crossmember spacers...?

[jeromio]

I should probably just finish reading the JTR manual that I just got (wife made me put it down at dinner tonight), but I'm gonna just start asking questions anyway:

 

The spacer plates that go between the frame and the crossmember, is everyone using those? Seems like something I'd like to avoid if possible. Would these be necessary for an LS1?

[patzky1]

as long as your harmonic balancer is less than like 8 inches you dont really need it.

but clearance will be an issue with the hood latch bracket, so make sure to use the removable setup. the spacers kinda screw things up (found this out after installation). it just makes your oilpan lower to the ground and slightly alters the steering. if you dont have to use them to squeeze it in, then don't.

[DavyZ]

It supposedly adds clearance from the top of the motor to the hood, but numerous guys (Pete for example) are not using it as it does not really seem to do anything. I'll have to think it through for myself to see if it does something and then decide to use it or not.

 

Davy

[jeromio]

I guess the thing I didn't understand was that since the motor is mounted to the crossmember, why would it be necessary to lower the crossmember? Hood clearance?

 

Anyway, the LS1 seems pretty low profile, and it's aluminum, therefore light, and there is no distributor, so, basically, I am not planning on using the spacers at all.

 

Like you say, seems like the spacers are gonna alter the suspension geometry.

[pparaska]

The reason I took them out was to help me get the same u-joint angles on the front and rear u-joints. With the spacers in, the engine/trans did not have a big enough "nose up" angle, compared to the diff, so I took the spacers out to raise the front of the engine. This helped. (see my site under: http://members.home.net/pparaska/drivelinemods.htm )

 

I moved the stock hood latch over next to the distributor (SBC install), so I didn't need the clearance above the distributor as I would have needed with the JTR bracket.

 

Luckily, with a Holley 300-36 hi-rise dual plane mainfold, 3310 Holley carb, and 14" drop base air cleaner, there's 1/2" between the hood and front area of the air cleaner.

 

BTW, it has nothing to do with harmonic balancer clearance, as the engine is bolted to the crossmember. It also has nothing to do with the front ride height. If you leave out the spacer, it does raise the roll center of the front suspension, and it raised the crossmember, and the oil pan!

 

[ August 24, 2001: Message edited by: pparaska ]

[Lone Star 1]

You want need the spacers and pulleies on the LS1 are small in back and a little larger in the front the motor needs to set with the smaller part of the pulley just over the top of the steering rack. This gives you about 3/8" clearence between the pulley and the steering rack. The motor sets almost 2 1/4" below the hood bracket and no modification is needed to the hood bracket. When I first set the motor in place I thought oh no it's not going to fit, but after rotating the exhaust flange it fit fine. Also I removed the four bolts holding the steering colum to the firewall and enlarged the hole about 1/4" towards the drivers side and slide the steering colum over about 3/8". Then drilled new holes in the steering colum plate and remounted using the firewall's threaded holes. This gives you an extra 1/4" clearence at the exhaust flange. This mod can help all on this forum who are having clearence problems between the exhaust manafold and steering colum.

[Lone Star 1]

You can also buy the LS1 street version 1 computor from Scoggin Dickey for about $550 this will eleminate VAT problem and the secondary o2 problem. There is also an ASA Holden computor avilable for the same money but no one seems to know if it will work with a stock LS1. or what the HP benifits would be. A company called Howell makes the wiring hornace that is suppiled with the GM crate motor. Their phone no. is 810-765-5100. If you buy this hornace be careful as GM has sent notice that the 02 sensors are miswired. Right hand sensor is controling left bank and visversa. It took three days to figure that one out. Motor would run full rich on one side and full lean on the other. I bought the GM F-body manualls and ck the wiring, made the swap at the computor end and all was well.

[Danno74Z]

Lone Star 1,

 

Question. I'm using the LT1 engine not the LS1 but I believe the same basic problem exists for both motors concerning the location of the AC compressor. First, are you using the stock GM AC compressor? I'm assuming you are living in TX. Second, how did you use the JTR setback plate on the passenger side with the compressor smack in the way? Last, what motor mounts did you use?

 

Thanks,

Danno74Z

[Modern Motorsports Ltd]

quote:

---

Originally posted by Lone Star 1:

Also I removed the four bolts holding the steering colum to the firewall and enlarged the hole about 1/4" towards the drivers side and slide the steering colum over about 3/8". ...This mod can help all on this forum who are having clearence problems between the exhaust manafold and steering colum.

---

 

Great info and ideer Lone!! That's the first I've heard of that and it could truly benefit fitting my upcoming 1-3/4's headers on my ZX which has always been tight in that location...

I'd just assumed that it was fixed from the wheel connection to firewall and not flexible at all, I assume there is a joint in their then?

 

 

U 'da man

 

[ August 24, 2001: Message edited by: Ross C ]

[Guest JESTER3798]

i just pick up the ls1 and t56 for the conversion. what vat problem are you reffering to? just asking so i dont pull my hair out when i get the thing running

tia

ryan

[BLKMGK]

FWIW - based on the advice here I too dumped my spacers and didn't use them. That was after they were powdercoated of course so far as I can tell driveline angles are fine but until I hit the highway I can't be too sure. (sigh)

 

VAT - this is an antitheft deal. If you look at the key on an LT1 or LS1 equipped car you'll see a small resistor. This is coded and the ignition lock has prongs that check it's value. Incorrect value = no start. since the Z column obviously doesn't have the probes to check this you're forced to disable this in the ECU code. I think the TPI motors might have had this problem too BTW. In some cases an additonal black box can be wired in to get around this too

 

Hrm, at som epoint I think we need to have a thread on theft prevention tips. My car could be hot wired with a bobbypin and since my solution to the hood latch issue was to use hood pins with no locks this is a real concern!

[Guest Anonymous]

Using the lt-1 or the ls-1, the hood latch will not be an issue because these motors don't have distributors. As for AC, street and performance makes very ($) brackets that will mount the AC compressor and the alt. at about the level of the valve covers. I used this set up for a while on my 73 with lt-1. The cross member spacers were used for a little more clearence but mine would work without the spacers. Mark

[jeromio]

The simplest solution for the various ECU problems is of course to just mail the ECU off to Speartech or some other tuner and have them reprogram it.

 

There's VATS, there's the lack of secondary (post Cat) O2 sensors, there's the whole fuel pressure regulator/sending unit/pump issue.

 

I'm hoping to avoid the added expense - about $250. This LS1 Edit thing is supposed to be available in a few months. In theory this will allow programming of all aspects of the ECU, without depending on $omeone el$e. When it's available, I'm gonna be all over it and it would suck to pay twice.

 

So, I'm getting a BDM with matching resistor along with my motor. I'm going to see about picking up the various fuel supply elements as well, or else comb the junkyards for them.

 

It's cruel and cynical to say, but one of the beauties of these LS1 and LT1 engines is that there are countless teenyboppers wrecking these cars, filling up the yards with parts.

[Mike C]

JTR manual "Swapping Chevy TPI/TBI motors" has information on the vats including the 10 different resistor combinations if you want to try and jury rig. This is a nice book in the same vein as the Z conversion manual. I have a buddy who just ordered the S10 conversion manual from them so I'll see in a week or so how that one is.

[Modern Motorsports Ltd]

FWIW, my father used the crossmember spacer strictly for extra tranny/T56 clearance in the tunnell and firewall (and possibly driveline angle/I don't recall). Did the rest of you T56 users clear fine without using a BFH or shaving fins?

[Owen]

For my T56 I hammered the tunnel and didn't use the crossmember spacers. The only fins that are in the way are the ones by the reverse sensor, which I won't grind off until I have to pull my engine again.

 

Owen

[BLKMGK]

I cutgrouond NOTHING on my T56 - it slipped right in. I did have to ding the firewall a bit up front where the tunnel begins on the passenger side. This was MINIMAL. The two fins by the reverse sender stick ut a bit, I'll trim those. When done the passenger side was too close to install the reverse sender and was nearly touching. I used a crowbar braced against the trans to expand that space - it is NOT noticable on th einside nor did I damage the metal. A tap with a hammer would restore this. Lastly, back my the trans mount it was REAL tight. Rather than bash everything up I had my mount sectioned a bit - pics on my site. This was actually a little bit too long still and I have mild depressions in my pantunnel. These were made by bolting the crossmember to my trans and jacking it up into position

 

Other than those mods and removing the old trans mounts with an air chisel (documented here somewhere) I made ZERO modifications to fit the transmission. Oh wait, up by the shifter I trimmed a little so I could more easily get to the shifter bolts

 

The T56, from an install point of view, is nothing to be feared. It does weigh a ton though - install it WITH your engine and set the STARTER clearance before bolting up the engine! Setting it later is next to impossible - trust me.

[Guest JESTER3798]

i just ordered the tbi/tpi manual from jtr so hope fully ill get some more good info. did any body notice the guy on ebay who is selling something(i wasn't really concerned until reading the last few posts) that eleiminated the thing for the rear o2 sensors. i was planning on running a cat(inspection sucks in NJ), couldn't i install a secondary o2 sensor and fix this problem? what issues have you guys seen with the fuel system as noted in an earlier post?

 

tia

ryan

[Dan Juday]

If you can get the key from the car the motor came from just measure the resistance with and an ohmeter. You must also get the vats box out of the same car, about the size of a pack of cigarettes. Be advised: GM hides these deep in the dashboards. A pain to get out. A little extra work to get the stuff, but once you have it, it's easy to subsitute the key for resistors. Cheaper too, that was important to me.

[jeromio]

You can put the 2nd O2 sensors in, it's just that they're expensive.

 

There are modules that simulate an O2 signal. There are also VATS eliminating modules, and modules for the fuel system (the ECU controls the pump, the regulator and gets a signal from a fuel pressure sender). But, by the time you've bought all that, you'll probably spend more than the $250 for either the ECU programming or the LS1-Edit tool (which I think will cost around $250).

 

Also, you should verify that you're car must pass emissions. In most states (including Cali which is by far the most restrictive), 73 and older are exempted. (which is completely ironic since about 90% of all the pollution is caused by the older cars of which I personally own 3 ).

 

Furthermore, even with an emissions test, you may not need the cats. The LS1 has high compression and some pretty fancy fuel/ignition routines to optimize combustion. If you don't already have the cats, they are crazy expensive (and of course they also restrict exhaust flow). Most yards won't sell them (at least around here they don't/can't), so they have to be bought new.