After solving my spring
issue the engine still pumped oil with that 2.76 Wiseco Piston. I noticed the the Wiseco Piston rocked slightly from side
to side. Maybe there's difference of some sort between the 69730 and the 60363. I have only tried that Wiseco Piston
in the New Hemi style Predator. At any rate I put the Stock Piston back in it and I'll be damned if it didn't start up on the
second pull. I ran the engine at 2500 rpm for about 12 min and it ran perfect. The Part number on that Wiseco Piston is
1982P194 from NR Racing. That Piston is Labeled as a Briggs Stroker Unchromed. I would be interested to know if anyone
has tried to run that Piston in a Predator Hemi. Remember I tried two different Pistons in two different engines. The first
one had been ran and the second one was brand new out of the box. They both pumped oil.
 
odd problem.
Obviously the wiseco is short skirt, which will attribute some of the side to side motion.
funny the stock one does not pump oil it is full skirt is it not.
have you got it vented well? which with the stock piston being ok , seems moot but the 2 ring may not take much crank case pressure.
same head and head gasket package?
 
If it was his valve guides the engine would still be smoking after he put the stock piston back in it....he said its not, meaning the piston or rings had to be the cause of the problem, not valve guides. I'm thinking you may have had too much piston/cyl clearance or something with the rings letting oil past the rings.
 
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