'06 3500 into 99 Malibu? What have I misssed?

[kerno]

Ahh, the wonders of a good forum! A week ago, I had very little knowledge of the 60 degree engines, but with the help of the knowledge I've gained here, I am now on a three legged point to do a swap!. So, I just picked up a very nice 99 Malibu LS with non running 3100. I now know why the engine cranking noise noise was so weird. Half the engine wanted to run and half could not. Talk about cylinder de-activation! Not a good cam design and I am glad to see solid ones are available.

Anyway, I got a great deal on a complete, low mile 3500 out of a 06 Buick Terraza. So, I spent several hours reading this forum to learn what I could about the swap. It looks like everything I need to do it is easily purchased and with the right pieces, it looks like the swap is pretty easy. Here's my list of what I think needs to be bought or done to make it work:

I'd like to buy the Wot-Tech 56 mm throttle body and their 3500 adapter plate to let me bolt the 3100's cable type TB to the late UIM. That would let me use the 3500 EGR solenoid and feed tube. The EGR connector looks identical and I'll need to use the early coil pack brackets, but other than that it looks like everything else up top will work just fine:

Question #1: I need to know if the 3100 fuel rail assy and injectors will bolt into the 3500 intake. If not, what's the fix?

I have the 3100 balancer and cover, timing cover, so that sensor problem is covered. I see that I can buy an external crank sensor to get around the problem of too many teeth on the 3500 crank.

The cam sensor problem can be solved by using the late sensor and making a jumper harness out of the original sensor lead and the harness that came on the 3500.

The 3100 oil pan has a level sensor in it and there is none on the 3500. The forum says the pans won't swap because of one bolt hole and the pan rail clearance for the rods. So:

Question #2: Any problem with chassis fit using the 3500 pan and bypassing the float by jumpering the sensor?

Some people have talked about a slight change in the location of the bolt holes for the mounting bracket that ties the front of the engine to the nose of the transaxle.

Question 3: Are there any other physical mounting problems I've missed, like the A/C pump?

In summary, it looks like an easy swap with a few purchased pieces. Is there anything else I ought to know before I start buying parts and bolting this mess back together? You can bet my order will also include a one piece cam as well.

[bszopi]

Welcome!

To answer your questions...
#1 - 3100 fuel rail should bolt in without any issues.
#2 - 3500 pan exterior dimensions are basically the exact same, so no fitment issues. I know people have bypassed the sensor, but you may also be able to drill and tap the pan for the sensor if you wanted to keep it.
#3 - Yes, there is an issue with the AC bracket as well. Goto the Pushrod Performance section, and there is a sticky thread for a 3500 swap. Do a search inside that thread for AC compressor and you should find the issues.

[kerno]

Excellent! I'll dig into the A/C pump problem, but other than that, the swap looks like an easy way to get more fun out of driving an otherwise sedate four door. I'm thinking about going up at least one step in cams to the 199/200 @.050 piece.

The sticky was a great source of info, even though it is 46 pages long. There's a lot to dig through, but it was worth the time and effort!

[SilverGAGT2002]

If you ever get this completed please post pics and video sounds like a bad ass swap! Good luck!

[kerno]

I ordered the cam, throttle body, external crank sensor and adapter today, so the project is moving forward.

[gar70614]

my 3500 timing cover had the mounts for the 24x under the balancer. i thought it was know all 3500s did and u only need a balancer with a timing ring like the one off ur 3100. but not the whole timing cover. the only mod i needed to use my timing cover was to cut off a mounting boss for a ideler pulley.

[kerno]

My 3500 cover has the mount holes also. It has a steel plate attached to the face of it about in the middle of the cover. Anyone know what it is for? It may be for sound dampening.....

[IsaacHayes]

No idea about the steel plate. Some said Rousch on them, but no one really knows WTF that meant...

[1988GTU]

All they are is a pita metal cover that you have to take off to use on certain models and it leaves a nasty sticky black goo on the tc.

Stupid manufactures.

[Weatheralls Auto]

Knowing how cheap engineers are, I am sure they had a reason for the plate, but I have no Idea what it would be for?

[kerno]

If the serpentine belt runs close to it, the plate might be there to avoid wearing through the cover if the belt wobbles or develops a harmonic.

[kerno]

Here's where we get reminded that the only "Bolt on" on we know of is the driver. Swaps are usually not without problems and this one has a couple to deal with.

The parts arrived from Wot-tech, so I assembled the engine last night. I was very impressed with Wot-techs products. Both the external cam sensor and the throttle body adapter are well engineered and beautifully made. I think they are a bargain at the price. I also ordered a stock pattern solid cam and was pleased to see that the solid cam had exactly the same cam sensor configuration as the 3100 cam. The 3500 cam is different in that instead of a notch, it has about half the diameter missing. Here are the two types of cams together. The one with the scored journals is the 3100:



Here's a shot of the external crank setup. The wheel mounts perfectly on the front of the balancer. FWIW, I live very close to the ocean, so a lot of the aluminum you'll see in this project is corroded and the block will look dirty and rusty. You need to leave the balancer bolt out to drop the engine into the chassis. The added length is too much to let the engine drop in.



Now we get to the problems. First the easy one and then the tough one. I had read that there is a problem with the A/C pump mounting when going from the 3100 pan to the 3500 pan. I can verify that problem. The boss on the 3500 pan is about 2mm too low on the wall and about 4mm too far away from the mounting boss on the pump. I am going to have to slot the pump and use washers under it or invent some other fix. Here's a shot from the side showing the gap between the pump and the pan. You can also see the vertical mis-alignment if you use your imagination:



And here's the one that stopped the project for the moment. The bracket on the right end of the transaxle should bolt to the block. There are even two sets of holes in the block, but the bracket does not come close. It is going to take welding and extending the bracket to fix the problem. The holes in the block are threaded, even though they don't look like it in the picture:

[pocket-rocket]

The difference in cam triggers is nothing to worry about. A minivan I worked on (more like rebuilt) with a 3400 is running with a 3500 cam in it with that same style trigger.

[kerno]

And now for today's problem.....

The 3100 LIM has a coolant temp sensor right by the water neck. It is in a 3/8 NPT hole. The 3500 LIM has a residual pad wher they changed the casting, but has no hole for the sensor. I can probably drill and tap a 3/8 NPT hole if I need to, but I'll bet someone else has found a way around the problem.

[bszopi]

Drilling and tapping is the easiest way to solve the problem. The 3500 went back to the temp sensor in the rear head, but it is a different size than the previous temp sensors, so you can't screw an older sensor in. And of course, the 3500 sensor reads differently than the older sensors, so you can't use the 3500 sensor either. A couple people had the older sensor turned down and rethreaded to fit in the head, but it took them a couple tries (and a couple wasted sensors) before it worked.