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#45
by
fatmobile
on 06 Apr, 2018 22:54
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No the cam rocker check isn't in the bentley.
I'm not sure how much you can remove but the prechambers get pretty sharp if you remove much with them in,.. then you have to line bore the cam.
Doesn't effect piston protrusion to remove metal from the head
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#46
by
ORCoaster
on 07 Apr, 2018 17:17
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Fatmobile, Doesn't removing some of the head affect the amount of extension the valves have when open? Or does measuring the piston protrusion and getting the right gasket keep it all in check?
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#47
by
fatmobile
on 08 Apr, 2018 22:20
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The valves don't extend any farther from the seat.
And where the valves are when open doesn't effect compression.
The piston shouldn't be near the valve when it's fully open.
Maybe someone else as a different opinion on this. But that's how I see it.
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#48
by
libbydiesel
on 09 Apr, 2018 19:49
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If the timing is set correctly, then the amount of extension of the valves is not a critical factor. Keeping compression ratio, squish, and quench correct is more important, IMO, and to keep those correct would mean using the gasket that is specified based on piston protrusion. Shaving the head does not change piston protrusion so it does not affect which head gasket should be used. All of it is conjecture, though, because VW states that the heads should not be shaved so there is no spec for that condition.
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#49
by
ORCoaster
on 09 Apr, 2018 23:06
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My brain was taking the day off again. Valves extend past the head but not on the compression stroke. They would both be up and closed. So at the seats. As they travel downwards so does the piston so never the two shall meet.
Unless you get the crank out of sync with the cam. Which we all know is liable to happen when doing the timing belt. That is why one always checks the clearance with a spin or two of the crank. It will go bump if not right.
Sorry for confusing anyone. I was only confused myself. Too much rain lately.
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#50
by
absenth
on 10 Apr, 2018 13:18
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Thank you to everyone for adding your insight.
Sent from my iPhone using Tapatalk
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#51
by
absenth
on 24 Apr, 2018 11:18
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I've measured the cylinders. I'll measure them again as it was my first pass with the bore gauge and micrometer. I can't get it to format nicely on here. Here is a link to the file.
https://drive.google.com/open?id=1-Ev0IjeW1eZzPtZXZ_fLJ0yY7sE2vdegFEQP0uO1v60 Below are the largest measurements in each cylinder. In Inches.
Cylinder I. 3.0130 II. 3.0135 III. 3.0140 IV. 3.0140
Variation I. 0.0015 II. 0.0020 III. 0.0025 IV. 0.0025
So my question is regarding boring the cylinders to the next larger size. Are there two independent measurements used to come to this decision?
One - is the variation in any one cylinder more than .0015? Then yes bore to the next size?
Two - Is the tolerance of the Standard size bore exceeded (3.0138) in any one cylinder? Then yes bore to the next size?
I am answering yes to both of these.
Am I getting this correct? I'm measuring variation between any two measurements in a single cylinder. Rather than the A and B measurements at a given level.
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#52
by
libbydiesel
on 24 Apr, 2018 17:39
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Hmmm, after deglazing the cylinders will you be over the limit? If I'm not mistaken, the spec is the piston to bore clearance. If your used pistons are worn, that wear adds to the clearance. If I'm reading your chart correctly it looks like cylinder 3 is over the spec for out-of-round (III 1A and 1B difference is 0.0020).
All of that said if you deglaze and rering it, you'll probably get a lot more miles out of it.
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#53
by
absenth
on 24 Apr, 2018 19:47
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Hmmm, after deglazing the cylinders will you be over the limit? If I'm not mistaken, the spec is the piston to bore clearance. If your used pistons are worn, that wear adds to the clearance. If I'm reading your chart correctly it looks like cylinder 3 is over the spec for out-of-round (III 1A and 1B difference is 0.0020).
All of that said if you deglaze and rering it, you'll probably get a lot more miles out of it.
Yes, you are correct.
The Bentley says if there are variations of .002 or more among the measurements made in any one cylinder then it must be rebored for a larger piston. I took that as any measurement to another, not comparing 1A to 1B, 2A to 2B, etc. I thought 2,3 and 4 were over. I see where that wouldn’t make sense when checking out-of-round.
Also, I’ve mistaken the Grading groups for the repair groups. I’ll circle back to Bentley reading 101 and rework my question.
I believe measurements in 2, 3 and 4 are above the third honing group of the Basic cylinder bore (3.0130).
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#54
by
absenth
on 27 Apr, 2018 12:14
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Hmmm, after deglazing the cylinders will you be over the limit? If I'm not mistaken, the spec is the piston to bore clearance. If your used pistons are worn, that wear adds to the clearance. If I'm reading your chart correctly it looks like cylinder 3 is over the spec for out-of-round (III 1A and 1B difference is 0.0020).
All of that said if you deglaze and rering it, you'll probably get a lot more miles out of it.
So you are saying even with measurements in cylinders 3 & 4 that are above the wear limit and at a minimum cylinder 3 is out-of-round, you think it would work to deglaze the cylinders and install new rings? How many miles would you guess before it would have to be bored up? How likely would this come with immediate oil consumption and blow-by? I'm trying to get a sense of what doing this would be like vs having the block bored up a size.
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#55
by
absenth
on 27 Apr, 2018 12:23
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General question regarding piston sizing. I've looked at new pistons on many websites and it seems I can find the Standard size, then 77.00, and 77.50. Are pistons no longer made that would fit into the Repair Stage 1 range of 76.73-76.75?
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#56
by
absenth
on 30 Apr, 2018 15:53
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General question regarding piston sizing. I've looked at new pistons on many websites and it seems I can find the Standard size, then 77.00, and 77.50. Are pistons no longer made that would fit into the Repair Stage 1 range of 76.73-76.75?
After digging deep on this, I believe the answer is these pistons were hard to find 15 years ago. And the rings even harder.
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#57
by
absenth
on 30 Apr, 2018 16:03
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Hmmm, after deglazing the cylinders will you be over the limit? If I'm not mistaken, the spec is the piston to bore clearance. If your used pistons are worn, that wear adds to the clearance. If I'm reading your chart correctly it looks like cylinder 3 is over the spec for out-of-round (III 1A and 1B difference is 0.0020).
All of that said if you deglaze and rering it, you'll probably get a lot more miles out of it.
So you are saying even with measurements in cylinders 3 & 4 that are above the wear limit and at a minimum cylinder 3 is out-of-round, you think it would work to deglaze the cylinders and install new rings? How many miles would you guess before it would have to be bored up? How likely would this come with immediate oil consumption and blow-by? I'm trying to get a sense of what doing this would be like vs having the block bored up a size.
After measuring again and reading my Bentley it seems that I could have the cylinders deglazed to 76.53 (3.0130) and use new 76.50 pistons. My current pistons are 76.48. All cylinder diameter measurements are within tolereance for the 76.50 pistons.
Any suggestions on what else I should consider?
Thanks.
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#58
by
absenth
on 29 May, 2018 16:51
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I'll be dropping my block off at a shop and have them take measurements. I think they could hone the cylinders and stay within the tolerance range (high end) for new 76.50 pistons and rings. But it seems a waste to pay to have work done and not be at specs. Maybe if I was honing it at home and could reuse the pistons and replace the rings I would feel better about it. I'm driving myself a little crazy going back and forth about it.
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#59
by
absenth
on 29 May, 2018 16:59
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Pictures and video of broken IM shaft, and outer bearing.
https://drive.google.com/open?id=1QLvWKthNRVxWEmJ8jfw8S8f_A57kM4va
I have two candidates for replacement. the gears are different sizes. I did read that the gears can be removed and pressed on. I've read how the thickness of the shaft changed from the 1.5 to1.6 engine as the 1.6 needed more room for the longer stroke. Also how the 1.5 oil pump was shorter and the 1.5 vacuum pump slot was lower to match. Anyone know, or know of a thread somewhere that explains the gear size difference? I'll probably throw the longer geared shaft in at some point and see if it works or not.
https://drive.google.com/open?id=1ypifmkWXvy8TajhUN5WChK0Coi4_UFxo
I did put both geared sized IM shafts in and they both seemed to turn smoothly. However, the one with the thinner gear seemed to turn easier. The shaft with the thicker gear stuck past the oil pump gear and seemed to serve no purpose. So, I can only guess the shorter gear is meant for the 1.6 diesel.