I have an argument with a friend via AIM on the spacing issue. I want to hear you guy's opinion who has rebuild motors before and understands internals of the motor. If the iron housings were lapped. The motor itself will be shorter due to less materials. However, My argument is that you don't need to change the spacers(the one between the needle bearings). The reason behind this is that the spacing was determined by the rotor lobe of the E-shaft in respect to the end of the stationary gear. eventhough the surface of the iron housing has changed, the stationary gear that mounts to the side of the housing hasn't been touched so that the overall length of the E-shaft remains the same in respect to the motor before lapping (because the length of the stationary gear, counter weight, needle bearings, spacers, oil pump pulley, OMP gear..etc remains the same). The stacking should be the same. The rotor however will ride closer to the stationary gear because the motor is shorter but I don't see any reason why the spacing will be different. anyone care to comment on this?

Steve

 

Hmmm Steve, you just gotta look at the assembly.

When you torque to final front nut and check the end float, what actually happens ? The front assembly gets pulled up to the shoulder of the crank right.

So like you said not matter what end plate resurfacing you do assuming you do not resurface the inner face where the front stationary gear bolts up to then you will not have changed the clearance run by the front spacer.

I am thinking on the "fly" here, but in all the engines I have done that have been machined from stock I have never needed to change a spacer, the only time I have needed to alter the spacer say go from an X to Y is when I have needed to put on more pre load on the front nut whcih has increaced the crush on the spacer.

Your way of thinking is correct cause when you have the short block together minus the front running gear the crank front bearing "shoulder"sits well below the stationary gear and is only pulled up into place once the thrust plate and all relevant timing/drive gear is placed on the crank then finally the front nut is done up to pull all these items together, the reference point is the recess in the front stationary gear, v's the length of the crank shaft to the shoulder just infront of where the front staionary gear bearing rides.

So from this logic you could remove as much material as you wish from the side housings, so long as you do not reduce strength, the only other problem is that you will change the bolt hole distances for your manifolds and your orings will not fit in the grooves

 

Thanks!!! I think I just won me a dinner at Macdonalds!!! hahahaha

 

Hmm....Just thinking about this. I thought you need to change the spacer, since the distance from were the thrust bearing sits changed, since it's closer towards the motor, front housing. I might be wrong or just can't see it. I'll see when i assemble my friends motor. I'm going by how the front assembly goes together, the front counterweight,spacker, oil pump gear and omp gear. Rice racer you said that everything gets pullled together when you have everything assembled, wouldn't the spacer keep it from been a certain distance anyways? So it wouldn't be pulled too much and since the stationary changed postion, sits more towards the motor, now the distance from thrust bearing is more to the contact to the stationary gear? Please explain this a lot more, since i can't see it.

 

I read what steve wrote, he says the spacing is determine by the rotor lobe in respect to the end of the stationary gear. From this since you lapped the housing the housing will sit close to the engine, hence changing the position of the stationary gear. Wouldn't this mean you need a different spacer? Since the space between the rotor lobe in respect to the end of the stationary gear changed?

 

heres the easy answer, just meaure it for each motor!

mike

 

Stop trying to defend youserlf.....You know I'm right!!!! where's my dinner???

 

hahahaha

 

Again, when you assemble a short block the crank "shoulder" sits well below the surface of where the thrust collar sits.

It only comes together once the front nut and all relevant gear is placed on the front of the crank and tightened up agains the spacer.

The only things that will change what type of spacer you need is the pre load you use on the front nut, or if some of the components you are placing on the front of the shaft are different, or if the shaft has been shortened ! or if the surface the front staitonary gear sits on has been lowered (never seen anybody do this!)

So thats it, go buy him dinner

 

For what it's worth, as with every other part there are specs on the measurements. I remember seeing them on side plates but I don't remember where.
If I find them I will post though. This argument actually hinges on if your plates are still in spec.