Sludge

[ricebubbles]

Hi All,
I am usually lurking on the BenzWorld W220 Forum but have a project to fix my son's 2000 Ford Explorer 4.0L SOHC which has broken timing chain guides on both sides.
I have spent hours reading your excellent forum and thanks to Members such as 2000StreetRod I now know what is in store for me.
Even though it was difficult, I used my magnetic base micrometer to measure the exact opening and closing points of the valves. From my measurements, it seems to me that the right bank (1,2,3) valve timing has slipped by as much as 160 degrees and the left bank (3,4,5) by about 130 degrees. When I get the engine to bits I will see which, if not all, chains and guides are stuffed.
The real purpose of my post to you guys is to find out what caused the sludge. It is not as bad as shown in some pictures on this forum but our engine has about 2mm of sludge inside the cam covers and over the internals. I have never seen anything like it before. My 2004 M-B S500 (5L V8) with over 200,000Km is pristine inside.
Our 200,000Km Ford has had regular oil changes and all I can think of is that something in the EGR has failed.
Any ideas much appreciated.
Regards from Down Under,
Brian in South Australia

 

[ricebubbles]

OK moving forward, but still waiting for your expert opinion as to why the engine was full of sludge in the first place.
The engine is now free of all ancillary equipment and hanging on the lifting crane, but will not separate from the auto trans housing. All 6 connecting bolts have been removed. The top two were a real PITA.
Any tips on how to separate the engine from the trans. much appreciated.
Regards from a very hot South Australia,
Brian
PS 26 homes lost to bush fires in the last 5 days just a few Kms from our home!!

 

[2000StreetRod]

thermostat?

Welcome to the forum. In my case I think the sludge was due to a previous owner using no thermostat or a very low temperature thermostat. The vehicle was owned in Texas where it gets pretty hot in the summer and in 2000 there was only a single row radiator in the stock configuration which has minimum cooling capacity. Some people think a lower temperature thermostat reduces overheating but all it really does is delay the engine from reaching normal operating temperature. Short trips and low operating temperature promote sludge formation. Once it is formed it is difficult to eliminate with just oil changes.

I assume that you have disconnected the flexplate to torque converter bolts. It is difficult to adjust the balance of the engine to remove the stress on the transmission input shaft - especially when having to lift the engine enough to clear the motor mounts. If you disconnect the motor mount brackets from the block then the engine can be moved forward without lifting much and there will be less stress on the transmission input shaft.

 

[ricebubbles]

Transmission and thermostat data logging

Thank you for the reply 2000 Street Rod.
I am certain the Thermostat is in good order having replaced it just a few years ago. I am very well aware of the importance of having a good thermostat and have had over 50 years experience with Fords (straight 6, and 289 V8), Volvo (V6), Jaguars (6 and V12) and now Mercedes-Benz (4 pot diesels and V8).
In fact I have worked out how to log the engine temperature using a WiFi Adapter which plugs in to the OBDII connector and records the data on my smart phone and computer. I have used this setup extensively for experimenting with air conditioner settings and thermostat performance in my M-B S500. Although I haven’t actually monitored the Explorer engine temperature yet (engine doesn’t work), I have used this method to read out the fault codes on the Explorer (there were none). For your interest here is a link to the published data logging method and results (see Section 14 in attachment to Post #49 ).
http://www.benzworld.org/forums/w220-s-class/1735481-question-about-star-diagnosis-5.html

We had removed the engine mount to block bolts, but hadn’t discovered the upper 2 trans to engine bolts. Now after re-reading your relevant linked documents, we have decided to remove the transmission with the engine. It will have to wait for cooler weather as it is over 40C again today.
Regards,
Brian
PS 38 houses have now been lost in the still uncontrolled bush fires raging in the Adelaide Hills.

 

[Flash]

I am certain the Thermostat is in good order having replaced it just a few years ago.

It's likely the sludge built up due to short trips and or bad thermostat with a previous owner.
Once the sludge is there it doesn't go away easily even with regular oil changes using high detergent oil.

 

[ricebubbles]

Help Needed with Repairs to Timing Chains.

Hi All,
Have been progressing slowly on my Timing Chain and Guide Repair Project for months now and finally got engine back in the car ready for the big test today.

Engine started and ran for 10 seconds and then stopped! It now sounds like it did with the broken guides. It cranks but doesn't even try to start.

I took my time during the repairs double checking everything was OK before progressing to the next step so I am 100% confident it went together properly. All went well except for one torque to yield bolt. I used all new bolts and the specified tension but I could feel this one bolt stretching just as I got to the specified torque. I stopped short of the specified torque setting for fear of breaking the bolt. I cannot remember which bolt it was now!

When the engine started it sounded very rattly which I expected as there would have been very little oil up at the cam tensioners.

I did pre-prime the new tensioners with oil when I fitted them.

I also cranked the motor with the sparks and petrol disabled before the attempt at starting to try to get some oil into the tensioners.

So why did it stop running? My thoughts are:

1. One or both cam chains could have jumped a cog due to not enough tension from the hydraulic tensioners. Is this likely?

2. The suspect bolt may have broken, or allowed a cam sprocket to slip thus upsetting the timing.

I will investigate more when I can get motivated again but would appreciate any ideas.

TIA,
Brian

 

[2000StreetRod]

Compression test

Did you manually test the hydraulic/spring cassette guide tensioners for free movement before installation? Some aftermarket tensioners are junk that can seize upon engine start. If they seize in the compressed position there will be slack in the chain. If they seize in the extended position the cassette guide will break. Performing a compression test is a simple way to check for timing chain slip.

Did you use the timing took kit to time the camshafts? If you used the 6485 socket extension to torque the right camshaft sprocket retaining bolt the torque value should have been 45 lb-ft instead of 63 lb-ft because of the lever arm.

 

[ricebubbles]

Hi Dale,
Thanks for the reply.

I should have posted an update after I got the engine in bits. As predicted by the Forum the plastic guides had all disintegrated and both camshafts plus the balance shaft chains had jumped sprockets and were badly mistimed. I found that both banks had jumped by about 130 crankshaft degrees. Fortunately the valves had only just touched the top of one bank of pistons. Three valves had removed the carbon coating on the pistons in a circular arc pattern but didn't even bruise the aluminium piston tops.

I then had no choice but to do a full timing chain overhaul and really appreciated your valuable posts and publications before I started. I followed them to the letter. That's why it has taken me so long to get the engine back in. I double checked everything and some things like the valve timing I triple checked.

Re the tensioners, they were genuine Ford ones as were all the parts which I obtained from Tasca Parts as per your recommendation. The tensioners were not seized and primed well in an oil bath by pumping in and out before installation. However they sat for weeks before I tried starting the engine so any primed oil may have drained back out. The rest of the engine was bone dry after thoroughly washing the block in a cleaning bath and removing as much of the sludge build up as I could. I did oil the crankshaft journals, timing chains and the cam shafts before putting the covers back on and as I said above, I cranked the motor with the spark HT and petrol disabled to try to get oil circulated before the first start. I now recall that I didn't prime the oil pump after cleaning though, but it sat immersed in oil for weeks before doing the priming cranks. With the engine all buttoned up I didn't check to see if the oil was circulating properly but cannot see any reason why it wasn't.

Re timing, I purchased an OTC6488 Ford Timing Chain Realignment Tool Kit which worked well with your guidance. I found I did not have to use the camshaft gear removal tool 6485 as I was able to apply the torque wrench directly, with the bolts tightened to 85 Nm (63 lb-ft).

I did have that issue with one new bolt seemingly stretching as it was torqued to spec but I cannot remember which one it was. The torque spec is ridiculously high in some instances but I guess it has to be with just a friction drive.

I have had a good sleep since the first attempt at starting and have calmed down a bit this morning. I have just tried starting the engine again and it coughed a couple of times but then nothing. It cranks OK but sounds like it did at the beginning of the project with no sign of starting at all. There is plenty of pressure in the fuel rails and after cranking there is a distinct smell of unburnt petrol. So I still think a chain has jumped a sprocket but at the moment cannot face up to the thought of having to pull the engine down again.

My next step is to remove the spark plugs and do a compression test and if that shows an issue take off the camshaft covers and recheck the timing by turning the engine over by hand and watching the valve positions versus the crankshaft angle. I can do that with my eyes closed as I spent weeks diagnosing the initial fault at the start of the project.

If I am lucky it will be the left bank that has slipped and I can retime that with the engine still in the car.

Your thoughts and opinion are very much appreciated as I now understand what a colossal job it is to repair the broken guides. You either need to be very desperate, a complete enthusiast, mad, or like me, retired with some time on your hands, to even attempt this task. It was interesting but I wouldn't say it was fun, especially the transmission bolts accessed from underneath.

Thank you again, it really helps communicating with someone who understands the issues.

Well having off loaded my tale of woes, I feel inclined to get stuck into it again. I will not let it beat me!

Regards from Down Under,
Brian

 

[2000StreetRod]

starting fluid

Brian,
After you check the compression and find it to be good I suggest opening the throttle plate and spraying some starting fluid into the intake manifold. Then quickly reconnect the MAF sensor and crank the starter. If the engine runs for a second or two then you know there is a fuel problem. If there is then check the fuel pressure. Also, if your fuel has been sitting in the tank for more than 6 months with no added fuel stabilizer it may have turned to noncombustible lacquer.

 

[ricebubbles]

I just tried a good squirt of Aerostart (ether) in the inlet chamber through one of the easily removed hoses but nothing. Not even a cough or splutter.
The fuel is over 2 years old but I think it should be OK. The ether test shows there is some other problem.
Compression test is next.
Brian

 

[ricebubbles]

Hi Dale,
I removed spark plugs 1, 2, 3, 5, and 6. Number 4 was just too difficult to remove without a lot of work.

With my compression gauge screwed in to cylinders 2 then 6, it showed 0 psi when the engine was cranked both times. Not even a flutter on the gauge. Repeated with 5 squirts of oil in the test cylinders but still get 0 psi. Didn't bother to check the other cylinders. The gauge checks OK against my air compressor so it looks like BOTH banks have slipped their valve timing. I cannot think of any other reason other than catastrophic failure of all valves or all pistons to cause no compression in all cylinders.

Next I will remove cam covers and measure the valve opening and closing points versus crankshaft angle. This is where I started 6 months ago.

The big question is what has slipped? Was it;
1. Both cam timing chains jumping their sprockets due to insufficient oil pressure in their tensioners. It seems that this is a definite possibility, or;
2. Did the friction coupling created by the securing bolts fail. Seems to me less likely.

I have read elsewhere on the Forum that other members have experienced severe rattling on start up until the tensioners built up pressure so I am surprised that mine would have jumped their sprockets.

It seems to me that it would be a good idea to apply a spot of weld to lock the chain sprockets in place, once the engine has been retimed correctly. There is not much to lose because unless I can get it going properly, the engine is just fit for duty as a boat anchor anyway.

Finally, assuming that both cam shafts have slipped, does this mean the engine has to come out to retime everything or can retiming be done with the engine in the car?

TIA
Brian

 

[2000StreetRod]

jackshaft sprocket bolt?

Even with no oil pressure to the cassette tensioners it is extremely unlikely that both camshaft timing chains have slipped. I suspect that the jackshaft front sprocket retaining bolt was not tight enough or broke and the sprocket has slipped which would affect both banks.

It is standard procedure to time both camshafts with the engine in the vehicle. The socket extension allows tightening/loosening the rear camshaft sprocket retaining bolt since a standard torque wrench with socket will not fit between the firewall and the bolt head.

After you retime the camshafts I suggest checking the compression before attempting an engine start - valves may have been damaged.

 

[ricebubbles]

So that explains what tool 6485 is for and why I didn't have to use it with the engine out of the car.
If I am lucky the valves should be OK as they survived the original failure of the guides.
It is good news that I don't have to take the engine out again so thanks for that.
It seems to me that it could be very difficult to determine exactly what happened, ie trying to tell if a sprocket slipped is probably impossible other than by the fact that the timing is wrong.
I will start the dismantle tomorrow.
Regards,
Brian

 

[ricebubbles]

Hi Dale,
Appreciate your thoughts again.

Got the cam covers off and right camshaft is now not aligned correctly.

At TDC the cam sensor is in the correct place and the left cam shaft alignment slot is parallel to the head and below the centre line as required when viewed by a mirror as it is at the firewall end. The right cam shaft alignment slot is not aligned with the head and seems to have slipped by about 300 cam shaft degrees. It could have jumped forward by about 60 degrees but this seems unlikely.

The good news is that there was plenty of oil coming through the cam oilers so the tensioners should have worked OK. Makes me think that one of the friction couplings slipped.

Now the really weird thing is that I still have zero compression. The left bank is timed correctly and I screwed my compression gauge into cylinders 4 and then 6, but don't even see a flutter when the engine is cranked.

I checked the clearance at the cam rollers and all but one had zero clearance. I loosened the left cam shaft bearing caps until I could fit a 0.008mm feeler gauge in on both valves on cylinder 6 and did a compression test again. Not even a flutter on the gauge. The gauge certainly responds when using my workshop compressor as a test.

At the moment its got me beat so any ideas much appreciated.

It seems to me that it is impossible to tell which friction joint has slipped, although it has to be either the rear jackshaft bolt or right cam sprocket. If it was the front jackshaft then the left cam shaft would be wrong as well.

Regards,
Brian

Later note: Just checked my compression tester gauge on a neighbour's car and it works great.

 

[Flash]

Are you absolutely sure the valves aren't bent?

 

[ricebubbles]

I am not 100% certain, except when the engine failed originally only 3 cylinders had slight, and I really mean slight, marks on the top. The valves in one bank had just touched the tops of the pistons. They removed the black carbon film and left a semi circular shiney mark. The other bank showed no sign of any contact.

When I cleaned the heads there was not the slightest sign of any bruising or indentations on the tops of the pistons and so I assumed the valves were all OK.

I even did a liquid test when the heads were in the cleaning bath. I picked a cylinder where the valves were both closed and filled the combustion chamber with cleaning solution with my finger over the spark plug hole. There did not appear to be any leakage past the valve seats hence confirming my original impression that all was OK.

At the moment I am at a loss as to what is causing the lack of compression. There is no compression in any of the cylinders. There has to be a large leak as the compression gauge doesn't even start to move off the zero mark. There were definitely no holes in the piston tops. Bad rings should produce a little compression and the gauge should show some compression with oil squirted into the cylinder during the testing. The head gaskets were brand new and were the correct ones. The heads were torqued to specification without any drama. The coolant did not leak into the cylinders.

So what else could it be?

Regards from a cold Adelaide,
Brian

Later note: In thinking about what to do next I have decided to try pressurising a cylinder using my compression gauge spark plug fitting and my air compressor and listening for leaks.

 

[2000StreetRod]

camshafts rotating

If the camshafts are rotating when the crankshaft is rotating and the cam followers are installed and there is no compression then the valves are probably not seating. Using your air compressor to check for airflow is a good idea. I purchased a valve spring compressor online that will work with the SOHC 4.0L V6, the SOHC 4.6L V8 and the DOHC 4.6L V8: 2V 4V V8 & 4.0L SOHC Valve Spring Compressor

 

[ricebubbles]

Thanks Dale,

Everything appears to be working (except for the incorrect timing on right bank due to the latest slippage).

It would be nice to know what actually slipped. Looking at the timing chains again and given that there was plenty of oil pressure, I would be very surprised if the chains could jump on their sprockets, so it must have been slippage of a friction coupling as no bolts have broken.

Have you any thoughts on my earlier comment "It seems to me that it is impossible to tell which friction joint has slipped, although it has to be either the rear jackshaft bolt or right cam sprocket. If it was the front jackshaft coupling then the left cam shaft would be wrong as well."?

Regards,
Brian

 

[2000StreetRod]

tighten as rotate

The sprocket retaining bolts are threaded to tighten as the crankshaft pulls the jackshaft via its chain and the jackshaft pulls the camshafts via the chains. That's why the rear (right) camshaft sprocket retaining bolt tightens counter-clockwise. Since the chain section between the jackshaft sprocket and the camshaft sprocket is in traction except when the engine is decelerating or cranking it is unlikely to slip during normal driving. I suspect when the chain does slip it is usually due to a cassette guide fragment getting wedged between the chain and the head casting.

I agree that if the right camshaft has slipped but the left is correct then either the jackshaft rear sprocket retaining bolt or the right camshaft sprocket retaining bolt slipped. Since you used the OTC 6488 timing tool kit I suspect that the jackshaft rear sprocket bolt slipped. How did you hold the jackshaft when tightening the rear sprocket bolt? The torque setting for the front sprocket retaining bolt is: Step 1: 33 lb-ft, Step 2: plus 90 deg and for the Rear: Step 1: 15 lb-ft, Step 2: plus 90 deg. So you can hold the front to tighten the rear but not vice-versa.

 

[Flash]

The only thing I can think of is to make absolutely sure no.1 is at top dead centre on the firing stroke when the cam timing marks are right.

I don't mean to be condescending here, I'm sure that when you eventually figure it out there will be some forehead slapping; no.1 is at the front and on the left side as you look at the engine bay - the driver's side rhd.