forged *60 crank

[Driver_10]

I got a question. Is there a way to offset grind a forged, 3500 crank for use in a 3400 block? Any idea of the price range for the machiningb if possible?

Also, has anyone here ever purchased one of the jbodyperformance forged cranks before? Ive heared ther're prone to flex, but anything is an improvement over the stock, cast piece.

[sharkey]

actualy, the stock cast crank is very strong. i have never heard of a crank breaking in one of these motors (aside from the early 2.8l small journal cranks).

as far as a i know, the jbp crank is just a treated stock crank that they claim is forged.

[Joseph Upson]

Here is what you are looking for, now go ahead and do what I talked about doing some time ago. Your best approach would probably be to offset grind it to use the smaller journal 3400 rods with the 3500 pistons in the 3500 block to get a 3.6 or 3.7L with an overbore, or go with custom pistons and have metal added and stroke it even more if the rods will clear the block.

http://www.flatlanderracing.com/crankshaft_services.html#weldedstrokers

[Driver_10]

Thats actually an awsome idea. A 3.7l na stroker would be awsome.

I was thinking of using an offset ground/ "knife-edged" 3500, forged crank with "small journell" 327rods, (maybe titanium if they ever get cheap enough) forged pistons and 3.4l "stock bore" block. A good "cap girdle" and windage tray combo wouldnt hurt either.

Since its forced inducted, id rather have a little meat in the cylinder walls, so no overbore. Although the 3500 is a better engine, modifiying the 3500 block to reverse engineer the DOD and VVT are not on my agenda.

One quick question though, would flatlander be able to swap on a 7x timing ring on the 3500 crank as well?

[Driver_10]

actualy, the stock cast crank is very strong. i have never heard of a crank breaking in one of these motors (aside from the early 2.8l small journal cranks).

as far as a i know, the jbp crank is just a treated stock crank that they claim is forged.

Its not so much yield strength that Im worried about. I wouldnt expect anymore than 700ft/lbs torque. Those cranks begine to develope microfractures after prolonged 7000rpms + operation. Id like a slightly higher revving motor, somewhere in the 7500-7800 rpm range. 8k is overkill, youll spin a cam berring or something.

[Joseph Upson]

Although the 3500 is a better engine, modifiying the 3500 block to reverse engineer the DOD and VVT are not on my agenda.

I take it you don't know that 2004-2006 3500 V6 engines are non VVT except for maybe the one used in the 2006 ~Impala & Monte Carlo. They didn't all go VVT until 2007, and none of the 3500s have DOD which can be left alone to work normally or replaced with stock lifters.

Go with the better 3500 block so if you decided to scale back you could use the .200 shorter 3400 rods with the stock 3500 pistons and either offset weld and grind the 3500 crank to make up the .200 difference for a serious stroker or offset grind alone for .100 and have lower compression for turbocharging using just the stock pistons. I know you want to go with forged pistons but that is an option if you decided you didn't want to spend the near $500 for adding metal for the offset settling for just the regrind offset at $200.

A 3500 bored .030 over with a .200 greater stroke would give you a 60 degree 3.8L and if you used the VVT block and eliminated the VVT cam which is no longer a difficult process considering you can take the easy way out and lock the stock cam into the correct straight up position you could probably end up with just shy of a 60 degree 4.3L using the 3900 and performing the same mods and replacing its 5.9" rods with 5.7" rods to compensate for the stroke increase.

I like the idea, it's just the added cost of rebalancing the assembly in addition to the crank work that would bring the total to somewhere around $700-$1000 and add no telling how much extra time to complete.

Do it man.

[ForcedFirebird]

^^^ and Driver 10, I would love to see you with a 3800 60*, just to spank the other fbod 90* 3800 who think the 60* is a waste of time

I actually read a thread over there where a newb asked "how much boost on a 3.4" and had actually got bashed by 90* people saying these motors aren't strong enough to handle boost! Can the 3800II see the kind of revs we do? Do they have forged parts from the factory? Sorry [/rant]

[Superdave]

the 3500 crank isn't forged.. it's just steel.

[Joseph Upson]

the 3500 crank isn't forged.. it's just steel.

It might be, I have noticed in GM literature that they don't always give the specifics or use the specific description for all like parts, for example, according to a right up I read about the turbo or supercharged solstice, the pistons are apparently forged aluminum. GM just calls them cast aluminum pistons and there is a little debate about the pistons in the 3.6 DOHC which GM says are forged but MAHLE piston says they don't make a forged piston in that series for GM as well as a GM Tech and even the forged rods are referred to by different names across different engines although they are manufactured by the same process.

One thing we do know, steel is stronger than cast iron with or without forging.

[SappySE107]

The 3.6 pistons are not forged. Brad has a piston and even asked GM about it. They made an error in some documents calling it forged when it is a hyper piston.

Doesn't the parting line on the crank indicate forged? Either way, its a heavy SOB. Better be stronger with all that extra weight.

[95SleeperAcheiva]

you mean the 3.6 DOHC? Ain't that the punched out 3.5 thats in the Intrigues? Thats another Olds motor, come on Ben, what did you expect for a crank in an olds motor? Oldsmobile lower ends have always been over-kill, your into them you know. Now I would rather have one of those in my achieva, I think I could make it fit, too bad no mods outside of custom.
But anyway, my original 3.1 crank broke in 3 pieces. Something let go around 6k. There wasn't much left to see what failed, initially.

[SappySE107]

Punched out 3.5? No. The 3.6 is a DOHC is a 60V6 and the 3.5 olds motor is not. The 3.6 is chevy.

[Will'sFiero]

While the 3.6 is a V6 with 60 degree bank angle, it is NOT in the same family as the pushrod V6/60's.

[95SleeperAcheiva]

disappointing. When I got money, if, I will make an Olds 3.5 DOHC fly. In the mean time, anyone got a complete 4.0L aurora drivetrain to sell? I need it for my sillouette mini-van. Oh and a M-90 blower too. Its fun to be demented.

[ForcedFirebird]

disappointing. When I got money, if, I will make an Olds 3.5 DOHC fly. In the mean time, anyone got a complete 4.0L aurora drivetrain to sell? I need it for my sillouette mini-van. Oh and a M-90 blower too. Its fun to be demented.

Got anything to tarde for an M90? I could use a bigger turbo...