Main studs & align hone.

[FlowSpecialist]

Originally Posted by DavidVizard-GFN

Flow Specialist, Cammer, Want-a-be, Mach 9 and Lasse,

My guess here is that in spite of sounding contradictory you are all right!

DV

Seems to me we were all saying about the same thing anyway. Well maybe except a slightly different take from Cammer.

I agree with you that only in very extreme cases, F1, Prostock etc, is it worth spending so much on bottom end prep. Grumpy had it right 30 years ago that the best possible bottom end prep showed comparatively little benefit for the effort compared to head work where the difference between good and bad could easily be 100 bhp.

Personally I've never had a block line bored in my life. Never seen the need. Never used a torque plate either. When you look at how out-of-round wet liner engine liners go after a few miles without apparently affecting cranking pressure or power you begin to wonder if piston rings are really that fussed about sealing to something with a minute amount of ovality. I've pulled apart Peugeot engines with 4 thou ovality on the liners (which actually disappears if you leave them on a shelf for a while for the stresses to dissipate) and they perform as well as iron block variants running the same tuning bits.

I think on small engines such as we use over here you're hard pushed to spot the differences on a dyno between best possible and 'decent' bottom end prep. On a 700 bhp V8 it's easier to see them but in percentage terms they're still negligible.

If 1 or 2 bhp is worth $1000 to you then by all means go the whole hog.

Dave

[Ol' CW]

If you're going to the expense of main studs,is it not false economy to NOT align hone? Presumably, you are using studs because you will be running at increased output or at least high output for prolonged periods.

Then, wouldn't you want to ensure that you have proper bearing crush by align honing with the studs in place?

Also, wouldn't you want a smooth finish on the saddles ensure the best contact with the bearings and transfer the most heat?

I guess it depends on what you are building

[Packard V8]

Also, wouldn't you want a smooth finish on the saddles ensure the best contact with the bearings and transfer the most heat?

FWIW, I always thought it was the oil wedge which carried the load and transferred the heat. Any time a main bearing shell starts feeling a lot of heat, isn't something fatally wrong somewhere?

Last time I installed main studs, I torqued down the OEM bolts, measured the bore, pulled them out, installed the ARP studs, torqued them down, measured the bore and there was NO difference. Maybe just lucky with that block.

thnx, jack vines

[Cammer]

"Seems to me we were all saying about the same thing anyway. Well maybe except a slightly different take from Cammer."

If you would like to debate this issue with an old engineer give it your best shot!

[Ol' CW]

Originally Posted by Packard V8

FWIW, I always thought it was the oil wedge which carried the load and transferred the heat. Any time a main bearing shell starts feeling a lot of heat, isn't something fatally wrong somewhere?

So the hot water pipe in your house doesn't get hot when you take a shower?

Last time I installed main studs, I torqued down the OEM bolts, measured the bore, pulled them out, installed the ARP studs, torqued them down, measured the bore and there was NO difference. Maybe just lucky with that block.

So you're saying there is no reason to align hone a block?

Did you torque the studs the same as the bolts or did you follow ARP's instructions?
How accurate were your measurements?

I don't mean to take a hostile tone, but if you never needed to align-hone a block, I think this process would have went out years ago along with knurling valve guides and pistons

[old blue 75]

Originally Posted by Packard V8

Last time I installed main studs, I torqued down the OEM bolts, measured the bore, pulled them out, installed the ARP studs, torqued them down, measured the bore and there was NO difference. Maybe just lucky with that block.

thnx, jack vines

This is what I was wondering about. Has any one els done this test?
Also what is the correct way to measure main bearing housing alignment?
A straight edge and feeler gages or surface plate and height gage, other?

[rookie]

When concreting a block there is a risk of overheating the mains, so this tells me that the mains transfer heat to the water jacket and therefore play a key role in cooling the main bearings.

The guy that does my machine work uses a small bore gauge to measure the mains after torqued to fastener spec, similar to the one used to measure the bore.

The reason I question the procedure is, when we run nitrous motors the cap walk is substantial enough the remove metal from the block and stick it to the cap and visa versa, but the main bearings are unmarked and reusable.

With this much cap walk the mains probably need trued and resizing, so I have done it more for reassurance than anything.

[want-a-be]

Originally Posted by Ol' CW

So the hot water pipe in your house doesn't get hot when you take a shower?



So you're saying there is no reason to align hone a block?

Did you torque the studs the same as the bolts or did you follow ARP's instructions?
How accurate were your measurements?

I don't mean to take a hostile tone, but if you never needed to align-hone a block, I think this process would have went out years ago along with knurling valve guides and pistons

I don't think he was saying line honing the block wasn't needed. Nor was I. Just that he didn't see any Difference in his test. Of which I have tried myself several times.

AFTER line honing the block with bolts I did the stud test and saw no difference in the measurement. Also...I have line honed a block with the studs and installed bolts just to see what happens...checked the same. I use a dial bore gauge with the .0001 graduations. I'm a huge advocate of line honing...even on my stock stuff. After the blocks season they need gone through. Just like the valve job does on new heads.

Don

[Packard V8]

So the hot water pipe in your house doesn't get hot when you take a shower?

When concreting a block there is a risk of overheating the mains, so this tells me that the mains transfer heat to the water jacket and therefore play a key role in cooling the main bearings.

Just asking - how did the old air cooled Porsches win all those 24-hour races all those years? What keeps the Pratt & Whitneys, Continentals and Lycomings from falling out of the air?

thnx, jack vines

[comp]

Originally Posted by Packard V8

Just asking - how did the old air cooled Porsches win all those 24-hour races all those years? What keeps the Pratt & Whitneys, Continentals and Lycomings from falling out of the air?

thnx, jack vines

oil coolers