Topper

Hey guys,
Well getting ready to put my 5.9 back together and wanted to make sure I'm not overlooking anything. I have decided to bore all the cylinders and start fresh. I have a new head coming from cummins as well. I ordered the cam from Peak Diesel and the springs, push rods and keepers from 4sight in Johnstown NY. I will be sending my turbo back to II to get rebuilt and probably upgraded to a 64. Does anyone know what increasing the bore size will add hp wise?(40 over) Not that I'm doing it for hp gain I want to start with a fresh bore and new pistons. I will be going with a fluid dampener as well.
Is there any mods that I should make to the freeze plugs? I know that there has been some decisions about freeze plugs blowing out. I was going to cut the intake off the new head but decided not to just to much money.

Thanks guys,
Topper

soulezoo

Certainly install the screw in plugs in the head. When those go, you won't know until too late. I've only heard of about 4 motors going that way, but that is enough for me. Also address the rear freeze plug while the engine is out.

HP in relation to increased bore depends on a few things but I believe .040" will pick up about 15hp. Not really certain on that.

Topper

Soulezoo,
Thanks bud. Just trying to do it right. It's not often (I hope) I get to do a complete rebuild so I what to correct my mistakes and make improvments where possable.
Does anybody have any recommendations as to what type of freeze plugs to use? The shop that is doing the machine work wants to install brass. The owner of the shop likes them the best.
Thanks,
Topper

Topper

Anybody balancing there engines before they put them together.

soulezoo

I balanced and blueprinted. Balancing is cheap and well worth it.

I don't know enough about the the difference in brass vs steel plugs to give an opinion. Just make them aware of how easy this engine will blow them out! For people (even very experienced machinists/mechanics) it is easy to dismiss any claim about the freeze plugs until you've seen it yourself. I mean, it just doesn't happen!

On the whole, give serious thought about your future goals and what you want. If you think you may grow to more HP, now is the time to address it. Things like girdles, studs, coated pistons, different rods, flycutting and etc. the list goes on. Research and think about it now...

Topper

Thanks for the reply Soulezoo,
I was going to check to see what it will cost to balance the reciprocating parts. I'm not trying to go crazy hp wise I just want the thing to be reliable. I absolutely love the way the truck runs and tows. This is a truck that needs to run 60-80 thou a yr loaded or towing a trailer alot of thoughs miles. I was just looking for some ideas so I don't say man i wish... It lasted 120,000 miles on the edge hopefully with the changes made it will last twice that this time.
By the way anybody know a good place to buy coated pistons?
Thanks!
Topper

Silver6spd

Get on Haisleys web page and order the rear freeze plug block. It botls into the block by 3 excisting threaded holes. Best insurance u can have. I'd rather blow the side plugs out b/c u can reach them, but the rear you have to drop the tranny and it's a pain...been there 5 times!! Now I've got a 1/2" stainless steel machined plate and over 50k miles with zero issues!!

soulezoo

You can source stock pistons and send them to Swain Coatings and use their Gold Coat.

Or go through Haisley's. There are others that I am not familiar with as well.

1985cucv

soulezoo, why do the plugs blow in the head, way to much pressure? would a bypass kit be well worth it to prevent head failure

Topper

Thanks for the help guys,
Topper

soulezoo

Same reason the back plug goes... pressure that has no where to go so it finds the path of least resistance.

For one member here, his mechanic took out his truck and romped on it while still cold. The thing is, when the head plug goes you don't know it until it is far too late...

Bypass kits are helpful, IMO, but not necessarily a cure, as I have found. I put screw in plugs in my head (on the truck folks!!) to make sure this doesn't happen to me. That is just my peace of mind.

Lost Lake

I think it depends on other mods. Boring the cylinder decreases compression.

mopardamo

Hello,

I agree with Lost Lake. The 4 to 5 cubic inch increase is nothing to be concerned about. The real advantage is the fresh and proper finish that allows your new package to make the most cylinder pressure. The required new pistons alone can increase or decrease the c.r.

Damon

Topper

I went with 40 over pistons from Cummins will this increase or decrease compresion?
Thanks
Topper

Silver6spd

You should've bored it to a 6.7liter. It's the same 5.9 block just machined bigger. There's alot of guys running a 6.7block putn down some power.