The main bearings oil clearance is what controls the oil pressure for the rest of the engine. The first place the oil goes out of the pump is into the mains. If the mains are worn the rest of the engine will have less oil pressure. It's like a hose with a leak. Yea it will still flow but not as good as without the leak. We all have seen motors that has the oil pressure drop at idle. That's always been from too much main bearing clearance in my experience. At the mains oil splits in two ways. One way goes to the rods and the other way to the cam/lifters. The oil to the rods goes through the crank and oil to the cam/lifters goes through passages in the block. Like you said it's got 100k on it do you think the mains are not worn??

My telling you about Mark Donohue and Penske Racing was to tell you what people that know way more then you or I have said they do to build a lower end that produces power and stays together. I suppose you know that if the bottom end fails it really doesn't matter how much power you can make with the top end.

Something that I found interesting was a report that a windage tray gained 40hp. I guess it takes a lot of power to slog the crank through the oil. So adding that to your motor is a quick way to pick up HP. So put new bearing in the lower end and add a windage tray and you have increased the oil pressure to the parts that need it and picked up around 40 HP. And I bet because you're pistons and rings are well seated you might be pleasantly surprised.

And by the way I looked on Amazon if "The Unfair Advantage" was still in print. They show three sellers that have a copy. The cheapest was $107. I guess I'm not the only one that thinks it's a great book.

 

You're a very knowledgeable individual. I see you've done your homework. That book sounds very full of useful information, and it would be an excellent source. What you said about the windage tray freeing up lost hp is very interesting, too. I like it. I also like the whole principle behind "The Unfair Advantage" about wearing in the bottom end to loosen it up.

What I don't understand is why that principle doesn't apply to my truck. It's got a loose, worn in bottom end, just like in the story you described to me. And now, I'm planning on building the top end, as in the story. In theory, as described in "The Unfair Advantage," the result will be a nicely broken in, loosened up bottom end, with a more power oriented top end. I absolutely DO believe my main bearings are worn, but isn't that a good thing? Doesn't that give me the "unfair advantage?" I do have adequate oil pressure.

 

If you have adequate oil pressure then your mains aren't all that worn. I think that you should be okay, at least for a while. The prudent thing to do would be pull the caps and Plastiguage the mains and rods and do a visual inspection.
As far as a windage tray goes, to get 40HP gain you need to have a motor that's making some serious HP to start with and spinning a high enough RPM that the oil mist around the crankshaft is causing some serious drag. Not worth the money for a truck IMO.
If you think you can put a windage tray on a 250 hp motor spinning under 6K and gain 40 HP, I've got some real estate you may be interested in.
I have to disagree with Paul on one thing, if the crank journals are smooth and check in tolerance, you can install new bearings, It's been done many times. The journals may or may not be egg shaped, in fact it is entirely possibly that the journals could have very little wear. Bearings are designed to wear easier than the parts that ride on them, and good oil pressure usually means bearings that aren't too worn out.
Edit- OOPs- wasn't thinking about the rods, but they aren't necessarily going to be egged either. The best thing is probably to do it all or leave it all alone.

 

Well actually I didn't mean to imply the crank would wear uneven.. it's a big piece of metal and chances are something else will wear before it does. The big end of the rods go out of round most of the time so new bearing on those without machine work is likely to be a problem, but the crank journals themselves should be OK. I saw this on my 351 block when it was rebuilt, the crank was perfect on all surfaces just needed a little polish, but all the rods had to be worked.

 

I know -hence the edit. But the big ends don't always go out of round, (at least enough to be a concern). You are right in that IF they are egged to certain degree then failure is certain, it's more the way you said that not doing machine work was a guaranteed engine failure that I disagree with.
BTW- I believe that 351W's are more prone to going out of round than 302's, (bigger diameter journal, basically same size cap, more reciprocating weight, more HP and torque, -more forces tending to make it happen).

 

That makes sense to me. Hey, I'm installing my new headers. I removed the old manifolds which were nasty, and realized I only have one O2 sensor in the passenger side manifold. Should I maintain that set up and just put the O2 in the pass side header reducer bung and only monitor the one bank? I am going to run true duals...

 

Yes just put it on one side right after the collector....Lew

 

Okay, thanks Lew

 

I agree with doug about plastiguaging the bearings, that is possible. But with that said if you have access to them why not put new ones in? You know it's got 100k on it and bearings are cheap ( about 35 bucks) and how many times do you want to pull that motor? ( Oh gee I can get another thirty thou from these bearings. So lets wait a year or two and pull this thing again. That doesn't sound like a good plan to me. Well unless you like pulling your motor.)

I think that doug is not completely correct about the windage try. It's not a mist of oil, it's oil period. The oil in the pan doesn't just sit there. It moves around a lot. This is easy to demonstrate. Just hold a glass of water in your hand and move that hand from side to side at say thirty miles and hour. I suspect after a moment or two there will be no water in the glass at all. This is what is going on in the crankcase. The oil is sloshing around a lot. Every time you accelerate, turn a corner, hit a bump or brake the crank has to slog through five quarts of oil. It's not a mist!! The oil holds up pretty good but you can also see a result of this when you get a water leak into the oil. When water gets into the oil you very quickly get this stuff that looks like mayonnaise, well sort of mayonnaise. I'm sure you know that water and oil doesn't mix, so why does it look like mayonnaise? It's because the crank has been whipping it up just like a wisk when making mayonnaise. It emulsifies the oil. When you make mayonnaise you add an emulsifier, usually egg yolk, so you can get the oil to emulsify. But when water and oil mix in the crankcase there is so much energy from the crank there is no need for an emulsifier ( it's like a giant food processor) and you get crankcase mayo. So you might not get 40 hp from a windage tray but you will get a substantial improvement. And the real interesting thing is you won't see this on a dyno. That's because the car, or truck, isn't moving! It's sitting still so there is not as much force on the oil to move. That means that the improvement you get from a windage tray is there only while you are on the road. One more thing that shows that a windage tray is worth the money and effort is ford put them in stock on their 2000 mustang cobras. Many years ago I knew an engineer from ford. He told me that if ford can eliminate one bolt from a car they save a million dollars ( that was thirty years ago, it's much more now). Ford would have saved a lot more then a million dollars by not putting in a windage tray. But there is so much hp to be gained from a windage tray ford spent the money. I suspect the engineers at ford have some idea what they are doing. And you just might be able to find one cheap in a junkyard. I'm sure there are a lot of cobras in junkyards that have been wrapped around poles or other non-movable objects.

One more word of advice. I have seen ford motors that have developed a crusty film on the cam bearings ( it's on the cam also but that's easy to get off). It's dark brown, almost like the oil has burned on the bearing ( actually just like that). I have found that you can get this off with lacquer thinner. The last thing you want to happen is spin a cam bearing after you do a bunch of work on your motor. It takes a little effort to get all the way in the back if the crank is in the motor so I have used a broom stick. I used a hack saw to put a slot in the end of the broom stick. Then I put a rag into that slot and wrap the rag around the stick. Put some lacquer thinner on the rag and you can get that crap off.

What it really comes down to is you can always do things half way. Sure you can drop an intake and headers on that motor and pickup some hp. Is that the best thing to do, maybe, maybe not ( at a 100k I'd say it's not the right thing to do). My experience has been that every time I cut corners it ends up costing me in the long run. So it's up to you what you want to do.

My advice is pull the motor. Put new rod and main bearings in it. Add a windage tray and a new timing chain. Get a good truck after market camshaft and lifter. Get a good intake, I recommend the cobra intake. The intakes that have huge runners really only work well at high rpms. The cobra intake has runners that are not overly large so the air speed stays high. This allows the cylinder to fill from the momentum of the airflow. Get the valves ground in the heads and top it off with some shorty headers and you are off and running.

I have used a store on ebay with good luck. It's called “the mustang depot”. They have shorty headers for $95. Jegs has the cobra intake for $390. Comp Cams Extreme 4x4 camshaft and lifter, #CL11-231-3, for $210. Comp Cams Magnum roller timing chain set, #2120, $37. Stainless steel rocker arms, from the mustang depot on ebay, $155. Rod and main bearing about $70. Ford racing windage tray from jegs $55. Windage tray mounting kit $35, from jegs. Gasket set about $125. Labor to grind valves, install push rod guide plates and face heads I'd guess around $250 (I haven't had to pay for this in a long time so it's a guess). This all comes to $1422. That's a new hi performance motor for under fifteen hundred dollars. Sounds like a damn good deal to me. You might also think about a new water pump. The mustang depot has aluminum high volume ones for about $65. This still brings it in at under fifteen hundred.

I assure you if you do this, and do it right, you will get a couple of hundred more thousand miles out of your motor and it will kick butt on what you had stock brand new from the factory.

 

Not quite. Five Quarts of oil? First off there is about a quart in the filter. Then you have oil filling the crank, lifters, pushrods,oil pickup, oil pump, passages to the cam, not to mention the pool in the lifter valley, and all the oil clinging to the side of the drain back holes and every surface it touches. Does some oil get splashed up on the crank? Yes. Is the crank splashing through a pool of oil? I don't think so. Most of it is in the sump and stays there. About as much falls on it from above as splashes from underneath. The crank does create an oil mist surrounding it. It is just as capable and probably more so of making mayonnaise as any oil from the pan and most of what feeds it comes raining down from the drain back holes. (And what is the oil pump doing to that oil?)
Acceleration. Front sump 10 second car- you bet it will dump some oil on the crank, especially if it pulls a wheelstand. Rear sump truck taking off at a red light, not so much.
Cornering. Most of the oil is going to climb the side of the sump in the pan, while the crankshaft is still in the middle.
Lastly, let's look at the dynamics of what's happening in the bottom end of that motor. You have a crank with big ol' counterweights and rod bottoms spinning around like mad. Take your glass of water and try to throw it in a fan and see how much gets on the blades. Put the fan in a closed barrel and pour some water in and you will get a mist that the blades cannot escape, so most of the oil the crank sees is in the form of a mist.
While we are on the subject of the glass of water, I frequently travel with a glass in my cup-holder and don't spill any at 30 mph. Occasionally, I have to panic stop or swerve to avoid something and spill a little. So I don't believe that eliminating an intermittent splash of oil is going to free up 40 hp.
And Ford put a lot of stuff on the Cobras that weren't on the trucks. I not saying a tray is useless, but an unnecessary expense that won't deliver much return.

 

First of all, I think we can all agree on this: Windage trays are a very beneficial, advantageous piece of equipment for high performance applications (as evidenced by its wide use on high performance vehicles); however, they are not necessarily of much value for a mild street application. They might produce "40hp" on an 8 second dragster, but definitely not on a truck with an '80s 302.

My only goal was to get a little more grunt out of my truck. I do not want to dump $1,500 into my truck to achieve that. Wait, yes I do! Unfortunately, although I would love to dump even $5k into that engine, it's just not a financially viable option for me right now. I am restoring a '69 GTO and that is where my play money goes towards for now. Upgrading my truck (at least $1,500 worth) will have to take a back seat for the time being. I did just replace my water pump and valve cover gaskets, and I also just installed some LT headers - couldn't resist!

 

The mustang in my sig does not have a windage tray, and an 8 second dragster usually will have a dry sump system. But if a windage tray would yeild 40 hp... That would be a good bang for the buck. The only thing a windage tray does is reduce crankshaft drag, or it wont make the engine gain 40 hp but simply put, wont draw 1 hp when its low journal isnt getting resistance from oil..

 

By the way LOL they didnt rate HP the same way then as now. Back then it was flywheel HP now its rear wheel HP...

Not to dig up bones, thought I'd mention it.

I couldnt beleive this thread is still going, I thought I read about this before LOL

 

I am willing to bet money that you have never driver a vehicle that had a windage tray and compared it to one that did not.

I was going to write a longer responce but I don't thiink it's worth it. You are going to have your opinion based on what you believe is correct. I'll base mine on what I know to be correct. So lets just agree to disagree.

 

You should have. If you KNOW but I only BELIEVE (implying that you are right and I'm founding my statements on incorrect information,) then prove it. Do some research to back up your claim that a crankshaft goes "slogs through 5 quarts of oil." Your perception of what is happening in the crankcase and what a windage tray really does is totally wrong.
Keeping the oil that sloshes around in the bottom of the motor is a side benefit and not the main purpose of a windage tray. There are baffled oil pans that do a better job of that.
You should have argued that if you take the glass of water and throw it into the BACK of the fan the blades would get wet. It's called a windage tray for a reason. The whirling crankshaft creates a vortex that traps oil and it spins around with the crank. While the crankshaft is trying to throw off this cloud of oil, the spinning oil sucks in what is returning from the top of the motor to the bottom. Hence there is a perpetual cloud of oil around the crankshaft that creates drag. A windage tray separates the crank from the oil. This can be measured on a dyno.
A crank scraper works in almost the same way, it cuts the cloud of oil off the crank and returns it to the pan. If you look at a crank scraper you'll see it's spaced a good distance from the crank, but it still removes oil from it.
Now for the oil that splashes up from the pan. When cornering the oil climbs the side of the pan. The crank is still way far away from it, but the vortex will suck it up, contributing to the small tornado of oil. The vortex will only hold so much oil as it is constantly getting shed so the effects of the splash are short lived. Same thing for acceleration and big bumps.
A windage tray has many benefits, but 40 HP is a hell of a stretch. What it does doesn't equate directly to HP. It reduces drag which will give you a few hundred more RPM. It reduces the weight of the reciprocating assembly, allowing for faster acceleration.
Some better arguments for the benefit of a windage tray can be made than HP. It reduces oil aeration. Air in the oil reduces the lubricity and at 30% will destroy bearings. So a windage tray can help your motor live longer. The best argument of all is that it will pay for itself in fuel economy. The amount of HP it frees up may not be that great, (10 hp is probably closer to reality), but a small gain in fuel economy will add up over time.
If you can afford one, great, they are worthwhile additions to ANY motor. If you are looking to get the most HP for the buck and have to limit the upgrades I'll give it the axe first.
I'll agree to disagree, and now you know something.