Castrol GTX classic Motor oil 20-50 weight

[keithb7]

When I took apart my engine the top ring was broken on #1 piston only. The second compression ring was intact. I don’t know when the top ring broke. I can’t say how long it ran like that. Nor how long it would continue to run. I suspect it could run for a long time. 
 

My limited experience tells me as carbon builds up behind the top compression ring, the ring cannot easily compress as it travels down the worn, slightly tapered cylinder wall. As carbon continues to build up, the ring will likely break from this stress.  Multiple factors may lead to Incomplete combustion and excessive carbon build up. Low compression is a big one. As piston rings wear and cylinders wear compression drops. Increased oil burning would also be a big carbon  contributor. Improper valve lash also causes unfavourable combustion conditions. An engine running too cool. Poor carbureration. Float setting. Sparkplugs and gap. Strength of spark. A  plugged air filter. Timing dwell. So many contributors and variables will effect complete combustion. Potentially leading to carbon build up. Inevitably getting behind the top piston ring, sitting in its groove. 
 

I’m unsure if any type of oil can prevent this. How much oil ends up at the compression rings? I tend the think not much. Isn’t it scraped off cylinder walls by the oil rings? Changing detergent oil at regular intervals gets abrasive by-products of compression out of the crankcase. Preserving your delicate bearings, cam, tappets, rings and cylinder walls. 

 

I do appreciate metal on metal wear like tappets and cams and could benefit from higher quality oil.

 

The use of oil & air filters, regular engine oil changes, keeping your car in a good state of tune including valve sets, in my opinion exceeds any decision of what brand of oil to use.  Just my .02 cents. 

Edited August 13, 2022 by keithb7

[kencombs]

1 hour ago, Los_Control said:

My opinion has been more solidified just asking myself questions about the oil I use.

I have a engine with unknown past maintenance. (Possible the school teacher took it for regular oil changes) We got it at 150k miles & failed at 187k.

A lot of miles for any engine but not uncommon to reach 300k miles with these engines.

 

What I found when I diagnosed the engine failure, A piston broke at the wrist pin. The rod destroyed the block ... total destruction.
I also found 2 other pistons when I removed them, the top ring was broke .... just fell off the piston when removed from the hole.
Just saying it was a time bomb waiting to explode.

My thinking is, possibly the piston broke because of improper lubrication at the wrist pin? ..... Just a WAG but not too far fetched.
How long will a engine run with a broken ring? This engine leaked 1/4 quart of oil in 3k miles, no smoke.
I would suspect after a few thousand miles with the rings "loose" flopping up and down, possibly breaking a ring landing eventually just destroy the whole cylinder.

So that's the question I'm asking myself. .... Did those rings break before the engine had 150k miles on it? ..... Or was it in the past 36k miles after it was switched to Castrol?
I just find it hard to believe the engine would run for over 40k miles with 2 pistons with broken rings. .... I could be wrong though.

 

I have no solid proof that Castrol caused this issue.

I certainly feel it did not help the situation at the very least.

Broken top rings in a modern engine(one without lots of taper and wear) are often caused by detonation or early ignition.  Same is true for broken pistons.   Is this the one you had issues with a crank postion sensor???

[Los_Control]

@kencombs yes sir you are 100% correct .... This is the engine the crank sensor failed on.

 

This could be the early demise of that engine.

 

But if what you say is true .... I have a different issue like a bad computer that caused the pre-ignition. .... whole lot easier to blame it on oil?

[kencombs]

1 hour ago, Los_Control said:

@kencombs yes sir you are 100% correct .... This is the engine the crank sensor failed on.

 

This could be the early demise of that engine.

 

But if what you say is true .... I have a different issue like a bad computer that caused the pre-ignition. .... whole lot easier to blame it on oil?

Not necessarily the computer.  It is totally dependent on the data source.  Old saying in the computer world:  garbage in...garbage out.  Sensor providing erroneous crank (piston) position, knock sensor failure etc could easily mess up the spark timing. Most have a fail- safe map in case of a sensor failure.  But, if the signal is there, just erroneous the fail-safe wouldn't be triggered.

[desoto1939]

Los-Control You stated that the engine used a 1/4 qt of oil every 3k in milage. With an engine with the mileage that you stated did you every record the type of mpg that you were getting when the car was using oil? Also did you ever notice that upon acceleration. I had a dodge gran caravan in the 80's in which they had valve guide issues and noticed that Iwould get blue smoke upon acccerlation.

 

Maybe you had broken rings whenyou purchsed the car. I also would think that there would have been other signs that the engine was getting tired prior to the piston failing.

 

Rich Hartung

 

[Los_Control]

@desoto1939 The oil usage was mostly the rear valve cover bolts being loose, the front seal seeping some ... It may have burned some but never that I could notice.

 

I respect @kencombs honesty & thank them for it.   I did replace the Crank sensor on that engine.

The procedure is the sensor has a felt washer on the end, you push the sensor snug & tighten it down .... `I did it wrong & admit it.

I pushed it snug, but then lifted it just a hair for breathing room. .... Seems I destroyed a engine but learned a lesson.

@kencombs just set me straight on that.

 

I still am going away from Castrol GTX.

My 1987 Ford E350 work van had a new factory crate engine in it when I bought it .... I drove it for well over 10 years using Castrol GTX ..... It ran perfect.

When I became disabled and important for me to sell it.  The first prospect customer took one look at the oil & refused to stay around to hear it run.

 

Castrol oil goes in dirty looking & within a few days it just looks black & nasty.

Naturally the used oil needs to go to a chemist to be analyzed for it's performance .....

Castrol GTX is pretty much the cheapest oil @ Wal Mart ..... I hear the dirtiness is simply a characteristic of Castrol .... I never heard anyone claim it was superior because of it's chemical abilities to change color. ..... It's just cheap oil.     But it is cheap & I change oil often so it is good enough.

 

I have to apologize, I love the idea of creating a oil for old cars. Being retired & more time to think about it ..... I'm not using Castrol anymore.

 

 

[belvedere]

Not here to defend Castrol GTX, but it meets SP (latest spec).  SP supersedes all previous specs.  The SP-rated GTX far exceeds the needs of a 1993 Caravan.

https://www.api.org/products-and-services/engine-oil/eolcs-categories-and-classifications/oil-categories#tab-gasoline

"For automotive gasoline engines, the latest API Service Category includes the performance properties of each earlier category and can be used to service older engines where earlier category oils were recommended."

[bluefoxamazone]

This is what I have been using for the last 5yrs. Runs ok on it.... Doubt if it is available overseas...?

[Sam Buchanan]

1 hour ago, bluefoxamazone said:

This is what I have been using for the last 5yrs. Runs ok on it.... Doubt if it is available overseas...?

 

I would buy that just to get the can!  ?