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[Mike m]

I'm very proud to do business with randy as he's gone far and above my expectations.thank you and this forum for its guidance

[Bill_Rockoff]

Somebody would deliberately build a 4-cylinder engine with two different types of pistons?

Ya learn something new every day.

[FJ_Hooligan]

Just a question;
Pistons 2 & 3 look to have a hole drilled in the wrist pin land.  Is that for splash oiling of the pin?

Is it any concern that 1 & 4 do not have that hole?

[fj1289]

Somebody would deliberately build a 4-cylinder engine with two different types of pistons?

Ya learn something new every day.

I’ll bet those four pistons are closer in weight than the production tolerances on the stockers. 

As far as building with different pistons — not the first choice I’m sure, but — depends on your goals and needs.  All out race engine - maybe - especially if it means getting a damaged engine back together for the next event/race/heat/round!  In order to get an engine back on the street within a budget?  Yep!  Bet it’ll go 100,000+ miles with no issues. 

Just slap any old set off random pistons together without regard to compression height, matching weights, etc - No!  Because then you are just relying on luck (but the funny part is, an FJ would probably run good and long even that way lol)

[FJ1100mjk]

Just a question;
Pistons 2 & 3 look to have a hole drilled in the wrist pin land.  Is that for splash oiling of the pin?

Is it any concern that 1 & 4 do not have that hole?

The holes on the wrist pin lands are only necessary to relieve potential pumping losses in the cam chain tunnel that cylinders two and three are adjacent to. The holes are not necessary on pistons for cylinders one and four, due to their respective distances from the cam chain's tunnel.

[Pat Conlon]

Just a question;
Pistons 2 & 3 look to have a hole drilled in the wrist pin land.  Is that for splash oiling of the pin?

Is it any concern that 1 & 4 do not have that hole?

The holes on the wrist pin lands are only necessary to relieve potential pumping losses in the cam chain tunnel that cylinders two and three are adjacent to. The holes are not necessary on pistons for cylinders one and four, due to their respective distances from the cam chain's tunnel.

Marty, I don't understand, can you help me?
 How do these holes thru to the piston pins, relieve pressures?

[fj1289]

Just a question;
Pistons 2 & 3 look to have a hole drilled in the wrist pin land.  Is that for splash oiling of the pin?

Is it any concern that 1 & 4 do not have that hole?

The holes on the wrist pin lands are only necessary to relieve potential pumping losses in the cam chain tunnel that cylinders two and three are adjacent to. The holes are not necessary on pistons for cylinders one and four, due to their respective distances from the cam chain's tunnel.

Marty, I don't understand, can you help me?
 How do these holes thru to the piston pins, relieve pressures?

Sounds like he is talking about the crank case webs

[racerrad8]

Just a question;
Pistons 2 & 3 look to have a hole drilled in the wrist pin land.  Is that for splash oiling of the pin?

Is it any concern that 1 & 4 do not have that hole?

Once again, a upgrade in design from Wiseco from the earlier version.

That is actually a drain hole for the oil to the wrist pin. The oil control ring land has a diagonal hole drilled in it to supply oil to the wrist pin. The early version just leaked out from either side of the boss.

The new version uses the drain hole.

Randy - RPM

[FJ1100mjk]

The holes on the wrist pin lands are only necessary to relieve potential pumping losses in the cam chain tunnel that cylinders two and three are adjacent to. The holes are not necessary on pistons for cylinders one and four, due to their respective distances from the cam chain's tunnel.

Marty, I don't understand, can you help me?
 How do these holes thru to the piston pins, relieve pressures?

Yea, they're there for oil drainage.

Sounded pretty authoritative though didn't it? 

[FJ_Hooligan]

Thanks Randy, that makes perfect sense.

Marty,
Nice try but everyone knows that the cam chain tunnel pumping losses are relieved by the auto adjusting cam chain plunger and the oil filter bypass valve. :-)

[FJ1100mjk]

Marty,
Nice try but everyone knows that the cam chain tunnel pumping losses are relieved by the auto adjusting cam chain plunger and the oil filter bypass valve. :-)

Must've missed that in the FSM. Probably in the back somewhere.

[Pat Conlon]

Pumping Pressures? Naaaa, not for me, I'm running an electric vacuum pump like the pro stock guys run.

Something I really think Chris should look into....

[Mike m]

As I was clean I g my oil pan after work last night I came across jb weld inside my oil pan as the previous owner repaired a crack in the pan.if randy hadn't recommend to me to change the pickup screen i would never have found that.

[ribbert]

 They are opposing cylinders, is that is why the piston are matched up the way they are.

Randy - RPM

If the pistons are physically the same, why does that matter?

Noel

[JMR]

So these are the pistons randy supplied Thier totally different are these ok to use as I've never mixed pistons

If Randy supplied them, I’d run them!  ........ Randy knows his shit and isn’t going to do anything on anyone’s build to compromise his business nor his reputation.  

  

Are you saying you would fit pistons so dissimilar in appearance and shape without question, just because you trust the supplier? Loyalty, trust, blind faith or being your buddy doesn't come into it, it's just common sense. I have seen first hand examples of this more times than I care to remember.

I don't care if God himself supplied parts, I would still check them, the onus is on the assembler to make sure they are correct before fitting and the difference in those pistons is more than enough to raise a red flag until an explanation is forthcoming, it is after all unusual.

What if he fitted them and they were wrong, everyone would look at the photo and say what an idiot, blind Freddie can see they're not the same.

Noel


Just to be perfectly clear, I have offered no opinion on the pistons other than acknowledging they are different in the photo and I have not been critical of Randy. I have only emphasised the wisdom in checking parts yourself before using them and presented a hypothetical scenario to make the point.

 

When it comes to checking the work, what and how do you check?  What you can?  What you have the tools to do?  What you have the know how and experience with the tools to do?  I’m sure I could take the same micrometer as Randy and get different measurements because my “ touch” is different.  Experience and expertise counts!  (Besides the fact I don’t even own a mic — how many here do?  And how many can use it to measure with repeatability?)

When it comes to swapping pistons I'd start with weight and move to crown displacement/shape. As for mics.....I'd suggest digital read out mics....they are easier to use if you want to get into precision tool measurements.