88GMCtruck's 98 Silverado Towpig Build: "Black Fox"

Re: 88GMCtruck's 98 Silverado Towpig Build: "Black Fox"

My work is never done......

So, I've been chasing down a rough idle in this truck since I bought it. Not quite a miss but it isn't as smooth at idle as it could (should in my opinion) be. I've had a oil leak at the pan for awhile, and it recently started dripping so I decided to replace it and the timing chain while I was in there.

Out goes a few things.



Once you get here, you have to drop the front diff. Let's just let it be known that a few curse words were said during it's removal and re-install.


Once it's gone you can have a peek inside.



The timing set.


Here is where the second cursing during this project came about. I ordered the GM Performance Parts 502 timing set - the same one I used on the 88, as it's designed for the aluminum timing cover in a gen 6 block. Well, it doesn't work out so well. The Vortec truck has a reluctor ring that fits over the crank gear, which causes it to be thinner. I knew this, but didn't take into account. So a bit of research and I picked up a Cloyes timing set locally for 2x the cost of the GMPP version. To make things worse, Cloyes makes the GMPP version and the only thing different is the thickness of the crank gear.

In order, Stock, GMPP 502 set, Cloyes Vortec 454 Set. The ear pictures show the difference in thicknesses.




Got all that back together, but while I had the radiator out I cleaned it. You'd be surprised how much junk gets stuck in these. Once it was back in I flushed and re-filled with coolant.




Since I was in the mode of chasing the rough idle and giving it a tune-up, I decided to eliminate the plastic shafted distributor with a drop in MSD unit. Not only is it pretty, it is all billet and has a much higher quality cap than the OE stuff.



So, once it was all together I got the timing set within .8 degrees of 0 (tolerance is +/- 2 degrees), did a CASE relearn and still have a rough idle. Not sure where else to look at this point, I've gone through 95% of this thing.......
 
Re: 88GMCtruck's 98 Silverado Towpig Build: "Black Fox"

Now, switching away from maintenance, I got around to building a cold air intake. And when I say cold air intake, I mean an actual box that is insulated and sealed from the engine bay...

Started out with cardboard for a template.......



Then I cut and riveted everything together using aluminum plate and angle. The first stages...



And here is the finished product.


The outside is covered in DEI floor and tunnel shield, rated to 1750 F to insulate the box. I decided I wanted a smooth lid so the inside is insulated on it. It's held on with stainless torx screws from a GM squarebody.


It's a bit of a squeeze, but I managed to get an OEM sized filter in it, plus i'm still able to disconnect and remove the battery with no issues.



To create a seal and flex joint, I used some sheet rubber and made a retaining ring that holds everything together where the pipe passes through.



That is all, for now. I plan to clean up the lid some more (brushed or polished, haven't decided) and do a few other things to it, but I'm happy with how it turned out. I'm not really expecting or hoping for any gains, other than the fact that my non-intercooled supercharger will no longer be pulling in hot engine bay air (you know that exhaust manifold is really close to it all).
 
May 2, 2016
10
0
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Oregon
Have you ever used an upper engine cleaner to remove the carbon from the valves. When I first started turning wrenches for a living the shop I worked at did that all the time on gmt400 s Gm use to have there own gm upper engine cleaner but I haven't seen it in a while. Sea foam is essentially the same thing. You use the engines vacuum to pull the liquid into the intake. Easiest way is with the brake booster hose. With pinch off pliers on the hose start the vehicle and run it at 2000 rpms Then slowly release the pliers sucking the cleaner into the engine. When most of the can is gone and engine is ready to die shut it off. With the engine off that liquid should be sitting on top of the valves. Leave it for an hour. When you start it there will be smoke everywhere. With a good test drive it will clear up don't worry


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Re: 88GMCtruck's 98 Silverado Towpig Build: "Black Fox"

Have you ever used an upper engine cleaner to remove the carbon from the valves. When I first started turning wrenches for a living the shop I worked at did that all the time on gmt400 s Gm use to have there own gm upper engine cleaner but I haven't seen it in a while. Sea foam is essentially the same thing. You use the engines vacuum to pull the liquid into the intake. Easiest way is with the brake booster hose. With pinch off pliers on the hose start the vehicle and run it at 2000 rpms Then slowly release the pliers sucking the cleaner into the engine. When most of the can is gone and engine is ready to die shut it off. With the engine off that liquid should be sitting on top of the valves. Leave it for an hour. When you start it there will be smoke everywhere. With a good test drive it will clear up don't worry
I've done seafoam 2-3 times on this truck, one was very recently. Didn't see any noticeable difference.

Also, most of the 454 truck have hydroboost brakes so there is no brake booster vac line - I used one of the crank vent vac lines.
 
Re: 88GMCtruck's 98 Silverado Towpig Build: "Black Fox"

Dave, I swear one of these days I'm going to have you buy me a truck! You always have rides I envy! Nice rig. I still want your old grey one with the 6.5 and the 5spd! I love your work. (honestly it's your fault my 97 has an NV4500 and Kodiak handles) :head:
 
Re: 88GMCtruck's 98 Silverado Towpig Build: "Black Fox"

Dave, I swear one of these days I'm going to have you buy me a truck! You always have rides I envy! Nice rig. I still want your old grey one with the 6.5 and the 5spd! I love your work. (honestly it's your fault my 97 has an NV4500 and Kodiak handles) :head:
Heh, I have no problem helping make decisions :lol:

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After updating to my latest tune it has smoothed out some, between that and the ignition upgrade it seems normal now.

Anywho.......

Made a trip to Reno and back the other weekend, here is what my mileage ended up at on the way down. I managed to go over 9 on the way home.


The other day I finished out the airbox lid, cleaned it up and added a little touch to it.



Also installed new LED clearance lights and solar on the camper this past weekend.





Pulled the 88 out to shuffle some things around, figured this was a good opportunity to put them next to eachother. It's amazing they are 10 years apart. Love these trucks.
 
Re: 88GMCtruck's 98 Silverado Towpig Build: "Black Fox"

Loaded up the quads and hit the coast.







On the way back I started getting a squealing sound which got louder and turned into a grinding sound..... Driver's side caliper decided to stick..... quick rest area pull apart and run to town for a new caliper... This is why it pays to travel with friends.


Made it home. Another issue I haven't touched on yet, as I wasn't sure if it was an issue, as a sound I started hearing in neutral. Kinda a bearing/rattling sound. It started getting louder on my trip to reno, and on this trip it turned into sounds while pulling hills as well... and downshifting. And it started shaking while taking off in 1st...........

All the same symptoms it had a year ago. Almost exactly a year ago. June 10th to be exact, is when I pulled the transmission from the truck.

So out comes the NV4500 fluid draining kit


Pulled my PTO covers to check the magnet......




Yup, that is metal. There should not be that much metal in a year/10k miles. After discussing this with a couple shops they are thinking I have a warped bellhousing, causing the alignment issue to eat up the end of the mainshaft. Lucky me, I've found the most cursed NV4500 on the planet.

Hopefully a new bellhousing and this will solve my problem.
 
Re: 88GMCtruck's 98 Silverado Towpig Build: "Black Fox"

Worked on the brakes late last week, ended up doing new Calipers, Rotors, and Ac Delco ceramic pads.


While I was waiting I got the wheels polished up. Photos don't do it as much justice, but the difference is pretty noticeable



My buddy also was due for brakes, so he brought his 98 over as well.


Got the transmission pulled. the input shaft was super loose, ended up popping it out and yup, exact same thing as the last go-round. Main shaft chewed up.


So, we checked the flywheel/crank for runout, there was none. my flywheel and clutch were perfect, there were still machining marks on them and no hot spots. Used a new oilite bronze pilot bushing, and just to make sure everything was good, a new bellhousing and brand new never ran NV4500.




So, it's together. New transmission is quiet and shifts tight and smooth. Lets hope this lasts...........