3500 Differences from Previous 3x00s

[bszopi]

Since I've got my hands on 2 3500 shortblocks right now, and Colin also has one, I think we need to start a thread describing the differences between the 3500 and the previous 3x00 engines. As I continue to look at the 3500 I have torn apart and one of the 3100s I have, I am noticing more and more differences, from subtle to extreme. Whenever possible, I'd like to include comparison pictures as well. Marty will have his hands on one of these 3500s soon as well, so he can join in the search. If anyone else has one of these (Ben and Phil, you guys can help with the top-end), lets see if we can get a good list going and eventually make an article out of it.

To start out (and I'll add pictures later), one thing I noticed last night was that there are a couple differences between the oil pans.

Oil Pan

- There is 1 bolt hole that is in a different location.
- Notched areas (6) in order to rod clearances (mirrored from the block)
- No oil level switch. I think this is on newer 3x00s as well. Why they got rid f it, who knows.

[onefastV6]

This is all I have as of now, but I am sure Ben will be able to add alot more.

The 3500 uses the electronic throttle body, the plate measures 65mm.




The 3500 cam appears to have the same base circle and lift as the previous 3X00 cam. Ben currently has a 3500 cam to send in with a 3X00 cam to get the specs.

The 3500 exhaust manifolds do not have a cross over pipe like the previous 3X00 engines. The ports also seem a little larger, and have a slightly different placement, but the bolt pattern is the same as the previous gen exhaust manifolds.

[v6h.o.]

Hmmm. Where to start.

Block:

Piston Oil squirter found ONLY on cyl's 5/6



Distinguishing 3.5L cast into the block at the front timing cover area:


"C" casting in the block



Front bolt boss holes are all different. The bolt boss protrudes from the block further out from the 3400 blocks here:


The bolt boss for the A/C compressor bolts at the bottom of the block are missing:




Rear Bolt boss' are different as well. The two Further Inboard (towards the rear of the block) bolt holes are still in the same location. However the Two outer bolt holes are pulled forward more towards the front of the block compared to the 3400.


Rods/Pistons

Rods are now a Powdered metal construction with Fractured caps. Rods are also longer now compared to the gen3, 2, 1 60v6's.
Rod Journals have changed from 2.125inch to 2.375 inch Rod Big End.




Piston bore has increased to 3.7 inch Diameter.
Pistons with the new longer rods also have a higher placed wrist pin.

Crank, Forged steel crankshaft, New Rod pin diameter at 2.250 inch for the rods. Mains have stayed the same for the crank.

Crankshaft now features 58x Crank trigger sensor ring.




Cyl heads:

The valves have been changed. They are Lighter than previous pieces. The valves are still the same size as the 3400 parts. But are lighter weight:
3400
exh 84.7 grams
int 98.6 grams

3500
exh 79.1
int 86.9

The combustion chamber has been reshaped,


Intake ports are changed, have a different shape to them at the top of the port, also do not feature the intrusive bolt boss from the rocker arm bolt into the casting of the intake port.




The exhaust ports have changed shape as well. I'll let Ben get into the specifics of the port changes.
However the relationship between the ports and the bolt holes have changed slightly between previous alum heads and the 3500's.



Lower intake manifold is similar to the previous LIM's save for the new matching port shape design

[onefastV6]

The 3500 lower intake manifold will not bolt to the previous 3X00 heads, and the 3500 fuel rail and injectors have also changed. I will see if I can't get Ben to post of pictures of these changes.

[SappySE107]

Ill take some pics when I get out of bed:P

The intake side of the head has a fin now in the bowl behind the valve. Exhaust has a raised ledge (or is it a recessed valley) making it sort of a fin to direct the exhaust flow around the outside turn. Intake valve is now the same shape as the DOHC motors, flat backed almost. Exhaust valve is slightly different on the back side but still a tulip shape. Margin is thicker on the face.

3500 lower intake has a bump that the injector faces. Injectors are much shorter, but ill take some pictures to show all that.

[SappySE107]

This is tricky to see but there is a fin in the bowl area right where you would normally see a carbon streak on 3400 heads. This should help direct air around the valve and keep the fuel in suspension

Again, hard to tell but there is a fin/raised area on the right/inside turn of the exhaust port that goes almost to the end of the port. Should help direct the exhaust flow. Port exit isn't really angled now and is wider (all biased to the outside of the turn, as I have a printout of the 3400 stock exhaust for a template to do Gen 2 heads and put it up against the 3500 head)

Backside comparison of the intake valves.

Exhaust valve comparison. Margin is thicker on the new valves and its got a slightly different tulip shape.

[SappySE107]

Fuel rail changed shape and is now the returnless fuel setup



Injectors are much shorter.

[bszopi]

Well, once my batteries for my camera charge up, I'll take some pics... But here are a few more things I've noticed so far.

The knock sensor is alot different than what I've seen before. This may be a change that occured prior to the 3500, but it is something new to me.



What is up with the huge brass hex plug (??) in the side of the block? Here is a blurry pic, but I'll get a better one:





The webbing in the lifter valley has gotten bulkier as well:



The new crank trigger is significantly taller (~0.35") than the old one. I am testing out an idea and found out that the old sensor almost touches the crank (with the 58x trigger removed) in some areas, and gets hit by the crank in other areas. Again, I'll take some pics once my batteries get charged.

One a side note, I'm tempted to see if I could trim down the old-style crank sensor to clear the new crank. Or possibly mount it away from the block more. Problem with moving it away from the block is the oring would have to move, therefore a new groove would have to be cut into the sensor body.

[bszopi]

Ok, here are some pictures of the old 7x crank sensor in the 3500 block with the 3500 crank: Notice how much the sensor sticks out when it is actually touching the crank.

[onefastV6]

I went and bought a digital caliper, so I measured the pushrods.
They are the same legnth as the 3x00 pushrods. Intake pushrods vary from 5.742" to 5.747" The Exhaust pushrods vary from 6.074" to 6.077"

[Guest]

Ok, well I tried to up load a pic and it's not working for me, if that is the KS that I think I'm seeing, then AFAIK, that's new for the 3500.

[Dave]

those oil squirters are so sexy!!

damnit I gotta get some of those and work on engineering some projects.

--Dave.

[Fierobsessed]

So, you've got my curiosity sparked again. I have a few things I'm wondering about...

I see that there is a piece of crank that the 58X backs up to, it doesn't line up well with the crank trigger, so it is kinda useless. Is the surface that the 58X reluctor was pressed onto the same diameter as the 7X reluctor on the 3.1? Im thinking a few minutes on a lathe to take off the ridge, and milling the 7X notches into the "new" reluctor will solve a few problems.

Edit: I just noticed that the backing surface only goes half way around, it will effect the balance, might have to mill the other side to compensate, or just go for a re-balance.

Im wondering how much clearance is needed for the 3.5 crank and rods to fit into a 3100 block. (more specifically a 3.4 DOHC) I think you see where I'm headed with this. I understand that because of the 2.25" journals are going to add 1/8" more swing room, that I will probably have to make some rod clearance paths, probably 1/16-1/8" of material might need to be shaved from the block. Im curious as to where these clearance issues might be located. The pan rail looks like the obvious victim. That is almost a non issue to notch. Other places might not be so forgiving.

If you can dismount the pistons (one would do it) and toss the crank and rod(s) into a bare 3.1 block, you would be doing all of us who are considering using the crank for HI Performance builds, a really big service. Specifically me, you'd save me at least $350 If there is no way it would work.

Personally I am counting on using this crank for my 3.4 DOHC project, in addition to "4.3" Eagle H Beam rods, witch have a 2.25" journal and are 5.7" long. This combo is nearly perfect for a 350-500 Horsepower build. After that, the mains would probably let go if the crank doesn't first.

[bszopi]

I've already plopped it into a bare 3100 block... well, the crank at least. If you look at one of my pics of the crank sensor, you will see a notch in the block for the rod clearance. It really isn't that much out of the block and could be easily replicated. I could probably even measure distances for people and document them as to where the clearances need to be.

As far as the trigger, yes the portion that the trigger slides onto is the exact same size as the old trigger. I actually already have a CAD drawing of a new trigger wheel that could be slid over the crank. Only issue to solve would be the mounting of the old sensor, since it would have to sit out almost 1/2" from its original position.

[Fierobsessed]

Perhaps... we can use the new crank sensor, and get (make) a reluctor ring that fits the crank, but has the 7X... Hmm.