main bolt to stud, line hone?

[CNC BLOCKS]

I never said 100's in the 38 years! That many was done in a few years....My engines i build including the 1 in my own car speaks for itself....I guess its a sin to have friends at many of machine shops around the world...Sorry for that...I also know how many of them other so call machine shops charge you for line-hones and other work they didn't even do...I did say i have ALL my blocks checked but i wouldn't line hone a block that didnt need it..Be kinda stupid wouldn't it ??? Like someone posted...This thread getting kinda funny & stupid...Always a smartass in every forum....Im out and all take care.....

I think thats why guys ask to have the main line to the high side of the spec and I radius all the housing bores and if there are any burrs left for that process they are taken care with the line hone process.

So far every one we have supplied blocks to have been very happy with what we have done HMMMMM

[falcongeorge]

Don't know the most important question, but by 10:1 the most common is "How much?" and the next is 'How come so much?" and then "How soon?" and finally then maybe stuff that really matters.

If the answer to "how much" is lower than the last three guys you asked, and the answer to How soon" is tomorrow, run away...FAST!

[falcongeorge]

Kieth, we haven't heard from you yet on what you actually think/speculate is going on with the increased fretting you have observed with the use of studs. I have read plenty of posts by you and jbv, and I may not always agree with what you guys say, but IMO, you both know enough to know fretting when you see it, so I am accepting the premise that there is something going on here. From what the 409 guy posted, it doesnt appear to be limited to sbc applications either. I want to hear more.

Seriously I'm not sure why. I see the most fretting with studded two bolt big blocks of all makes. One guess is the more elastic stock bolt tends to recover better when pushed away by force or detonation than the more rigid stud. I do believe the stud is stronger however.

Interesting. Thats what Bob said.

I have also found lower than expected breakaway torque when loosening caps on the studded blocks that have heavy fretting. Now we can see from responses that different builders observe different results.

Maybe we are using different procedure and lubricants? I use the finger tight stud into the block method (not the alternate loctite method) I use ARP thread lubricant and then torque, break-away then re-torque 2-3 times to burnish the threads. What does everyone else do?

I put the studs in finger-tight too. I was taught that if you reefed down on them, you could crack the main webs. Your comment about breakaway torque is interesting, in light of this.

[falcongeorge]

Like ---> DART and some other Big Name engine builders say! No need to line hone with better after market 4-bolt blocks' When changing to studs...With stock weaker blocks 'They all say yes...

And you machine how many blocks to be able to answer this?

Those of us that do this can tell you for fact this is not so, they need finishing & as with any other block they may or may not need align honing if you change the fasteners

The fact is many of them change size as delivered by just loosening & retorquing the main bolts
And most come on the small size so we can finsh them without having to cut the caps

I posted this a few years ago in another thread but here is a short list of what needs to be done to finish a Dart block
Some applies to just the BB but you should be able to get an idea of what goes into these things
===
Some block notes:
I deck all of them all to a finished number depending on gasket & desired piston height
Block needs to be honed with a plate or bored & honed depending on bore
Bottoms of bores need to be chamfered
Most need the lifter bores honed, at the least checked
Most need align honing
All pipe threads need to be retapped
Oil return from fuel pump cavity needs to be done
Core plug holes need deburiing
CHECK THAT THE DISTRIBUTOR GEAR DOES NOT CONTACT THE BLOCK BY THE CAM. There is a big cast blob down there you may want to relieve.
You can machine the gear to clear if you forget but it is nicer to fix the block if necessary
Check all the timing bolt holes with air, some may go into water. Same with the motor mount bolts.

Oh hey WAIT A MINUTE! The magazines tell us that we save money in the long run by using aftermarket (usually off-shore) heads,cranks and rods, because it costs too much to machine the old factory stuff! Why, they wouldn't be mis-leading us would they??!!

[Kevin Johnson]

Kevin,

Interesting thought.

Yes, I believe the concept would be torsional deformation but swapping frames of reference such that the deformation of the threaded hole and surrounding structure is considered. The premise is that permanent deformation occurs -- a convexity. Examining the Kent engine block next to me shows that the threaded holes in the web are countersunk and the corresponding mating areas of the cap have increased diameter to match this. This seems a tacit admission in sound engineering practice that such deformation does occur in the web structure/surface and to some degree is permanent. So, a convexity of the web surface and concavity of the mating cap surface.* A stud threaded in finger tight will not impart a (significant) torsional load to the web but instead transfers this to the nut and engaged threads.

* This convexity/concavity creates a dynamic "register".

[Kevin Johnson]

kinda off topic, but if we are talking about cap fretting, why do some people swear that a girdle is a good idea, while others claim their only use "is to hold pieces of broken cap together"

I would ask engine builders what their experience has been with halo girdles that are integral with the main caps and where the plane of the "halo" is significantly removed from that of the plane of the normal bolt pad.

Here are some examples to consider:

Compare the early G63B (4G63) separated cap engines versus the 1st gen turbo engines with linked 1-2 and 3-4* versus 2nd gen engines with an integral halo girdle linking all five caps.

Look at the 6G72 -- what was gained by moving to the 4-bolt girdle versus the 2-bolt girdle? Also note an intermediate 2-bolt design with side straps offering additional bracing.

Is the "extended" halo design of the Nissan VG30 series superior to the "lower" halo design of the Mitsubishi 6G72 series?

* There are many variations of non-integral "girdle" design in the Mazda BP and BF engines. Some linked 1-2 and 4-5, others link all five caps together. Is there any empirical difference in the durability of the various designs?

I am purposely avoiding cross bolted blocks and those with bedplate designs. Baby steps lest the discussion become too complicated.

[Lem Evans]

You sure can type Could a halo girdle make a 2 bolt main cap block think it has a 4 bolt main cap?

[Kevin Johnson]

You sure can type Could a halo girdle make a 2 bolt main cap block think it has a 4 bolt main cap?

Yes, I think so to some extent. A case to study there would be the 6G72 with its progression from 2-bolt halo to braced 2-bolt halo to 4-bolt halo. I do not know if that engine series ever came with unlinked caps. I would be curious as to what failures were being seen to drive the development. I don't think it was all about NVH.

[trmnatr]

I never said 100's in the 38 years! That many was done in a few years....My engines i build including the 1 in my own car speaks for itself....I guess its a sin to have friends at many of machine shops around the world...Sorry for that...I also know how many of them other so call machine shops charge you for line-hones and other work they didn't even do...I did say i have ALL my blocks checked but i wouldn't line hone a block that didnt need it..Be kinda stupid wouldn't it ??? Like someone posted...This thread getting kinda funny & stupid...Always a smartass in every forum....Im out and all take care.....

Below you said out of 100's so that means like 200

Man your a busy fellow. So most people that are very busy and sell across the country use say 40-50 Dart/World/GM blocks then use 10-20 Factory blocks or more. Your using several 100 Dart's. That is amazing. You should be buying from Dart

Well lets see! I don't machine blocks' but have built many engines in my lifetime....about 38 years in oct...I have been to many machine shops all over and have watch them go from bolts to studs and watched them check line hone...All the better machine shops say the better blocks WILL NOT distort like your stock blocks..Don't get me wrong! I always make a run to have all my blocks checked...But i have only had 2 out of 100's of Iron Eagle & sportsman blocks that had to be line honed...Also' im not taking nothing from what you know' cause i dont run a machine shop like i said...But spend lots of time in them....Thanks

All the "better machine shops" say the better blocks wont distort like your stock blocks? Well being you do several hundred of them what is your opinion? Im asking you your opinion because it is very minimal right now.

Maybe if you torqued the mains correctly they would distort the caps because procedure makes a huge difference

As to the original question, here is my opinion. Just my $.02 and what I see with factory blocks.
- when the blocks have nodular caps I use ARP studs, they go 85/oil & 80/moly and the GM nodular caps IMO are fine with this force
- when the block has a std cap, 2 or 4 bolt, I use Milodon studs because you have the gain of the stud (more clamping force just being a stud) yet not too much. I have seen issues with non nodular caps and the ARP studs. I think they stress the caps way too much but the Nodular caps I dont see the issue with. So on these use Milodon studs or bolts

As to the studs IMO you should keep the nut and washer with the stud it belongs on. Maybe I go over board but it is my belief and nothing will change that.

I think the bolt "COULD" help locate the cap a little better if the register was loose so if the register is loose with a stud I could see it moving a little compared to a tight register and studs.

Also when your seeing the fretting of the main caps is it after installed? One year later? Three years later?

An ARP main stud or main bolt should be treated like a rod bolt. They have a great deal of stress on them from both increased clamping force & loads in the engine also detonation. So knowing this main bolts or studs should be changed IMO ever few years to the same part that came out (I have not seen issues installing new studs and/or bolts of the same design unless their is a change to torque as their was with SBC studs a few years ago) The GM bolts do not have the stress an ARP does.

One reason it is possible you dont see a ton of failures from GM bolts but do with the caps is the crankshaft could be tweaking the cap. Hard to explain. The bolts are in the block straight, the crank doesnt push straight down, it side loads the caps (this is where worn registers and splayed caps come in to play) and the side that is taking the abuse is stretching the bolt yet the other side is tight, BOOM you have a broke cap sort of like locking a lid down on one side (the tight bolt side) and lifting up on the other side (the side of the cap stressing the bolt/cap) of the lid WILL BREAK IT SOONER OR LATER.

Also if your using loctite are you running them in hand tight with the loctite WET and torqing the stud and letting it set up????? You should IMO burnish the threads first before doing final torque with loctite. Based off rod bolts that give the correct stretch (Scat's Pro Comp I Beams are pretty much on) I would burnish the threads 4-5 times on the main studs. I prefer to torque it down until the cap seats and pull them snug (10-20) then in one full steady pull, pull them to tq level needed

[strokersix]

Necked-down main bolts will twist as well as strech when you torque them. While running that twist will tend to unwind and actually screw the threads deeper into the block a little bit.

Studs with full diameter body will not only twist less but also will not screw into the block because they are bottomed out with loctite or whatever. Studs can screw themselves into the nuts instead but less twist plus fine thread means this effect will be reduced.

I think this explains two statements I read above. One, that breakaway torque has been observed lower with studs and two, more fretting observed with studs. Both observations could be a result of the bolts screwing themselves in a bit versus the studs not so much.

[Kevin Johnson]

Necked-down main bolts will twist as well as strech when you torque them. While running that twist will tend to unwind and actually screw the threads deeper into the block a little bit.

For a bolt shaft to twist (and stretch), doesn't it entail that the threaded portion has a higher collection of forces forcing it to stop whilst the head continues to rotate ? [Or the relative rates of rotation are biased to the head.] It would seem that the path of least "unwinding" resistance would be to overcome the friction between the underside of the bolt head and the cap surface. I understand that the physics of a gradually relaxing bolt could be very different from that while tightening -- it is a very interesting topic to think about. Surely the answer to this is already known. (?) The position of the head could be indexed relative to the cap.

Studs with full diameter body will not only twist less but also will not screw into the block because they are bottomed out with loctite or whatever. Studs can screw themselves into the nuts instead but less twist plus fine thread means this effect will be reduced.

I think this explains two statements I read above. One, that breakaway torque has been observed lower with studs and two, more fretting observed with studs. Both observations could be a result of the bolts screwing themselves in a bit versus the studs not so much.

I am thinking/predicting that there will be a difference between the fretting seen with main studs installed in a new block versus installed in a used block previously running bolts, other conditions being held constant.

[colormebad]

For your info' i do buy from dart like 4 or 5 times a week...And also for your info' ARP that makes all these studs we all are using will tell you the same thing i did....I have videos/timeslips and plenty of friends can back up my engine building skills...Lets see some videos and posted cars and times on these bad@ss blocks you say will explode if they don't have a line-hone done on them after changing from bolts to studs...I guess you think your the only person that does the best machine work in the world....I THINK NOT!!!!

[MrBo]

These 7/16" studs are about .425" dia and they call for 65 ft*lbs with oil.
The inner factory 7/16" bolts neck down to about .390" and call for 70 ft*lbs with oil.
I can't see how a fine thread nut is going to stretch the stud the required amout.
Something here seems way wrong to me. I did not use them, and I am the crazy nut that runs motors out of "balance".

[Wolfplace]

Necked-down main bolts will twist as well as strech when you torque them. While running that twist will tend to unwind and actually screw the threads deeper into the block a little bit.

For a bolt shaft to twist (and stretch), doesn't it entail that the threaded portion has a higher collection of forces forcing it to stop whilst the head continues to rotate ? [Or the relative rates of rotation are biased to the head.] It would seem that the path of least "unwinding" resistance would be to overcome the friction between the underside of the bolt head and the cap surface. I understand that the physics of a gradually relaxing bolt could be very different from that while tightening -- it is a very interesting topic to think about. Surely the answer to this is already known. (?) The position of the head could be indexed relative to the cap.

Studs with full diameter body will not only twist less but also will not screw into the block because they are bottomed out with loctite or whatever. Studs can screw themselves into the nuts instead but less twist plus fine thread means this effect will be reduced.

I think this explains two statements I read above. One, that breakaway torque has been observed lower with studs and two, more fretting observed with studs. Both observations could be a result of the bolts screwing themselves in a bit versus the studs not so much.

I am thinking/predicting that there will be a difference between the fretting seen with main studs installed in a new block versus installed in a used block previously running bolts, other conditions being held constant.

Kevin
Great thought provokers,, thanks
I will leave the girdle thing for another time but,,,
Thinking out loud,,,, in other words conjecture
With regard to twisting
With a bolt you are tightening threads that are XXX distance down a column & at least a good part of the friction is going to be in the threads
Would it not follow that the column would twist more because of this distance?

With a stud, washer & nut
You are tightening threads that are at the point you are measuring & while the stretch is going to be along the column (mostly in the threads if not a necked fastener)
I would assume that the column twisting seen with a bolt would be almost nonexistent?

With regard to loosening torque I would not put too much stock in this as most of what you would be feeling is break away torque & most of that is friction related rather than actual fastener loading same as trying to final torque with too little difference in value

As far as the bolt screwing itself in more I don't think this would happen
I can see the bolt head backing up if it was in twisting tension just like a spring & relieving some load & in fact have felt it do just that many times with head bolts when using a real good lube under the head which tells me there is more friction in the threads than at the bolt head/head junction.
I never feel this with studs???

The more we think we know the more questions,,,,

[CNC BLOCKS]

For your info' i do buy from dart like 4 or 5 times a week...And also for your info' ARP that makes all these studs we all are using will tell you the same thing i did....I have videos/timeslips and plenty of friends can back up my engine building skills...Lets see some videos and posted cars and times on these bad@ss blocks you say will explode if they don't have a line-hone done on them after changing from bolts to studs...I guess you think your the only person that does the best machine work in the world....I THINK NOT!!!!

Now seeing your an engine assembler not an engine builder big differance between the two

Lets see some videos and posted cars and times on these bad@ss blocks you say will explode if they don't have a line-hone done on them after changing from bolts to studs...I guess you think your the only person that does the best machine work in the world....I THINK NOT!!!!

Could you please quote where this was said about the blocks exploding if not line honed??

I deal with alot of engine shops and engine builders all over the world and I know what they expect and what they ask for and so far no issues.

I think boys we have a wanta be engine builder here