trading out 3400 in van?

[90210GTP]

I just had my camshaft break on my '98 Montana 3400. I tore the motor down to see about replacing the camshaft, but found it was running into too much time and money to continue. This is my wifes daily driver, and right now we are carpooling, screwing up both our schedules. Any way, I found a good deal on a 05' impala 3400 and was going to jump on it. The junk yard did not want to do the deal at first, because they said the engine was not compatable, but after initial research, I felt the 3400 was the same block from 96' on and I could just change over any brackets that didn't match up. I've since learned on this site and others that there were some changes through the years. I found that the cam sensor is different, but can have the harness spliced with van's, so no problem. The crank sensor seems to be the same for both. I just wanted any input as to whether I am missing anything on what would make this swap a problem. I just need to know if I can go with the newer motor without any unforseen major problems or extra costs that I don't know enough about. Thanks for any ideas.

[bszopi]

First off, welcome to the site!

Next, don't worry about the cam sensor, as the output of the sensor is the same regardless, so the PCM won't see any differences. As far as other issues, as long as you have the old engine, anything can swap over between them. Things that come to mind are possibly the timing cover, as bracket mounting and belt routing may be different between the 2 engines. I would recommend changing out the lower intake manifold gaskets (with the Fel-Pro or Dorman metal gaskets) on the new engine prior to installation just for piece of mind. These are the biggest issue for these engines, so better to do it while its easy than having to tear the engine down in the car in the future.

[90210GTP]

I already have all gaskets for mine. I pulled everything down to the block to check things out and also so I could pull the engine out of the top (I really hate vans). I assumed I would tear down the new motor the same way, and then reassembly would be consistent with how I removed them. So do the cam sensors use the same plugs, or will I need to splice? I figure the motor will come with all the wiring connectors cut off where ever, as other junk yard pulls have been so I will have the new style connector if needed. Thanks for the info. I'm glad to know I can go forward with this.

[pocket-rocket]

Welcome to the site! The plugs should be the same, the only thing I can think of being different between sensors from what I've experienced with the 3x00s is pigtail length, but it's only 1 8mm bolt holding that sucker in there. I second everything Brad said, but can offer up a little more info. I've worked on a 99 TranSport doing pretty much a rebuild on it, and yeah, the engine can come out the top. It's really tight and there will be some scraping, but I pulled an engine minus the upper intake and alternator out the top, and it went back in the same way too. I've also done the same type of van by dropping the cradle and trans, assembling the engine/trans on the floor, set engine/trans assembly on the cradle on the legs of the hoist, removed the strut/knuckle assembly on the passenger side (I had more room on that side of my garage), lifted the body enough to slide the engine/trans/cradle in through the side by using the wheels on the hoist, then used the hoist to pull the engine/trans/cradle up to the body to bolt the cradle back in. This way actually went really smooth thanks to my load leveler. Hope this helps

PS, the only other thing I can think of is some heads (forgot the year) came with AIR injection ports in them, but there's been a member on here that found the thread size/pitch and stuck a bolt in it and ground it down with a die grinder flush with the exhaust port floor to get around the difference.

[bszopi]

Connector is the same, so your harness will plug right in. No splicing necessary.

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[pocket-rocket]

To clarify what I'm talking about on pigtail length, I think one is around 10" long and the other is around 15" on the cam sensor, so if you have one around 15" you should be good either way.

[90210GTP]

Thanks to all. I'll definetly go with it. Also, I had thought to try to fit it back in without messing with the heads, since I assume the 05 headgaskets were done right from the factory. or not ??? That way I use the new upper/lower intake and valve cover gaskets. I know I could drop the cradle, but I don't think I have what it takes to roll the whole assy back under the van. Either way, it will be the same or less work as I've got into it now. I spent 2 1/2 days so far getting it down to everything but pulling pistons out. The guy didn't say anything about a core, so maybe I can part somethings or recycle for scap pricings. Thanks for all the help, and keep any other tips coming.

[90210GTP]

PS, the only other thing I can think of is some heads (forgot the year) came with AIR injection ports in them, but there's been a member on here that found the thread size/pitch and stuck a bolt in it and ground it down with a die grinder flush with the exhaust port floor to get around the difference.

Thanks, I'll be sure and check for those.

[bob442]

If anything you can just change the cam sensor with the one 8mm bolt like Jon said, the only difference is length, and i would not reccoment splicing those wires as they are some sort of silver or hard metal, making soldering impossible.
Timing covers will possibly be different as said by Brad, manifolds might change and O2 sensors might aswell. the fuel injector harness will most likely be different, but you'll be right in there anyways. Upper and lower intakes will be slightly different with heater core line connection and upper intake EGR. if you wanted to use the new lower intake you can simply tap out that hole with the proper tap, its already sized to the tap required to use the old push and lock heater core line. That is if its different.

Bottom line, the blocks are identical, just small bolt on changes are different so look over everything twice before you install the motor.

Bob

[90210GTP]

More helpful advice. I'll definitely make a point to check everything twice before installing. I need this thing running yesterday.

Also, Just finalized purchase for $500. It's being shipped Mon or Tue, once I can finalize a commercial drop off point. It's too late to turn back now.

[90210GTP]

Well, I got the motor Fri night after work. Spent all day Sat. swapping out parts between the two. It took a lot of comparing, more because my engine was tore down basically to the block. But I stuck with the new motors block, heads, LIM, valve covers, and oil pan. So far I have it about half re-installed. One small thing I missed was a sensor in the bottom of the oil pan (not sure what it is). The new pan has the mold for the sensor, but it was not drilled out. I'll deal with that later. The big thing was the compressor bolts. I had read how some had trouble with the bolts on the 3500 being a little off on the bottom bolt. I fooled around and got the bottom started, although with a lot of pressure on the bolt, but once I got all three started I thought I was home free. NO!! not by a long shot. All of a sudden I heard a strange hissing sound and soon saw green oil bubbling and dripping from around the compressor. Obviously the pressure from the bolts stressed the casing and cracked the compressor somewhere. So yet another expense I was not planning on. A word of caution to anyone dealing with the compressor holes not lining up between models or years. It will be a costly lesson for me. More when I get everything on and running.

[pocket-rocket]

Doh! That sucks. As for the sensor in the bottom of the pan, that's the low oil warning sensor. It's almost useless anyways, since by the time it gets low enough to trip the light I'm sure your bearings and lifters will have already let you know the level is down.

[bszopi]

Wow, that is crazy! I've never heard of a compressor casing cracking!! But I am a little confused... In the original post, you talked about getting a 3400 from a 05 Impala. In your most recent post, you referenced the compressor bolt holes being slightly off on a 3500. So, did you get a 3500 or a 3400? There shouldn't be any differences in the compressor bosses between 3400s, at least that I've ever seen or heard about.

[bob442]

Wow, that is crazy! I've never heard of a compressor casing cracking!! But I am a little confused... In the original post, you talked about getting a 3400 from a 05 Impala. In your most recent post, you referenced the compressor bolt holes being slightly off on a 3500. So, did you get a 3500 or a 3400? There shouldn't be any differences in the compressor bosses between 3400s, at least that I've ever seen or heard about.

i was kinda confused with that too...

[WrathOfSocrus]

Rock auto shows the parts interchange ending in 2003 and a different number for some '04-'06 applications. It appears to be a physically bigger unit. If your old one is cracked now, then you may need to upgrade to the newer unit. From the pics it looks like the same connection for the refrigerant lines but mounted on the side instead of the top. If you have a short van with a single evaporator then you should be able to snag the newer line. If you have front and rear A/C then you may need to make your existing line work.

I wonder if this larger unit is a direct bolt-on for 3500 swaps.

EDIT - If you have front and rear A/C and can't make the lines work you may have to use your old oil pan in order to bolt on the older style compressor. If you could take some measurements of the mounting boss, specifically from where the pan meets the block down to the center of the bolt hole, it would be very useful for anyone in the future making this swap. A pic with a ruler up next to it would be even better!