Cleaning sludge

Recently bought a Mazda JDM engine with supposed low miles. Before I drop it in the Protege I decided to take off the oil pan to clean it out as well as the pickup. What I was faced with was a lot of sludge. Cleaned all that out and started doing the timing belt and seals. Took off the valve cover and the head had a lot of sludge buildup too. I was thinking about soaking the head in a Kerosene bath to flush out the sludge. Is this a good idea or not? Also, if I do go this route do I need to take out the lifters and soak them in oil before reassembling?

Thanks

If there's that much sludge you need to look at the oil passages and make sure that they are clean. There are many in the head and block that can be plugged up or could become so since you have loosen all that sludge and you don't get it all out.

Also why all the sludge? Most times I see an engine that way that isn't worn out due to not changing the oil, it's due to coolant in the oil. Oil and AF do not like each other. Mix them together and you get sludge!

Oil passages look good. Head gasket even looked good. Crosshatching on the cylinders looked factory fresh. No scoring. Cam lobes and lifters looked almost new. Cam bearing surfaces looked good. Pistons had minimal carbon on them. I'm thinking that maybe the po did oil changes infrequently and the car was used for just short runs and never really got warmed up. Just speculation though.

Low mile jdm? Two things watch for- yes they do make frequent, short trips in Japan. It's expensive to operate a vehicle there. The other is to make sure it isn't a tsunami engine. When that event happened in Japan, the engines sitting in crates got swamped. I've met a few ppl that had to return the crates they got. Salted engines that were shined up for resale. Total garbage inside.

Other thing is that is a really old engine and has not been in a running car for awhile in Japan. I guarantee it. Likely it's "brominated" oil or additives (since Japanese engines are swapped out before a hand full of oil changes happen)

Cleaning sludge off aluminum is nasty work. I use aircraft paint stripper (spray or brush) to eat through the crud.

My low milage car bit me like this. Bought a 14 year old car with 78,000 miles and it started to rattle a rod in just a few months. Dumbfounede i pulled the motor and found it horribly sludged. Had to rebuild.

If yours is/was running OK, I would pull the head off and dissassemble the rotating assembly. Get the block tanked and put it back together. Use a fresh oil pump and rings.

honestly I'd buy a sleeve of cheap oil filters via amazon or ebay and 3-4 5 liter bottles of (non synthetic is fine if it meets the required engine specs) oil and a can of engine flush (Amsoil, redline or CRC) do an oil change, drive for 100 miles, add can of flush when hot and idle for 10 minutes, or add cold and drive for 60 miles continuously, and change oil while engine is still warm. drive for 50-100 miles to a week max, do another oil change (change #3) drive for 100-500 miles to a month max, do 4th oil change. drive for 1000 miles, then change to synthetic oil of your choice. when changing to the synthetic send an oil sample of the cheap oil off to blackstone for an analysis. I'd also do this when sending your first regularly scheduled synthetic oil change as well.

Bah. It's jdm yo. Just scrape all the sludge out that you can, then slap it in and run a can of sea foam through it. Then, flog.

Perhaps just fill the crankcase like normal but with mineral spirits? Drain then refill with drained spirits. When it gets gross consider it done or change to fresh spirits and continue. Then at least most the crud is out. also when it's running, a quart of atf added to the crankcase does wonders for cleaning a motor out. It's safe to run a long time like that but generally dump in a quart and drive it 10-50 miles

Trackmouse wrote: Bah. It's jdm yo. Just scrape all the sludge out that you can, then slap it in and run a can of sea foam through it. [/drive gingerly for a few hundred miles, change oilb]Then, flog.

Also, I am crap at using bold and Italy CX, also spelling italcx

Lol. That's funny. Yeah, I guess if you care about the engine then drive gingerly. I myself prefer the Italian tune up 24/7.

Dunked the head in Kerosene and it came clean pretty easily. None of the sludge seems to be hard. More of a pudding consistency. None of the passages appear to be stopped up.

Think I learned my lesson on JDM engines. Got to looking real close and it has a Mazda oil filter and Mazda spark plugs. I wonder if they're original or if the original owner always took the car to the dealer for service........