side pin vs top pin

[eli]

when did this come about and why .

[baja200merk]

Side pins were falling out. Top pin cannot come out but a lot of the experts like side pin so both ring gaps do not line up with each other. Done correctly side pin will not come out.

[racervboat]

I know it happens but just don't get how the pin can get past the ring gap? but it sure does happen.

[BUZZIN' DOZEN]

when did this come about and why .
'95 is about when they switched from Mahle's to wiesco's, if you have, from the factory, 141 rods then wiesco, if 5250 Mahle.
I've never heard of a Mahle losing a pin!

[racervboat]

Thought it was the factory 2.4 Bridgeport that started to loose the pins first?

[BUZZIN' DOZEN]

I never heard of a problem till they switched to wiesco's. the top pin 280 wiescos came out in 03'-04'? :confused:

[eli]

reason is i have a set of side pin mahle's i bought from jay smith racing and being low hour and fine condition was thinking of using them without having top pin till next go around ring job.

[BUZZIN' DOZEN]

I wouldn't have a problem running the "real" Mahles, but not the pro marine junkers!:nonod:

[Dave S]

1949 mercs were top pinned. Maybe 1954 they went side pin so the gaps didn't line up. No problem ever with merc rings turning till V6 big bore motors. Because the exhaust port is big and has no bridges. Every time the ring goes past that big hole it beats the locating ring. Bigger hp bigger hole. The shape also makes things happen differently. A nice shape will ease the ring back better. The pin on some pistons are fully covered by the ring....most 2.0/2.4s. Those are bigger pins than the ones on 2.5 motors that are half covered by ring. Most stock pistons will live till you bear/rev too much.Wiscos grow more and the pins fail. The males have trick wrist pin locks..... try to get them.

[BUZZIN' DOZEN]

Ain't buyin' it, never had a problem with the Austrian made Mahles, throw the wiesco's in and BOOM!

[JPEROG]

Detonation is the biggest culprit. Out of all the 2.4s and 2.5s that I have run, I had one pin rattle out. It made a mess but I shouldn't have been running old fuel and knew better.

Joe

[racervboat]

Thing was how does the pin get out past the ring gap? heat?

[eli]

Think it keeps wearing gene trichel from Oshkosh showed me many years ago how to properly stake pins in 86 200 so they don't move outward

[eli]

Think i,m going to lighten these and run them

[Dave S]

I think males are good.....don't know where ya going to lite em. 6000 rpm....100 per sexond.....things are happening fast. Turn up the speed....Ring flutter.

[coffeeguy]

What is meant by "staking" the locator pin and how is it done?

[eli]

I think males are good.....don't know where ya going to lite em. 6000 rpm....100 per sexond.....things are happening fast. Turn up the speed....Ring flutter.when I am strollin in my boat I get heart flutter

[Da Bull]

Very interesting thread

[FORBESAUTO]

Detonation is the biggest culprit. Out of all the 2.4s and 2.5s that I have run, I had one pin rattle out. It made a mess but I shouldn't have been running old fuel and knew better.

Joe

Im in this same boat. I think on a hot rod with extreme cylinder temps it's s good idea to top pin. But, I've never lost a side pin yet ( my tight wod self too cheap to get top pinned). I think heat and age is the culprit, as long as you don't run em hot, lean, and run um for 20 years you prob. won't have a problem. I do believe it's good insurance, but hasn't bit me yet.

[gfinch]

Having quite a few OMCeizures thru the years, I acquired a drum of dead or dieing pistons. Of those that dropped or loosened the locating pin it is my opinion ;-) that most if not all were caused by quick temperature change. Dissimilar metal expansion/contraction. Example: not warming up the engine thoroughly before accelerating hard. I now make it a point to drive below 4,500 for a few minutes. Also after flogging it running at a slower speed to allow it to circulate water to cool the block and let the pistons cool off also.
Doing WOT plug checks is an example.
If the cooling system was a closed loop rather than all the water draining out as soon as the engine stopped, the water/block/pistons/locator pins would cool gradually.
I have had staked pin pistons fail and top pinned pins push the weld up. The only way...again IMHO ;-) , is to bend the pin so it would have to wallow out the whole hole to fail.

[Dave Strong]

Think it keeps wearing gene trichel from Oshkosh showed me many years ago how to properly stake pins in 86 200 so they don't move outward


Not sure on the 2.5 but Gene told me the Wiseco's were better than the Mahle on a Bridgeport. He gave a new part number when I did pistons in my BP that had not even been released to the public yet.


Dave