super1c
Super Moderator
Phaze one of the engine rebuild done. Now what to do with the numbers HAHA!
By the looks of the pistons the rings (as i knew) they were past due for change 8000mi. Lots of blowby by what ive seen in other piston pics. Pic of pistons below what do ya think? Also by the bottoms of the pistons i would say im still running toooo much oil. Not able to read piston wash as sled was summerized with fogging oil. Domes are black and carboned though. Only the pto had pinky nail wash marks at the ports. Dont remember for sure but im running on the rich side of the pump setting with yamalube. Pistons and cylinders spec'd and seem fine. Now take in mind im not a machinest and this is my first time using micrometers on anything so leave a little room for error.
Numbers as follows PTO CENTER MAG
Pistons 2.7137 2.7138 2.7137
cyliner bore 2.7164 2.7165 2.7167
clearance .0027 .0027 .0030
So im going to reuse the cylinders for sure, they look fine and spec out so just a good cleaning. What to do about pistons?? They spec out fine so what would the experts do here??? Let me know if ya need more info and what ya think. Thanks guys!
By the looks of the pistons the rings (as i knew) they were past due for change 8000mi. Lots of blowby by what ive seen in other piston pics. Pic of pistons below what do ya think? Also by the bottoms of the pistons i would say im still running toooo much oil. Not able to read piston wash as sled was summerized with fogging oil. Domes are black and carboned though. Only the pto had pinky nail wash marks at the ports. Dont remember for sure but im running on the rich side of the pump setting with yamalube. Pistons and cylinders spec'd and seem fine. Now take in mind im not a machinest and this is my first time using micrometers on anything so leave a little room for error.
Numbers as follows PTO CENTER MAG
Pistons 2.7137 2.7138 2.7137
cyliner bore 2.7164 2.7165 2.7167
clearance .0027 .0027 .0030
So im going to reuse the cylinders for sure, they look fine and spec out so just a good cleaning. What to do about pistons?? They spec out fine so what would the experts do here??? Let me know if ya need more info and what ya think. Thanks guys!
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It's just amazing that these engines can go 8000 miles and still remain in spec!
Those piston do look good, you can check with dye for small fractures if your heart set on re using them...but if it were me I would go with new oem piston for piece on mind...they got you 8000 miles so to me that's well beyond there service life
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Those piston do look good, you can check with dye for small fractures if your heart set on re using them...but if it were me I would go with new oem piston for piece on mind...they got you 8000 miles so to me that's well beyond there service life
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roudyroy1
Active member
well it all depends, do you see yourself getting your moneys worth out of it? hows the crank? if you put a top end in and she lets go(knock on wood) then it would of been a waste. how much are those pistons in spec? if they are on the closer side the the limit you may want to think about putting new ones in. if i was you, and they are reasonably in spec i would re ring and ride it. the only time i would do a new top end is if, A: something is out of spec so its not fit for service, or B: i am doing a complete overhaul so i know something else isn't going to let go and take it away with it. if your doing a complete top end you might want to think about getting the crank looked at as well, just for some insurance.
staggs65
Moderator
Run em
2muchhp
VIP Member
I agree with staggs.Your piston to cylinder spec is. 0027-.0028 what are you gaining by replacing them.Just dont wait another 8000 before you re-ring...assuming this is an srx
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Devilin AblueDress!
New member
If its in the budget by new and save yours for good used replacements for one of the other what 3 or 4 Vipers currently in the pit. I haven't ever torn into one with out a major problem first. I have read on here about some guys getting pistons coated to bring them tighter into spec, not sure of the numbers or cost.
Chris with running rich on oil this is why your parts look so good. But also don't forget to take into account that you fogged the motor... but also with minimal wear that is a great sign that your mixture is optimal to safe.
The leaner the oil to fuel ratio only gets you closer to meeting Mr Squeaky... and the more parts will show wear by being out of spec. I would take reliability over trying to squeeze every available ounce of horsepower... That's just me though.
The leaner the oil to fuel ratio only gets you closer to meeting Mr Squeaky... and the more parts will show wear by being out of spec. I would take reliability over trying to squeeze every available ounce of horsepower... That's just me though.
As they say an ounce of prevention is worth a pound of cure...I like keeping up on wear items so that the machines run the best...haven't blow or been towed home since I was a teenager, and I'd like to keep it that way! Bhaha
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bead blast them to remove all the carbon from ring grooves and reinstall with new rings.
YAMMIEGOD3:16
Active member
new rings, alittle clean up and go. enjoy another 8000. 3:16 (yammie tony)
What media is best for doing this on pistons?Glass,walnut shells?
I would think glass bead would be the most aggressive, then onto walnut, then soda being the least aggressive... Just my guess, an I am NO abrasive expert.