Main bolts

[zachdeagle16]

My new block that I have didn't come with any main bolts. Can I use the main bolts from my old block in the new block?

 

[TSIfreek]

If your going to use stock hardware use brand new bolts. You can get them from slowboy.

 

[zachdeagle16]

Ive heard that if you use Arp Main studs, you have to get the block line bored, is this true?

 

[92GSXman]

The manual says to measure the bolts and if they are within limit they can be reused.

 

[TSIfreek]

Hardware is cheep and good insurance. I will always have the mains line honed if using main studs. Using the studs distorts the block a bit and will throw off the cylinder walls and the main bearing trueness.

 

[defrag010]

not to mention that the ARP studs are smaller in diameter than the stock bolts, so you will need to dowel your maincaps as locators if you use ARP's as well.

 

[Suparata]

http://www.dsmtuners.com/forums/showthread.php?p=960360#post960360
Pictures moved here http://www.engintecs.com/gallery2/main.php?g2_view=core.ShowItem&g2_itemId=1063
Let me know what you think after reading the above.

 

[zachdeagle16]

Well, Is it safe to still use arp's, without the dowl kit, as long as i get the block line bored?

 

[Suparata]

It is not only safe, it is better to use ARP and align HONE the mains. Align boring would change the deck height too much and it is not recommended unless you spun a bearing. As far as the dowels goes my blood pressure goes up every time I read about using them in a block that was not machined from the beginning for that.

 

[zachdeagle16]

So, all I need to do is install the studs and have the mains line honed correct? Do I need to give the machinest any special instructions?

 

[Big Woo]

All engines use some means of “registering” bearing caps. This is done to ensure the alignment of the bearing cap and saddle. For example on the Mitsu 4G63 engine we have several examples of differing ways to do this.

1: Connecting Rods and the rod caps are aligned by a shoulder on each of the rods bolts, and a corresponding counter-bore within the rod-bearing cap, on the OEM style rods. On the Eagle rods since a through bolt and nut are not used to retain the rod and cap a dowel pin is pressed in one half and again a corresponding counter-bore is machined into the other.

2: Cam bearing caps are aligned by steel dowel pins pressed into the head, and yet again the caps have a machined counter-bore within the cam caps.

3: The main bearing caps are registered by yet another means in the 4g63 motor. The bearing caps are machined to a specific length across the bearing (front to back as the engine sits in the DSM). Then you will notice that on the block where the main caps attach there is a corresponding machined step that forms an interference fit with the main cap. This is why the main caps have to be tapped or drawn into place. This is the mechanism that is used to align the main bearing caps to the engine block. Big block and small block Chevy’s use this same type of cap registering.

Bolts or studs should never be used to align bearing caps, and with the exception of connecting rods (which use very specialized bolts) seldom are. Bolts and studs are fasteners, and therefore by definition are used as a means of attaching things

 

[TSIfreek]

It is not only safe, it is better to use ARP and align HONE the mains. Align boring would change the deck height too much and it is not recommended unless you spun a bearing. As far as the dowels goes my blood pressure goes up every time I read about using them in a block that was not machined from the beginning for that.

I knew that was coming

 

[zachdeagle16]

Well I bought the block from a guy off dsm trader and it didn't come with any mainbolts, so if I just bought stock ones would I have to still get the block line honed?

 

[Suparata]

First thing you need to do is measure the main bores and check for straightness. Then based on that and the rest of the measurements (crank and ID of the bearings used) your machinist can make a decision. Just the fact that you use stock fasteners does not mean that it is safe to assume everything is OK.

 

[defrag010]

As far as the dowels goes my blood pressure goes up every time I read about using them in a block that was not machined from the beginning for that.

So it's ok to use them in 7 bolts where they just slide right in?

Why does Concept Racing make dowel kits if they aren't necessary?

Not everyone does things the same exact way.