Sc finally coming apart

Pulled the engine out of the SC this morning and disaasembled the motor. Everything looked good. No wear on the cam even though the cam bearings looked wore. Timing chain, heads and valve train showed nothing wore. Pulled the oil pan and dissasembled the main bearings. They look Ok. No problem there. Pulled the rear cap off the rod. Found nothing but copper showing. Must be the bad rod. Pulled the rest of the rod and pistons out and they looked OK untill I got to #1 & #4 rods and you can see from the pictures one rod bearing had ate the copper completely away. the bearing in some places was only a few thousands thick. the bearing in my hand had copper on the edge of the side. creating drag. It didnt come out easy. It is easy to see why the lower end was squealing. Before you guys ask. I have not tore the oil pump apart yet to see if it failed. I ran out of time today. I will take it apart tomorrow. The car ran 12 WOT runs on the dyno trying to tune it and than I dorve it about 3 miles. My question to the experts out there is how much of the wear was before the tune, during the tune and the 3 miles I drove it. Just speculating if a lot of this was shot before I tried to tune it this last time.

Ken

Why not rebuild this one? Instead of throwing an unknown engine and possibly doing the Job twice. have a machine shop turn that crank at the rod bearings put oversize bearings and fresh stock main bearings and put it back together. Check the rods and pistons for signs of detonation.

That seems like an awful lot of bearing wear for detonation. I put a high volume pump on my 72 stang 351C years back. Worked great for 4 years around the city but when my brother borrowed it on short highway trips to work in another city, the pump starved for oil and took out rods 1 and 5.

ricardoa1 said:

Why not rebuild this one? Instead of throwing an unknown engine and possibly doing the Job twice. have a machine shop turn that crank at the rod bearings put oversize bearings and fresh stock main bearings and put it back together. Check the rods and pistons for signs of detonation.

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I would still have a high milage wore out engine. Car has 145,000 miles on the clock. The short block is coming from a local club member that I beleive I can trust or I wouldn't buy the block from him. Now if I was buying from someone just advertising a short block for sale. I wouldn't feel that secure that I was getting what I paid for. The time has come to get this car running, tuned and out on the road. I need to work on more than just the engine on the car.
The #3 piston had signs of detonation but I beleive when the oil pump is oppened up I will find the real cause of all the carnage

Detonation, by itself, doesn't cause a rod bearing to completely demolish the copper layer. What exactly do the main bearings look like? Reason I ask is, if they look wiped at all then the only reason a main bearing can be wiped is not enough clearance or it just isn't getting any oil (mainly from lack of oil in the pan.)

I have become skeptical as to how many quarts the motor should actually have. Dipstick aside, I figure there can be some type of breakdown. You have about 3 quarts to break even (meaning the pump won't suck air) then you have 2 quarts in the passages and up in the cylinder heads. That oil cant drain back down fast enough so lets call it another quart. So that means you have 6 quarts atleast to break even statically. Then wait until the oil gets hot. Hot oil pumps literally three times faster than cold oil does. Rhetorical question, so how many quarts do you think should go in? I call seven. Just a thought though, not saying thats really your problem.

I can guarantee you that the bearing had eaten the babbit layer off by the first run, through the lead layer the second run, and copper was getting beat out of it from there on.

Do you know what the clearances are on the mains and rods? This is also dependent on what oil you choose to run. People like to run 20w-50 on a motor with .0015" on the mains and .002" on the rods. This is a no-no. Oil pressure, at the gauge, is only measuring the backpressure from the oil pump until the beginning of the oil passages BEFORE getting to the crank. Just because the oil pressure is reading high, or good, doesn't mean you are getting that to the rods. Use light oils for tight clearances and heavy oils for loose clearances.

Needless to say, this is definitely why your car had power problems. For one, your crank is dragging on the rods (50 crank HP) and the computer was pulling out timing from knock.

CMac89 said:

Detonation, by itself, doesn't cause a rod bearing to completely demolish the copper layer. What exactly do the main bearings look like? Reason I ask is, if they look wiped at all then the only reason a main bearing can be wiped is not enough clearance or it just isn't getting any oil (mainly from lack of oil in the pan.)

I have become skeptical as to how many quarts the motor should actually have. Dipstick aside, I figure there can be some type of breakdown. You have about 3 quarts to break even (meaning the pump won't suck air) then you have 2 quarts in the passages and up in the cylinder heads. That oil cant drain back down fast enough so lets call it another quart. So that means you have 6 quarts atleast to break even statically. Then wait until the oil gets hot. Hot oil pumps literally three times faster than cold oil does. Rhetorical question, so how many quarts do you think should go in? I call seven. Just a thought though, not saying thats really your problem.

I can guarantee you that the bearing had eaten the babbit layer off by the first run, through the lead layer the second run, and copper was getting beat out of it from there on.

Do you know what the clearances are on the mains and rods? This is also dependent on what oil you choose to run. People like to run 20w-50 on a motor with .0015" on the mains and .002" on the rods. This is a no-no. Oil pressure, at the gauge, is only measuring the backpressure from the oil pump until the beginning of the oil passages BEFORE getting to the crank. Just because the oil pressure is reading high, or good, doesn't mean you are getting that to the rods. Use light oils for tight clearances and heavy oils for loose clearances.

Needless to say, this is definitely why your car had power problems. For one, your crank is dragging on the rods (50 crank HP) and the computer was pulling out timing from knock.

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You make some very interesting points regarding oil pressure and viscosity and such. Perhaps you would like to open a new thread that would take a discussion in that direction? I know I, and maybe many others, would be very interested in such a discussion.

Call it adding to our learning curve

Ira

Dont know the clearances exactly. I figured it has 145,000 on the motor so it sure to have a lot of wear on it. I had 5qts of 10W40 motor oil in it. The mains look good, no damage I can see. I just oppened the oil pump and found no problems there at all. I can only assume the antifeeze must have had some residue still in the engine and destroyed the bearings.

Ken

To quote another respected SC mechanic - "10w40 oil should not be used in anything." But that's probably not the cause either.

The fact is that your rod bearings were into the copper before you ever started any mods. In fact they were into the copper before you even bought the car. Every SC motor I have ever seen has always had copper showing on the rod bearings.

I have been told that this is typical for a motor that sees detonation on a regular basis over a long period of time. SC motors typically detonate so rod bearing wear is a fact of life. Just because the rods are showing copper doesn't mean the motor is shot. It does mean that your clearances are wide and it also means that you have no margin of error. Copper doesn't react well to contact with the crankshaft.

The key to saving a high mileage SC motor is to anticipate this wear and run an oil that will stand a better chance of maintaining it's film under severe load. My wife's XR7 (the one that made 440rwhp) came apart with copper on every one of the rod bearings. The crankshaft was absolutely perfect other than one or two or three minor scores from debris. The journals were all on spec and did not require re-grinding at all. This motor saw 6500rpm many times, over 20psi boost, and plenty of detonation.

In your case if I were to guess it would be to say that likely you had contaminated oil on the dyno when the gaskets blew. Most likely some bearing contact occurred which created an irregular surface on the bearing and prevented it from being able to hold a film. Combine that with oil that's not up to the task and some severe dyno use and that was the end of that.

That's about all there really is to say IMO because you'll never know exactly what happened and when but as Casey said, it is pretty clear that it was in BAD shape already when you hit the dyno the second time. An oil pressure gauge might have saved the crank but it wouldn't have prevented the teardown. Chances are pretty slim that the crank is salvageable anymore at this point.

Well...time for a billit crank and Chevy rods. Are you going to look for a 94+ timing cover/pump? Also, why would you not run 10-40 in anything? Is the 40 to thick or is the 10 just not enough for start up?

Chris

XR7 Dave said:

To quote another respected SC mechanic - "10w40 oil should not be used in anything." But that's probably not the cause either.

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So is 15w50 not recommended to use anymore? Back to 10w30 being the ideal oil to use in these cars? I was planning to run my car the first 500 mile break-in period on 15w50. From the sounds, 10w30 is what we should use from that post I believe you are referring to.

I think the aversion to 10w40 is partially due to too much reliance on additives. IE, 30 points of viscosity is a lot of distance to make up, when oil really wants to act something like 30w15.

Interesting. So thirty is a bad number?

Chris

um,,,, they should have 5w30 run in them as far as i know, thats what ive always put in all of mine. no wonder it died with 10w40. and a high volume oil pump is not needed, especially with a stock bottom end, you can actually move oil too fast just like coolant.

Like I said earlier, loose clearances need heavier oils and tight clearances need thinner oils.

On a stock SC motor with mid to high miles, the bearings start to wear. When they wear, this means that the clearances open up. Henceforth, you need to run a heavier oil.

If your motor has high miles on it, then run at or between 15w-40 and 20w-50, end of story. If you have a new motor, with known clearances around .0015"-.002" clearance on mains/rods, then you should run 5w-30 or 10w-30 max then forget about it.

The more viscosity there is, then the more lubricity it has. This is true, but less oil gets to the mains/rods. You will loose a little bit of lubricity, but you will get more oil to the mains/rods. Not to mention, they make synthetic oils. This makes up for lubricity lost.

Hey, guess what. The thinner the oil, the more HP you make from less drag on the crank too. But how much oil do you think it takes for the crank to drag on a torn up bearing? Choose the correct oils.

Disclaimer: I'm not a petro engineer nor an expert on engine oils.

However.

If you ask people who DO know, they will tell you the same things with only slight variation so after awhile you start to get the idea.

1) Do not use synthetic oil for break in! The increased lubricity of the oil will hamper ring break in. If you want your motor to last for 1,000,000 miles and take 20,000 miles to break in, well then in that case go ahead I guess. BTW, 15w50 is only available in synthetic so that means don't use 15w50 for break in.

2) Ford specified 5w30 oil for our cars for the purpose of increasing gas mileage, reducing emissions and possibly to improve cooling. That specification has nothing to do with the mechanics of what is going on inside the motor. The SC engine does not require a low viscosity oil even when brand new. The SC engine will TOLERATE 5w30 if you go easy on it. If you run it hard I can pretty much guarantee what will happen to it over time and non of it's good.

3) Many NEW engines require 5w20 oil. These are OHC motors that need a low viscosity oil to lubricate the top end of the motor on start up. OHV motors, as a general rule do not require this. Our motor is as old school as it gets when it comes to lubrication requirements. I would not run lighter than 10w30 oil in an SC. There is no requirement in the SC engine for 5w30 oil.

4) Oil viscosity. Perhaps an engineer will chime in, but as I understand it the lighter number (the 5 in 5w30) represents the oil's true weight. The bigger number reflects the oil's ability to retain viscosity at operating temperature. This higher number is typically achieved with the use of viscosity enhancers which are NOT oil. The more viscocity enhancers an oil has the less lubricating it can do. A wide spread in the 2 numbers is not typically desirable. Keep in mind that synthetic oils by nature will comparatively speaking be capable of a wider range of viscosity with less viscosity enhancers than standard oil due to their superior molecular composition. There is a 15w30 oil available for racing. This represents a heavier base oil with less modifiers which will perform like a lightweight 30 oil under heat and load. Many racers recommend and use this weight of oil but remember, what is great for a 1300hp drag motor isn't necessarily good for a street SC that sees a wide variety of conditions.

5) Detonation. I do not believe that Ford engineers expected SC's to suffer prolonged detonation over their life times. However, that it occurs is a fact and so dealing with it in the end is our job. If you ask an engine builder or engine designer how to deal with detonation you will get a dumb blank stare as they consider you an idiot. You are not supposed to "deal" with detonation, you are supposed to eliminate it. In a perfect world we would do so. However, the reality is that most SC's detonate regularly and so we end up having to deal with it. It is the held opinion of at least one engineer and engine builder that running a higher viscosity oil than is exactly required for lubrication may provide some "cushion" on the rod bearings during the detonation events that destroy the bearings. The fact that I was able to run my motor with detonation AND worn out bearings without damage or failure lends credence to that belief. I realize that personal experience is not acceptable as scientific evidence, but some of us are having success where others are not. Take that for what it's worth.

6) I still recommend Mobil 1 15w50 for an SC motor with 80K miles or more on the bearings or one with less miles that may have wider than stock clearances.

If you disagree with anything I've said that's no problem. Do what works for you.

Dave, you're getting pretty warm.

Say that you have .002" clearance on a rod bearing. This means that the clearances are .001" radially, in other words, there is .001" between the crank and rod bearings throughout the whole circumference of the journal. So if everybody thinks that the journal rides the bearing at all times, it doesn't.

That .001" clearance is for an oil film to ride in. What happens when bearings start to wear is whenever the surface tension of a .001" thick oil film is broken then there is metal to metal contact. This happens as a result of heat from detonation and clearances. Too light of an oil will spew oil out the side of the rods excessively, but the right oil will build a proper film and sustain surface tension. Heat is indirectly proportional to lubricity as well.

The higher the viscosity, the more surface tension there is. The higher the surface tension, the more clearance you can run.

Many newer European cars are broken in using synthetic oils...This is one for Myth busters

Also climate should dictate what oil you use. Lower viscosity in the winter, higher in the summer. The nice thing about synthetics is that they maintain there viscocity better under extreme temperatures.

You can't just arbitrarily add quarts of oil to an engine because you think the recommended amount starves the engine for oil. This may be the case and it may not.

If you add 2 quarts and the engine does not require it or benefit from it, you will greatly increase windage and aeration which is just as deadly to bearing surfaces as not enough oil. If there is too much oil in the system, after a short run, the oil will look foamy.

Generally the addition of a windage tray allows for 1 extra quart or if a deep pan is installed that has increased the volume the pan is capable of holding. Usually the addition of a high volume pump necessitates the addition of a deep pan.

Dave,
No reply to my PM or the post on the tuner.