3500 swap questions

[bszopi]

The 24x sensor has nothing to do with SFI. SFI is controlled by the cam sensor. The 24x sensor has to do with having a more accurate timing at low RPMs in order to allow for a smoother idle at those RPMs (below 3k).

[Guest]

The 24x sensor has nothing to do with SFI. SFI is controlled by the cam sensor. The 24x sensor has to do with having a more accurate timing at low RPMs in order to allow for a smoother idle at those RPMs (below 3k).

Funny, my old 3.1 idled much smoother than my current 3100.

The 3500 front cover still has the three bolt holes for the power steering pump. It just has an additional threaded bolt hole for the idler.

[Superdave]

the 3100/3400 cover will bolt onto the 3500 fine, altho i don't know why you'd change the 3500 one out. I used a 3400 timing cover gasket on my 3500 cover.


I don't use the 24x crank sensor or the cam sensor, just the 7x external trigger. Mine idles really rough but that's not the sensor's fault


Yes, the 3400/3100 pump will mount to the 3500 timing cover. I have one from a '95 Beretta on my 3500. Just some other notes, i'm using a 2.8 alternator bracket with the stock alternator for my car, a 2002 3400 fuel rail, '98 FPR and multech 1 injectors. I'm also using the stock 3500 MAP sensor, stock 3.1 OPSU and knock sensor.


*also, i figured out a way around grinding the TB neck for FPR clearance. I'll post up pics tonight of my modified FPR. It clears the 3500 neck w/o problems.



in all reality the 3500 swap isn't much different than a 3400 swap, just a few things like the block mounting bosses are slightly different and the CTS setup. You can drill and tap the rear head larger to accept the newer 3 wire sensor if that's what you need. I have a 2 wire in each head (one for the gauge and one for the computer/fan).

[IsaacHayes]

Brad, right, but the SFI cars were the first ones to use the 24x on the 60*'s AFAIK. The MPFI motors didn't have a 24x sensor AFAIK. I wasn't implying SFI needed the 24x, it just has them.

You'd need to swap the cover and crank pulley to use the 24x setup if your car came with that setup. Like mine.

PCGUY's car is a 96 so he already has a 3 wire CTS. I'm not positive but I don't think the block mounting will be a problem for him either... He'll just have to swap his 3100 timing cover over with the crank pulley and his accesories (could probably even use the 3500 alt), and hook up the external crank sensor. Then there's little stuff getting the 3500 plenum to work, or you can just bolt on a large port 3x00 plenum and call it a day.

[PCGUY112887]

Now I am slightly confused, 1 person says I don't need to change the timing cover, someone else does.

To be honest I really don't know how the crank trigger works. Do I have to get the external setup in the store here no matter what or what?

I figure the cost of head gaskets and intake gaskets/etc is about the same as the external trigger setup.... I haven't done the math but you end up with a whole new engine...

I would prefer to NOT have to rip apart an almost new engine if I don't have to...

Anyone have pictures of how the external setup from the store goes on?

[Superdave]

sorry, i don't have to use those extra sensors. If you need to have that 24x sensor hooked up then you'll have to swap over the 3100 timing cover.

I don't think the 3500 cover has the spot to mount that sensor (since the 3500 dosen't use it)

[CNCguy]

OBD-I uses:
7X crank sensor. (Reads from 7 slots in crankshaft)

OBD-1.5 & OBD-II uses:
7X crank sensor. (Reads from 7 slots in crankshaft)
24X crank sensor (Reads from 24 notches in back of dampener)
cam sensor (Reads from a notched ring on camshaft)

LX9 3500 uses:
56X crank sensor. (Reads from 56 notches on crankshaft)
cam sensor (Reads from a notched ring on camshaft)

LZ series engines use:
60-2 (60 teeth with 2 missing) crank sensor
cam sensor

OBD-I cars do not require the use of the 24X crank sensor there is no need to change the front cover and dampener. Superdave is running this setup.

Your car has OBD-II and requires 7X & 24X crank sensor inputs. The external trigger from the store takes care of the 7X sensor. Using the front cover and dampener from your current engine will give you the 24X sensor since the 24X sensor is mounted to the front cover behind the dampener.

Hopefully that makes it a little clearer.

Changing the front cover is pretty easy. It can be done without dropping the oil pan if you want. Just pull the dampener and remove the front cover. For a good seal, be sure to use a little silicone in the corners where the pan and block come together before putting the front cover on. Also, make sure to use the new front seal for the dampener since it should come in the gasket kit.

[PCGUY112887]

Very informative thank you!

But... dampener/front cover, where are we talking here? I don't have an actual engine to look at yet so I am trying to picture everything in my head :P

Thanks again.

[CNCguy]

Very informative thank you!

But... dampener/front cover, where are we talking here? I don't have an actual engine to look at yet so I am trying to picture everything in my head :P

Thanks again.

The dampener is also the pulley on the crankshaft. The front cover is on the same end of the engine as the dampener and covers a large portion of the end of the engine. It has about 8 bolts holding it on and a gasket between it and the engine. There is also a seal that is in it to seal around the dampener to keep the oil in. The waterpump is mounted inside the front cover and the PS pump mounts to it.

[PCGUY112887]

Ah ok that gives me a better idea of it. Hopefully I will have my hands on this engine soon so I can figure out how things work... I believe I am a visual learner so hopefully it won't be too bad.

I started to research how pushrod engines work to figure out what has to be done to install a cam in a 3500. It looks like the rods/lifters have to come out... then the cam somehow comes out but I don't quite see how it comes out? When you watch TV shows they just slide the cam in/out the side of the engine (I'm assuming it would come out under the timing cover and all) however when you look at the picture used for the cam regrind in the store, you can see teeth on the end that turns the cam... which is what puzzles me since I don't see how it slides in with those teeth there. How does the cam install process go?

Thanks again!

[Superdave]

it's easy..

you need to pull out the lifters (which means the pushrods gotta come out too), pull out the distributer shaft piece on the bellhousing side of the block..

Of course the crank pully and timing cover off the front, then the bolt for the timing chain sprocket comes out..

there are 2 hex bolts in the cam retainer that need to come out as well...

here is a pic of my 3500, you can see the cam sprocket is allready off, the cam bolt was threaded back in. the cam retainers is still bolted in as well...


after the retainer is off, the cam just slides right out. be care full and do it very slowly as to not damage the cam bearings...

http://www.3500z.com/3500/Block/3500%20159%20(Medium).jpg

[IsaacHayes]

DONT mix up the pushrods. They are different lengths. You can ruin a motor fast putting them in the wrong order.

[PCGUY112887]

DONT mix up the pushrods. They are different lengths. You can ruin a motor fast putting them in the wrong order.

So I've heard

I was looking into the whole AC compressor mounting issue and I found this...

http://60degreev6.com/showthread.php?t=32367&highlight=3500+pics

On that page in the second post onefastv6 notes missing AC compressor bolt holes, and the front/rear bolt holes being different.

It seems that if those front/rear bolt holes were different, the engine wouldn't even bolt up correctly?!? Surely I am missing something. Considering I don't even know how the engine actually mounts and pulling an engine will be a learning adventure :P

Anyone have any input on the AC compressor issue?

[IsaacHayes]

Looks like the compressor is just moved up higher. If you had a complete 3500 to look at with the AC bolt up you could measure and see if you'res would fit. That picture doesn't show the pan which is where the bottom bolt would go for the AC.

At least mine is like that 2 in the block one in the pan.

[PCGUY112887]

Will the engine even mount correctly? I've only seen 1 mention of someone saying that the mounting points had changed (in the thread linked above with all of the pics) but I have NEVER heard of anyone else talking about the mounting points changing when others ask about a 3500 swap.

I must be missing something, or everyone would just say "it doesn't bolt up" when asked about a 3500.