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will this be ok?what to do?
by
carrizog60
on 09 Jun, 2013 02:48
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hi
just got this block from a friend,its a passat 1.6 block,engine code SB.
it has some bits missing on the top of 2 pistons(1&4),as you can see from the pics being the first one th worst
valve damage was caused by some old head since now it had a low miles AMC head on it(for my friendīs engine)
should i left then as is or skim them?
1.6 with 1,9 head build so afraid of lowering compression too much...
cylinders have some marks, don't know how much is too much...
also the pistons moves a bit when on top of its stock from side to side,i know they must do that but how much is acceptable?
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#1
by
CRSMP5
on 09 Jun, 2013 03:00
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hone the bore to see how worn it is.. then decide what to do...
ive seen/used pistons like that w/1.6 heads with little issue... no idea what 1.9 head will do... but non damagee pistons they clatter/smoke anyways.. so may be a issue
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#2
by
carrizog60
on 09 Jun, 2013 04:02
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since rings are way down on the piston wont that damage be acceptable?
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#3
by
CRSMP5
on 09 Jun, 2013 08:23
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rings come up to dark area, carbon, in the bores.. i see some nice lines like broke rings plugged w/carbon...
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#4
by
carrizog60
on 09 Jun, 2013 09:15
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got to dismantle all and check for that...
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#5
by
libbydiesel
on 09 Jun, 2013 10:30
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Those pistons look hammered. You can measure the bores ahead of time, but I'll be surprised if they are within spec. Very likely the right course is to bore it.
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#6
by
carrizog60
on 09 Jun, 2013 10:34
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how can i measure them?
i have a caliper bit only will mesure the top...
they have little ridge on top so my hopes were they were ok...
it was free,if i could get away with just hone and rings will be great but since its for a somewhat power/cheap build(is that possible?lol)
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#7
by
745 turbogreasel
on 09 Jun, 2013 14:08
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Measure your piston stickup, esp along the axis of the wrist pin.
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#8
by
carrizog60
on 10 Jun, 2013 09:29
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Measure your piston stickup, esp along the axis of the wrist pin.
what is piston stickup?
sorry but some english terms are not familiar to me,i am portuguese...
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#9
by
745 turbogreasel
on 10 Jun, 2013 12:06
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Height of piston face above engine deck at TDC, AKA Piston Protrusion
If a rod was bent while kissing the valve, that one will not stick up as far.
.004" max variance between cylinders IIRC.
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#10
by
RabbitJockey
on 10 Jun, 2013 12:40
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i reringed an engine that had worse dents than that. it also had an amc head on it. after it was back together it got excellect fuel mileage even with its automatic transmission and me as the 18 year old pilot.
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#11
by
carrizog60
on 10 Jun, 2013 13:46
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Height of piston face above engine deck at TDC, AKA Piston Protrusion
If a rod was bent while kissing the valve, that one will not stick up as far.
.004" max variance between cylinders IIRC.
i will check that but i dont believe rods could have been bent,i have seen worse valve marks with good rods.
i reringed an engine that had worse dents than that. it also had an amc head on it. after it was back together it got excellect fuel mileage even with its automatic transmission and me as the 18 year old pilot.
i will take it apart and take more measurements and pics but its good to know that from the "top" look it will still work fine.
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#12
by
R.O.R-2.0
on 12 Jun, 2013 16:12
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Height of piston face above engine deck at TDC, AKA Piston Protrusion
If a rod was bent while kissing the valve, that one will not stick up as far.
.004" max variance between cylinders IIRC.
i will check that but i dont believe rods could have been bent,i have seen worse valve marks with good rods.
i reringed an engine that had worse dents than that. it also had an amc head on it. after it was back together it got excellect fuel mileage even with its automatic transmission and me as the 18 year old pilot.
i will take it apart and take more measurements and pics but its good to know that from the "top" look it will still work fine.
my n/a engine lost its timing belt at roughly 8000 revs, it cracked the cam in 4 places, and destroyed the old head..
the rods and bottom end were fine.. the day i lost the timing belt, i had that sucker running 12 hours later with a TD head.
there were valve kisses worse than that on all 4 of my pistons, but the engine is still running like that to this day.. protrusion was in spec.
i would say that the engine is likely fine if the bores arent trashed.. my engine doesnt have pretty bores either, but it still starts/runs great!
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#13
by
carrizog60
on 14 Jun, 2013 15:10
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piston 1,2 and 3 have almost the same protrusion, around 0.70 to 0.75mm.
odd number 4 only has 0.20mm.
really light valve marks so i doubt a rod is bent...
also with piston on top i can insert a 0.20mm feeler gauge on the side of the piston,is that normal or too much?
funny is that it doesent have a bad top ridge,actually is pretty normal...
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#14
by
rallydiesel
on 14 Jun, 2013 20:16
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If #4 is that much lower then its rod is surely bent. Valves are not the only thing that will bend rods. Runaway or a stuck injector are just a couple non-contact causes of bent rods.