Varnish: Is it really harmless?

[OVERKILL]

Originally Posted By: Clevy

I doubt very much overkill would post any info he believed to be incorrect. It is very troubling though that an interval that short still led to varnish of any kind.


I think that the factory interval on the BMW/Castrol 5w-30 led to it. But his short-changing of the oil after he acquired it didn't appear to do anything to get rid of it. That in itself is worrisome, as it indicates that varnish may not be all that easy to get rid of once you have it.....

Quote:
Overkill,don't you use M1 0w-40 in yours. How is it performing as far as cleanliness and have you seen the insides of it lately.


I check the fill cap periodically. It looks like it did in the pic I posted a bit earlier. I don't think it is possible for it to get cleaner, LOL!! And yes, It's on its 3rd OCI of M1 0w-40 right now.


Though (blasphemy!) I've ordered two cases of Pennzoil Ultra Euro 5w-40 to try out when the weather warms up

Quote:
5000km intervals and still it looks like that. Is this perhaps evidence of something bigger being wrong and can we imagine if the owner just blindly decided to extend the oci because he is using a synthetic oil?
Makes me think twice about extending an interval without data for sure.

Great thread topic overkill. Very interesting.


BMW uses an OLM and you are advised to follow it. I posted about it earlier in this thread, but I'm not all that keen on following mine anymore..... LOL!

 

[Garak]

Originally Posted By: OVERKILL
Push-rod motors have chains too.........

Except in my F-150, but it doesn't have 600 lb valve springs like your Town Car, either.

 

[Hokiefyd]

Originally Posted By: threeputtpar
A timing belt would cure all of the problems discussed so far. It's worked quite well in the A6, and only needs changing every 75-95k miles. Plus, it gives me an opportunity to obsess over my car every now and then.


I used to be a timing chain snob, turning my nose at any engine inferior enough to use a timing belt. But we had a great vehicle offer from my parents (our Acura) come at a time when we were struggling with a lemon of a minivan, so in a matter of a week's time, I went from turning my nose at an engine with a timing belt to owning one.

And I'm planning to change it next month. And you know what? After actually doing some research on it and watching a number of videos on it and talking to folks who have done it before...it's really not that big of a deal. It's a Saturday morning with a few buddies and a few hundred bucks. Once every 105k miles (for ours).

Now that I own one, and have actually studied more on how they work and the pros and cons to both systems, I appreciate the simplicity of a timing belt, knowing that as long as they're changed within the recommended interval they have an excellent reliability record.

 

[meep]

Originally Posted By: OVERKILL
meep:

But if we assume that most of the BMW engines that HAVE this failure also have varnish, and the overwhelming number of engines running that DON'T have this failure may also have varnish (it is surprising difficult to find a clean BMW engine run on the factory oil and intervals from what I've seen) then is the design itself faulty? Is it the maintenance practice? The choice of lubricant?

I mean even if we consider what you've stated at face-value, that it is the design that is more susceptible to failure in an operating environment where varnish is present, would not keeping the operating environment as varnish-free as possible make sense in ensuring longevity? And in that vein, just because other engines don't have noticeable failings due to varnish build-up doesn't mean it isn't an issue. Coked and varnished up piston rings rob power, pollute your oil with blow-by.... but there are no audible signs that this is an issue. And it happens so gradually that most never notice it. Is varnish harmless there because the end-user is oblivious to it and its effects?

With respect to BMW, yes, they do some pretty weird things at times. I've been lucky not to have to set the cam timing or buy the tool as of yet... fingers crossed

I am enjoying this discussion, I hope others are as well.


@overkill---- well played. I like you.

Ok--- yes I will concede that varnish could be a culprit in tensioner failures in BMW engines if it can be shown that non-varnished engines of equivalent miles have considerably lower tensioner failures.

Then one can either move towards choice of lubricants, chemical flushes, etc..

If the tensioner uses o-rings or other rubber bits for seals, then it would be an interesting wager on if it's their use of rubber. Think vanos seal failure ~100k.

on the cam tool. You can get it close without the tool. but you just can't get it spot-on.

Mike

 

[meep]

Originally Posted By: Hokiefyd
Originally Posted By: threeputtpar
A timing belt would cure all of the problems discussed so far. It's worked quite well in the A6, and only needs changing every 75-95k miles. Plus, it gives me an opportunity to obsess over my car every now and then.


I used to be a timing chain snob, turning my nose at any engine inferior enough to use a timing belt. But we had a great vehicle offer from my parents (our Acura) come at a time when we were struggling with a lemon of a minivan, so in a matter of a week's time, I went from turning my nose at an engine with a timing belt to owning one.

And I'm planning to change it next month. And you know what? After actually doing some research on it and watching a number of videos on it and talking to folks who have done it before...it's really not that big of a deal. It's a Saturday morning with a few buddies and a few hundred bucks. Once every 105k miles (for ours).

Now that I own one, and have actually studied more on how they work and the pros and cons to both systems, I appreciate the simplicity of a timing belt, knowing that as long as they're changed within the recommended interval they have an excellent reliability record.


@hokie

same boat here. i used to find belt irritating back with 60k intervals, and sometimes less. but now that 100 is the norm it doesn't seem as bad. for me, really, it's more of a, "is there a defect in THIS engine?" regardless of belt or chain. The belt-driven v8 in the truck is very nice example of belt drive timing. Decent to service too. I've never had to service the chains in any of the chain driven engines I've owned (5.7 mercruiser, 3.3 chrysler, 3.8 chrysler, 4.0 jeep, 3.7 jeep, 283chevy, 440cc honda) but the one time I did a chain on a 4-cyl beamer it was no harder than a belt, likely easier. Granted, the chain drives I had were mostly older tech, a different animal. All in all though, unless it has a known problem, I don't judge anymore.

 

[rslifkin]

Originally Posted By: OVERKILL
That in itself is worrisome, as it indicates that varnish may not be all that easy to get rid of once you have it.....


I'd tend to agree. My Jeep had some light varnish on the heads and in the lifter valley when I got it. Once I knew about it, I ran some MMO through it for about 2k miles (1/2 a quart and 4.5 quarts of T6). I've since replaced the heads, which have remained clean. The varnish in the lifter valley, however, has lightened slightly, but hasn't disappeared. I was able to wipe the lifter spider clean, as it's smooth metal, but the porous cast material of the block looks almost the same as it did. Between when I first saw the varnish, and then ran the MMO, and when I last had stuff opened up was about 30k miles (running T6 the whole time).

 

[OVERKILL]

Originally Posted By: meep
Originally Posted By: OVERKILL
meep:

But if we assume that most of the BMW engines that HAVE this failure also have varnish, and the overwhelming number of engines running that DON'T have this failure may also have varnish (it is surprising difficult to find a clean BMW engine run on the factory oil and intervals from what I've seen) then is the design itself faulty? Is it the maintenance practice? The choice of lubricant?

I mean even if we consider what you've stated at face-value, that it is the design that is more susceptible to failure in an operating environment where varnish is present, would not keeping the operating environment as varnish-free as possible make sense in ensuring longevity? And in that vein, just because other engines don't have noticeable failings due to varnish build-up doesn't mean it isn't an issue. Coked and varnished up piston rings rob power, pollute your oil with blow-by.... but there are no audible signs that this is an issue. And it happens so gradually that most never notice it. Is varnish harmless there because the end-user is oblivious to it and its effects?

With respect to BMW, yes, they do some pretty weird things at times. I've been lucky not to have to set the cam timing or buy the tool as of yet... fingers crossed

I am enjoying this discussion, I hope others are as well.


@overkill---- well played. I like you.

Ok--- yes I will concede that varnish could be a culprit in tensioner failures in BMW engines if it can be shown that non-varnished engines of equivalent miles have considerably lower tensioner failures.

Then one can either move towards choice of lubricants, chemical flushes, etc..

If the tensioner uses o-rings or other rubber bits for seals, then it would be an interesting wager on if it's their use of rubber. Think vanos seal failure ~100k.

on the cam tool. You can get it close without the tool. but you just can't get it spot-on.

Mike


Thanks

I like you too Mike, this is certainly a good discussion we have going here!

With respect to the seals, of interesting note is that on the VANOS units, the O-rings that fail on them? Do you recall the replacement recommended o-rings? They are the stock rings for the M5

They are Viton instead of the regular rubber used on the normal cars

 

[morris]

i started driving OHV in 1966. have had nothing else. and NO trouble yet. when i was young the OHV was the latest best thing. and Clevy is right the times change. the latest best will all ways be changing.

 

[martinq]

Originally Posted By: OVERKILL
Thanks

I like you too Mike ...

I don't know how to explain this to an outsider, but we have an oil-varnish bromance happening here.

My question is, can that ploymer wear-strip in the BMW be replaced on it's own or does it only come with the aluminum casting?

 

[OVERKILL]

Originally Posted By: martinq
Originally Posted By: OVERKILL
Thanks

I like you too Mike ...

I don't know how to explain this to an outsider, but we have an oil-varnish bromance happening here.

My question is, can that ploymer wear-strip in the BMW be replaced on it's own or does it only come with the aluminum casting?


It only comes with the casting as far as I know. And no "bromance", just the appreciation of polite discourse and intelligent conversation.

 

[martinq]

Originally Posted By: OVERKILL
And no "bromance", just the appreciation of polite discourse and intelligent conversation.

Heheee.

 

[artificialist]

Honestly, my hate for timing belts is as much based on emotion as logic. When the belt snapped in mom's 1985 Maxima, it killed the only car my parents had that I ever loved. Nobody in our family knew what a timing belt was until it was too late.

Imagine one of your parents had a car that made you feel like a movie star every time you took a ride in it. Imagine it had a huge influence on your life. Now imagine it gets taken away and replaced with something boring.

After that, Mom and Dad knew what a timing belt was, and the next 2 cars they had got their belts replaced. Then the water pumps died halfway through the life of the belt. Over $1000 wasted on both cars in a matter of months!

No timing chain ever let down anybody in our whole family.

So if I sound a little too emotional, I am sorry.

 

[KrisZ]

Originally Posted By: artificialist
Honestly, my hate for timing belts is as much based on emotion as logic. When the belt snapped in mom's 1985 Maxima, it killed the only car my parents had that I ever loved. Nobody in our family knew what a timing belt was until it was too late.

Imagine one of your parents had a car that made you feel like a movie star every time you took a ride in it. Imagine it had a huge influence on your life. Now imagine it gets taken away and replaced with something boring.

After that, Mom and Dad knew what a timing belt was, and the next 2 cars they had got their belts replaced. Then the water pumps died halfway through the life of the belt. Over $1000 wasted on both cars in a matter of months!

No timing chain ever let down anybody in our whole family.

So if I sound a little too emotional, I am sorry.


Same here, I was never let down by a timing chain but a poor timing belt job almost killed my 95 Accord I once had. When buying a brand new car this would not be an issue for me because I know what needs to be done during TB change, but when buying used it's a different story. People want to save a buck and don't change water pumps, tensioners or idler pulleys, then they go to sell the car with paperwork showing that the TB was changed, but the new owner has no way of knowing if it was a proper job or not.
To me it's not which one is better or not, both have their strengths and weaknesses, but with timing belts there is still a lot of ignorance from owners when it comes to do the job properly.

 

[BearZDefect]

Originally Posted By: KrisZ
.... When buying a brand new car this would not be an issue for me because I know what needs to be done during TB change, but when buying used it's a different story. People want to save a buck and don't change water pumps, tensioners or idler pulleys, then they go to sell the car with paperwork showing that the TB was changed, but the new owner has no way of knowing if it was a proper job or not....

I second this point, from my experience too. I've seen shoddy timing belt replacements cause big problems soon after second or third owner gets the vehicle. Yet when serviced correctly, I've seen them carry on problem-free for the full interval. As mentioned above - the water pump and its seals, belt tensioner, oil seals, etc, are often skipped or done incorrectly with inferior parts, leading to expensive problems down the road.

When buying a vehicle with ~ 100k miles that has a timing belt, I'd rather get it before the timing belt is replaced so I can be sure the job is done correctly.

 

[OVERKILL]

Some cool (not related to the original topic) pics:

Ford 427 SOHC:

And with a timing belt setup:

 

[BearZDefect]

Why does the chain setup need two chains, yet the belt setup need only one belt? Is it just the reduction ratio?

 

[OVERKILL]

Originally Posted By: BearZDefect
Why does the chain setup need two chains, yet the belt setup need only one belt? Is it just the reduction ratio?


You'll notice the chain setup has your regular old "pushrod" timing chain running the OHC chain

This is because the engine family is a pushrod family. This is an OHC variant.

The belt setup, being aftermarket, did away with the "idler" timing chain and just used a different ratio to get the same effect.

 

[meep]

Originally Posted By: martinq
Originally Posted By: OVERKILL
And no "bromance", just the appreciation of polite discourse and intelligent conversation.

Heheee.

I'll comment.

how often do folks compliment vs flame on forums? We're quick to debate, which can ruffle feathers. And flaming and bickering happens more often here than it used to. I'd rather not be about that. And I appreciate it whenever I see any member here counterpoint without making it personal. Respect is a really cool thing.

no bromance. I'm not about bromance....!

 

[KrisZ]

Originally Posted By: OVERKILL
Originally Posted By: BearZDefect
Why does the chain setup need two chains, yet the belt setup need only one belt? Is it just the reduction ratio?


You'll notice the chain setup has your regular old "pushrod" timing chain running the OHC chain

This is because the engine family is a pushrod family. This is an OHC variant.

The belt setup, being aftermarket, did away with the "idler" timing chain and just used a different ratio to get the same effect.


Also, the chain has to be lubricated so it has to stay withing engine's envelope so that a cover can be bolted to the engine block/head and be tight. Belts on the other hand can run anywhere and any plastic cover can be used to just protect them from elements.

 

[OVERKILL]

Originally Posted By: KrisZ
Originally Posted By: OVERKILL
Originally Posted By: BearZDefect
Why does the chain setup need two chains, yet the belt setup need only one belt? Is it just the reduction ratio?


You'll notice the chain setup has your regular old "pushrod" timing chain running the OHC chain

This is because the engine family is a pushrod family. This is an OHC variant.

The belt setup, being aftermarket, did away with the "idler" timing chain and just used a different ratio to get the same effect.


Also, the chain has to be lubricated so it has to stay withing engine's envelope so that a cover can be bolted to the engine block/head and be tight. Belts on the other hand can run anywhere and any plastic cover can be used to just protect them from elements.


Good point! Though I must add that I believe this belt setup was run "in the nude" to show off the extreme levels of awesome