block machining

[ebola]

OK, now I have one spare common block left, and Im planning to built it next season.Now local rallye guys annoying me with their confidence, telling me to consider next "very important, key procedures":
- perfect inline match machining of cranshaft necks;
- perfect main cap inline machining with block deck and cylinder bores;
- cylinder machining for perfect inline match between themselves and also angle between shaft center and rod necks line....
They are saying, I have to machine everything I can, but say nothing about torque plate. Im telling that we have a little bit different concept engines - they normaly do small japs for n/a high rew opperation. They rew 10 000 rpm!
But they are telling me, that there is no difference, I HAVE to do these mods if I want engine to go wild and alive.
What do You think about these mods above - is it that important, I mean perfectness in stroking dimensions?
Thanks
Andrius

[Mike B.]

All of that machining is not usually necessary. Yes, you should have the cylinders machined/honed with a deck plate (torque plate). The block only needs to be line bored if you switch to studs for the main caps. If you keep using bolts no machining is necessary.

[ebola]

what do You exactly mean under "line bored"? And what actualy changes if I switch for main cap studs?

[more_power]

line bore is worth it.Over time your block will rlive stresses and twist and shrink and expand. Im talking small numbers like tenths but it happens it is just aging and reliving sttress over heat cycles. A good machine shop will start with the mains and do every thing else to them. If you are gona go and get your block sqared then its a good thing to have. I would also get every thing balanced from your presure plate to the front pulleys. Balancing is just not for hi revin motors it really helps with the over all life of the motor in any aplication. And for "perfect inline match machining of cranshaft necks" never really heard anything about that. But that just might be me.

[Mike B.]

"Line boring" is when the machine shop installs the main caps without the crank and bores through the holes where the crank would go. This process insures that the main caps are perfectly aligned for the crank. I really do not think it is necessary if you are using bolts. With bolts you put the caps in place and bolt them down. The caps are relatively free to move until the bolts are tight. With studs the caps are held captive by the studs, *then* tightened down. The theory is that the studs could cause the caps to be slightly misaligned, therefore, requiring honing.

[Mike B.]

When you check into how much all that machine work is going to cost you'll begin to see it my way.

[puppet]

^ ... Heh

[minimopar]

Actually, when they line bore they actually remove a very small amount of material from the bottom of the rod caps, which makes the journals slightly oval. Then they hone all of the journals at once so that they are perfectly rounds and lined up. Decking the block is also part of this process and it is done such that the plane of the block deck is perfectly parallel with the axis of the crank journals.

Every engine rebuilding book I have seen says that this process is definately worth while on a "seasoned" block. You only need to have it done once because a seasoned block is fairly stable. What happens is that slowly, over time the journals become misaligned and out-of-round. The process is very slow, thus the bearings have plenty on time to wear such that the crank remains properly aligned and supported. However, you then go and put new rod bearings in, which conform to the misaligned block and you then have problems. The same out-of-round principals apply to rod journals as well and not having the rods corrected is probably the reason behind a lot of spun bearings in peoples' new motors.

Basically, if you are going to go through all the effort of tearing down and having a shop go through it, why not have them do it right? Maybe I'm just weird, but I am willing to spend a little extra if it increases the chances that I won't have to do it all over again.

[Turbozcs2003]

Quote:

Originally Posted by minimopar Actually, when they line bore they actually remove a very small amount of material from the bottom of the rod caps, which makes the journals slightly oval. Then they hone all of the journals at once so that they are perfectly rounds and lined up. Decking the block is also part of this process and it is done such that the plane of the block deck is perfectly parallel with the axis of the crank journals. Every engine rebuilding book I have seen says that this process is definately worth while on a "seasoned" block. You only need to have it done once because a seasoned block is fairly stable. What happens is that slowly, over time the journals become misaligned and out-of-round. The process is very slow, thus the bearings have plenty on time to wear such that the crank remains properly aligned and supported. However, you then go and put new rod bearings in, which conform to the misaligned block and you then have problems. The same out-of-round principals apply to rod journals as well and not having the rods corrected is probably the reason behind a lot of spun bearings in peoples' new motors. Basically, if you are going to go through all the effort of tearing down and having a shop go through it, why not have them do it right? Maybe I'm just weird, but I am willing to spend a little extra if it increases the chances that I won't have to do it all over again.

I think you meant they machine the main caps(you said rod caps), bolt them back onto the block and then align hone. I beleive decking simple trues up the deck surface
perpendicular to the bores. also prevents issues with the head gaskets.

Also cant the machine shop check to see/measure to determine if the block
needs the align honeing operation? I hade my block decked, bored/honed with deck plate, rods resized etc. I do agree though, if it needs it do it. How much was you machine work for the align hone? Cliff told me he doesnt see many issues for align honing on ones he has done.

Mike

[turbovanman]

We could go on about this for years, lol!

My .02 cents. Check the main bearings, if there worn and there worn evenly, IE tops or bottoms then line boring isn't necessary. If you the bearings are worn to the sides or show weird patterns and the crank is checked as true then yes, get it done. Now, if you have lots of money, go for it anyhow, lol!
Get the deck squared is another great idea, mine was out a few thou.
While your at it, deburr all the casting flash, open up and port match the oil pump hole and I also made the passage to the oil filter larger. Deburr as much of the casting flash at the water jackets as humanly possible to reduce aeriting, I think thats how you spell it, basically foaming the coolant, lol, and get your engine balanced, worth every penny!

[Reaper1]

Polish the crankcase under the bores then seal it with Glycol to promote oil return...

[ebola]

Quote:

Originally Posted by turbovanman Now, if you have lots of money, go for it anyhow, lol!

I live in East Europe(and thats a reason I cant translate properly all procedures), and labor costs here are very very low! Ex:

Line honning of all cylinders - 30$
Block squaring(deck line with cranck mains) - 20$
Rod necks lineing on cranck- 30$
Head shaving - 14$
Mains lineing in block - 110$

So its not that much in total. But to be honest I doubt that all of this is realy needed.Block square'ing - all it does is equals all cylinders in CR. Rod necks - it should very mislined to make impacto on operation I think, because bearings are soft, alowes a lot of flex. Only true need I see only on mains to be inline and under exactly same angle with ALL cylinders.
Rgz
Andrius

[Phreakish]

if costs are low, then get it ALL done!

squaring the deck is a MUST - otherwise you may not even be able to hold a headgasket.

Line hone - maybe, but I'd get it done (I DID).
Bore/hone is needed if your piston to wall clearnace is too large, or you're going to larger pistons for any reason.
Install new intermediate shaft bearings!
Rods reconditioned - do it, its worth it. After having mine done, WOW.
Head shaving - only if its not square, or has gouges or scratches.

I had it ALL done, and I'm very happy I did! Otherwise the motor would be more of a hassle then its worth.

[Mike B.]

Quote:

Originally Posted by Reaper1 Polish the crankcase under the bores then seal it with Glycol to promote oil return...

I think you meant "glyptol," right?

[Reaper1]

Ooops...yeah...