Eagle Crank and Rods?

[Spln_Hrd]

Im getting ready to assemble my engine here in the next few days and Im not sure about bearing clearances. Crank and rods are brand new and the mains were align bored. Question is if im shooting for .0020" to .0025" would i get standard size bearing or undersized bearing? Im planning to make 500whp with this engine that is why im on the loose side for oil clearance unless experiended dsm'r tells me otherwise. Let me know if there is anything i should tell machinist before he is done as well. As you can tell this is first build and have few things to learn. Dont need any haters though.

This is a 2.0

I supplied machinist w/ standard size bearings and I told him the clearances im after and his response was since im assembling it, it is my responsibility to get the clearances i want. I thought maybe he would machine it so those clearances were achieved through the machine work? He did tell me that eagle rods are often out of round and would be sure to get them all the same hence giving me the necessary clearances.

As for the mains im not sure what i need to due to get the clearances I want.

I dont want to plasticgauge this engine. I plan to rely on there measurements with proper tools.

 

[steel_3d]

Mitsu has separate part numbers for select fit bearings. So once you figure out what your clearance is with the current bearings, you can buy the ones you want.

I haven't really heard of anyone adjusting clearance by honing out the journals, though I'm sure it can be done. Honing the mains is pretty standard, but doing the rods is extra work. If he's not lying about the fact that he can fix whacky eagles, then there's no reason why he can't hone them a bit more for a bit more clearance.

But from what I know the general practice is just to *check* clearances and make sure they're not too whacky. I don't know how important it is to be at exactly .0025. In the real world you'll never end up with anything being perfectly round, so the same journal might have .0015 clearance at one point, and .0025 if you measure at another point. The roundness/taper also changes between the bare journal and when you put a bearing in, so the bearing doesn't conform exactly to the journal either. I gave up on perfection, noone seemed to be able to give me round and non-tapered mains, and the eagle rods were off as well at the specified bolt stretch. But as long as the minimum clearance is decent, like at least .001, I'm guessing it would be acceptable. My clearances were all over the place but somewhere in the neighborhood of .0010-.0028. On average it was decently loose. I'll try running it with 20w50.

If you're assembling the engine yourself, I would buy a set of measuring tools. Or watch the guy measure everything right in front of you. Otherwise I don't trust them. If you're gonna do it yourself, you need a bore gauge that measures between 1.4" and 2.4" (the rods are in the 1.77 range and mains I think 2.3x), and it's good to have one 2"-6" to measure the cylinder bores with. You need a set of mics (up to 4" to measure piston to wall clearance). Plastigage is pretty useless. Then it's a good idea to grab a rod bolt stretch gauge, because in my case the recommended torque didn't provide anywhere near the recommended stretch. Going by bolt stretch is a more reliable way to gauge clamping force. I have all these if you need them.

 

[absolute_DSM]

steel, Ive wondered this for a while, whats suggested to check the bearing clearance instead of plastiguage?

 

[steel_3d]

Dial bore gauge and micrometer.

First you measure the diameter of the crank journal with a micrometer. Leave the mic set at that measurement. The bore gauge will give you an arbitrary value for the inside diameter of the bearing. Then you measure the width of the mic with the bore gauge, and the difference between the two bore gauge measurements is your clearance. So basically you're comparing the outside diameter of the journal and the inside diameter of the bearing.

The tricky part is measuring the width of the mic opening with the bore gauge. Bore gauges are made to self-center in cylindrical holes which restrict one degree of freedom, but since the mic's faces are parallel, you have two degrees of freedom to worry about. But with enough wiggling you'll get the hang of it, and the minimum reading on your bore gauge dial will be the answer.

I might have some pics somewhere if this makes no sense.

Professional shops have a "standard" to calibrate the bore gauge to, so they don't have to measure the mic, they just read right off the bore gauge. Basically they measure the journal with a mic, set the standard to the same value, place the bore gauge in the standard (it's set up so it removes both degrees of freedom I just talked about, so you get an accurate reading with no twiddling) and zero the bore gauge dial to that size. Then when you measure the bearing with the bore gauge, the clearance will be a straight reading off the gauge. Depends how much you trust that their bore gauge standard agrees perfectly with their micrometer. At the shop I went to it did - I got the same clearances at home.

 

[absolute_DSM]

Makes perfect sense.

Quick question, wont the mains being torqued down affect the measurements?

 

[steel_3d]

Yes it will.

You always measure with everything torqued down the way you want it torqued down at final assembly. The main bolts affect the cylinder bores, and the head bolts might affect the mains to a small extent. The rod bolts of course only affect the rods so they can be checked independently, but again they need to be checked at the final torque/bolt stretch.

Personally I measure my cylinders (roundness, taper, and piston to wall clearance) with the actual head torqued down, as well as the mains. The bore gauge will reach most areas of the cylinders from the bottom.

By the way, it's really nice to have a dial indicator that reads to .0001 instead of .0005. Much easier to read and in the end you end up with more accurate numbers. They're not easy to find cheap, though.

 

[absolute_DSM]

I definately agree to that. I prefer checking out www.goodson.com for engine tools. Although expensive, they are top notch.

So how can you measure the inner diameter of the bearing with it torqued down with the crank in the way? Maybe I missed something.

 

[Spln_Hrd]

Rods
#1 .0026
#2 .0027
#3 .0027
#4 .0028

Block
#1 .0028
#2 .0028
#3 .0029
#4 .0030
#5 .0027

Thats with standard size ACL Race Bearings

Let me know what ya think. Thanks

 

[steel_3d]

I definately agree to that. I prefer checking out www.goodson.com for engine tools. Although expensive, they are top notch.

www.shars.com has the cheap stuff, but works pretty damn well.

So how can you measure the inner diameter of the bearing with it torqued down with the crank in the way? Maybe I missed something.

Everything is torqued down without the crank. In the ideal sense it's irrelevant to the measurements since it's not solidly attached to anything. Ie: since there is clearance everywhere around the crank, it can't pull the block out of shape.

 

[steel_3d]

Rods
#1 .0026
#2 .0027
#3 .0027
#4 .0028

Block
#1 .0028
#2 .0028
#3 .0029
#4 .0030
#5 .0027

Thats with standard size ACL Race Bearings

Let me know what ya think. Thanks

Looks too good to be true. But if it's true, it's great for running 20w50.

I assume those are the numbers the machinist gave you. I've never seen numbers that consistent. In reality there's (much) more than a tenth of a thou or two out of roundness and taper on the same journal, not to mention between journals.

Mains for example are never round after a line hone job. You can grind as much as you want off the caps, but you'll never make the diameter at the parting line any narrower. So the more times you hone it, the wider the mains will be near the parting line, while vertically they may be in spec. This probably doesn't hurt anything, it's just reality, and it's reality that's being hidden by the pretty single numbers he's giving you.

I've dealt with two blocks from two different machinists who both claimed they were the shit and can make shit round. I've also dealt with eagle rods which aren't perfectly round and parallel even from the factory. The reality is that steel moves around and settles after it's been honed (heat), or even just from being unbolted and retorqued, you'll never get the same measurement twice. The variance is several tenths of a thou in my experience. So the fact that the measurements are so close looks fishy to me. He's probably giving you some prettied up averages, or just made the numbers up alltogether. If it's prettied up averages, then you're golden. But if I were you I'd like to see some bore gauge readings in person that are at least close to those numbers he gave.

Did he say if he did any special work, or things just came out that way? Ie did he hone the mains or rods at all? In my experience things come out a bit tighter (especially if you look at the minimum measurements), but I was also using coated ACL bearings, not sure how thick the coating is. I think the factory claims .0005. Remember to have the small end of the Eagles honed to about .0007-.001 clearance, you can't just leave them as they come from the factory, they're too tight. I would hope the machinist would notice that without you telling him, just making sure.

 

[absolute_DSM]

Remember to have the small end of the Eagles honed to about .0007-.001 clearance, you can't just leave them as they come from the factory, they're too tight. I would hope the machinist would notice that without you telling him, just making sure.

Seriously? Does everyone know this, or I did I miss that memo.... yikes

Is that with stock pistons or aftermarket?

 

[steel_3d]

Seriously? Does everyone know this, or I did I miss that memo.... yikes

Is that with stock pistons or aftermarket?

If you read a bunch of threads on eagle rods you'll find the info.

I believe the wrist pins are standard size, so yeah I would think this applies to stock pistons as well.

I'm guessing Eagle leaves them tight consciously to force you to hone it to the proper clearance. From the factory they usually take some force to push the wrist pin through, making it pretty obvious that there's no oil clearance.

 

[Spln_Hrd]

When i installed the pistons on rod I had no trouble with installing wrist pin. Not sure what was done to them though if anything at all. I told the machininst i wanted .0020-.0025 so if he was going to lie i would think he would have had me atleast in that range. However they were all .0027-.0030, I'd sure like to think its true. They are a top notch machine shop who almost soley machine and build the old skool Cobras. This was there first entire longblock they had done for a 4 cylinder though and were very eager to do it. When I picked it up they asked if I had a scattershield for it, so they must realize the potential of the 4g63. www.gessford.com is the shop that did it.

I hope those numbers are somewhat realistic.

 

[steel_3d]

Did the wristpin have enough clearance to slide in and out of the rod without you touching it? If it takes a slight bit of force (I'm not talking hammering on it, just having to push on it with your finger) it's probably not enough clearance. Not sure if it would hurt anything to run it like that, but for high performance applications a full floating wrist pin with up to .001" clearance is usually recommended.

 

[Spln_Hrd]

Most of the effort was lining it up, Im sure if i shook the shyt out of it I could get wrist pin to fall out, unless it got into a bind.

Wow I just notice they were voted machine shop of the year in 2004 by Engine Builder Magazine. Perhaps those too good to be true numbers are the real deal, I only hope.

 

[absolute_DSM]

Wow I just notice they were voted machine shop of the year in 2004 by Engine Builder Magazine. Perhaps those too good to be true numbers are the real deal, I only hope.

That would be a good feeling.

I'm guessing Eagle leaves them tight consciously to force you to hone it to the proper clearance. From the factory they usually take some force to push the wrist pin through, making it pretty obvious that there's no oil clearance.

Is this a machine shop only process or can the rod be honed few .0001" in the garage to get the right clearance?

 

[steel_3d]

Well if you wanted to eyeball it and you had a small enough hone, sure. Bore gauges that measure that small are pretty hard to find cheap. I don't think it's worth it, it's a few bucks per rod at the machine shop.