3500 swap questions

[CNCguy]

The 3100 cover should bolt on fine but I have never tried it before. I make billet front covers for the 60V6s and they are interchangeable with 3100, 3400, LX9, LZ4 & LZ9. Perhaps Superdave would know for sure since he just finished his swap.

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[PCGUY112887]

Excuse me for my ignorance but I don't quite know what you guys are talking about.

I'm not even sure where the timing cover is. And the crank pulley with the 24x sensor? Would swapping these over do the same thing as buying the external crank trigger from the store here, or are these 2 totally different things/issues with this swap?

As far as the PS pump goes, since there isn't one on the 3500 are the holes to even mount one still there? Would a different belt size be needed after adding it?

[ProjectMM]

insted of doing all that work, what about doing a 3500 head swap, and lower intake? if it's even possible? it would save alot of work and would give a grate topend increase.

I've been looking into this for my car, sense i live in california and a turbo or supercharger would fly for somg!

[PCGUY112887]

Well I'd need to get a 3400 vs the stock 3100 to use the heads from the 3500... by the time I do that I might as well just use the whole 3500. Since it's newer, it should take to boost better if I so chose to do so. Plus it has those fancy oil squirters.

This is a huge learning experience for me which is why I want to do it on a project car so I have as much time as I need. I've learned lots about engines over the past year or so but I still lack information, which is why I ask here.

[IsaacHayes]

Superdave doesn't have a SFI car, so he doesn't need the 24x sensor. Not sure if he swapped timing covers for the accessories or not?

24x sensor is a 2nd crank sensor us SFI guys have and you still need the 7x for spark. The timing cover is the thing on the end that all the pulleys and stuff bolt on to, and is also the water pump housing. Swapping over the 3100 cover and all the accessories solves the problems you are worried about.

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...

[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).

[The_Raven]

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?