Engine problems...

[turbokinetic]

Just got back from working on my project car, the 84 Century. I got the pan and rod caps off the engine to determine the damage. The number 4 rod bearing is pretty melted. I am also fairly sure the crank is too badly damaged to use without being reground.

I was working on the ECM tune when this happened. All the parameters were looking good and I was working up to higher RPMs with each pull. I made 4 runs but didn't exceed 4000 RPM, and the engine is good to 6000. Boost was set at 7 PSI.

I had the data logger running when the problem showed up. That was good because I know it was not a tuning or driving mistake on my part that caused it. During the last "pull" in second gear from 2000 to 4000 RPM, it felt like it lost power so I let off the gas. As the RPM's came down, I could hear a knock. Oil pressure still looked fine so I drove it slowly to the barn and in that 1/2 mile it got worse so I parked it. It had a rod knocking and fine metal in the oil.

The only thing I can figure caused the failure is plugging of the oil pickup screen by the sludge in the pan. I'm a little surprised to find this much sludge because the engine was very clean up top. I had the manifold off and there was little sludge to speak of. I guess it took some running and heat to break loose the crud and cause the damage. It is 24 years old afterall.

I changed the oil 2 times and the filter 3 times to prevent such a problem, but apparently it was ineffective. I should have pulled the pan and cleaned and inspected the bottom end when I had the engine out of the car. I don't know if the turbo is damaged but I strongly suspect it is seized. I felt a power loss on the last run that led up to the engine knocking. It was either friction as the #4 bearing failed, or the turbo quit. I never pushed it beyond 4000 RPM thank goodness. Another few seconds and it would have been all over highway 216!

On the good side, my ECM tune worked great today. It was 24°F out and this engine started in 4 seconds of cranking. I put it in gear so it wouldn't rev up in cold idle mode (knowing the engine was damaged). Even without any chance to warm up it drove into the barn with no hesitation or hint that it might stall.

If the crank has to come out (pretty sure it will) I may change to a 3.8 crank if it can be done. I have one but unsure of its condition.

These pictures tell the story. I should have inspected this engine closer before running it. It spent 24 years as a 100 HP carburetor motor with the resulting sludge and crap in the pan and I expected it to jump up and run. It has only an idiot light for oil pressure warning, and it never warned me. The gauge I used to test pressure after turbo install was temporary. Oh well live and learn.:(
David

http://68.209.87.173/Temp/bearings_close.jpg
http://68.209.87.173/Temp/bearings.jpg
http://68.209.87.173/Temp/crank.jpg
http://68.209.87.173/Temp/pan1.jpg

[85_Ciera_Rebuild]

1. crank...reground....
2. plugging of the oil pickup screen by the sludge in the pan.


1. Submerge-able Welding...machine shops are few/far between...but it might be possible to re-use crank, and via reasonable cost to be done; hot rodders cranks, and big diesel cranks are done this way, in years past...not current now...but that's what you did years ago.

2. Check Oil Pump's Bypass...maybe stuck open a pinch...not sure if sludge alone would do it...have to be some hard particles in pan to cause starvation via screen plugging.

[turbokinetic]

The crank really is not as bad as it looks in the picture. There is some aluminum transfer from the failed bearing but the crank its self doesn't look like it is undersized. It has some burned oil clinging to it that looks like a deep ridge. Will clean it up with emery tape and measure.

Caterpillar used to do welding called "metal spray" that would build up a layer just a few thousandths thick. It may be similar to the process you describe. It was for things like this. I don't know for certain why they don't do it anymore but I have a theory. I heard it used some nasty (EPA) metals in the alloy and nasty compounds in the sheilding gas mixture.

The pump bypass could be sticking. I'll check that and re-install the oil pressure gauge. This time it will be mounted in the car where I can see it while driving. Before it was just for testing turbo oil PSI. I would expect a very low pressure at idle with a stuck bypass, then it would have more PSI at higher RPMs. I never got any oil pressure warnings, before, during, or after the failure.

The screen was plugged. The material looked like hard carbon crumbs. I could mash it through the screen with force, but it was too hard to go through by suction. There is no screen byass valve on this engine.

I said "sludge" but it was more of a "slurry" to be accurate. The car sat for years, and there is no telling how long that old oil was in there before the car was parked. The new Rotella oil probably broke loose all sorts of garbage that was clinging to the inside of the engine.

I had already run the engine for several hours with the TBI on the original manifold before pulling that manifold to install the turbo manifold.

I bet by that time the Rotella oil had already cleaned everything and caused the hard carbon to fall into the pan where I couldn't see it.

Thanks,
David

[LordDurock]

get wire wheel brush a drill and a file and even the ruff spots out and it should be fine that id very fixable. the junral messed up?

[85_Ciera_Rebuild]

...pump bypass...screen was plugged...carbon crumbs....no screen byass valve on this engine

Cam-Shaft's gear will produce "nylon crumbs," ...they were in bottom of my 2.8's pan....GM mechanic informed me they had a problem with screens being plugged on 2.8s....and kaput...there goes the motor.

On any of these older motors, the pan needs to come off, cleaned, and then install a new stock oil pump....mine had small amount of sludge in it...with some "nylon crumbs."

The original 2.8 Oil Pump in my 88 Beretta was in excellent condition, gear wise, but it was by-passing...oil pressure just about doubled with new stock pump.

Having a screen by-pass can also destroy the motor when enough "nylon crumbs" cover the screen, and then go direct via by-pass to oil filter, and then starve the motor when oil filter plugs.

Replacing the OEM Cam-Gear with a metal gear is most important....any motor with 75,000 miles plus needs to have OEM gear replaced. Yes, I've heard of people getting 250,000 miles...but unless you know actual engine hours, I'd use 75,000+ miles as a good time to replace it, especially on older vehicles...once it starts....either it slips time, or it kepts shredding pieces.

[85_Ciera_Rebuild]

Caterpillar used to do welding called "metal spray"



Building up of crankshaft journals by chrome, metal spray or submerged arc welding.

In Kansas City, Kansas, there was a shop that did submerged arc welding on all types of cranks, including Caterpillar cranks.

It's been too many years when I had one done, but it was quite reasonable for building up a thrust bearing, and grinding the crank, with new bearings...for $120.00 UPS shipped on VW 4 Banger crank.

[turbokinetic]

Well I guess I didn't kill my engine afterall. Just like Durock said, the crank throw cleaned up with little more than emery tape. I thought it was history.

Thankfully the rod was not messed up. Somehow that severly damaged, paper thin bearing insert did not spin in the rod and oversize it. The locating tangs were still intact. Since I have worked on engines since I was a kid, my mind is very in-tune with engine sounds. I guess I shut it down "almost" in time; yet before it actually blew up. I still don't know if the turbo is damaged or not. Because of te draw-through carb plenum, you can't see or feel the turbo impellers without major disassembly.

Got a temporary gauge installed now, will keep it in place for the durtion of the tuning. I think the crap in the pan caused this but I am not 100% sure. I could find NOTHING plugged in the engine's oiling system. I blew air and solvent through all the oil galleries and it exited each rod journal oil hole with equal force.

I cleaned the pan and pickup screen thoroughly, installed 6 new rod bearing inserts and lubed it with StaLube assy lube. After reassembly I cranked it with the starter until the gauge showed oil pressure. After that I plugged in the ECM fuse and hit the starter. In 3 seconds she took off running like nothing had happened.

I let the coolant and oil temp get up to fan-on temperature and let things run at varying speeds for about 30 minutes. No sign of knocking or any other malfunction. Will change the filter again before I start it up next time.

I haven't driven the car yet, so I don't know how that crank journal will hold up. It has some visible scratches but they can not be felt. The rod was not tight on the crank as it might be if there were raised areas or metal transfer left on the crank. The #4 rod felt like the others, as far as the side-clearence and oil clearences go. I did not measure, just based on feel.

I'm going to put a few miles on it easy, to make sure no additional crud breaks loose, before I continue with the full power ECM tuning. The inside of the block is clean, as you can see in the pictures. There is a thin varnish on it but no crud or sludge to speak of. It was all in the pan. I think the Rotella oil already cleaned everything!

Yes I hate those nylon/auminum cam gears. On the Buick 3.8 V6 (and maybe all Buick V6), it will not only put nylon crumbs in the pan it wil bend all valves. I have repaired 2 motors this happened to. Both were 86 or 87 3.8 SFI motors. Neither had any bearing damage, just bent valves. After the sprocket stripped, it was over in an instant and the engine didn't run long enough to suck the pieces into the pump.

The first thing I did to this engine was replace the timing gear. It has only 43,000 miles and everything was original (including the OIL possibly!?). The nylon gear had lots of cracking but no chunks were missing yet. Now, it's got a new Cloyes timing set and new tensioner.
Later,
David

http://68.209.87.173/Temp/crank_fix1.jpg
http://68.209.87.173/Temp/crank_fix2.jpg
http://68.209.87.173/Temp/gauge.jpg

[86euro]

I'll keep my fingers crossed for ya:thumbsup:

[turbokinetic]

Thanks, I appreciate it!

May be a week or 2 because I have service calls at work now. As soon as I put a few "easy" miles on it, it will be "sink or swim."

If it takes 7 PSI boost at 5500 RPM, then I will breathe a sigh of relief. If anything else engine-related happens, it is off to the rebuilding stand for it.... :( I am tired of patching it that is no way to build a good engine.

[MR2Di4]

Try using the high-strength magnets from a computer's hard drive on your oil filter. That should help trap any ferrous particles working through your engine as it wears in...

[turbokinetic]

Sounds like a good idea. I do have a few of those magnets here somewhere....

[85_Ciera_Rebuild]

If it takes 7 PSI boost at 5500 RPM,


Heads Up - I know by 1987, GM had redesigned 2.8 block-crank...they increased journal surface area...larger bearings. It was called "Generation II," and it has aluminum heads with splayed valves.

I would have to double check, but it was this engine that was being boosted since it could handle the stress better...I recall coming across something at GM Performance Parts (http://www.gmperformanceparts.com) and V60 Forum that mentioned these tidbits.

[85_Ciera_Rebuild]

...7 PSI boost at 5500 RPM...

I believe you are working with a 3.0L Buick Turbo V6 / EFI..but I thought I'd pass those tidbits along about 2.8 motor.

I found a GM document (http://www.s-series.org/htm/tech/GMPerfParts/144-148.pdf), which illustrates these tidbits:

First generation V6/60°s have cast iron cylinder heads with inline valves; second
generation engines have aluminum cylinder heads with splayed valves.

First generation V6/60°s are produced for front-wheel-drive and rear-wheel-drive chassis, while “Generation II” engines are installed in front-wheel-drive vehicles exclusively. Parts are interchangeable between the two versions except as noted in the part descriptions below.

Chevy V6/60° engines are available with 2.8–liter (173 cubic inch) and 3.1–liter (189ci) and 3.4-liter (207ci) displacements. 1985 and later V6/60° blocks have larger main bearings than pre–1985 engines; these late-model blocks are recommended for high-performance and competition applications. All Chevy V6/60° engines use metric fasteners exclusively.

I have forgotten the boost recommendation for these GM engines...but seven or less seems in the ballpark figure.

[86euro]

I believe that there were post-'85 S-10's that still had blocks with the smaller bearings. Maybe some carbed FWD's too.

[turbokinetic]

Yes, 85_C_RB, the engine that just had the bearing failure was the Buick block engine. I want to install that steel 3.8L crank in this engine. That's my ultimate goal. It is running now and not knocking. But in reality the engine needs to be rebuilt since it sat for so long anyway. I'm going to play with it some more and get the rest of the car fixed up until the wether gets better and I can retreive that 3.8 crank. It is in a juk engine, covered up, but out in the wether and I can't get a vehicle near it due to mud conditons.

When I put together the 60° motor (my 86 T-Type), I started with a junkyard core iron head 2.8 with a carburetor. It was a big journal engine. I ran it for a couple years with the carb.

When I went stark raving lunatic crazy and decided to turbo it, I found a core 3.1 and took the crank. It was an aluminum head motor with DIS reluctor on the crank, The crank fit my block correctly, as shown here. Look at the second picture down on the right side column:

http://home.hiwaay.net/~davida1/mtr.jpg

Had to get 3.1 pistons (wrist pin offset is different to accomodate the longer stroke) to use this crank. Same rods worked.

Looking through the piston book we found the 3.1 pistons with the "deepest" dished top to lower the C/R for turbo application. I beleive we calculated it to be 8:1. They are "hypereutectic alloy" pistons which are a stock replacement part. These are .060 over (IIRC) and the displacement of the engine is 3.2 liters.

Never ran any sort of boosted carb setup. I installed a MPFI manifold from a 1985 Z24 Cavalier along with the sensors and wiring, and the "large valve" iron heads, which I ported and gasket-matched to the intake and exhaust manifolds.

This setup would take about 6 PSI boost without pinging. I tried a mechanical boost-retard distributor but had limited success.

Finally I installed an intercooler from a Volvo sedan, and was able to up the boost to 9 PSI without detonating,

I ran the car for nearly 100,000 miles like this with no engine problems. Did have to mod the transmission though.

About 2 years ago I switched to a speed-density ECM that I could fully tune with Cats RTTuner. With this I was able to rework the spark table and fuel tables. As a result it can run boost as high as 15 PSI. This is the limit of the 2-bar MAP sensor. At 15 PSI there is no detonation and the AFR stays near 12:1. It overpowers the transmission badly.

The boost limit I run now is 13 PSI. It feels like the transmission is at its limit here. The car can be wildly uncontrollable in low gears but BOY IS IT FUN!!

When I was studying all the options for making outrageous power, I learned that there are 2 ways to do it. Either make LOADS of torque, or turn EXTREME RPM's. Either way you are moving a larger volume of air through the engine.

Looking at cams, intakes, headers and the like, I determined that my valves are too small (iron head engine) and I would need roller cam to do any good. Might make 200 HP and the RPM's would be sky-high. The powerband would be way above normal driving range. I would only have power when I "kicked into passing gear."

Instead of the above, I used a turbo. The engine kept the same RPM range as before, but now has increased torque. The other engine parts are basically stock or stock-replacement parts. Power begins at 1800 RPM and has full torque by 2500. Holds torque up to 4500, and starts to taper off a little by 5500 (the redline).

The power is there anytime needed at the tip of the throttle. It's not a peaky kind of power, it is a "push you back in the seat and hold you there" kind of torque. No downshift required.

Using a dash-mounted "performance analyzer" we measured the car's power. I only consider this a rough estimate and it is not official. With the boost set at 15 PSI the engine measured 318 HP. This device measures acceleration and has a factor for car weight. It calculates HP based on how fast you accelerate the given weight. It is an estimate.

Anyway it works and takes 13 PSI boost daily driven. The full writeup on it can be found here: http://home.hiwaay.net/~davida1/turbo2.htm