What makes an engine a sludger?

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MatrixMulisha

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Real newbie question here...but what exactly makes an engine susceptible to sludging up? Is it mostly due to poor maintainence schedules, hard driving, wrong oil choices, or just engine design?

Probably all of the above but it was just a question that has been in the back of my mind.

Thanks all!
 
heat, degradation of motor oil, chemical reaction such as oxidation,etc., contamination of the lubricant (from PCV systems, etc.), inferior base oil quality (Gp1~Gp2?)/weak resistance to base oil breakdowns,etc.

Most of these can be properly taken care by the owners by means of rigid yet extremely conservative OCI, tuneups (replacing spark plugs, etc. and also ensuring that your ignition timing, EFI control systems, EGR,etc. are in top shape), replacement of PCV valve on a scheduled basis, etc. will minimise "sludge" buildup.

Yes, certain engine designs will exacerbate this problem further (high heat, small displacement/high power output, turbocharged, etc.)

Q.
 
It can be from many of the things you have listed. For toyotas, sludge problems occured in toyota and some lexus models(4 & 6 cylinder engines) from 1997 to 2002. At one point Toyota took the stance that it was the consumers fault for not changing the oil at the recommended interval which happened to be 7,500 in most of these vehicles. But the funny thing was that people were seing these sludge issues at even 3,000 mile services with different brands of oil. There are many posts concerning this on online forums such as corrolland.com and others. The second interesting part of this story is that Toyota vehicles with similar engines from before 97 and ones produced after 2002 dont have these problems following the same interval of 7,500 miles. But yes alot of things contribute, short trips with high humidity, lack of service, hot running engine, poor engine design( toyotas problem). Alot of the blame is focused on poor oil flow in the toyota engines from 97-02.
 
Originally Posted By: strombony
Pennzoil..LOL... Just kidding ya'll. I love the YB


27.gif
LOL...good one
 
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My first 'first hand' experience with a sludge monster was with my Chevelle 300 2 door with a 307" V8. This 'emmissions engine' was designed by Chevy by using a 283" block and a 327" crank to arrive at the 307". This was supposed to help meet the stringendt emmisions starting to be imposed back then. I pulled the valve covers one time and saw that they were packed full with black jello. I don't know how any oil ever got to the rocker arms. I was using Quaker State oil BTW. I have never used Quaker State oil since that experience. However looking back, it was probably a combination of many things that caused this extreme sludging : the 307" V8 design, the heat of south Texas, The Quaker State oil of that era, and so on. I did change the oil at reg. 3k intervals. Several notes- I know Quaker has changed their oil formula many times since then and may be a great oil today. Still I don't trust it because of that experience. Chevy did make a 302" V8 using a 327" block and a 283" crank. This was one of the best engines Chevy produced. Not so for the 307" emmissions variation.
 
That is interesting, Jim.

When I do a variety of 3000 mile oil changes, it seems the worst engines require a huge variety of smog devices attached, while engines that run clean by themselves require little.

I remember being blown away by what I drained out of a 1992 Jaguar with an inline six. It was every bit as dirty and smelly as oil from an old V8 that used a carb, air pump, and EGR. That Jag had sequential fuel injection! However, it needed multiple catalytic converters, air pumps, and an EGR system to pass US smog tests!

My grandma was once nervous about having 3400 miles on her oil (2003 Dodge Caravan) and I explained to her that the 3000 mile oil change was from a time where pollution was really bad, and oil chemistry was really low tech. Grandma was still very nervous because she was used to 3000 mile oil changes for most of her life.
 
Jim:

I recently aided a friend in pulling apart a newer GM 3.8 supercharged motors (of which he has two of), both out of Grand Prix GTP's. Both engines had significant sludge build-up throughout and both engines had died from bearing failure.

I do not know what oil was run in the 2nd engine, but the first, the owner had thought he was doing it a favour running Quaker State High Mileage in it. Engine only had ~140,000Km on it when it failed.

I have some great pictures of two 302's of the same vintage with the same mileage, one using unknown OCI's with probably the cheapest oil available, the other using Amsoil and Amsoil filters, and VERY frequent (5,000Km) OCI's. The pictures speak for themselves. I will put them up if anybody is interested.
 
Poor PCV systems - either by design or if they are faulty is the #1 sludge causer.
A close second is neglected oil changes.
#3 is excessive heat, but you would have all sorts of other problems with this.
 
Originally Posted By: OVERK1LL
Jim:

I recently aided a friend in pulling apart a newer GM 3.8 supercharged motors (of which he has two of), both out of Grand Prix GTP's. Both engines had significant sludge build-up throughout and both engines had died from bearing failure.

I do not know what oil was run in the 2nd engine, but the first, the owner had thought he was doing it a favour running Quaker State High Mileage in it. Engine only had ~140,000Km on it when it failed.

I have some great pictures of two 302's of the same vintage with the same mileage, one using unknown OCI's with probably the cheapest oil available, the other using Amsoil and Amsoil filters, and VERY frequent (5,000Km) OCI's. The pictures speak for themselves. I will put them up if anybody is interested.


Yeah, show the pics.
 
I have to tell this story. Only those BITOG devotees will appreciate or understand the moral. My uncle had a 1958 Chevy station wagon he used for his business and personal driving. Being a traveling salesman, he racked up many miles on it. Very basic car- straight six engine and no A/C. For what ever reason, he was reluctant to get the oil changed in it. Finally he got his eldest son to take it in and get the oil changed and the chassis lubed. The mechanic put the station wagon on the lift and removed the drain plug ....and no oil came out.He looked at it a minute and then went to his tool chest and got a screw driver. He twisted the blade inside the drain hole and finally the syrup thick oil dribbled out. He drove the wagon for many miles more before it gave up. How it lasted, I don't know.
 
OK, here they are:

1990 F-150 302:
f150swap01.jpg

f150swap02.jpg

f150swap03.jpg


Note that the Maple Key fell into the valley when we removed the intake, it was not in there to begin with. This engine had unknown OCI's, unknown oil type and we pulled a green Quaker State filter off it.

And the 1990 Mustang 302: (same mileage), Amsoil w/Amsoil filter, 5,000Km OCI's.
f150swap04.jpg

f150swap05.jpg

f150swap06.jpg



The first motor was swapped out for the 2nd motor. A good friend of mine bought the truck to use as a plow truck and when we tore into the engine, that's what we found. Subsequently the search for a suitable replacement commenced and was quickly fulfilled when this motor came up for sale on a local Mustang forum that I frequent.

Enjoy the pics :D
 
mechtech2, I also would like to see the photo's. The 302 cu. in. engine was designed for the Trans Am racing and used by Camaros. The limit was 5.0 L and they had to sell at least 500 to the public. One of the most famous and successful was the Sunoco Camaro in royal blue. It is still raced today in vintage races. With the Toyota 4 and 6 cyl. engines and Audi and VW 1.8 L Turbo, what caused the sludging? PVC or heat or some other design flaw. I know the manuf's try to shift the blame to the buyers with: you didn't change the oil enough, but with so many BITOG devotee's out there, all the Toyota/Lexus and Audi/VW owners couldnt be running the oil past the OIC limit.
 
Ford's version of course was the BOSS 302, which were basically Cleveland-style canted-valve heads, on a 4-bolt 8.2" deck Windsor block.
 
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