Gen 3 vs 4 blocks and cranks

MoparMap

VCA National President
VCA Officer
Joined
Jan 7, 2013
Posts
2,443
Reaction score
274
Location
Kansas
So I have some whacky questions for the day. I just blew a rod on my 04 at the track yesterday and am surveying the damage and looking at my options to get things fixed. I had a few different ideas I'm chasing down and figured I'd throw some wild longshot questions out there while I was at it.

The first one is will a gen 4 crank physically fit in a gen 3 engine? The ****** appears to be the same. I know the gen 4 uses a crank mounted tone wheel, but my 04 uses a flywheel crank trigger, so I would just ignore the crank one, assuming it doesn't cause interference issues in the block. Along those lines, is the oiling setup in the gen 4 crank any different than the gen 3? I have read about plugging some of the holes on the main journals to prioritize rod oiling, but I wasn't sure if this was unique to the earlier gens or something that is still present on the gen 4+ cranks. I toasted the 3/4 journal all over again on a rebuild with only 5000 miles on it and a fresh oil change right before the track. I run street tires on a course with limited high speed sweepers, so I really don't think a swinging pickup would have made any difference, though I could be wrong. Just trying to understand how the gen 4 oil system is different than a gen 3.

Second wacky question for the day. Will gen 3 parts bolt on to a gen 4 block? IE could I take a gen 4 short block and bolt all of my gen 3 stuff to it (heads, front cover, accessories, etc.)? How different are the blocks themselves? I know the bore is slightly different (0.5mm or so) and the gen 4 has the variable cam, but I wasn't sure if the block had anything to do with that. I thought it was more in the timing cover, but maybe not. I'm a little more interested in this particular idea as my block has a fair amount of damage from the rod letting go and I'm thinking I'm going to need a new one one way or the other. It might be salvageable, but at this point I think a short block is going to make more sense to get the car back on the road. I'm looking for gen 3 stuff to start with, but didn't know if a gen 4 short block might be another interesting option just to open up the amount of parts that might be out there to look for. Same issue with the crank trigger, but if I'm triggering off the flywheel it seems like I could just leave the gen 4 sensor in place as a plug and do nothing with it.

Anyone else out there done any frankenstein work like this? I know more people put gen 4 parts on a gen 3, but figured if that worked them maybe the opposite would as well. I'm looking for a short block regardless at this point, but until I get the whole engine out I'm not sure the full extent of the damage. Pretty sure I can salvage the top end at least. Hoping my cam and lifters are still okay, but won't know until I get them pulled out.
 

wisetechscott

Enthusiast
Joined
Jul 1, 2022
Posts
1
Reaction score
0
Location
Detroit
I'm curious about these questions as well. I think it would be worth while to at least be able to figure out for the 05-06 Gen 3 that is also tone wheel crank sensor mounted. how much work needs to be done to be-able to use a gen4/5 crank seeing as the later model gen 3 cranks are impossible to find now.
 
OP
OP
MoparMap

MoparMap

VCA National President
VCA Officer
Joined
Jan 7, 2013
Posts
2,443
Reaction score
274
Location
Kansas
Well, as it turns out you can use a later crank in the early gen 3s at least, or that's my plan so far. I talked to Prefix about it and they said they'd have to repin the flywheel ****** to correctly clock the flywheel for the early gen 3 sensor, but the crank itself should fit fine. That's what I'm doing on my car at least. Not sure about the later gen 3s though. I thought the tone wheel changed on them between gen 3 to gen 4, but I can't quite recall. I remember the gen 5 part number showed as superseding several others, and the late gen 3 cranks might have actually been on that list. So long story short, you can put about whatever crank you want in an early gen 3 at least with fairly minimal rework. Later I can't quite say.

As for blocks, I didn't get an answer on that one as it looks like mine could be saved. From what I've heard, the 05-06 gen 3 block is more or less a gen 4 block without the VVT setup and maybe a little less gusseting, though I'm unsure on that one. Seems sort of like the old gen 1.5 cars where it was a transition between the gen 3 and gen 4 and shared elements of each. Physically I'm sure the block would fit in my car, but I'm less sure if I could make my computer work with it and what you'd have to do about the VVT. Maybe you could just cap it off or maybe you put the VVT solenoid it and just leave it unplugged, but the cam sensor becomes a problem. I think you might be able to bolt a gen 3 timing cover to the gen 4 block, but guessing you can't just straight up run a gen 3 cam and timing gear in the gen 4 block.
 
Last edited:

Viper Specialty

Legacy/Supporting Vendor
Supporting Vendor
Joined
Feb 14, 2002
Posts
5,710
Reaction score
53
Location
Cape Coral, FL
Short version:

There are 3 versions of G3 blocks:
1. 2003 Only. Flywheel Pickup, No Knock Sensors, oddball oil cooler line adapter that screws onto the block.
2. 2004 Only. Flywheel Pickup, No Knock Sensors, Revision to eliminate adapter.
3. 2005-2006. 2004 Block with Knock Sensor Mounting Bosses & center crank sensor location boss grafted. Flywheel Pickup deleted.

All G4 blocks are the same.

G4 blocks are effectively 05/06 blocks with rather involved revisions. All of the hardware is changed to Metric, all of the VVT gallery changes made, and all of the bulkheads strengthened. Changes made on dowel pin sizes and such as well. General layout remains the same.

G3 Cam is nothing like G4, and in no way, shape or form will fit. Your timing cover will not bolt up. All of the hardware will differ.
Can it be done? Yes. But it would require a lot of one-off parts to make it proper... definitely more than simply locating a G3 block.

And yes, you can use a G4 crank in a G3 block pending the crank trigger modifications and the fact that again, flywheel hardware is different and dowel pin is missing... not to mention balancing is totally different.

Anyone looking to do this kind of stuff would be best served to call me, as this is the kind of oddness I get involved with constantly... I am not guessing.
 
OP
OP
MoparMap

MoparMap

VCA National President
VCA Officer
Joined
Jan 7, 2013
Posts
2,443
Reaction score
274
Location
Kansas
What exactly do you mean about balancing being different between the cranks? I feel like I've read that before, but never quite understood exactly what it means. In my head balanced is balanced, but I know that a rotating assembly is just that, an assembly, so it's more than just each part being individually balanced. Is there a significant difference in rod/piston weight between gen 3 and 4/5? I would think the flywheels are probably fairly similar throughout all the gens, though I know the gen 4 went to a different clutch setup. Just curious if there's anything I should looking out for when putting the later crank in my car.
 

Viper Specialty

Legacy/Supporting Vendor
Supporting Vendor
Joined
Feb 14, 2002
Posts
5,710
Reaction score
53
Location
Cape Coral, FL
You answered your own question. G3/4/5 rotating assembly components all have different weights. You cannot bolt G3 parts to a G5 crank and expect it to be balanced. You NEED to have the crankshaft balanced by an engine machine shop or you may as well just flush the money down the drain. Balancing a crank is not like balancing a tire. Its a calculation, not a true zero balance.

External components are Zero Balance in an internally balanced engine, they are irrelevant to the calculation and balanced individually so they dont upset the actual crankshaft balancing.
 
OP
OP
MoparMap

MoparMap

VCA National President
VCA Officer
Joined
Jan 7, 2013
Posts
2,443
Reaction score
274
Location
Kansas
Makes sense, I'll be sure to double check everything. Thanks for the heads up! Good to know the external parts shouldn't cause any issues at least.
 

1slosnake

Enthusiast
Joined
Sep 12, 2022
Posts
2
Reaction score
0
Location
Alabama
Short version:

There are 3 versions of G3 blocks:
1. 2003 Only. Flywheel Pickup, No Knock Sensors, oddball oil cooler line adapter that screws onto the block.
2. 2004 Only. Flywheel Pickup, No Knock Sensors, Revision to eliminate adapter.
3. 2005-2006. 2004 Block with Knock Sensor Mounting Bosses & center crank sensor location boss grafted. Flywheel Pickup deleted.

All G4 blocks are the same.

G4 blocks are effectively 05/06 blocks with rather involved revisions. All of the hardware is changed to Metric, all of the VVT gallery changes made, and all of the bulkheads strengthened. Changes made on dowel pin sizes and such as well. General layout remains the same.

G3 Cam is nothing like G4, and in no way, shape or form will fit. Your timing cover will not bolt up. All of the hardware will differ.
Can it be done? Yes. But it would require a lot of one-off parts to make it proper... definitely more than simply locating a G3 block.

And yes, you can use a G4 crank in a G3 block pending the crank trigger modifications and the fact that again, flywheel hardware is different and dowel pin is missing... not to mention balancing is totally different.

Anyone looking to do this kind of stuff would be best served to call me, as this is the kind of oddness I get involved with constantly... I am not guessing.
Are there bosses for knock sensors in the G3 block?

Great Intel BTW!
 
OP
OP
MoparMap

MoparMap

VCA National President
VCA Officer
Joined
Jan 7, 2013
Posts
2,443
Reaction score
274
Location
Kansas
Are there bosses for knock sensors in the G3 block?

Great Intel BTW!

Only 2005 and 2006, but I think you also have to have a computer to match that. Guessing you couldn't put a 2006 block in an earlier car and run it on a 2004 computer for instance. You'd have the crank sensor issue as well. Seems like the 05/06 was kind of like the old "gen 1.5" in that way. Almost closer to a gen 4 computer in a way, though gen 4 obviously had a lot more going on (DBW, VVT, etc.).
 

Viper Specialty

Legacy/Supporting Vendor
Supporting Vendor
Joined
Feb 14, 2002
Posts
5,710
Reaction score
53
Location
Cape Coral, FL
Are there bosses for knock sensors in the G3 block?

Great Intel BTW!

As I said,they are 3 versions of G3 blocks. One version has them, two versions do not.

These things can be mixed and matched if you know what you are doing. We can enable/disable knock sensors with hardware/software depending on configuration, etc. You can run a newer knock-block in a 2004 on a 2004 PCM and just "ignore" them being there, or "add them" if desired. If there is a wallet, there is a way.
 

proedge

Enthusiast
Joined
Apr 15, 2014
Posts
54
Reaction score
5
Sorry to bump this up. Trying to figure out if this will work. I have a 2004 block and my friend has a 2006 that needs a new bottom end. Obviously his crank sensor is crank pickup and he has knock sensors. The 2004 block I have doesn’t have knock sensor mounts and has the flywheel pickup. So my questions are, can we use my 2004 block in his car and figure out a way to mount his knock sensors and relocate the crank trigger to flywheel pickup? I’m pretty sure the 2006 flywheel is the same as a 2004 one and has the pickup points on it for a sensor. Any input appreciated.
 

Viper Specialty

Legacy/Supporting Vendor
Supporting Vendor
Joined
Feb 14, 2002
Posts
5,710
Reaction score
53
Location
Cape Coral, FL
The crank sensor adapter can be made without a problem. Generally I would not advise a Knock Sensor retrofit, as the bosses really need to be welded, and it cannot be done with the engine in the car very easily. To add, the knock sensors are programmed for a specific boss type and mounting, and this cannot really be imitated. An aftermarket programmable knock detection system would ideally be tuned for the added knock sensors.

Your best course of action in this case would be disable the knock sensors in the programming and run the no-knock calibration style from 2004.
 

proedge

Enthusiast
Joined
Apr 15, 2014
Posts
54
Reaction score
5
The crank sensor adapter can be made without a problem. Generally I would not advise a Knock Sensor retrofit, as the bosses really need to be welded, and it cannot be done with the engine in the car very easily. To add, the knock sensors are programmed for a specific boss type and mounting, and this cannot really be imitated. An aftermarket programmable knock detection system would ideally be tuned for the added knock sensors.

Your best course of action in this case would be disable the knock sensors in the programming and run the no-knock calibration style from 2004.
Thanks for the response. The engine is currently just a bare block, I could have the machine shop add something for the knock sensors. His car being a 2006 he wants to keep the knock sensors, if possible. As far as the crank sensor, would you just extend the harness and run a 2004 style flywheel sensor? Any programming changes needed?
 

Viper Specialty

Legacy/Supporting Vendor
Supporting Vendor
Joined
Feb 14, 2002
Posts
5,710
Reaction score
53
Location
Cape Coral, FL
No programming changes needed.

Yes, you can extend the harness and run the 2004 sensor location. The quality required in doing this correctly is paramount. High hz signal wiring has no tolerance in being done cheaply.

All of that said, be aware that doing this is inferior in every way compared to an 05/06. There is a reason they changed back, and that is because the 03/04 flywheel pickup is problematic.
 

proedge

Enthusiast
Joined
Apr 15, 2014
Posts
54
Reaction score
5
Any other way around this? Ideally we’d use the original crank trigger location, but I’m not sure that can be done and if the 2004 crank has the pickup points on it?
 
OP
OP
MoparMap

MoparMap

VCA National President
VCA Officer
Joined
Jan 7, 2013
Posts
2,443
Reaction score
274
Location
Kansas
The 04 crank doesn't have the tone notches machined in. Not sure if they could be added or not, but even if it could I'm not sure how practical that might be.
 

Viper Specialty

Legacy/Supporting Vendor
Supporting Vendor
Joined
Feb 14, 2002
Posts
5,710
Reaction score
53
Location
Cape Coral, FL
03/04 has no slots or mounting boss for the sensor.

A machine shop can add them with a sample and a full disassembly, but the ring will still be undersize and require a custom made sensor and block machine work.

What you are doing is not simple stuff to complete... if it was that easy, everyone would do it!
 

Greg Val

Enthusiast
Joined
Nov 16, 2021
Posts
3
Reaction score
0
Location
Brewster NY
For anyone looking for a used or rebuilt Viper block(s) Don Scharf's 1-800-338-4002 ext.109 ask for Todd. And I believe that place and/or people can answer any questions you might have. I know its in Wisconsin so times ect.
 

SketchyPete

Enthusiast
Joined
May 15, 2022
Posts
44
Reaction score
0
Location
Concord NC
Piggy backing here, does anyone know what hardware is needed to switch from a cam in cam to a solid cam? From what I can tell it looks like removal, swap and a plug.
 

BadAzp

Enthusiast
Joined
Jul 19, 2022
Posts
51
Reaction score
11
Location
Las Vegas
Short version:

There are 3 versions of G3 blocks:
1. 2003 Only. Flywheel Pickup, No Knock Sensors, oddball oil cooler line adapter that screws onto the block.
2. 2004 Only. Flywheel Pickup, No Knock Sensors, Revision to eliminate adapter.
3. 2005-2006. 2004 Block with Knock Sensor Mounting Bosses & center crank sensor location boss grafted. Flywheel Pickup deleted.

All G4 blocks are the same.

G4 blocks are effectively 05/06 blocks with rather involved revisions. All of the hardware is changed to Metric, all of the VVT gallery changes made, and all of the bulkheads strengthened. Changes made on dowel pin sizes and such as well. General layout remains the same.

G3 Cam is nothing like G4, and in no way, shape or form will fit. Your timing cover will not bolt up. All of the hardware will differ.
Can it be done? Yes. But it would require a lot of one-off parts to make it proper... definitely more than simply locating a G3 block.

And yes, you can use a G4 crank in a G3 block pending the crank trigger modifications and the fact that again, flywheel hardware is different and dowel pin is missing... not to mention balancing is totally different.

Anyone looking to do this kind of stuff would be best served to call me, as this is the kind of oddness I get involved with constantly... I am not guessing.
Dan, how much clearance to the block do you think a rod needs at 6k rpm?
Thinking of crank/rod flex with heat/rpm.
See my problem here

I'm guessing I'm screwed and need to
1. find an 03 crank/piston/rods for the 03 block.
2. Make the 04 crank garage art
3. Put the 05 pistons/ rods/ring/bearings on the shelf until i find an 05 block/crank
 

Viper Specialty

Legacy/Supporting Vendor
Supporting Vendor
Joined
Feb 14, 2002
Posts
5,710
Reaction score
53
Location
Cape Coral, FL
Dan, how much clearance to the block do you think a rod needs at 6k rpm?
Thinking of crank/rod flex with heat/rpm.
See my problem here

I'm guessing I'm screwed and need to
1. find an 03 crank/piston/rods for the 03 block.
2. Make the 04 crank garage art
3. Put the 05 pistons/ rods/ring/bearings on the shelf until i find an 05 block/crank


I generally target 0.100" whenever possible. in some cases things can be squeaked closer, where inertial forces, component rocking and deflection arent really a concern.

With regard to your problem, clearance your block galleries like an 04+ and move on with life.
 

GTS Dean

Enthusiast
Joined
Jul 22, 2000
Posts
3,787
Reaction score
209
Location
New Braunfels, Texas
A guy on FB V-O-G is selling a complete '06 motor with all accessories that picked up a rod knock from a scuffed rod bearing. $7500. He already has a new motor sourced.
 

BadAzp

Enthusiast
Joined
Jul 19, 2022
Posts
51
Reaction score
11
Location
Las Vegas
I generally target 0.100" whenever possible. in some cases things can be squeaked closer, where inertial forces, component rocking and deflection arent really a concern.

With regard to your problem, clearance your block galleries like an 04+ and move on with life.
You think there is that much extra metal in the 03 oil galley to take out? Attached is pic of rod contact
 

Attachments

  • 20230805_143513.jpg
    20230805_143513.jpg
    139.1 KB · Views: 11

Fire196

Enthusiast
Joined
Sep 9, 2023
Posts
3
Reaction score
4
Location
Peterborough, ontario, Canada
So I have some whacky questions for the day. I just blew a rod on my 04 at the track yesterday and am surveying the damage and looking at my options to get things fixed. I had a few different ideas I'm chasing down and figured I'd throw some wild longshot questions out there while I was at it.

The first one is will a gen 4 crank physically fit in a gen 3 engine? The ****** appears to be the same. I know the gen 4 uses a crank mounted tone wheel, but my 04 uses a flywheel crank trigger, so I would just ignore the crank one, assuming it doesn't cause interference issues in the block. Along those lines, is the oiling setup in the gen 4 crank any different than the gen 3? I have read about plugging some of the holes on the main journals to prioritize rod oiling, but I wasn't sure if this was unique to the earlier gens or something that is still present on the gen 4+ cranks. I toasted the 3/4 journal all over again on a rebuild with only 5000 miles on it and a fresh oil change right before the track. I run street tires on a course with limited high speed sweepers, so I really don't think a swinging pickup would have made any difference, though I could be wrong. Just trying to understand how the gen 4 oil system is different than a gen 3.

Second wacky question for the day. Will gen 3 parts bolt on to a gen 4 block? IE could I take a gen 4 short block and bolt all of my gen 3 stuff to it (heads, front cover, accessories, etc.)? How different are the blocks themselves? I know the bore is slightly different (0.5mm or so) and the gen 4 has the variable cam, but I wasn't sure if the block had anything to do with that. I thought it was more in the timing cover, but maybe not. I'm a little more interested in this particular idea as my block has a fair amount of damage from the rod letting go and I'm thinking I'm going to need a new one one way or the other. It might be salvageable, but at this point I think a short block is going to make more sense to get the car back on the road. I'm looking for gen 3 stuff to start with, but didn't know if a gen 4 short block might be another interesting option just to open up the amount of parts that might be out there to look for. Same issue with the crank trigger, but if I'm triggering off the flywheel it seems like I could just leave the gen 4 sensor in place as a plug and do nothing with it.

Anyone else out there done any frankenstein work like this? I know more people put gen 4 parts on a gen 3, but figured if that worked them maybe the opposite would as well. I'm looking for a short block regardless at this point, but until I get the whole engine out I'm not sure the full extent of the damage. Pretty sure I can salvage the top end at least. Hoping my cam and lifters are still okay, but won't know until I get them pulled out.
All gen 5 internals fit gen 3block I did it with mine
 
Top