Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Will an S/C Kill your Contour

I haven't really examined them yet. I took off the pan and tapped them each with a small hammer until I found the one that was a little bit different sound than the others... all go thump except the rear middle cylinder that goes cling! Rod bolts aren't loose for it to make that noise and the cap's a bit caramel colored, but I don't think I hurt the block or crank to bad. Does Ford sell bearings for these things? It could be rebuilt if they do...

Oil starvation/cavitation is all that could cause such a thing. I will post pictures after I get the new engine in and running as that's my main priority.

everything i have read suggests that oil pressure is only a problem at low rpm range and once you get into higher rpms the pressure should be sufficent. unless you are suggesting that there just isn't enough oil being supplied to the crank case to keep the bearings lubed. but if that was the case then you would have had problems at lower rpms because oil pressure would be lower. sorry if that comes off as incoherent, i am trying to think this through as i type...

From what I saw, the rods are fine but posibly the one that spun. All mains are A.O.K. There was no premature bearing wear, only lack of oil flow to the crank, thus the caramel color on the two center rod caps (burned that color from the heat of no lube). What the engine needed is one of three things: 1. Knife edged crank 2. A better windage tray or crank scraper 3. An external oil source to the heads to keep the drainback flow to the crank plentiful. The oil in the crank case isn't enough for the rod bearings at high engine speed because of oil wrap-up. Any one of the three things I mentioned would have bettered the chance of survival, only one of which is easy and inexpensive... #3. High RPM for sustained amounts of time... Must I say it again? Anyone? Beuller? :P

Ok, anyone who was at the SZ dyno day right at the end when we were talking with Jack (the owner of the place) about oil starvation remember what he was saying! hehe
Also, I talked with Jack about the pans this morning... look for something good and at a lower cost then the Mirko pan sometime this winter.
-Mark

The other things I listed above need to be added to your knowledge. Low RPM's the pressure is lower, you're correct. That's why my oil light didn't come on though, I had good pressure. High RPM, pressure is high, also true, but pressure has nothing to do with the crank getting oil. Pressure has to do with getting oil to the top of the engine, not the crank. When the crank spins at high RPM, the oil begins to wrap itself around the crank in such a way that the air actually forms a barrier around the crank starving it from oil. It also actually makes the level of oil in the center of the pan dip down so the crank isn't getting the splash it's supposed to. This is called cavitation (SP?).

The knife edge idea is an old one and works very simple. Sharpen the edge of the crank so that there's less surface area to carry oil around the crank and leaving the oil where it's supposed to be, in the pan so that the pump can pick it up.

The other way to cure this wrap up is a crank scraper. A simple piece of metal about an 1/8" away from touching the crank as it passes past the edge of the block on it's upward side. This scrapes the oil trying to follow the crank and forces it back into the pan where it can do it's work.

The second theory of mine is starvation which can happen two ways. One, buy the crank spinning so fast the oil becomes frothy with air bubbles. The oil pump sucks air bubbles along with the oil, not getting the full amount of oil to the heads because of the bubbles of air, therefore meening not enough drain back to the crank... boom.

The other way starvation can happen is that the oil pump is working so well that it sucks the pan almost dry and the gravity feed return holes don't flow well enough to get it back to the pan in time to be repumped back around.

A windage tray is made from either mesh or partly soild sheet metal directly under the crank to keep the oil off of the crank durring high RPM splash.

In all of these conditions, the external oil pump/resivoir (SP?) would work wonders by keeping a constant return supply to all parts of the crank.

Does that help any?

Anything like what I just posted? I have only a little experience with the Duratec and have never done anything mechanical other than my snomobile engines and a few small block Chevys, big block Pontiacs, turbo four Mopars, and a motorcycle every now and again, but I think I have the jist of it, don't I?

I wish I could have seen the dyno shop, but 94W about 10 miles away is as close as I got...
I wonder what the Uhaul would have put down?

iirc, cavitation is something that happens when pressure falls below the vapor point, bubbles are formed in the liquid, the bubbles are then carried to areas of high pressure where they are released causing a wave in pressure...



I guess I would have to study the direction and path of the oil to better understand that one. If the Pump is pickin up bubbles from the crank case then wouldn't the crank case be the last place to receive the bubbles, meaning wouldn't other parts (like the cams) be starved before the crank?



one more thing, if the crank is causing a barrier of air around itself how would increased oil in the crank case help this problem any?

More oil in the crank case is like ganging up on a bully in the playground. At a certain point, the crank isn't able to throw it around any more. The external oil system idea is to keep oil going to the heads giving two paths for the oil to get there... redundancy. If the oil in the crank case gets tied up, you still have a quart or two doing some work via the external system. The cams keep some oil up there without returning all of it. The reason it's pumped up there is to keep it fresh. The cams also need less oil than the crank to survive because of the lower amount of stress on those parts.

You are right about cavitation, I miss spoke (typed)...

brad... yeah Jack pretty much said the same thing you did above, but he is also going to be doing some other tweaks to the pan to get rid of some of the other problems.
-Mark

so basicly by increasing the overall oil capacity you will increase oil in every location, mainly the crank case, which in turn stops the crank from self destuction at high rpms... ok sounds good, but the accusump only pumps oil into the system when it detects low oil pressure, and like i said before high rpm = high oil pressure... so... how do you solve this problem?