84 suburban 454

[JHandley]

Does or has anyone used an 84 suburban c20 2wd with the 454 engine to tow with? Im in need of either a carbrebuild or replacement and was wondering what would be the best plan of action. Any advice as far as making this a better tow vehicle would be greatly appreciated. I tow a 24ft CustomTrailers Inc trailer, probably 6k t0 8k loaded.

[FASTDAD]

Is yours a 1/2 ton or 3/4 ton? I have an 89 suburban 454 2500 (3/4 ton) throttlebody fuel injected. I pull a 28ft featherlite with a FC and tools & support equipment. I found that with a with a tow behind trailer of this length I needed an anti-sway setup. The anti-sway is also part of the load leveling system. I use two 1000lbs bars for this, it controls the trailer with excellent weight distribution and sway control. About the only difference to your 84 (if yours is a 3/4 ton) is the fuel injection or engine management. Rebuilding the carburator is not real hard but you do use some pretty powerful chemicals to get it really cleaned out. It's very important to make sure all the little passages inside the carb are clean or there may be some driveability problems. Things like the choke pulloffs/secondary diaphrams/float levels all need to be set to spec for a nice rebiuild. All the carb specs are usually in the directions (what? read the directions?) that come with the kit. If not, go and get an Automotive manuel by Haynes that covers your year. Another area to check for good performance is the diaphram for your vacum advance at the distributor if you have one. If you have a hand vacum pump, hook it up to the advance on the distributor and apply vacum. It should hold vacum and with the engine running you should hear a noticeable rise in engine rpm. If not remove the distributor cap and make sure it's hooked up to the advance plate. If the plate still doesn't move it may be siezed on the distributor body. There are several areas to look at for improving towing performance, if you want I can list the areas I serviced/changed in greater detail. I figured that with all I did, the only thing better would be to get a fifth wheel with a diesel, in other words it turned out great. Let me know. Good luck
FASTDAD

[Steve Demeter]

Jeff,

You can put a rebuild kit in the Carb, but all you will do is restore the seals etc.

those old 4 barrel carbs are a mechanics nightmare, except for the few magicians that know them.

Especially if it is a Carter, Rochester or most any other brand that GM uses.

After I rebuilt the 4 barrel in my 73 and with little improvement in performance, I took it to an old time hot rod shop (guys that actually worked on these things when they were state of the art, and for $150, it was better than new.

New throttle shafts, with inserts into the body, slightly rejetted based on their knowledge.

Bolted it on and it started right up and ran like a champ for another 12 years.

[10rmotor]

My Dad had an 83 suburban 454 3/4 ton that he towed a 27' travel trailer with all over the country. He had the carb worked on a few times by a local place called Ace Fuel Systems,

http://www.acefuelsystems.com/service.htm

Give them a call and they might be able to help them out.

[JHandley]

Thanx for all the great advice you guys. I'll have someone do the rebuild as the exploded view in my shop manual looks like a thousand piece jig saw puzzle. I can see why it takes some worldly knowledge to rebuild these properly.

[Jerry B.]

ah yes..reminds me of my Crew Cab that I usta....

You do want the torsion/load bars. Especially if the tounge of the trailer is short...the trailer tends to push the tow vehicle more with a short couple.
You also want to use an LT tire with an E load range...these are 60 psi tires and dont use the lower 40psi tires. Do the tires first and see if you get whip or adverse movement when a tractor trailer blows by you on the freeway. Then do the bars if necessary.
If you have a lot of tounge weight you might need to level out the rear and so use Firestone Ride Rite air bags.

The 454 in those years has peanut ports that are real small for emissions but still has good torque. An easy(er) fix to gain needed hg.p. is a 2 1/2" dual exhaust system all the way back. Pretty sure there are no cats on your Burban. The headpipes are fine ...it's the stock muffler exits that taper down inside the muff to 1 3/4" and suck about 20 h.p. This was done to cut down noise and resonance. Use big long 2.5" in and out mufflers and a 2.5" tailpipe and exit them out in back of the rear wheels outward...not in the back. You might get a bit of resonance inside but you pulling a trailer.....heavy.

The carb is a Rochester Q-jet and the key with those is the fuel filter. They run well and work well forever as long as you use an inline filter and change the filter screen at the carb inlet (7/8" nut). Also in the air filter...change it yearly. You will find an inner liner in the air filter housing.....remove it. You might want to put a larger snorkel on the housing and bring it forward with ducting to the grille area. Cooler fresh air is worth h.p.

You also want a large trans cooler. A really large trans cooler....with a lot of flow capacity. Bypass the cooler in the radiator. Make sure that your fan clutch is working properly. Pulling a trailer the engine bay gets blistering hot. You dont want anything even close to the exhaust manifolds or the headpipes.

[10rmotor]

Check the rated pressure on those E rated tires Jerry. I believe mine are load rated to 80 PSI.

You shouldn't need bags for the rear unless the tongue weight is really high, and if thats the case you will certainly need equalizer bars. Make sure the trailer is level by adjusting the hitch ball height if possible with trailer loaded.

[JHandley]

I just purchased a set of the load range D tires from the company that I work for and produces them, Titan Tire. 65 psi cold is what they call for.They are DICO branded. I hope they will work for a couple of years. Also, I have the Equalizer brand hitch, and it woks great, second season with it.
The only other issues I have are the carburator and what i am told is possibly a valve rotator that is defective. The exhaust was updated last year to free flow mufflers and 2 1/2 pipe, exiting behind the rear wheels.

[10rmotor]

Its been a long time since I played with a carb, but what is a"valve rotator"?

[Matt King]

Valve rotators sit on top of the exhaust valvesprings to rotate the vavles as the engine operates to supposedly increase seat life. Common on Fords and some Chevys in the 80/90s. Don't think they really did much except make for oddball spring and valvestem combinations.

[Steve Demeter]

On early and mid 70's chrysler trucks and vans, particularly used as motorhome chassis, they made the difference between valves burned every 10-10K miles and never burning for the next 60K miles.

I am a fan of them and fit them to anything I have that they are available for.

Actually quite often they take the form of a keeper pair that has an it a few thousandths larger than the valve stem so the valve is free to turn inside of it.

[FASTDAD]

When I installed new valve stem seals on my 454 (upgraded to teflon push on) to cure blue smoke on startup I did not have the rotators. I have seen them on small blocks, not big blocks. If you decide to check on if you have rotators or service them some how be sure to install upgraded valve stem seals. at that point the valve spring will be off the stem anyhow. You may have the old rubber style that come apart/crack inside the valve springs. This will cure the smoke on startup and reduce oil consumption.

[Steve Demeter]

If one has the springs off, replace them.

Cheap insurance