does the northstar share rods with either the SBC or 60 degree V6?

is the piston height/bore similar to any SBC? or are N* specific rods needed?

thanx.

i don't know the answer to u'r question but the compression height of the N* piston is 32mm (~1.259"). i have a set of brand new N* pistons if u want them, 0 miles, straight out of a crate motor from CHRFAB. they have rings, wristpins and wristpin locks. $200 shipped to u'r door if u want them. let me know.

Eric

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Eric
'87 GT 5-speed Gold/Tan NOW with a 4.10 4-speed <- edit broke 4.10 back to 3.65 4-speed
3.1 TDC + other goodies coming eventually

SAVE THE SHAUN!!!

AFAIK, the FIRST aftermarket pistons available for the N* were Arias and they were made with the cooperation of Alan at CHRFab. I know at one time, if you tried to call Arias and order the pistons from them, they'd direct you to Alan. Rods are available from Eagle and Crower, but typically they aren't the weak link, the pistons are.

I'm using stock pistons in mine that have been coated by Swain Technologies with a creamic coating on the domes and a molydisulfide coating on the skirts. I'm still waiting (after almost 6 months) for my Total Seal Gapless piston rings. They offer one set as a stock number, but they didn't think they were suitable for my application. If you're going to use stock pistons, the earlier ones are better because of the land widths.

John Stricker

The rod length, pin diameter, bearing ID and journal size are differnt, but other than that they would interchange. I'm using Eagle ESP rods in my BUILT motor with stock pistons.

Curious as to why you chose to go with the Eagle rods and stock pistons since Alan kind of steered me the other way. That is, he felt the stock rods would handle more hp than the stock pistons? At least that's the way I understood him, although he does say the early pistons are stronger than the later ones.

John Stricker

quote Originally posted by wcapman: The rod length, pin diameter, bearing ID and journal size are differnt, but other than that they would interchange. I'm using Eagle ESP rods in my BUILT motor with stock pistons.

I'll go out on a limb then and say no stock N* piston's are forged?

quote Originally posted by zenon: does the northstar share rods with either the SBC or 60 degree V6? is the piston height/bore similar to any SBC? or are N* specific rods needed? thanx.

A) No.
B) No.
C) Yes.

Just no cheap way to do it.

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'87 Fiero GT: Northstar, Getrag, TGP wheels, rear sway bar, rod end links, bushings, etc.

'90 Pontiac 6000 SE AWD: Leaking ABS unit fixed, load levelling rear suspension fixed, still slow

No stock pistons are forged. The early rods were forged, the late rods were powdered iron (Not unlike the LS1/LS6).

John Stricker

quote Originally posted by zenon: I'll go out on a limb then and say no stock N* piston's are forged?

quote Originally posted by jstricker: No stock pistons are forged. The early rods were forged, the late rods were powdered iron (Not unlike the LS1/LS6). John Stricker

All the rods are PM. My '95 shop manual calls out '95 rods as PM, and those are the ones that people usually think are forged. Interestingly, it also says the '95 pistons are cast.

N* rods are 151 mm center-center with 54 mm journals.

There is some confusion in the nomenclature in the GM manual. In the early days GM referred to Powdered Metal rods as forged, since they are pressed at 20,000psi and then scintered. The process is nearly as strong as a forging, more precise shape wise, and cheaper. All N* rods are PM processed.

I talked to Alan at length about this. I have a set of early pistons. All years are cast hypereutectic. This is one step above cast and not quite as good as forged. Hypereutectic is a way to cool down the casting to control it's grain structure. The difference between the early pistons and the later ones is ring size. The early model pistons had the same size top two rings. Late model had a smaller top ring. The early model are preferred.

I went with the Eagle ESP rods because Paul Vanderley didn't like the PM rods in a high reving engine. He said he's had too many LS1 rods break. He has no experience with N*s but he has built a few NASCAR motors and Busch series motors. Paul got them for me cheap so that's what I did. They look great, and the rod bolts are deffinitely stronger than stock. I figure if I'm going to rev this engine above 8K it needs to have the right stuff in it.

I will have to go back and check, but I looked into this.

In my parts book, it shows the first year with a different rod p/n than the later years. IIRC, there is a service bulletin that describes the first year rods as forged while those after that were PM.

I'll take a little time in the morning and look them up again to be sure, but that's what my memory seems to think.

John Stricker

quote Originally posted by wcapman: There is some confusion in the nomenclature in the GM manual. In the early days GM referred to Powdered Metal rods as forged, since they are pressed at 20,000psi and then scintered. The process is nearly as strong as a forging, more precise shape wise, and cheaper. All N* rods are PM processed. I talked to Alan at length about this. I have a set of early pistons. All years are cast hypereutectic. This is one step above cast and not quite as good as forged. Hypereutectic is a way to cool down the casting to control it's grain structure. The difference between the early pistons and the later ones is ring size. The early model pistons had the same size top two rings. Late model had a smaller top ring. The early model are preferred. I went with the Eagle ESP rods because Paul Vanderley didn't like the PM rods in a high reving engine. He said he's had too many LS1 rods break. He has no experience with N*s but he has built a few NASCAR motors and Busch series motors. Paul got them for me cheap so that's what I did. They look great, and the rod bolts are deffinitely stronger than stock. I figure if I'm going to rev this engine above 8K it needs to have the right stuff in it.

I went back and looked this morning and the '93 engines have a different P/N for the connecting rods than the '94- engines. I poked through the service bulletins and found this:

According to service bulletin 47-61-42 dated 2/1/1995 on "Metallic Knock
Sound from Engine" regarding the '93-'94 Northstar engines, it says

1993 Model Year 4.5L Northstar Engines are equipped with forged connecting
rods. The connecting rod bolts may be reused in 1993 engines with forged
rods.

1994 model year 4.6L Northstar engines are equipped with powdered metal rods
which use rod bolts designed to yield when torqued to specification. Thus,
the bolts must be replaced in a 1994 4.6L engine whenever a rod cap is
removed.

Connecting rods must not be interchanged between 1993 and 1994 model year
engines due to crankshafts used specifically with each type of connecting
rod. If the connecting rods are interchanged, the engine will be out of
balance.

IMPORTANT: Never reuse connecting rod bearings with run time. Whenever a
rod cap is removed, always replace the bearings and perform a clearance
check with plastic Gauge. Refer to section 6A2 of the service information
manual for the plastic gauge procedure.

So, at least according to GM, the Northstar used Forged Rods and a different crank for the '93 model year.

John Stricker

Hmm... Interesting

N*'s are factory balanced, aren't they?

It may not be a different crank so much as the same crank balanced for the forged rods vice the PM rods.

Yes, they're factory balanced. The reason I remembered this was that I needed a crank and was looking at options. '93 is a different casting # entirely (which still may be nothing different than balance).

John Stricker

quote Originally posted by Will: Hmm... Interesting N*'s are factory balanced, aren't they? It may not be a different crank so much as the same crank balanced for the forged rods vice the PM rods.

http://www.bbandtracing.com/EAGLE.html
http://www.rosspistons.com/custom/eightcylinder.php3

I wonder if they changed rod/crank specs in the middle or latter part of 93? One of the engine I took apart was a 93 and the rods were the same as the 95 rods. I'm using the 93 pistons in my built motor.

Paul said the crank from a 95 was way out of balamce. Not to mention he had to rebalance it for the Eagle rods.

quote Originally posted by bushroot: http://www.rosspistons.com/custom/eightcylinder.php3 "Cadillac 331, 350, 390, 425, 429, 472, 500, Northstar"

What? Other than the nameplate, there's no relationship between the old Caddy engines and the Northstar.
They lump the Ford mod-motors in with the old small blocks, though, so maybe they're just organizationally challenged.

[This message has been edited by Will (edited 09-22-2003).]