3500 Venture swap

[WrathOfSocrus]

The beaten old 3400 in my mother's 2000 Venture finally decided to piss coolant from multiple places at once. It has 199K miles and is ready to be pulled. It is being brought to my house tonight and I so far have a 3500 short block ready to be fixed up with a few new pieces and all the old sensors and what not from the old motor.

I'm not quite sure if it being a van will make it much more difficult to swap. The only problems I see running into at the moment are with the passenger side motor mount bracket and the A/C. I might have the A/C system discharged and deal with that last.

Right now the biggest problem will probably be the crank sensor. I was hoping it wouldn't take more than a week or two to do the swap if I spend most of my free time on it. However, if I can't get the crank trigger within a few week's time, I may have to find another option than using the 3500. Anyone have an idea of how long the wait will be till the next batch?

If i know it wont be too long I can start and get the bulk of the swap done. I need the old engine out for certain no matter what, so that's going to begin tomorrow after I get it down here. Any tips would be greatly appreciated! I'm looking to go with a stock swap over. I need to buy some 3500 heads and a LIM. I have a friend who said he can help me get the tuning squared away after I get it going. I'm hoping the stock 3400 tune will be enough to drive it to the front yard after the swap.

I'm gonna get ready to start tearing down and cleaning that beast.

[zofo61]

Good Luck with the swap......please keep us posted and do not hestate to ask ask ask......wonder where you got that short block from?....hmmmmmmmmm

[LeftVentricle]

I'm hoping the stock 3400 tune will be enough to drive it to the front yard after the swap.

In order to answer this question we'll need to know the answer to this question:

wonder where you got that short block from?

Early 3500s are more closely related to 3400s, since they are essentially a slightly bored out 3400 with a new intake and head design. Later ones, like the one in the Uplander, are based on the larger 3900, and at this time are not all that compatible with 3400-based vehicles. So if you got your short block from, say, an '04 Malibu, I'd say you'd be all right, but if it came from an '06+ Impala or something it might not work.

[WrathOfSocrus]

He was making a rhetorical question; I got it from him lol. It is an LX9 bottom end. I just got the van here a little while ago and start tearing into it good tomorrow. I don't see it being that hard. I know the connectors at the back of the engine will be fun to reach. I should be able to drop the cradle with the engine and trans and have at it from there.

The crank trigger is going to make or break the swap. I can't do it without it. Luckily I can afford to take some time with it. I hope those things coming in soon, I will probably buy two so I wont have to wait next time around!

[Superdave]

not sure what mounting points you plan on using but several changed between the 3400 and the 3500.. not by much but just enough to be annoying.

[Erich]

what do you do about the cam sensor to keep it from going into limp mode?

[WrathOfSocrus]

In my search for a set of 3500 heads and a LIM I found a whole LZ4 3500 vvt for sale. Are the heads and LIM on that motor the same as the LX9? They have the whole motor for cheaper than I can find the individual heads and LIM pieces I need. Plus it is within driving distance. If I can use the parts from that motor I would be well on my way to getting this thing done.

I also really need to know approximately when the external crank triggers will be available. If anyone could give me an idea it would be a really big help!

[bszopi]

Nope, totally different beast. No swapping of any of the top-end components.

[Joseph Upson]

Nope, totally different beast. No swapping of any of the top-end components.

Actually that's not correct, the heads will bolt to the earlier block with a little overhang and the upper intake can be installed, baisically the engine would have to be setup to run the U-flow coolant path and you would have to make sure the valves clear the cylinder bore. I'm not sure how the slight offset of the combustion chamber may or may not affect the combustion process but unless I was like to or the source was mistaken it has been done by an individual who apparently works for GM and purchased a crate 3900 dirt cheap intent on swapping it into his non VVT 3500 car only to find that it was more trouble than it was worth.

He purportedly swapped the top end and gave the short block to the guy on the Fiero forum that told me the story. For authenticity, a thread regarding the swap consideration had been started weeks before the actual end result.

Also I sat the 3900 heads on a 3.4L block and they sit in the proper location at least as far as I could tell to allow the upper half of the motor to be installed and bolted down.

[bszopi]

Ok, well then... To sum up your thread and include my opinion...

more trouble than it was worth

[WrathOfSocrus]

Cool, good to know. If I didn't have time and money constraints I would probably pick it up for how cheap it was. But I will just have to order the heads and LIM from a reasonably local used parts dealer.

I spent most of my time fixing other vehicles so far this week and building a carport for the van. It's up in the air and I am trying to take as many pictures as possible to aid in reassembly. Luckily there is tons of room inside the van so I wont have to go far with the parts.

I still have to make a crate to hold the old motor and start ordering the parts/gaskets I need. And a longer chain, I just barely got my Cutlass over the subframe and trans last time around. The chain was short and the car was about to run into the hoist lol.

Plus the oil had been leaking into the coolant and I have to somehow degrease and flush the radiator out really good. I have a bunch of parts to look over and see what can be done to fix or replace them. A tie rod broke in the driveway a while ago and tore the boot to the steering rack. A few other odds and ends. I'll post back when I have some real progress made. Thanks again for all the help!

[CNCguy]

I also really need to know approximately when the external crank triggers will be available. If anyone could give me an idea it would be a really big help!

External triggers have been shipped and will be in stock later today.

[WrathOfSocrus]

That is some of the best news I have heard in a while! Thanks a ton! I'll be sure to order mine as soon as possible!

[WrathOfSocrus]

Alright things have gone pretty good so far, for the van at least. I have a bad back and messed it up pretty good the other night. I destroyed a disk and every once in a while little pieces go where they aren't supposed to.

However the drivetrain came out WAY WAY WAY easier than I expected. There wasn't a single wire or bolt that was too hard to get at while it was in the van. The only thing that gave any resistance was trying to lift the power steering pump out of the hole on top of the engine. The metal lines hang up easy and the pump hits the fuel rail. I just left the whole steering assembly attached to the subframe and removed it after it was sitting in front of the van.

Guess I need to go to the dealership and pick up a gasket kit. I have looked online and the only kits I see seem entirely too cheap. Head gaskets in a $30 kit are probably not the best quality.

I'll have to get some studs as two of them broke taking the front exhaust manifold out. My '89 Cutlass with similar mileage had no breaks but this thing had two hahahah.

I got all of my parts in almost. The crank trigger came in fast (THANK YOU!) and my heads look great aside from the way they were tossed in the box. It was covered in about 4 trees worth of paper so they survived the trip. They came with a few extra bolts, coolant sensor, basically whatever would have caused extra work to remove was left behind. I wont complain at all. The only part I'm missing now is a LIM. If I can't find one this weekend I will have to order a ported one from the store.

I'd like to give a big thanks to all the people who contribute to this site. I wouldn't have tried grabbing anything other than a direct replacement for the van if I didn't have a place to go and learn what I needed. Heck if I wasn't so slow this swap would be about done by now. I'm gonna take it easy and let my back heal up this weekend and focus on cleaning. The cooling system had tons of oil get into it from the old engine and an oil pan leak destroyed the lower motor mount. Once I start getting things together I'll get some pics up!

[WrathOfSocrus]

I have some conflicting pushrod measurements that need clarification. I went to Advance Auto's website and looked for some parts they might have instead of going to the dealer. I'm definitely getting my head gaskets from the dealership but I figured I could get away with regular aftermarket parts for the other few things I need to finish this project.

According to their website the intake pushrod length for the LX9 is 5.746" overall. Under the specifications here it says the length is 5.67". It also has the same numbers for the 3400 the van came with. I didn't see a length listed for the 3400 here.

Should I test out the ones from Advance or should I just get ones from the dealer? This is just a bone stock 3500 build to replace a tired 3400. I guess I can take the rods out of the old engine and test fit them to see if they are close, but with 199K miles on them I'm sure they will measure out a tiny bit short. Can anyone tell me if the 3400 and 3500 rods are the same length and perhaps give me an actual measurement of the stock rods?

On a side note it looks like my accessory drive and front engine mount will fit with minor modification. It appears that the two upper A/C bolt bosses in the 3500 protrude from the block about a 1/4" more than the 3400. Hopefully I can take that much out of the mount I have without weakening it. I could take it off the block but I figure it would be cheaper to replace a messed up mount than a messed up block!