Hey The_Maniac

Still working on my car, I have injuries that limit how much I can do, plus I moved over to polishing Aluminum Valve Covers I got and the L26 upper.

I just plugged my coolant ports on the LIM with brass plugs, pretty much looks like yours and I was about to open up the coolant return area near the Thermostat just as you did in your project at:
'04 Monte Carlo SS - Port Matched LIM

But I looked over that U-Tun area and got to thinking. Its a normally closed path because it leads to the thermostat, so coolant only flows thru the U-Turn and thus the TB as well when the thermostat is open.

Here's is a clip from what you said there:

"The big concern some people have about blocking those ports on the L36 is that in the winter you may experience the throttle plate freezing/sticking in place. I know we can have some bad winters, but I know my current Grand Am (3100, so it's NOT the 3800 L36 my Monte has) does not heat the throttle body at all. I've also heard some speculation that heating the throttle body has something to do with fuel efficiency. I'm not sure, so I am admittedly taking a bit of a gamble."

Yes coolant will defrost the TB like you said people believe but when you start up the car the coolant is cold as the arctic (was going to say hell) so that isn't going to warm up the TB, most people are long gone before the coolant and TB are even 100 F but I'd think engine heat would do that just as well.

The thought of not running coolant thru the TB would improve gas mileage would be because the air is cooler, thts better for HP but I'm not sure about mileage.

I read in the Theory of Ops section in my AllData subscription is that the cooling system in the TB is there to KEEP IT COOL !!! Perhaps due to heat from the crossover pipe?

Wow, I wouldn't have suspected that, wish I read that before I JB welded my tapped plugs into the coolant ports in the LIM.

My thought was removing the coolant from the TB would help keep it cooler as 200 F plus water isn't heating it, but think about it, it gets heat transferred to it from the UIM and now that I have an L26 aluminum UIM there its much more efficient at transferring heat then the plastic L36 UIM.

So back to getting to my original point. From the GM theory of ops the thermostat intentional creates a restriction by just opening a bit. This restriction creates a pressure difference which prevents cavitation at the water pump and forces coolant to circulate through the engine block. So anyone who thinks they are keeping their engine cooler by removing the thermostat..NOT..you are bypassing coolant from the block.

Anyway seeing how this is such a restricted area I thought do I really need to open this U-Turn area up as you did. I mean that with alot of respect because you have done great work and helped alot of us. IT does seem to be a logical conclusion to open it. You certainly didn't hurt anything and you mentioned the loss of flow from TB being blocked, but the coolant lines are so small in the TB I can't imagine that's very much of a loss.

Anyway just a thought on that and I thought the info about the thermostat design is interesting information. Thats a reason why we shouldn't try to out think Engineers at GM who designed a system a certain way. Which I just did by blocking the coolant ports.

I'm on the fence now about opening that area up, but it couldn't hurt as I'm sure the thermostat is by far the limiting component to flow in that area. But it would be fun tearing up metal !!!!! Thats for sure !!

If anything I'm a bit worried that my TB will be over heated. I'm going to keep tabs on the temperature and place a thermocouple on it. I suppose I could rig a fan to blow on it to keep it very cool. That would be a neat mod.

 

Did you pick up F-body aluminum valve covers to polish?

Interesting finds from your research. I have never heard the theory that the coolant is to cool the throttle body. I still wonder a little about that, since it's a small pocket of coolant, granted it is at the base of the throttle body (so I suppose the goal is to move the heat from the cross over as you mentioned). I am not 100% sure, but I want to say somewhere people have done heat tests on the concept.

And I agree 100%, the aluminum UIM is a better conductor of heat then the plastic UIM, but I think that would probably work to the benefit of the car (that and not running the engine cover).

Since I did this write up (and others on these topics), I can share some other input (and it may put your mind at easy). Not long after I did the port matched LIM, which included plugging the coolant ports and expanding that bypass, my father had a '98 Grand Prix with a L36 in it. The car had seen better days and had reached a point where it was now "how cheap can it be kept on the road". Well, he had to change the LIM gaskets. During that time, found that a pin hole leak between a coolant passage on the plastic UIM was now leaking coolant into the intake by way of the EGR stove pipe. Again, name of the game was keeping it on the road cheap and he did not want to spend money on a new UIM (this was before I did the L26 swap on mine). I recommended we plug those ports on the LIM. So, with the LIM in place, he used brass plugs like you did. He did not expand the coolant bypass to accommodate that change (left it alone). Good news, no more leak. Better news, he never noticed any changes in MPG as a result (and even if there was a change in HP, it would be so minor, you would not notice it).
My guy feeling was that I had no real need to expand that coolant bypass, but as you said, it was not going to hurt anything. When I plugged my LIM ports, I did it with two ideas in mind. The first was to stop adding heat to the throttle body. The second, since I did not have the L26 UIM plan at the time, avoid the common UIM failure.
When you mentioned the narrow passages and they should not really affect anything, you do not know how true that is. At some point shortly after the L26 swap, when I was looking over my old plastic UIM (which is genuine GM from the factory), I was looking at those coolant ports. The casting on them is CRAZY poor. The one is 50% obstructed by plastic casting material, and it's thick enough that I cannot just chip it out with a metal pick!! I left it as is. Seeing that really brought home how much overkill expanding that coolant bypass was.

But I can tell you this. Between that and what is commonly considered a "Series III" water pump (has a nice cast aluminum impeller, the factory Series II pumps are 99% of the time stamped steel impellers), my car never runs close to too hot. It does hit operating temp, but it's never exceeded that as best I can recall.

BTW - Some guys in in the Bonneville world that deal more with the L67 and the superchargers did some heat testing. They found that if you properly wrinkle paint things like the supercharger housing and/or valve covers, because of the wrinkles, the paint provides more surface area to better radiate heat off the parts. Something I found interesting.

I know this was a bit long winded, but I hope it helps. Some of the things I've done were (for me) experiments at the time and I think each one was a success (even if some were overkill).

 

Yep I got the F body valve covers from a 97 camaro, all the way at the end of a very large graveyard of former hot running cars, the guy pointed at them and told me I'm lucky cause one still has a gasket. I didn't bother to say what I was thinking about that statement.

I've been sanding down the sand casting marks on the top stripes and alot of many other imperfections on it. I can now see the hell you must of went thru to sand down everything you did as this pales to what you did, although I'm still have the L26 to finish sanding down. But just going over them with a long narrow wire cup bush made them look shiny enough to pop on, but I'll polish them well.

Yeah I thought it was weird that it said the coolants purpose was to cool the throttle body, how could it do that with a 1/8th to 3/16ths coolant passage way?

Glad I put in the plugs on the LIM, I will never worry about coolant leaking again. There was alot more metal to grab onto then I thought, they fit tight.

I'm going to port out that bad bump on my UIM after I put the LIM back in, we'll see if I break into the PCV tube, I'll post pictures. Still debating the HV3 insert but if I spend another dollar my wife will kill me, unless I buy her something...mhhh that could work.

I asked ZZP if I could get the HV3 without the gasket as I already had a felpro one, they said their gasket was modified and needed. Did you note any difference in the UIM gasket for the HV3.

I also asked them about performance across the low RPM, they stated "You will have the same performance under about 4.5K rpm. after that, instead of falling on its face, it will continue to make peak power until after 6k". That answer is about 2 weeks or so old so for all those out there who wonder, there you go.

I'd like to port my LIM but I'd need to do same on the cylinder head covers as well , meaning I'd have to remove them, I just removed the rockers, push rods, guides and lifters to clean out the valley and cycl head covers of 120K or random gunk and put loctite 272 back on rocker bolts, to late to pull them now. Anything at all worth doing to the LIM runners?

Well I keep you posted on my bad UIM porting, I'm looking forward to doing that, will post some pics when done.

 

I believe the only difference in the gasket ZZP provides with the HV3 is that they cut the pieces used to hold a tube on the factory gasket. Remove those and the tube, as the tube cannot fit with the HV3 installed. That is something you can certainly do yourself (just have to make sure the pieces are cut flush to allow the gasket and HV3 to sit properly, overall, no big deal).


As for the aluminum F-body valve covers, I was lucky, someone polished up a set and clear coated them for a project they were doing and then had a change of heart, put them for sale. I got them for a little more then it would have cost me to get the covers from the junk yard! Cannot argue that! But the L26 UIM.... I did not go for a polished look, I wanted a brushed metal look (admittedly I thought it would be easier then polishing, and I'm sure it still is, but it was a PAINFUL amount of time spent, but I am VERY happy with the results).


As for the LIM and porting, there is some room for improvement! If you gasket match the ports, then as you mentioned, you have to do the same to the heads. I port matched mine (so they better line up with the heads) using information I got from the Bonneville guys and it seems to be be spot on (I did not mock the LIM with the heads, but I have checked the runners out by running a camera scope down them and they are dang close to spot on matched to the ports on the heads). I did this to my intake and one other (onces the intake is cleaned, I think I got the actual work down to 30-40 minutes a runner).
I have more information on the subject available here (as well as all the info about my other mods):


'04 Monte Carlo SS - Port Matched LIM


I did not polish the runners (in the pics, it may look like that). I wanted the entire runner to have the same basic texture that matches where I had to port match the thing (as I don't have a way of remaking that casting texture). I did not want to polish them under the concepts I got from the Bonneville guys. That concept is that you want to knock down high casting marks, but not polish/smooth the runner, as the texture helps influence the air to be turbulant going into the runner and down the head and that promotes mixing the air and fuel spray better, which in theory should result in a better BANG in the cylinder.


I found doing all this metal work a little addicting and a lot of fun. I wish I had a true way to prove it, but I swear after I did the L26 UIM swap, the car runs a lot better. Either I fixed something I did not know was broken (as the car ran great before the swap and to my knowledge nothing was broken/failing) or I changed something for the better with the UIM swap (perhaps what I felt were little changes really made a big improvement or maybe the extended snout changed the game somehow).


I'm curious how things pan out when you grind that opening larger, if you run into the PCV tube or not.

 

Maniac! Glad you replied, I wasn't going to gasket match the prots, way to much metal for me. I was thinking the runners on the heads needed to be cleaned up as well. I did see your project page for porting out the LIM ans was wondering why you didnt show the ports on the heads. Just looked at mine and see they are fine.

Got way to many chemicals sitting out on my bench here, I was cleaning out my fuel injectors yesterday using a secret chemical !!! I'll have to make that a separate post. Guess I inhaled to much.

So I may tackle this now and try porting out the LIM runners. So you left the inside surface still gritty sandy like and just knock down anything big, otherwise just leave the inside of runner surface as is except for the obvious that I need to grind away? I do see there are casting lines on each side high up near the top that run the length, although the top surface is not so long, thats the biggest mismatch I see in there except for the injector boss.

I just need to figure exactly how to know what and where to take off, I did see your measurement pictures. I 'm going to try dropping in the LIM and seeing what I can see. I'd have to get a flex usb camera, guess thats why you used. Or Just go little by little on the LIM and see when it lines up on the heads. The heads look a bit bowed out and wider in the middle.

I've got some time as I ordered a new coolant, IAT and oil pressure senor and need to wait for at least the coolant sensor to get here, don't have a problem but figured why not now, especially the oil pressure sensor, I've got the PS pump off now for bleeding out the system.

On you UIM, to get your brushed metal look was it just working down to finer sanding wheels, then leaving the ruff look. What did you use for the final finish look, rough 3M greenie like material?

If something ever comes up where you need FSM info let me know, I got all the detail here. They include the time needed for each job, telling us what we all ready new. The time for warranty repair job is X, the time for same customer work is 1.8x.

thanks Maniac

 

Take a look at the pages on my site from when I did the install of my port matched LIM and other mods a few years back. I actually took measurements on the heads to see if they matched my goals on the LIM:
http://crzyz28/mycars/2004montess/pr..._modding2.html
As for a camera, it was not until I did the L26 UIM swap that I had access to flexible camera (the one sold at Harbor Freight). I never thought to take pics with it, I was just curious and then moved on.

After I finished with the runners, most of that gritty look is gone. It's hard to describe, but I rapidly ran a variety of dremel de-burring bits in the runners. Got the high spots and as a result a new texture overall through the runner. FYI, if you never shopped for dremel stuff at WidgetSupply.com, I highly suggest it (great prices and lots of good stuff).

As for the brushed metal look, I never touched it was sand paper. It was a wide variety of tools. Wire wheels on the drill and on the dremel. A variety of sanding drums for the dremel (took some experimenting, but I found a grit that worked well for removing the rough texture and then another grit to finish it, I also used a drum down the valley of the "ribs" on the UIM so they had a unique texture after I finished everything else).
I also used different grits of what looks like a scotchbrite pad on small disc tool for my drill. I used a green scotchbrite pad by hand at one point near the end of the process.
It's been long enough that I don't recall what worked best, it was trial and error and make it up as I go along. Near the base and parts of the snout were a pain. In some cases, it's best to hit the tight nooks and crannies with tools that may not get the exact results, but it looks better then the original casting and gets hidden/blended by the larger areas hit with the better tools.

 

Got some new issues. After last message, I did a fit check and just placed the LIM in the bay without gaskets to see how the LIM runners and cylinder head runners would match. Its very visible, I didn't need a camera, with the exception of the LIM being a bit low due to no gaskets they looked incredibly well matched. I try tomorrow with the gaskets.

So I thought why not do a dry run and put in the UIM and TB and see what happens.

Well I found that my brake lines are in the way, the TB throttle and cruise cable bracket is blocked by one and the other line will block the cables even if I fixed the first. I looked back at you pictures and saw you mentioned you bent the lines. How did you do that? I would need to move both alot.

I have metal tubing coming out and up of the mstr cylndr that crimp to flex line that makes a U turn then back to crimp on metal tube for both the offending brake lines but I can't see how to bend it without breaking or kinking them.

I was thinking maybe running flex lines from the master cylinder and then adapting to metal tubes that are out of the way. I just need to find the right fittings. Doesn't look like a trivial thing, you just bent it ? L36 cable brkt must be different than L67. I can post pic tomorrow to this.

While trying this I put on the ZZP adapter plate to see how it lined up with the UIM remembering your pictures showing the steps. I see on your "finished setup picture" of the UIM, adapter plate and TB all put together you have hex bolts at the bottom holding the TB to UIM thru adapter where the long studs use to be. Did you get different bolts from what ZZP supplies. Their bolts did not fit in the small threaded holes on the adapter plate that the long studs go thru coming from the bottom of the UIM. Only the top peak threaded hole fit the threads. I thought I'd try to find bolts but the zzp adapter threads would have to be the same size as the UIM threads, I haven't pulled the studs out from the UIM yet. Plus the ZZP bolts would not be long enough for all that, so I'm guessing you got different bolts, remember what they are?

I knew I would have problems with the air box but the brake lines really surprised me and took some wind out of the sails.

I still have stock air box intend to keep it for now but that I can figure out a way to rotate it or something cause aint no way the TB is connecting to it as is now. Is that air dryer type tubing I see connecting your TB to the air tube? Good thought may need to do that?

Feel like I'm your number one project these days, thanks for all the help. -Don

 

Take another look at the heads vs the matching ports on the LIM. The heads are nice clean rectangles, the exist ports on the LIM are not. When you look down the runner, it looks like it matches, but there is room for improvement.

As for the brake lines, usually when I replace brake lines I can bend them by hand safely (no tubing benders or any special tools). So when when my lines were in the way (which was by the master cylinder) and they are very clean/rust free, I just gently bent them literally by hand (no tools, never even disconnected them). That was all I needed and I did not have to bend them much.

As far as the bracket for the L36 vs L67 to hold the throttle cables, to my knowledge they are the same. The bracket I am currently using was from the L67 throttle body.

So for the ZZP adapter plate. Remove the studs from the UIM. I do recall that the hols on the ZZP plate were not tapped all the way. I happened to have a tap set and re-tapped the holes all the way through. Outside of that, unless ZZP sent you the wrong hardware, my plate had no issues. To attach it to the UIM, the bolts enter the adapter plate and exist into the UIM (the heads of the allen key bolts are then sunk into the recessed area of the plate).

I did not use the bolts that came with the kit to hold the throttle body to the plate. I believe I got regular hex head bolts from the local hardware store (I wanted to limit where I used bolts that required odd ball tools). I got stainless bolts for the LIM and UIM from AlloyBoltz.com (they now have a kit for this):
https://alloyboltz.com/catalog/index...i042gnpeuebge7

 

Hey Maniac,

I'm disassembling my L36 TB. Saw your pictures but have a question about removing the throttle plate, associated springs and TPS sensor bar. Looks like I just need to remove 1 nut and 1 snap ring on the bracket side. But what about the TPS sensor bar under the TPS?

Will the plate and that cross bar assembly for TPS just release? Another big questions is alignment upon reassembling. Will the sensor bar, plate and cable spring mechanism line up nicely and I just tighten the nut, or is it keyed somehow to ensure the TPS sensor bar is in the correct position for the TPS sensor?

Right now my TPS cross bar is a bit ahead of my TPS sensor, meaning the TPS of the TB is 4.5K but when I put it back and align the senor holes to TB holes a little rotation on the TPS occurs and its now 4.25K.

I'm not worried about that, don't know if thats assembly slop on GM's side or intentional but is it a big problem to realign or is it keyed and fall into place. Did you have that condition.
Thanks -Don

 

It's been a while since I took one apart, but I believe most of what you explained is correct. The jam nut and c-clip hold the linkage and spring in place. And there are two torx screws that hold the throttle plate in, remove those and you should be able to wiggle the throttle plate out. Re-assembly of those parts is pretty easy, if I recall it all assembles pretty much one way.
FYI - If you are going for the half-shaft routine I did on mine, I had a junk throttle body I experimented with. I wanted to try and see if I could get screws that I could counter sink with the throttle plate (so the heads of the screws would be flush with the throttle plate). I failed at that idea. I could not get the plate to line up properly. I was tempted to use hex head bolts/screws after that, but opted to just use the original torx screws. I did use a dab of red loctite with those screws when I re-installed everything. Then I grinded the excess threads of the screws. Just make sure that you can rotate the plate as freely afterwards as you could before.

NOW, the shaft and the small bar for the TPS. That bar for the TPS does come out if you want the shaft out. You have to be careful, as you could bend that bar. I believe I used a pair of pliers and oriented the jaw of the pliers to force/push the bar out (hard to describe) and then I could grab it with some needle nose pliers and pull it out. Again, if you are half shafting that shaft, mark the sides so you know your limits where to cut. Once the TPS bar is out, use a hammer to tap/pound that shaft out.
You may or may not have the seal and bearings left in the throttle body. If so, I recommend putting some masking take to cover them while you are doing any metal work to the throttle body (avoid debris in there).

OH and I believe you mentioned a "dryer duct" used between my throttle body and CAI. That is actually a tube that came from ZZP with my Wizaird CAI. I believe it is a part silicon and it holds it's form very well. That is helpful considering the weird angle I have to use with it.