1980 Pontiac LeMans Station Wagon - G-T-faux (stuck with it, and can't shake it... like a bad case of herpes)
- Thread starter motorheadmike
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Added some much needed ballast in a critical location.
Got the AC charged up and working just in time for humidity season. Its blowing ~5-10*C out the vents on MAX - which is uncomfortably cold.
At this rate I am going to run out of things to do soon. Naaaah! 😉
But, there is something to be said for having built an LS swapped, mini-tubbed, nitrous injected, air conditioned, drag-ready family war wagon.
At this rate I am going to run out of things to do soon. Naaaah! 😉
But, there is something to be said for having built an LS swapped, mini-tubbed, nitrous injected, air conditioned, drag-ready family war wagon.
Installed the UMI front UCAs this weekend.
Initial impression out of the box: Good.
Once I got into working with the product: Meh.
The long and skinny of it is that UMI Performance did okay with these arms. They were my choice because they offered the shortest adjustable arms with the least failure points and had droop limiters - it helps that I have been using UMI products for years with good results on the street and in competition. That said, I learned a lot in the process of installing this product.
The instructions are decent (more on that in a minute), the assembly out of the box was sketchy with each arm being torqued differently (one was a Wednesday, the other a Friday), and the general finish is okay.
So once I got the arms apart I found that the cross shaft bolts were packed with anti-seize... okay that makes sense. What doesn't is UMI's instructions telling you to put Loctite on the bolts during final assembly. Yeah, that doesn't work. The lock washers provided are good enough.
Now! Getting those cross shaft bolts off and on in the car is a PITA. Achieveable, but not a simple undertaking - expecially the rear two bolts. The good news is nothing binds. Definitely support the LCA with a jack when doing any adjustments. The rear heim joint jam nuts are almost unworkable as there is very little room between the frame bracket and A-arm leg. You almost need a narrowed open end 15/16" wrench or a special tool to pop the heim free of the cross shaft and to tighten it. I managed to get them snugged down with a small adjustable wrench. There were lots of swear words. It is highly unlikely that these arms are ideal for quick changes (at a track day or autocross) - there are other options for that - but, these do work fine as a set it and forget it option that you should expect to tune with shims.
Something else missing from the instructions is what to set the arm length to depending upon your ball joint option (standard, 1/2" or 1" tall). Before I bought these arms I talked to UMI's tech line and they told me to set the arms up to a maximum of half of their full adjustable leg when using a 1/2" tall BJ, full in for a 1" tall BJ. So what is that dimension? The instructions don't say. But, what they do instruct is that for safety to have a minimum of 14 threads engaged on the hiem joint. So after pulling the heim all the way out of the arm it was showing 22 threads, so 22 - 14 = 8. And half of 8 is 4. 8 threads of adjustment is .400", so I set these to .200". This resulted in a centre-line of the cross shaft to centre-line of the BJ of approximately 7.500". If I was using a 1" tall BJ the total length would be 7.300". Interestingly the stock arms measure out at approximately 7.910" from CL to CL.
The next part of this study was what the shim stacks looked like using the stock arms versus the UMI arms. To get my previous alignment figures using the stock arms (with the stock BJs) were: 3.5* caster, -1.25* camber, and hair of toe in (~1/16"). This required .315" front and .640" rear on the DS, and .438" front and .911" rear on the PS. For giggles, or science, I checked the UMI arms raw alignment specs (set to 7.5" length) without shims which were: 3.75* camber and -1.375* caster (surprisingly close to the heavily shimmed stock arms). My final alignment specs with the UMI arms are: 5* caster, -2.5* camber, and 1/16" toe in. The UMI arms required no shims front and .375" rear on the DS, and .125" front and .375" rear on the PS. However, it is important to note that the DS arm need to be lengthened to: 7.6125" to balance the chassis out L to R. I am pretty sure this thing got hit or was built like crap, or both.
Another interesting comparison between the UMI arms and stock units is the placement of the BJ mounting pad. The stock pad is all wonkily dropped 1 to 2" below the CL of cross shaft, and the UMI pad looks like it is at or slightly above the CL of the cross shaft.
One last added bonus of the UMI arms (and a contributing factor to my purchase) is that with their cumulative design considerations is just how much further away they are from the header primaries. The heavily shimmed stock PS arm had the bushing 1/8" off the primary tube = don't touch my fooking HOOKERS!
In addition to the UCAs I added a set of ZQ8 progressive bump stops, they are noticeably taller than the stock units (those are brand new MOOGs). One of the reasons I wanted these is because my wagon is maintaining stock suspension travel with the 2" drop spindles. I have determined that the wagon could stand to benefit from reducing the spring height by about 1/2" to get the LCA parallel to the ground, but I'd be splitting hairs (and pulling mine out) by attempting to make that minor change.
Driving impressions with the new settings? The steering is much heavier, the car tracks well, and it is as I anticipated. It reminds me more and more of how my Buick used to handle. This makes me happy.
Because race car.
Initial impression out of the box: Good.
Once I got into working with the product: Meh.
The long and skinny of it is that UMI Performance did okay with these arms. They were my choice because they offered the shortest adjustable arms with the least failure points and had droop limiters - it helps that I have been using UMI products for years with good results on the street and in competition. That said, I learned a lot in the process of installing this product.
The instructions are decent (more on that in a minute), the assembly out of the box was sketchy with each arm being torqued differently (one was a Wednesday, the other a Friday), and the general finish is okay.
So once I got the arms apart I found that the cross shaft bolts were packed with anti-seize... okay that makes sense. What doesn't is UMI's instructions telling you to put Loctite on the bolts during final assembly. Yeah, that doesn't work. The lock washers provided are good enough.
Now! Getting those cross shaft bolts off and on in the car is a PITA. Achieveable, but not a simple undertaking - expecially the rear two bolts. The good news is nothing binds. Definitely support the LCA with a jack when doing any adjustments. The rear heim joint jam nuts are almost unworkable as there is very little room between the frame bracket and A-arm leg. You almost need a narrowed open end 15/16" wrench or a special tool to pop the heim free of the cross shaft and to tighten it. I managed to get them snugged down with a small adjustable wrench. There were lots of swear words. It is highly unlikely that these arms are ideal for quick changes (at a track day or autocross) - there are other options for that - but, these do work fine as a set it and forget it option that you should expect to tune with shims.
Something else missing from the instructions is what to set the arm length to depending upon your ball joint option (standard, 1/2" or 1" tall). Before I bought these arms I talked to UMI's tech line and they told me to set the arms up to a maximum of half of their full adjustable leg when using a 1/2" tall BJ, full in for a 1" tall BJ. So what is that dimension? The instructions don't say. But, what they do instruct is that for safety to have a minimum of 14 threads engaged on the hiem joint. So after pulling the heim all the way out of the arm it was showing 22 threads, so 22 - 14 = 8. And half of 8 is 4. 8 threads of adjustment is .400", so I set these to .200". This resulted in a centre-line of the cross shaft to centre-line of the BJ of approximately 7.500". If I was using a 1" tall BJ the total length would be 7.300". Interestingly the stock arms measure out at approximately 7.910" from CL to CL.
The next part of this study was what the shim stacks looked like using the stock arms versus the UMI arms. To get my previous alignment figures using the stock arms (with the stock BJs) were: 3.5* caster, -1.25* camber, and hair of toe in (~1/16"). This required .315" front and .640" rear on the DS, and .438" front and .911" rear on the PS. For giggles, or science, I checked the UMI arms raw alignment specs (set to 7.5" length) without shims which were: 3.75* camber and -1.375* caster (surprisingly close to the heavily shimmed stock arms). My final alignment specs with the UMI arms are: 5* caster, -2.5* camber, and 1/16" toe in. The UMI arms required no shims front and .375" rear on the DS, and .125" front and .375" rear on the PS. However, it is important to note that the DS arm need to be lengthened to: 7.6125" to balance the chassis out L to R. I am pretty sure this thing got hit or was built like crap, or both.
Another interesting comparison between the UMI arms and stock units is the placement of the BJ mounting pad. The stock pad is all wonkily dropped 1 to 2" below the CL of cross shaft, and the UMI pad looks like it is at or slightly above the CL of the cross shaft.
One last added bonus of the UMI arms (and a contributing factor to my purchase) is that with their cumulative design considerations is just how much further away they are from the header primaries. The heavily shimmed stock PS arm had the bushing 1/8" off the primary tube = don't touch my fooking HOOKERS!
In addition to the UCAs I added a set of ZQ8 progressive bump stops, they are noticeably taller than the stock units (those are brand new MOOGs). One of the reasons I wanted these is because my wagon is maintaining stock suspension travel with the 2" drop spindles. I have determined that the wagon could stand to benefit from reducing the spring height by about 1/2" to get the LCA parallel to the ground, but I'd be splitting hairs (and pulling mine out) by attempting to make that minor change.
Driving impressions with the new settings? The steering is much heavier, the car tracks well, and it is as I anticipated. It reminds me more and more of how my Buick used to handle. This makes me happy.
Because race car.
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