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  #81  
Old 05-22-2011, 05:39 PM
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ok so I will ask what is the reason behind doing this never seen or heard of this before
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  #82  
Old 05-23-2011, 12:42 PM
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Quote:
Originally Posted by entropy View Post
Wow, where to start! I've seen offroad-modified Novas before, but usually they are more the backwoods mud-bogging type based on truck chassis. In this case we're dealing with a 2x4 '80s racer. It looks like they kept the front subframe, adding long lower arms and doing who-knows-what for the uppers. The number of shocks and the mounting is... um... interesting? I guess it's appropriate to the period. I am not a purist - I actually like vintage car-bodied 4x4s, but I've only seen a couple cases where the execution was accepetable. It's not something I would ever do to my car.

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Originally Posted by camaro 77 View Post
ok so I will ask what is the reason behind doing this never seen or heard of this before
Lowering the UCA frame-side pivot on the 1st gen Camaro / 3rd gen Nova increases the rate of camber gain on bump, which can be beneficial for cornering. After this modification the tire will lean inward at the top on compression, better following the angle of the pavement when the car rolls in a corner and also generating camber thrust. The dimensions I'm using are from Dick Guldstrand and this is commonly referred to as the "Guldstrand mod". Volumes of information exist on the net for this and it's effect on suspension geometry. I recommend doing a search or checking out www.pozziracing.com for info. The method I'm using is an alternative to simply redrilling the holes lower on the UCA tower. The redrill method is much easier to do and produces exactly the same suspension geometry and performance. When using aftermarket tubular arms, it also allows you to retain the original hole locations - unfortunately not an option with stock arms because for them to clear you must trim off the portion of the tower that has the holes. I chose to do this the hard way by cutting and rewelding everything into new positions. One of the reasons I am doing this is to maintain a flat surface for the alignment shims. When using the redrill method, the new hole locations are on a contoured portion of the metal, so the first shims must be trimmed to sit flat and this is not ideal for mounting. I also feel the cut & weld method produces a cleaner result. It gives me an excuse to play with metal.
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  #83  
Old 07-11-2011, 01:23 AM
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Here's some evidence that I've been doing more than just changing diapers laterly.

Driver's side Guldstrand mod cutting & fitting:









I was very happy with the fit on everything on this side and it went much faster than the passenger side. Much less head scratching and more just working to get it done. Here it is welded up. Even after all these years, they're still not OFN quality welds, but I will keep praticing!





Both sides complete. Feels good to have that out of the way!



I also made some progress on my driver's side adapter. First I roughed out the shape:



Then I added the pocket to clear the indent on the motor mount



Then counterbored the four mounting holes.



Then drilling a few more holes, tapping the 3/8-16s for the old style SBC mounts, and clearancing the lower back side around the oil gallies and bosses that protrude from the side of the block.



Here is the matching passenger side that I did a few months ago. I still need to pick up the rest of the socket head cap screws; hardware store was out last time I went.



Next I ground down the "humps" that are formed into the engine frame stands. These cause interferance with the mounts when flipped upside down. I am not yet sure if I'll reinforce under these. I took away a good deal of material, but I don't suspect it will be an issue. You can see one mount with the hump ground away against an unmodified mount on the right.





Finally I attached the two engine frame stands to the frame, along with the upper control arms. Kinda neat to see things coming back together, but they will need to be torn back apart for paint later.



I ordered Dougs D3337 headers last week and hope to see them any day. Once they arrive, I'll check fitment around the mount adapters. Then I'd like to do a trial fit of the engine to make sure the mounts, oil pan and the headers are going to fit with this revised engine placement. It will also help me map out where the frame notches need to go for the low mount ac & alternator.
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Last edited by TheBandit; 07-13-2011 at 12:30 PM.
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  #84  
Old 07-15-2011, 10:26 AM
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Here are some pictures of the Dougs D3337 swap headers mounted finger-tight to the engine. Engine fitment looks great. I haven't tried putting in the starter, but I don't anticipate any problems there. Plug access looks good. Overall the quality of the headers is very good and the finish excellent, but equal length they certainly are not! They do not come with collector flanges either.





The area around my thick adapter plates was my biggest concern. Here you can see it clears the #1 and #3 primaries.





More progress hopefully to come this weekend. In the meantime here is a bit of nostalgia to enjoy. First picture is me porting my old iron small block heads circa 1998 when I was in high school. The girl near me is my then highschool girlfriend who came over to help out. You might recognize her from other pictures in the thread - today she's my wife!



Here is another picture for the history books; the old small block in roughly the same state as the new engine, just after I received my Dynomax ceramic coated headers. Oh the good old days!



And can you believe this is the same subframe that I've been "hacking" up lately? Used to be so purdy.



Okay enough fun for now...
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  #85  
Old 07-20-2011, 01:13 PM
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Unfortunately my plans for test fitting the engine this past weekend didn't go through. Mrs TheBandit kept me busy doing yardwork all weekend, clearing flower beds, digging trenches, and hauling off old plants. We're getting ready for our son's first birthday party next month and she wants the yard to be perfect for the BBQ.

I did get a little time in the garage on monday and decided to map out the camber curve after doing the Guldstrand mod. Here are my results:



Here is how I measured:
- "Anglecube" digital angle finder (+/-0.1deg repetability) on the brake rotor
- tape measure to nearest 1/16th from the floor to a mark on the center of the wheel bearing cap
- cycle suspension with a jack, move to a new position and measure, repeat
- 0 determined by measuring the position where the LBJ is approximately 3/8" below the average position of the front and rear bolts of the LCA frame pivots
- data includes 3 cycles completely up and down with approximately even spacing between measurements to collect a locus of points
- max and min ride are where the bumpstops just made contact with the frame; there is likely a little more travel available as these get compressed
- frame supported by jackstands, suspension assembled and tight, approximately steered straight





It is interesting data, though I'm not sure yet what to make of it yet. I have been surfing the net hoping to find curves of other vehicles to compare, but haven't found much yet. There is a linear portion of the curve around estimated ride height with a camber gain of about 0.5deg for the first inch of bump. Beyond about 1.5" of droop the curve flattens out and even hooks back. I'm not sure what portion of this curve I'll be using most of the time after going to stiffer springs, bigger swaybar and good shocks. The camber curve is just one piece of whole suspension puzzle that I'm trying to put together - we'll see where I end up.
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Last edited by TheBandit; 07-20-2011 at 01:18 PM.
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  #86  
Old 07-20-2011, 02:00 PM
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Nice work!

I would think you're going to end up staying in the "linear" part of that camber curve for the most part, especially with stiffer springs and better shocks. I'm sort of surprised there's only 2" or so of travel before getting to the bump stops. It looks like you're getting about 1/2 deg or a little more camber gain per inch of wheel travel, which I think is a pretty reasonable compromise between ride and roll. You're helping yourself with the stiffer springs and bigger bar (the car won't roll as much), in addition to the more favorable camber curve.

What you're seeing on the droop side of the curve isn't unusual. Suspension design is such a compromise that you can only really control the camber curve for a certain part of the travel and maintain the other characteristics you're looking for. Usually, it's the droop portion of the curve that is compromised, because at that point the tire isn't really loaded, so it really doesn't have too much of a detrimental effect on grip.

I would be interested to see what this did to your bump steer, if anything. When you get to that point, if you find you need corrections, Howe Racing in Michigan makes some very nice tie rod ends and ball joints that have optional stud lengths (in 0.100" increments) to adjust geometry.


Last edited by Graham08; 07-20-2011 at 02:03 PM.
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  #87  
Old 07-20-2011, 02:42 PM
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Thanks for the feedback Graham. It's really hard to get good information on this stuff and you seem to be very knowledgeable on these things.

I do hope to stay in that linear region, but I don't know where my ride height is going to end up. I wish I had measured some things before I started taking the car apart so I'd at least have an idea of where I was at before. What I'm calling zero in that graph is merely a guess based on a suggestion that the LBJ should be slightly below the frame pivot for "optimal" position. Optimal for what, I don't know. That came from a phone conversation with Marcus Svetiski, author of the SA design book "How to make your musclecar handle". I have adjustable coil spacers (AFCO "hidden" type) for targetting ride height, but I have to be honest the decision will be weighted more by the stance of the car (aesthetics) and streetability (ground & tire clearance) than the suspension performance.

Do you have any feel for the rate of camber change in that linear region? Should I be looking for more or is this a good starting point? Marcus suggested that even with moving the UCA pivot, I should use a slightly taller UBJ to increase the rate of camber change, but he also said I would see around 0.1deg/in from bump whereas I'm seeing a little over 0.5deg/in. He said I should target around 0.75-0.8deg/in. I don't want to get too aggressive with camber change since I imagine it will be detremental to straight-line braking performance.

I've been told that lowering the UCA pivot doesn't have a strong effect on bumpsteer. That makes sense geometricaly since the spindle & tie rod positions don't move much with this change. However excessive bumpsteer is a noted issue in the stock suspension design. I may go to a taller TRE to help, but I'd like to make sure I have a problem first before I start trying to correct things. Do you have any suggestions for measuring the bumpsteer? Should I cycle the supension and measure from say the edge of the rotor to a fixed position on the frame?

Regarding the ~2" of uptravel, that is based on the bumpstop just making contact with the frame. It has a good deal of compression before it really bottoms; there is probably another 1" of wheel travel available while the bump is still in it's softer portion of the compression. Some people go to lower profile bumpstops in this application, but I was thinking something more like a progressive bump would be good to keep from upsetting the tires.

I haven't talked caster at all, but I'd like to get more. The stock UCA limits the range of adjustment, so I may need to go to a tubular or adjustable arm. Right now I should be able to get a max of around 3deg static caster whereas with aftermarket arms this could be increased to around 6deg, maybe more. I don't know what my caster curve is; I would be interested to know if increased caster on bump is a good thing.

I chose a 600lb/in spring which is significantly stiffer than the stock ~325lb/in rate, but still a little bit softer than what the "hardcore" autocrossers like to run (650-750lb/in seems common). A good ride is one of my considerations and I don't want to go overboard with this. I calculated a ride frequency of about 1.9hz with these springs vs. about 1.4hz with the stock springs. I'll be using a 1-1/8" OD hollow tube swaybar. The stock bar was a tiny 11/16" solid bar. This should be about 5 to 6 times the roll stiffness. Shocks will be Bilstein with valving selected by Hotchkis specifically for this spring rate and application.

I haven't addressed the rear suspension at all yet, but it's going to need some changes to complement the front. At a minimum I'd like to put an adjustable sway bar back there so I can attempt to balance the car, but springs and shocks should also be part of the equation.

It amazes me how complex and interdependent a vehicle's suspension system can be. It's not the sort of thing where you just "upgrade" one piece - you really have to balance a whole chain of parameters and there are always compromises. I find it all very interesting.
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Last edited by TheBandit; 07-20-2011 at 02:48 PM.
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  #88  
Old 07-20-2011, 03:44 PM
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Thanks for the compliment. This is what I do for a living, so I'm glad I at least sound like I know what I'm doing.

I know what you mean about your ride height. That's going to be affected by both the height of the chassis off the ground and tire diameter. The arm angles look pretty reasonable at your "zero" position, so you're probably close. If you think you're going to run the car much lower, I would repeat the exercise with the bump stops removed to make sure the camber curve doesn't get too nonlinear. I doubt you're going to end up very much higher than your zero.

As far as camber gain, I would run what you have now. My philosophy on this is I would rather have a slightly slower camber gain and control body roll than to try to compensate for camber loss in roll with suspension geometry. In the end, you're going to have to adjust static camber to see what settings work best for your tires on your car. You're right about braking performance, too. Less camber is nearly always better for tire performance in braking because you have more footprint in contact with the road.

In regards to measuring bump steer, top level NASCAR teams still use a fixture similar to that illustrated by Carroll Smith in Tune to Win. It's a flat plate that bolts on in place of the wheel, with lines marking zero travel, 1", 2", etc. There is a stand on the ground with two dial indicators that ride against the plate, and are zeroed at zero travel. The suspension is cycled with a jack under the lower ball joint, springs out. The pictures in the book do a much better job of describing it.

I think you're right that you probably didn't affect bump steer much with your mods. It would be interesting to know what it is, and try to minimize it.

I would try to max out caster with the stock arms before getting too crazy with it. I would concentrate on making it the same side-to-side. You have power steering, right? Big caster is going to increase steering effort noticeably if you don't.

I would bet your caster change is pretty minimal because the axes of the upper and lower control arms are close to parallel. NASCAR front ends have the rear leg of the lower control arm splayed out at approximately 30 deg to the vehicle centerline, so they have built-in caster loss, which isn't good. I would try to keep the caster curve pretty linear since it has a big effect on steering feel.

I think you're definitely going to have to do something in the back, too. I'm guessing you're going to have pretty strong understeer to start out since you have stiffer front springs, and a stiffer front bar. A rear bar would be a good start. That has leaf springs in the back, right? If they're stock, you may want to look into aftermarket springs with a stiffer rate. Another option would be to add a Panhard rod to raise the rear roll center, but I would try to work with the springs first, since stiffer springs will also help combat wheel hop. Carroll Smith also talks about this stuff in Tune to Win. BTW, that, and Prepare to Win, are two of my favorite references even though they're nearly 40 years old. At least 90% of the information is still relevant today.

I think that may be my longest post ever here. No pictures, even.
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  #89  
Old 07-20-2011, 04:49 PM
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How I managed to ellicit your longest reply ever is beyond me, but I hope I can figure out how to do it again since it seems like you do nothing but spout great info . My biggest challenge has always been knowing what questions to ask so it's very helpful when you volunteer input outside the rhelm of what I've considered. Thank you! You say this is what you do for a living; what exactly do you do? I suppose I should know after spending years on OFN now - sorry if I've missed it.

I'm embarassed to say I have neither of the two books you mentioned, though I have looked at Tune to Win several times and always wanted to pick up my own copy. I don't have Marcus's book either. I do have a very well laid out set of lecture notes from my ground vehicle design course and it's a phenominal resource.

I have been considering a set of adjustable control arms like these to allow a wider range of static caster & camber adjustment. I'm not really sure what to think of them since anything you adjust here also affects the effective arm length. Perhaps over the adjustment range that isn't a big deal. What do you think?



I do have power steering and plan to keep it, so steering effort should still be okay. A faster ratio box is also on my wish list, but probably not for a long while.

I am completely with you on the rearend. It is not going to balance with the front at all and I fully expect understeer. I also have a very narrow, tall sidewall tire up front: 215/60R15. I wish I could do everything at once, but budget and time wont allow so I'll have to ease into it
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  #90  
Old 07-20-2011, 05:14 PM
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I work for a company called Stackpole Engineering Services, our website is here: www.stackpoleengineering.com. Our specialty is vehicle dynamics simulation and software. I write a lot of the physics and solvers behind our products. Currently we're contracted with Ford Racing to support their NASCAR efforts, but we also do work with other companies in the Automotive, Tire, and Defense industries.

Those arms are okay. I'm not real wild about them because they're heavier and less stiff than a simple welded tube arm. I would be more in favor of a NASCAR-style upper. On those, the cross shaft is slotted to take a "slug" for caster adjustment, and camber is done by shimming between the cross shaft and the mounting plate on the car. The tubular part of the arm is welded solid...no adjustment.

Here's a link to something similar to what I'm talking about:

http://www.joesracing.com/index.php?...roduct_id=1085

I'm glad to be of some assistance...
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Old 07-23-2011, 03:22 AM
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Tonight after my son went to bed, I went to the garage and finally had some intimate time with a hoist and an LSx engine.







I couldn't imagine a smoother drop in. The spacing on the motor mounts was spot on and everything slid in without a hitch. I spent probably 80% of my time mating the TH400, mainly because I was doing it by myself and that sucker is heavy! Here is a closeup of the mounts:





I got so giddy after putting it in, I decided to mockup the passenger header right away. Wouldn't you know it, somebody's looking out for me because this header is going to clear the factory AC suitcase with room to spare! I absolutely can't believe it.









Here is the clearance to the firewall. Plenty of room to tuck wiring.



Here you can sorta see the clearance with the brake booster and wiper motor. Nothing close to interfering. Only real concern I have in those areas is the coils.



And here's an overall from the front. This is going to look great!



I have lots of clearances and dimensions to check while the engine is in. Would anyone like to add to my checklist?

-Pass header to ac
-Driver header to steering box
-Headers to steering lock-to-lock
-Headers to floor
-Orientation for header flanges & O2 bungs
-Accessory clearance and needs for frame notching
-Driveline angles
-Required tranny crossmember movement
-Flexplate mating to stall converter
-?

For now I'm just celebrating having it in there. Things went so smoothly today I fully expect a show stoppper once I dig further.
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Old 07-23-2011, 11:04 AM
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Can you get to the various sensors and valve-covers for the not so routine maintenance.

On the AC box since it looks like you have it open I would heat shield it to block radiant heat off the header (think stuck in traffic for hours). I do this by using 0.030 aluminum sheet and bolting it with stand offs to the AB box with about 1/8" air gap. When everything is formed (0,030 bends and forms sweet) I give the side to the heat a quick polish.

Looken~good
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Old 07-25-2011, 12:19 PM
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I think access will be okay. Getting to spark plugs on the AC side will be tight, but not much different from the small block. I like the idea of adding heat shields, but I'd have to come up with something easily removed for changing plugs.

It's funny how that bent pushrod has snowballed over the last year. Thanks for your always valued input.
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Old 07-25-2011, 04:05 PM
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IIRC that AC box is FRP can you section it and move it away from the header and glass it back togeather?
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Old 07-25-2011, 04:46 PM
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Yeah it can be glassed, but the area closest to the headers has the evaporator directly behind the housing. Honestly it was closer with the smallblock. I think it will be fine without modification or shielding.
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Old 07-25-2011, 06:32 PM
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Yeah it can be glassed, but the area closest to the headers has the evaporator directly behind the housing. Honestly it was closer with the smallblock. I think it will be fine without modification or shielding.
Just a FWIW you can shield that area an use no more then 3/32" of the space and you will be surprised how much heat you will block.
1/32 thick alum and 1/16" air gap.
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Old 10-12-2011, 01:56 PM
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It has been a while since I updated this, mainly because I haven't had time to work on the car, but also because I was fighting some fitment issues and didn't want to go through the gory details on OFN. The executive summary: headers didn't clear the steering box and steering was interfering with the pan before reaching the stops. I tried a few different engine positions and made different adapters before finally giving in to the fact that I was frustrated and didn't have time to mess around with it. I'm embarassed to say I ended up buying a set of adapters from the header manufacturer (Dougs). If you want to read the details, I posted them on ls1tech.com here.

Here are the Dougs adapters, SK100, as they arrived to me. They came with hardware (eight countersunk screws for the block and six hex screws for the mounts). One detail I noticed immediately was an angle ground into the front lower corner, block side of each mount. On the driver's side this helped clear a boss in teh block, but I'm not sure what it's for on the passenger side.



Here you can see the holes give you the option of 1/2" or 1-1/4" setback. The third hole is also 1/2" below the block mounting holes. I am using the 1/2" setback position. My prior mounts were 1/4" forward.



One of the first things I noticed was the adapters interfere with the hump on the Energy Suspension mounts. This would be a simple thing for Dougs to acomodate, but not all mounts (especially OEMs) have this hump.



To get it to clear, I ground the hump down on my old backing plates. This took all of a half second with the angle grinder.



I was very pleased when they bolted up and the engine dropped in without a problem. The frame stands lined up perfectly.



In this side view you can see the Dougs SK100 1/2" setback position puts the front machined face of the block about 1/2" behind the front face of the subframe crossmember.



Here you can see I have very little clearance between the cylinder head and the AC suitcase, but it does fit. The closest point is a rib on the lower suitcase mounting ear. I think I will take the Dremel to this rib for more clearance.



And still plenty of clearance around the passenger side headers.



The drivers side headers now clear, but just barely. In these pictures the gasket is not installed, but I did try slipping it in and I have somewhere between 1/16 and 1/32 clearance at the pitman arm. I may need to put a small dent there to prevent contact.





The one thing I didn't take pictures of is the steering. It still contacts the pan on the driver's side, with less than a paper thickness of spacing at the steering stop. I hope I'm just toed out right now, but if not I will just limit the steering a little. I have seen a bunch of swaps that use this oil pan and at full lock their tierods don't seem to be nearly this close to the pan.

All in all I am happy I went this route. I saved myself some time buying the Dougs adapters and I think the position will work. Most of all I'm relieved to have this figured out so I can forge ahead. I've started mapping out the notch for the alternator and I have an idea for the compressor. Next step will be pulling the engine for cutting & welding.
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Old 10-12-2011, 11:00 PM
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Quote:
The drivers side headers now clear, but just barely. In these pictures the gasket is not installed, but I did try slipping it in and I have somewhere between 1/16 and 1/32 clearance at the pitman arm. I may need to put a small dent there to prevent contact.
That is what I like to call a 'self clearancing fit'. If needed, it will doubtless make its own dent, and in the PERFECT location too! Like the deep, perfectly radiused channel in the stamped steel oil pan on my friends toyota from his SAS / hi-steer setup. Measure? nah. just drive it LOL!
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Old 10-19-2011, 01:21 AM
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Haha, I like your thinking CaptainAirTime!

Since I'm no longer lifting the engine, I need to come up with a solution for low mount accessories. The Trailblazer 5.3/6.0 compressor (TRSA12B or Sanden 4911) will no longer fit in the OEM location because the unflipped adapters interfere with the compressor case. This is a real bummer because it's a very compact fixed displacement scroll compressor and has great port locations. Rather than cut my losses, I am going to try out something new. I really like this compressor, so I did some more research to see if I could find a six rib pulley/clutch that would allow me to move the compressor forward. Sure enough, the Trailblazer 4.2 has a TRSA12 compressor Sanden 3450 that uses a six rib pulley. That compressor is completely different from the 4911 and in fact mounts on the other side of the engine, but I decided to take a gamble that the pulleys would be interchangeable. $30+shipping got me a 3450 clutch assembly from Jensen Auto.

First, off with the original pulley. This required removing the retaining nut, then a snap ring, then a 3-jaw puller.



It came off easily, exposing the electromagnet behind it.



Here is the Sanden 4911 four rib pulley on the left and the Sanden 3450 six rib pulley on the right. As far as I can tell the hubs were identical and the bearings the same (although my new pulley came with a fresh aftermarket bearing).



You can see the overall dimensions are the same. The belt rib patterns are centered on eachother.



I pressed the new pulley on and we're in business.





The pulley is an integral component of the clutch assembly. One surface of the pulley engages with the hub when the electromagnet is energized. The gap between the two needs to be right or it will not engage properly. This requires an appropriate shim at the hub. I *think* the appropriate gap is somewhere between 0.010-0.020in, but do not know for sure. I got this number from a video off Youtube. I have not measured mine yet. The eyecrometer says it's about 0.015.

My plan is to make some custom brackets to mount the compressor in a forward position, still notching the frame for clearance. The brackets will need at least one idler to get the belt routing to work. I'm a bit disappointed to be putting this compressor on the same belt as the other accessories, but apparently it works okay for others so I wont sweat it. The important thing is I'm having fun doing detective work and that is what this swap was for in the first place.
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Old 10-19-2011, 10:42 PM
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jackalope jackalope is offline
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This is lookin' really good! This will be one helluva fun toy when "finished". Keep it up.
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