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vwnc
Samba Member
Joined: March 07, 2002
Posts: 173
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 Posted: Tue Jan 22, 2019 10:00 am Post subject: Piston/Cylinder - Recommendation |
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| Rebuilding a 1600 dual port to a 1776 build for my '69 Bus. I've done this with other builds using new Mahle pistons and cylinders. The challenge is that when I installed the Malhe pistion and cylinders (not forged), the engine would burn some oil. I would have to add sometimes a quart every 1000 miles. This has happened to me on two builds. I spaced the rings 120 degrees apart. Obviously I'm doing something wrong or Malhe parts are not machined that well. Any input would be appreciated. |
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airschooled
Air-Schooled
Joined: April 04, 2012
Posts: 12722
Location: on a bike ride somewhere
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| Posted: Tue Jan 22, 2019 10:39 am Post subject: Re: Piston/Cylinder - Recommendation |
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A few thoughts…
One quart per 1,000 miles was considered acceptable by Volkswagen for a Type 1 bus in the seventies.
New pistons and cylidners, regardless of manufacturer, MUST be scrupulously cleaned before installation. I'm talking hot water with aggressive soap and scrubbing with a sponge or lint-free rag. They should pass the "oily white glove test" before installation. (If you don't have white gloves, spray some carb cleaner on a paper towel and firmly wipe the cylidner wall. The towel should be spotless; NO grey allowed.) The last set of Mahle cylinders I cleaned all took about 15 minutes of scrubbing in near-boiling water. The set before that had one cylinder that took about 30 minutes of the same cleaning. The rings should be removed from the pistons, and all the ring lands must be cleaned as thoroughly. That's also a good time to check the ring gaps, lands, and clearances too, since you are your own QC department.
The new oil control rings in the last few decades have been three-piece deals, with an inner band that MUST show their non-overlap indicators (usually red and green bands.) It is very easy to overlap the oil control ring by a tooth. The oil scraper rings are gapped separately, or should be, in my opinion. However, it is known that rings rotate during use, and sometimes line up oddly, allowing a puff of smoke at startup or deceleration.
I think you're going to be fine if you clean clean clean, and check your oil every so often. At least, VW thinks so. 
Robbie
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Last edited by airschooled on Tue Jan 22, 2019 10:50 am; edited 2 times in total |
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Manfred58sc
Samba Member
Joined: October 05, 2009
Posts: 3382
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| Posted: Tue Jan 22, 2019 10:39 am Post subject: Re: Piston/Cylinder - Recommendation |
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I've seen this too. I've switched to Moresa brand, they give you hasting rings (nice touch ). Or scrounge up OE set, hone and re-ring. I had a Grant ring set fail because of a manufacturing flaw that made the rings too wide. I personally do like the AA sets ( but others do ). The CoFap outta Brazil may be good as well, although I have no personal experience. Welcome to the world of rampant parts failure.
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vwnc
Samba Member
Joined: March 07, 2002
Posts: 173
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| Posted: Tue Jan 22, 2019 11:26 am Post subject: Re: Piston/Cylinder - Recommendation |
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| Thanks for the advice about cleaning and inspecting. |
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SGKent 
Samba Member
Joined: October 30, 2007
Posts: 41031
Location: Citrus Heights CA (Near Sacramento)
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| Posted: Tue Jan 22, 2019 11:31 am Post subject: Re: Piston/Cylinder - Recommendation |
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| Manfred58sc wrote: |
| I've seen this too. I've switched to Moresa brand, they give you hasting rings (nice touch ). Or scrounge up OE set, hone and re-ring. I had a Grant ring set fail because of a manufacturing flaw that made the rings too wide. I personally do like the AA sets ( but others do ). The CoFap outta Brazil may be good as well, although I have no personal experience. Welcome to the world of rampant parts failure. |
if one looks in Bentley they give specifications for ring end gap and ring land clearance. Be sure to check those. On the 3 piece oil control rings that end gap will be different than the book. The book is for 1 piece cast oil control ring that has a spring in it. One thing I have noticed here over and over when people are building engines is that they are not doing this. The rings seal the pistons in the cylinders and if those measurements are off then the seal does not work correctly.
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21519
Location: Oklahoma City
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| Posted: Tue Jan 22, 2019 12:29 pm Post subject: Re: Piston/Cylinder - Recommendation |
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| SGKent wrote: |
| Manfred58sc wrote: |
| I've seen this too. I've switched to Moresa brand, they give you hasting rings (nice touch ). Or scrounge up OE set, hone and re-ring. I had a Grant ring set fail because of a manufacturing flaw that made the rings too wide. I personally do like the AA sets ( but others do ). The CoFap outta Brazil may be good as well, although I have no personal experience. Welcome to the world of rampant parts failure. |
if one looks in Bentley they give specifications for ring end gap and ring land clearance. Be sure to check those. On the 3 piece oil control rings that end gap will be different than the book. The book is for 1 piece cast oil control ring that has a spring in it. One thing I have noticed here over and over when people are building engines is that they are not doing this. The rings seal the pistons in the cylinders and if those measurements are off then the seal does not work correctly. |
This is a spot on point.
The ring end gaps on most ...not from the factory ...cylinder sets almost all need to have the ring end gaps carefully checked and set.
By not from the factory I mean they may be the very same brands and part #'s...but the ring end gaps are not perfectly set.
Back in the day when a local VW centric flaps may have a dozen sets of cylinders on the shelf and you could simply take a set back if they were not up to snuff....these days you may be stuck with what you have and what you have may be all that you can easily get.
If the ring end gaps are too tight...thats an easy fix. But...over the past 15 years or so I have found a few ring ring sets that come with cylinders and pistons (all the common brands....Mahle, Cima/Mahle, Cofap, KS)...that are too large....because the bores vary just a little within a set. In most cases I can get things straight by simply mixing and matching rings with bores.
This is why...the days are long past that you can simply buy piston and cylinder sets and clean them and slap them in. You need a dial bore gauge to check what you are using.
Also...and this is just my experience...count on the fact that you may need to buy a new/better set of rings about half the time...and file them to fit.
Also....check the damn ring gaps for burrs. More than a few...have razor sharp edges. Not only will those score the bore on the first stroke....leaving a nice sharp groove....the ring with a sharp burr on the outer edge will not rotate to equalize wear and they will burn oil at the groove the cut.
As for cleaning bores....I am finding that whatever oils have been used for preservative are tenacious. Like more than they were years ago.
One thing I have found that really helps to get ultra clean faster....is trisodium phosphate. It has actually been used for eons by the plating industry in final cleaning before plating.
Old school name is "washing soda". Mix it up with hot water....put your degreaser in with it and it magnifies the effectiveness many times by altering the surface tension to allow getting detergent into microscopic pores to get oil and particles out of the pores.
DO NOT buy phosphate free tridsodium phosphate. Its the phosphates you want.
https://www.grainger.com/product/10L523?gclid=Cj0K...031680837!
You can buy this at almost any hardware store for under $5
Ray |
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vwnc
Samba Member
Joined: March 07, 2002
Posts: 173
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| Posted: Tue Jan 22, 2019 12:57 pm Post subject: Re: Piston/Cylinder - Recommendation |
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| Thanks Ray. |
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SGKent
Samba Member
Joined: October 30, 2007
Posts: 41031
Location: Citrus Heights CA (Near Sacramento)
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| Posted: Tue Jan 22, 2019 2:27 pm Post subject: Re: Piston/Cylinder - Recommendation |
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Thanks Ray. We use the real TSP, not the substitute, in heavy laundry loads like the car covers etc., when things need a little stronger than normal cleaning. It used to be part of laundry detergent years ago but the phosphate causes algae blooms so it has been removed from almost all cleaners and soaps. Many hardware stores here in California don't carry the real stuff anymore, but rather a substitute. A few do carry it if one looks.
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ac78
Samba Member
Joined: March 18, 2008
Posts: 330
Location: Nashville
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| Posted: Sun Feb 17, 2019 4:37 pm Post subject: Re: Piston/Cylinder - Recommendation |
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| asiab3 wrote: |
A few thoughts…
One quart per 1,000 miles was considered acceptable by Volkswagen for a Type 1 bus in the seventies.
New pistons and cylidners, regardless of manufacturer, MUST be scrupulously cleaned before installation. I'm talking hot water with aggressive soap and scrubbing with a sponge or lint-free rag. They should pass the "oily white glove test" before installation. (If you don't have white gloves, spray some carb cleaner on a paper towel and firmly wipe the cylidner wall. The towel should be spotless; NO grey allowed.) The last set of Mahle cylinders I cleaned all took about 15 minutes of scrubbing in near-boiling water. The set before that had one cylinder that took about 30 minutes of the same cleaning. The rings should be removed from the pistons, and all the ring lands must be cleaned as thoroughly. That's also a good time to check the ring gaps, lands, and clearances too, since you are your own QC department.
The new oil control rings in the last few decades have been three-piece deals, with an inner band that MUST show their non-overlap indicators (usually red and green bands.) It is very easy to overlap the oil control ring by a tooth. The oil scraper rings are gapped separately, or should be, in my opinion. However, it is known that rings rotate during use, and sometimes line up oddly, allowing a puff of smoke at startup or deceleration.
I think you're going to be fine if you clean clean clean, and check your oil every so often. At least, VW thinks so.
Robbie |
I'm in the process of trying to clean and reuse a current set of Mahles with about 15k on them. Based on your cleaning procedure for a brand new, carbon free set, I think I'm in a losing proposition. The piston sides are looking pretty good, but my carbon ring inside the jug is proving difficult. If a piece of lint is problematic, then a chunk of carbon would be disastrous. I have the funds to buy a new set and have no problem doing that if it's the preferred way to go.
Should I just buy a new set?
Thank you in advance for your input!
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Danwvw
Samba Member
Joined: July 31, 2012
Posts: 8892
Location: Oregon Coast
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| Posted: Sun Feb 17, 2019 5:31 pm Post subject: Re: Piston/Cylinder - Recommendation |
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I would bump up the bore to 92mm using these: VW9200T1K They are the AA Performance Brand and I would use Better Rings with them even the Grant would be better. Some light sanding of the cylinder with some 400 and 600 emry would help but don't over do it. You have to after the motor gets broke in a bit take it out on the freeway and drive it hard for a spell for the rings to seat though. Is your engine a Dual Port with the correct fan housing and fan etc.?
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skills@eurocarsplus
Samba Peckerhead
Joined: January 01, 2007
Posts: 16879
Location: sticksville, ct.
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| Posted: Sun Feb 17, 2019 6:37 pm Post subject: Re: Piston/Cylinder - Recommendation |
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| ac78 wrote: |
I think I'm in a losing proposition. The piston sides are looking pretty good, but my carbon ring inside the jug is proving difficult. If a piece of lint is problematic, then a chunk of carbon would be disastrous. I have the funds to buy a new set and have no problem doing that if it's the preferred way to go.
Should I just buy a new set?
Thank you in advance for your input! |
for the 3/16-1/4" of carbon at the top of the cyl...use some carb clean and fine scotchbrite...you'll be fine (I think its grey for the fine stuff)
if you are doing a re-ring run a bottle bush hone thru the cyls...it will be the best you can do without bringing them to a machine shop with a torque plate to do a "proper" hone.
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scubaseas
Samba Member
Joined: May 24, 2013
Posts: 442
Location: ME & Texas, in a Bus or on a boat somewhere
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| Posted: Sun Feb 17, 2019 6:58 pm Post subject: Re: Piston/Cylinder - Recommendation |
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X2 on thick wall liners on a Bus. But you might want to toss the AA rings and hone the liners, preferably with a torque plate on them. Last set AAs I used were tight on one cylinder. Deves and Perfect Seal rings have worked well for me in the past.
92 Thick Walls don't cool any better but the do hold their shape and tolerate some overheating better than 90's will.
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08/1970 T2a Westphalia owned since 1980
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