ARP main studs

[GRNDSM]

Is there really that much difference (in OD) between 6 bolt motor OEM head bolt and ARP head stud? I am not at them at the moment, but I thought that they were pretty much the same…

Leon
RR

 

[Mackzero]

Suparata...
That is great that you have such a passion for the work YOU do on our motors and others as well. BUT in the real world, MOST machinists are actually rather poor at what they do... Especially the "old school" guys that are used to working on V8s.... I am going to school right now to be a machinist and I share the same attitude for perfection that you do, but I have had THREE different machinists F' me over the years. All of them give excuses for their work failing or being out of spec because they say the motors are for "race purposes." Shoot, I have owned high powered cars, but never a race car. Anyway, to say what everyone else says... The OEM is just fine for most DSMers but if you are building a reliable HIGH output motor, than yes, you would be better off with the ARP product. As long as you know that there is A LOT of machining that must be done also, to make it all work. MOST Importantly though, is chosing the right machinist that WILL NOT F' your motor up, and WILL stand behind his work... If there is one in your area. When I get ready to do my new block I will be getting a hold of you, so we can see just how perfect your work is. I am sure you can back up anything said here, not questioning that, just want to make sure you know I will be getting a hold of you for.

Later.

 

[Suparata]

Is there really that much difference (in OD) between 6 bolt motor OEM head bolt and ARP head stud? I am not at them at the moment, but I thought that they were pretty much the same…

Leon
RR

Take a look at this link and you will find what you are looking for.
http://www.dsmtuners.com/forums/showthread.php?t=117015
Mitch.

 

[Suparata]

Mackzero do yourself a favor and get the #### out of this "business" while you still can It is one of the greatest job there is but you will always be dirty and poor. When you will make some extra money you will invest it in new equipment so after 20 years you will have nothing but a bunch of machines and nothing in the account.
Go out now and make some "real" money and the come back to this to do it out of pleasure. Hell I'm still waiting for that loterry ticket that will give me the chance to choose what I work on
Mitch.

 

[GRNDSM]

Take a look at this link and you will find what you are looking for.
http://www.dsmtuners.com/forums/showthread.php?t=117015
Mitch.

I do not see anything there on head bolts/studs.

Leon
RR

 

[Suparata]

Stock 1G is .439" where it is narrowed domw and the ARP for 1G is .470".
Unfortunately I don't know where I put the 2G ones but I know they are a lot "thinner". That’s why the 2G head bolt holes needed to be enlarged.
Mitch.

 

[98TsiAWD]

Is there really that much difference (in OD) between 6 bolt motor OEM head bolt and ARP head stud? I am not at them at the moment, but I thought that they were pretty much the same…

Leon
RR

The stock stud is 10.9xx mm at top by the head of the bolt, then about 3/4" down it tapers down to 10.1xx mm until the threads. I cant remember the exact measurements.

The ARP is 10.9mm throughout. So as you see its about .8mm difference in diameter, not much but it adds up when accounted for all the way around the stud.

So if anyone is reading, when putting a 7 botl head on a 6 bolt block, DONOT skip boring the headstud holes out .8-1mm

EDIT, this measurements of a stock 6 bolt head bolt vs. 6 bolt ARP head stud.

 

[MNGSX]

.
Doweled caps are a great idea. Unfortunately that’s all they are: an idea. It is a concept based on wrong assumptions. While it would definitely help, it is supposed to fix a “design flaw” in an engine that was not designed for Dowels.

I disagree... Any V8 I have seen built to withstand over 1000hp has dowels over studs at the mains. Most are 4 bolt splayed mains.

1500hp + Block Just one example

2, 3, 4 main caps are cross bolted with 4 cross bolts. Main caps are billet steel and cap alignment is further enhanced by integral dowel sections in the main studs

Yes this block was built from scratch that way but it has been added on countless std production engine blocks to increase reliability and power capacity. Certainly nothing new, radical or unproven for ANY engine regardless of a inline four or a V8,V10,V12, I5 or I6 etc...

The idea started on the assumption that the bolt holes in both caps and block were machined at the same time: FALSE. Take a good look at the difference in size between the holes in the caps and the ones in the block and explain why they are different if the two pieces were machined at the same time? BECAUSE THY WERE NOT!

They are different diameters mostly because one is threaded and the bolt just passes thru the other one. It leaves some movement and production hole alignment is'nt perfect but there is no more or less slack between the cap and the bolt than on engines that came with dowels from day one.

When dowels are installed in the block and the caps are machined to the size of the dowels you loose al that adjustment margin and this is when you are screwed.

Any machine shop that machines to stock production tolerances is'nt going to touch my block.... If the right guys do it you don't need that margin.. The dowels lock all caps in dead on everytime...

The reason for using the full kit not just the thrust cap dowels is that it locks all the caps into the block stiffening the web and keeping the main bores round under load..

 

[Suparata]

I’m not going to stay up late tonight too so I will just ask you a few questions.
1. What are the machining processes needed to install the Dowels? Tell me how you see them done?
2. Tell me if you agree that the machining was not done at the same time in both the block and caps.
3. Why do you think that only the caps no. 2, 3 and 4 are doweled?
Thanks,
Mitch.

 

[MNGSX]

I’m not going to stay up late tonight too so I will just ask you a few questions.
1. What are the machining processes needed to install the Dowels? Tell me how you see them done?
2. Tell me if you agree that the machining was not done at the same time in both the block and caps.
3. Why do you think that only the caps no. 2, 3 and 4 are doweled?
Thanks,
Mitch.

1. Im certain that a good machinist would ream the cap and saddle for the dowel at the same time.. Align the cap with the saddle and ream thru the cap and into the block the needed distance. This is'nt being done by some guy with a B&D cordless and a c-clamp get it..

2. What machining? They were actually align honed assembled. To what accuracy? As for the bolt holes no.. I'm prety sure each cap is a seperate casting and was'nt cut from the block casting.. Kinda like some rod caps are plasma cut from the main casting and others are seperate castings.

3. They are all doweled on that engine.. Only 2.3.4 have 4 bolt splayed caps where as the others are just two bolt caps..

 

[Suparata]

I'm busy at work so I will try to get back later. Untill then take a look at the picture and think "what's wrong with this picture".
Mitch.

 

[Suparata]

I’m glad we agree upon the fact that the two holes were machined separately and that they might not be concentric. Maybe now people will start asking themselves if an idea based on wrong assumptions IS a good idea. People also need to listen to what Mr. Walgreen says about the things that work out just the way we want in the town called Perfect but we don’t live anywhere near Perfect so things might not work out the way we would like.
Reamers are fairly accurate little tools but they can not make miracles. They are used to finish size an existing pre-drilled hole but they will always, I repeat ALWAYS follow the original hole. So what do you think happens when the reamer comes out of the first hole (the cap) and goes in the second hole (the block) that is not concentric with the first one? SOMEBODY HAS TO “GIVE” otherwise bad things happen. That’s why you may end up with a misaligned cap that loses the required margin for adjustment. So if you really want to Dowel the caps on a 6 bolt using the kit we are talking about go ahead and do it on the 1, 2, 4 and 5 and leave the Thrust one (3) alone. The 7 bolt is hopeless no matter what you do so I don’t even want to talk about it.
I know you read about a lot of doweled blocks out there but, unless they are designed with the sleeve type dowels from the beginning, it is not a great idea to install those in.
As you can see from the picture doweled block might mean something else than a lot of people think. That kind of dowels I would be more than glad to install in a 4G63, unfortunately there is no room for them.

 

[MNGSX]

I was'nt refering to enlarging the holes with a reamer in a die grinder.

Probably a CNC drill press setup. With the cap rigidly in place, the block held accurately and firmly, low run out on the drill chuck and making slow progress with the drill the holes will line up...

I guess maybe you can see why I saw most people should run the stock stuff...

When done right the dowels are worth it for those who want to play tag with guys like shep...

 

[Suparata]

Machining is not done based on “probably”, “I think”, “assume” and “hope for the best”. I can understand why it’s difficult for you to understand why it doesn’t work like that since you don’t do this everyday. I did my best to make you understand why that kit is not the right way to do it and I know you are a smart guy but you are also an idealist and you have to realize where wishes end and reality begins.
It doesn’t matter if the quill is the size of China, the block is in a fixture as strong as a tank and the feed rate is .001”/week. You will end up either shifting the cap or having egg shaped holes that will defeat the purpose of the dowels. So if the holes are misaligned enough you cannot “do it right” so it’s not worth doing it.
I guess that picture only helped you to be sarcastic. I know you’re better than that.
Bottom line, while you certainly improve things using ARPs without any dowels, you can screw it really bad by installing those kind of dowels.
Mitch.

 

[MNGSX]

The probably and assume come about because I am not a machinist..

I know a few that I know could find a way to make them line up... Just how they would do it I dont know..

For example the thrust bearing cap.

Maybe measure the hole location from the thrust side to the bolt hole and the center of the main. Ream it... Then macine the cap so that it's hole is located the same. There is no such thing as 100% dead on but I am very certain that these guys can get it withing as close of tolerances as their align hone jobs on the main bore. As for the other caps use the dowels and just ream.. On a non thrust cap the alignment of the cap horizontally is'nt as critical as the thrust cap.

 

[eclpsegsx12]

After reading this post, i became very frightened about whether or not they line bored when they did the ARP main studs. So i reached for my reciept from my machine shop in fear of not seeing an machine work being done with the main studs. I look at it and see "Install main stud & CK line bore. OK" ....So im guessing they were fine or something??! Im not sure exactly what that means but im guessing everything is fine. The first set of main bearings i had were previously checked in a 4g63 before but wernt used because he needed oversized. I remember my machine shop telling me that the reading were inaccurate when they measured 3 times and they told me to get new bearings so i did and i never heard anything about it again. Do you think im fine here? I sure as hell hope so, my motor is going in in about 5 days!

 

[Suparata]

These two caps are from two of the engines I’m working on.
The one on the right looks like it was installed wrong, doesn’t it? Well, even though it looks way off compared to the one on the left, I have to say that it is from an engine with 160.000 miles on it and the bearings looked in great shape and the crankshaft is in “as new” condition, it is one of the best crank I found.
So if you were to get that block, would you like to have it “aligned” with dowels? I wouldn’t.

 

[bjones18]

Studs used for engine building has little to do with potential for failing the fastener (stud or cap-screw...proper name for bolt)

As I understand Studs are used for two purposes:

1. Maintaining correct clamp load (torque) through useage. Torquing a fastener involves micro-mechanics which are different for studs and bolts:

BOLT - tightening a bolt applies friction under the bolt head, imparts elastic twist in the bolt length, and friction in the threads. Upon engine usage the elastic bolt twist can relax and reduce clamp load (torque).

STUD - only friction is right under the nut, therefore less elastic twist is imparted to the stud shaft which helps to maintain a more consistant clamp load. CLAMP LOAD IS WHAT YOU WANT and a torque wrench is an indirect way to estimate the clamp load (clamp load is significantly different whether you torque with dry fasteners or lubricated at all friction interfaces.)

2. Less chance for stripping the threads in your cast block with re-occurring rebuilds (racing) by using studs.

 

[EvoGun]

Well if its a street car, then IMO there is no reason you would ever push the limits of a factory bolt on pump gas. Tuning aside.

For a all out track car, you would have the bugget to do ARP bolts and anything else needed to win.

This is just my idea and experiance with biulding engines. I never stretched or snaped a head bolt.

Thanks