Cleaning a filthy engine.

[FastWoman]

Hi all,

I could use a bit more advice, regarding the 160K mi original engine in the '78 I recently bought:

I flushed my engine today (Gunk) and changed the oil. Then I opened up the valve cover to adjust the valve lash. I was rather surprised at what I found. Although the moving parts were more or less clean, the valve cover and top of the cylinder head looked like the inside of my smoker after a 16 hr round of smoking. There was a varnishy/gummy crust that averaged maybe 1mm thick, with much thicker build-ups in some areas. The Gunk took down some of it from the valve cover walls in sheets, in line with oil spray from the valve train. I scrubbed the remainder of it from the valve cover with B-12 and a toothbrush, and I scooped out the piles of compacted sludge from the large cap-head bolts with a screwdriver. I then wiped down the valve train as best I could to remove additional deposits.

As I looked down the timing chain tunnel, I could see incredible amounts of sludge everywhere -- perhaps as much as 2-3mm thick. I'm sure there are similarly impressive deposits in the crank case.

I'm presuming this engine has never been flushed or cleaned, and I've frankly never seen the inside of a 160K engine that hasn't been flushed. I've always bought younger engines and have periodically flushed them. Would this degree of sludge accumulation be expected/ordinary?

So I'm wondering how I should approach cleaning out the rest of the stuff. I'm thinking of using a quart of Rislone, to work away at it with detergent. Perhaps I'll change oil again in 1K miles, or when the oil gets black, whichever comes first. Then I'll change oil/filter after another Gunk flush, using old-fashioned, non-synthetic oil (I used blend this time) with Rislone. Then I'll repeat and repeat until everything is clean.

Will this work? Is this too aggressive? Do I have to worry about loose sludge in the oil pan at this time? Do I need to pull the oil pan? I've never been down this road and would appreciate any advice -- and any modifications to my plan of action.

Thanks!

Sarah

[beandip]

DON'T DISTURB THE CRUD! Using a good oil will clean the engine if it is changed every 3k miles. Scraping the buildup can dislodge chunks that will block oil passages . As well meaning that you are in doing this , it is a bad idea. Rislone is a good product . I have been using Quaker State 10W30 and for years and for about 8 years in my Z. This engine was not badly sludged but was dirty. It looks like a freshly rebuilt now. One thing, you SHOULD check is the PVC valve, because if it is faulty this could cause a sludge build up.

In using a flush , it could cause the engine to start burning oil now. I am not in favor of a flush. I have been driving my own cars and doing all the oil changes for 54 years and have never flushed out one of my engines. I have used Reslone to free a stuck lifter once . I recommend that you use a good grade of oil and let the detergent do its job. Now that you have disturbed things , you might change the filter only at abut 500 miles . The detergent will keep things in suspension so the filter will collect them. Then depending on how dirty the oil is do it all at 1K and every 2K for a while.

Gary

Edited July 23, 2009 by beandip

[hls30.com]

Every New to me Z I get goes through this first oil change-looks like Gary and I are of the same opinion.

1) Change the oil with Shell Rotella 20w50 and a new filter

2) drain the gas tank-if what came out was essentially clean, pour in 2-3 gallons of new gas, pull drive to the gas station, empty a can of carbureator and choke cleaner(or seafoam-but the carb cleaner will not make the horrific smoke the seafoam will) into the tank, and fill it up.

3) drive home-check the oil!

3) Flush the radiator

4) Drive the car carefully and daily, for at least the first 500 miles, checking the oil every time the car gets back home-you are looking for massively dirty oil-add more Carb cleaner or seafoam in the next gas-up.

5) Change the oil and filter again when it gets dirty or at your normal interval-use Rotella again, untill the oil stays clean through your normal interval.

6) Put in your prefferred oil, and a seafoam or an oil safe detergent additive for two additional oil changes, then change as normal.

Usually, the sludge is seriously headed out by the second oil change-I usually get 1000 or so miles on the first oil change, and then the second goes another 3k or so. The sludge in the head bolt recesses I do normally dig out-not much oil lows through those recesses, so what ever is in the oil that makes it in gets trapped.

I have heard several other methods of cleaning a dirty engine, from diluting engine oil with kerosene, Mineral Spirits, heating oil or ATF. While I would not hesitate to use

any of those to clean a part by its self or in an assembly I could move by hand, I don't think I would be willing to put those in an engine-because as Gary noted-taking too much nastiness lose to fast will overwhelm the filter and could cause oil path blockage, and engine possibly failure.

I have used my method for more than 15 Zs, and never had an issue-other than the thin oil does seep by seals and make the car burn some oil until changed to the "normal". With the Rotella, usually it smokes a little at startup, and under heavy acceleration, but not in normal driving-when the oil is changed back, the smoking stops-but that will depend on the actual condition of the engine.

I started this when I had a 280ZX that kept throwing rocker keys-the oil was so sticky if you put a drop between your finger and thumb, and pull them apart, the oil will pull into strands! I pulled the distributor and spin the oil pump to prime the oil system after changing that oil out and the problem left with the old oil. I still have that car, I bought it off ebay inop and towed it back from Newnan, Ga, with over 200k on the clock, and she still runs strong!

Will

[FastWoman]

Thanks for your advice, Gary and Will!

Given that I've done what I've done, where do I go from here? I've got Castrol 10W40 Syntec in it and a fresh Bosch filter. Gary, are you suggesting a complete oil change at 500 mi or simply a filter change?

The order of oil flow seems to be from the sump to the pump to the filter to the oil passages, and the pressure sender is on the output side of the filter. I would presume if my filter became clogged, the pump would blow out the filter material, and then I'd still have oil pressure, but with contaminated oil. I probably wouldn't notice anything on my oil pressure gauge. Correct?

I'm guessing the conservative approach would be to immediately drain the oil, pull the oil pan, clean it, and then put in fresh oil and a fresh filter. Should I do this?

Thanks again for your help!

Edited July 23, 2009 by FastWoman

[a7dz]

I've put approx 1000 mile on my car in the last year and have changed the oil and filter twice. For the cost of the oil and filter cheap insurance. Because of this practice the inside looks really clean, better then I expected.

[70 Cam Guy]

I am another person against many kinds of flushes. Though I have to say I have used, and like Rislone and Restore for other uses.

Sludge can be caused by infrequent oil changes and I agree with Gary and Will regarding their advice. While I use full synthetic in my new Civic, my 240 receives a nice, basic Valvoline oil. It might make your wallet a little sore draining the syntec prematurely, I agree with these guys to use a good, high detergent oil like the Shell. Once clean, you can use your oil of choice. If I recall correctly, full synthetics have very low, or no detergents

I have also heard using Chevron Delo can work wonders to clean engines without the use of strange chemicals. Oil for diesels has more detergents than conventional oil. It will work in gasoline engines (my friends run it in their turbo drift car engines- SR20s), but I don't know how long people keep it in for this purpose.

Use a quality filter, ie not Fram. I like Napa Gold filters, they are cheap like $5 and are actually Wix premium filters. OEM/Nissan oil filters are always a good option as well. I would consider Bosch to be a quality brand as well:beer:

[70 Cam Guy]

I would leave pulling the oil pan to your discretion. I would say it depends on what you see coming out of the drain but I am curious what the others might have to add.

I am most curious what the pickup screen looks like currently but if the screen is that bad, you would certainly see a loss in oil pressure.

[beandip]

Thanks for your advice, Gary and Will!

I was saying to change filters at 500 miles. Much depends on what the condition of the oil is in. If it looks black change both. If you use Dello or Rotella both of witch are outstanding oils. But find the NON EMISSION oil. The emissions rated oil is lacking in Zink and this is needed for our engines to save the valve train.

But this is a different topic.

[doradox]

Thanks for your advice, Gary and Will!

The order of oil flow seems to be from the sump to the pump to the filter to the oil passages, and the pressure sender is on the output side of the filter. I would presume if my filter became clogged, the pump would blow out the filter material, and then I'd still have oil pressure, but with contaminated oil. I probably wouldn't notice anything on my oil pressure gauge. Correct?

The oil filter has a bypass to prevent blowing out the filter material. However it will no longer filter the oil as you concluded. You should use a gasoline engine oil that explicity states that it passes the API rating recommended in your owners manual. That will give your engine the wear protection required by the manufacturer. Out of the three oils I have in my garage right now both Valvoline SYNpower and Quaker State Peak Performance state " exceeds all preceeding API and ILSAC gasoline categories" Catrol GTX however does not and only meets or exceeds SM, SL, SJ, SH. As an example a 73 240Z required SE or SD rated oil so GTX should not be used. The zinc issue has been debated extensively. If you feel the need for zinc I would recommend using a quality oil that meets the API rating you engine requires and then use an additive such as STP. Using racing oil or diesel engine oil in a quest for zinc means you will have to run an oil that is not recommended by the engine manufacturer for the use the engine was designed for.

Lastly, change, change, change. I once had an SBC that had so much sludge that it was literally 1/2 inch thick in places. After many frequent oil changes about 2 years later I tore it down for a rebuild and it was virtually spotless.

Steve

Edited July 25, 2009 by doradox

[FastWoman]

Thanks for all the great advice, guys!

OK, then. Drawing upon all of the advice above, I'll go ahead and drive the car, cautiously, for a few hundred miles, swap the filter, top off with Rislone, drive another thousand, and then change the oil. I'll make a switch to the Chevron Delo w/ STP (for zinc) at that point, with a fresh Bosch filter.

If anything becomes "different" on my gauges -- either oil pressure or temp, I'll go ahead and change oil right then. Of course I'll let the appearance of the oil (black) also tell me when I need to change. Wish me luck!

Edited July 25, 2009 by FastWoman

[beandip]

A friend of mine is a top engine builder of Z engines . He told me that because of the changes in the oils now in use the failure rate of cams and rockers arms has increased to the point that soon NO REUSABLE rockers will be available to re builders. This was due to the lack of the Zink compound that was eliminated in most oils. Our engines and those that have flat tappets need the Zink additive . Newer engines have roller cam and rockers and also all have Catalytic converters and the Zink compound is not computable with the Cat. So the oil companies pulled it from there oils. Diesel rated oils that are NOT emissions rated have the Zink. Valvoline RACING oil also has it. So the debate goes on. Redline has a additive you can add to any oil and it has the needed Zink compound. Assembly lubricants for rebuilding your engine all have the Zink compound. Wonder why?

Gary

[70 Cam Guy]

Interesting about the Zinc, I was not aware of that but I'll definitely look for it in the future. I'll have to also look at STP again. I've always written off oil additives as snake oil. Who knew one might actually serve a purpose