Hey Vortec Guys! / Sierra pickup / Suburban / Yukon etc - Finally has Index!

[Bear in NM]

Kojack,

Do you think that the H2 springs are rated for heavier loads, i.e. are stiffer in compression than the stock Sub. springs? I just completed my lift with 1 inch spacers. Thinking that the slight compression will start the working range of the compression more on the stiff side, which does give me a little lift, and hopefully less squat. I have not tested mine yet at full load out, gear and small trailer, but if I am squatting, I might have to look towards the H2 and/or bags.

And I agree about the softness of the stock suspension. My Avalanche is 14 years old, so not sure if it is just age, or age and design, but my ride is so much better now with the keys up front, and 1 inch spacer in the rear. It is certainly stiffer, but much more firm on the road.

Craig

 

[justcuz]

The H2 springs are definitely rated for heavier loads. The H2 was a heavier vehicle and was usually loaded heavier than Suburbans.
They don't hurt articulation much either. I have 285/75x16's on my 2000, without my sway bar and I rubbed the inside of the rear fender well while on Cleghorn or in Holcomb Valley a few weeks ago.
I posted pictures of the springs and my rear vehicle height on a thread somewhere here.
In my driveway facing uphill, I have 39 or 40" to the top of the fender well.
I can take pictures later if anyone needs more.

Edit; The H2 springs are progressively wound like a Moog Cargo Coil, so they coil bind with weight on them. With 6 adults in the Suburban and our luggage, the back end dropped maybe 3/4" on a trip to Colorado last year. Coil spacers do not improve your spring rate or load capacity, thats why I opted for the H2 springs. They are still available and I think I even posted the part numbers.

 

[Burb One]

The H2 springs are definitely rated for heavier loads. The H2 was a heavier vehicle and was usually loaded heavier than Suburbans.
They don't hurt articulation much either. I have 285/75x16's on my 2000, without my sway bar and I rubbed the inside of the rear fender well while on Cleghorn or in Holcomb Valley a few weeks ago.
I posted pictures of the springs and my rear vehicle height on a thread somewhere here.
In my driveway facing uphill, I have 39 or 40" to the top of the fender well.
I can take pictures later if anyone needs more.

Edit; The H2 springs are progressively wound like a Moog Cargo Coil, so they coil bind with weight on them. With 6 adults in the Suburban and our luggage, the back end dropped maybe 3/4" on a trip to Colorado last year. Coil spacers do not improve your spring rate or load capacity, thats why I opted for the H2 springs. They are still available and I think I even posted the part numbers.

+1 to what justcuz said, all true. On the flipside (and why I prefer SHORT less than 2" spacers.) is that they still give me the same rate, but bring the resting height back up to level when loaded (compare to stock length springs at least). This allows for greater articulation in a given situation because of the softer spring rate. Even in towing my trailer to go the the race track, I don't have much sway (probably because the rear of the truck isn't as loaded with camping crap as it would be on a camping weekend.)

Now if I went camping with a camping trailer fulltime, and loaded stuff in the burb, the H2 or heavier springs are probably a better call, but in some situations the softer springs are better. IMO

 

[justcuz]

+1 to what justcuz said, all true. On the flipside (and why I prefer SHORT less than 2" spacers.) is that they still give me the same rate, but bring the resting height back up to level when loaded (compare to stock length springs at least). This allows for greater articulation in a given situation because of the softer spring rate. Even in towing my trailer to go the the race track, I don't have much sway (probably because the rear of the truck isn't as loaded with camping crap as it would be on a camping weekend.)
Now if I went camping with a camping trailer fulltime, and loaded stuff in the burb, the H2 or heavier springs are probably a better call, but in some situations the softer springs are better. IMO

You still have your rear sway bar correct? I broke a link in mine and never knew it until my oil change, lube and undercarriage inspection. Since I never noticed a difference in handling, I removed it.
My articulation is still pretty good, as mentioned above, I rubbed the inside of the fender well with the tire.

 

[Burb One]

I still have mine. I also broke mine (When i got the lift kit one of the bolts sheared) I also didn't notice a difference until I saw it. I left it awhile without it connected, but because I tow ended up reconnecting it and put in grade 8 bolts, and it's been a while now and a few harder trips and it's fine. I must have not tightened it enough first time around.

I have not noticed a difference with our without them on road. I am thinking about doing a quick disconnect for it for off road, but honestly the articulation with it on, isn't too bad and it's just one more thing to break/ loose quick pin....

 

[kojackJKU]

They are available on ebay, as replacements for the air suspension.

 

[Bear in NM]

Great discussion, gang. I am new to the coil game, so this gives me much to ponder. Justcuz, yes, I saw the H2 springs you posted with the part numbers. I would not have guessed the Hummer was set up heaver in the rear than Suburbans.

I think my Avalanche is a tad lighter in the rear than a Suburban, as the sail panels and cargo covers are certainly lighter than the back third of the enclosed Burb. I will be able to get a better feel for things on the Labor Day weekend, as I will have my off road trailer, and the trip to the cabin definitely requires some articulation. Looks like I have a few options to fine tune things.

Craig

 

[kojackJKU]

Yeah, the H2 is WAY heavier in the back than a suburban. Just because of the sheer size of the body it has. I will have the springs soon and report back on flex, and ride. I am expecting better handling and weight carrying capacity, but still have good off road flex. They are not THAT much stiffer, but just take the weight better and give some lift.

 

[justcuz]

I am pretty sure the wire diameter is close, but the H2 springs are taller and have the progressively wound coils up top. Kojack, the articulation is pretty good with the H2 rear springs, I rubbed my inner fender wells with the tires a couple weeks ago. I am not running my rear sway bar though.

H2 Hummers were not only heavier body's, but had 14 bolt semi float rear axles and much bigger wheels and tires.
I would estimate in stock form the unspring weight of the H2 rear axle and tires at almost twice a stock Suburban.
Remember the H2 axle is a few inches wider than a Suburban axle also.

An Avalanche with H2 rear springs would be an easy 2" lift with very little difference in ride quality, but a major improvement in load capacity. I'd love to build an Avalanche with H2 rear springs heavier front T-bars, Cognito UCA's and Fox shocks. With a lock right in the rear it would make a nice tow vehicle for off road.

 

[rayra]

well for now I'm thinking to just bump the rear spacer up a bit and call it good enough for now. I can re-visit the H2 spring idea later, maybe a year from now, after I get a bunch of other projects and some travel done in this thing.

I think I'll get a set of 1.5" spacers from the vendor Jelorian used (for his 2") - http://www.ebay.ph/itm/Black-Alumin...324454?hash=item4adf067da6:g:NQAAAOSwjVVV4PGo
Then I'll have sufficient height gain / stance for my purposes. I can't go much higher anyway, as it's my daily driver and I've got some parking structures in my normal routine which are cutting it pretty close already.

I got the shock boots in the mail while I was out of town, swift service, shipped price under $6ea. Got 5, either one will go on a future steering stabilizer (something else that's useful in my southwest desert terrain) or it will be a spare. Given the location of the rear shock strut location, right next to the rear tire tread and exposed to it, I expect I'll need a spare. They're bound to get cut up at some point.

And after I decide / commit on the spacers I'll get the steering tie rod sleeves too and put everything on at once, and the re-alignment. In the short term I'm going to turn the torsion key adjustment bolts down another turn and a half. Still ahead of where I was before the kit install, but lots of adjustment room to go (back) up still.



...in other news, I've got a new potential maintenance issue. I've been driving my Sub hard around L.A. lately. No problems noticed, but late last night after a return trip from Temecula (~140mi drive at too high a speed) when I exited the highway and came to a stop I got a 'low coolant' warning message. Engine temp needle still pegged around 205F where it always is. No smell or sounds of a coolant leak, no trail of fluid when the light turned green. Took about 3/4 gallon. Topped the reservoir off, started it, some was taken in, topped it off again and idled it to operating temp, no sight or sound of any trouble. No vapor at the exhaust tip. I just got back from some errands and again no sight or sound or smell. I'll check level again after it cools down and draws in. And then we'll see.
Doesn't bode well.
I'm not even going to say 'head gasket' aloud.
The coolant system is the only part I haven't done any maintenance on yet. Thanksgiving will be 2yrs since I purchased it. I probably ought to get around to that before next summer at the latest. New hoses, fluid, pump, thermostat, bypass hose. About $175. Rockauto.com's pricing is ridiculous.

 

[justcuz]

Check under your oil cap for signs of moisture, milkshake looking stuff. It usually wont show up in the oil or on the dipstick.
My daughters Tahoe looked like that and it was a cracked head. Hers was a 2004.
Google Castec heads and see what comes up, I don't remember all the particulars.

 

[rayra]

I did, looked and smelled normal. Nothing unusual on stick or cap.
I ran it around in the heat of the day today, then parked and idled a bit in the driveway while I got back to work on carpeting my storage drawer build. Still no sign of any leaks or smells or tailpipe vapor.
Will lay eyes on my water pump weep hole tomorrow after another run to normal operating temp. Only other inexpensive culprit I can think of. Ran and sounded fine today. And haven't been an strange noises of late. It's a mystery. But I'll be taking a 5gal jug with me on my next 300mi jaunt and checking things often.

eta

Thinking about it some more I'm hoping it's just the reservoir / radiator cap. I'm pretty good about checking fluids and keeping tabs on things (part of why this apparent sudden loss is worrying). And at the age and mileage the cap's a likely suspect. The overflow drain hose is 36" long and would neatly remove all evidence. And when I'm fooling around at 80mph with some occasional wide open throttle, I could very easily be venting coolant without notice.
And my reservoir is stained, sometimes the fluid level is hard to see without giving things a shake. rockauto.com has a Dorman reservoir for $30. And delco for $60.

I can get a water pump w. gasket for $60; 187F thermostat and housing for $16; Upper and Lower Gates hoses for $27 together; Fan Clutch for $42; Reservoir for $29; 2' of 1/2" hose to the tank; 3' of 5/8" for the heater return (already replaced the heater supply). That's $175 for all the parts from rockauto. About $300 at Autozone. And a couple gallons of Dexcool.

Call it $230 for parts and materials to replace everything but the radiator & heater core. And an easy morning''s work. I already did all this on the Tahoe. But I'm starting with a radiator cap tomorrow. $8 autozone, <$4 at rockauto. Cheap insurance before my next road trip this weekend. Might as well get a gallon of coolant to haul along with the 5gal MWC.



GMpartsDirect.com

 

[justcuz]

I replaced my coolant cap too. My Suburban will discharge coolant if I fill it too full. It's likes to be right about the midpoint of the reservior, right above the seam, if more than that it will discharge it.

With the daughters cracked head, I never found any signs of leakage until I pulled the plugs. The coolant had discolored the porcelain. I hope that's not your problem though.

 

[justcuz]

Picture of the H2 springs next to stock. After looking the progressively wound coils are on the bottom.

 

[rayra]

I got just a momentary whiff of coolant today on starting, hopped out and found no sign or further smell. Drove it hard again this afternoon after I finished carpeting my storage drawer build, running errands around town in 102F+ heat. Again no sign of trouble. Picked up the new radiator cap, it's sitting on my dash to remind me to change it before I start it up again.


That's certainly an impressive comparison between the H2 coils over stock. I'd like to find out if there's any apparent size difference between the Z71 springs and those on the LS/LT, or if it's just spring rate.
I've dropped my torsion adjustment the additional 1-1/2 turns mentioned earlier. And next week after Labor Day I'll be passing thru one of the parking structures I have to deal with. It's the tighter of the two and I'm really curious to find out how much room I have left, as it sits. The structure's design at the base of the ramps is the problem, large structural support beams loom right over the start of the ramp. The longer wheelbase and height already put the Z71 within ~4" even though the clearance sign says 7'.

So I really dont have a lot of room to work with, and since the GMT800 Z71 rack design we haven't been able to fit in our attached garage, anyway.