1987 Pickup 4x4 revival after left for dead

[slimbobaggins]

Hey all,

My name's Jim. My money pit is an '87 Pickup 4x4 carb:

It belonged to a colleague of mine, he bought it used and it was his DD for several years until the engine blew up back in 2010. Freak accident; he had just replaced the timing chain, guides, water pump, etc, and he managed to break one of the steel guides and wrap it around the crank gear, which locked up the motor. Engnbldr said he's only seen it happen once or twice, it's caused by over-torquing the tensioner to the point of seizing it, and driving the engine with the chain rattle until it breaks the guide:

 

[slimbobaggins]

So anyhow, the truck sat in front of his house for a few years, rotting back to earth, and then he gave it to me.
I got it home, and decided rather than rebuild the locked up motor (at the time didn't know it was the timing set), bought a 1994 junkyard 22RE:

Stripped it down to the short block, replaced all the gaskets with an Engnbldr kit, cleaned up the head and lapped the valves really good (has 180 lbs of compression on each cylinder now), and put the motor completely back together, including the carb stuff:

 

[slimbobaggins]

Dropped the motor in the truck just in time to move, limped it from my old place to my new one, running like complete garbage. That was June 2014.

Since then, I have tinkered with it on and off in my limited free time, fighting carb problems with the stock carb. I have had that thing apart a million times now:

 

[slimbobaggins]

As you can see from the first post, it is drive-able now, sort of. Carb bogs on wide open throttle, but isn't too bad part-throttle.

I know the popular 'Yota thing is to go to a Weber, but I decided to try something out of the box, and recently bought a Motorcraft 2100 off of Craigslist for very cheap. It's a 2 barrel synchronous carb, and this particular one came off of a 1973 302 Mustang.

You might think it's way too much carb, but I think it'll work out. It's got 1.08 venturis, which means the flow is roughly 280 CFM. That puts it well below the Weber 38, which is the closest comparison since it's also synchronous. That flow is less than a 32/36 even, but the 32/36 is running off of 1 barrel most of the time anyways.

Anyhow, I think it'll be fun to mess around with. I'm going to use the LCE Holley 2 barrel adapter plate to get it on the truck... rebuild kit for the carb is $15, and I'll buy a couple smaller jets because I assume the ones in there will be too big. I'll be using my brother in law's wideband to help tune it.

 

[slimbobaggins]

My main snag at this moment is the brakes. I was playing in the snow last week, and the pedal started to fade bad, to the point it was nearly to the floor, and I had almost no stopping power. No fluid leaks, and master wasn't low, so I figured the 28 year old master needed replaced.

I bought a new one, bench bled it, installed it, bled the ever living crap out of all 5 points (including LSP-BV), both with a vacuum bleeder and pump/dump, and the pedal was firm.

Start the truck up, and same issue- hold pedal to the floor, and it starts to fade. At this point I noticed that the engine RPM was changing with brake application, which indicated a booster vacuum leak somewhere; disconnected the booster and plugged it, and the pedal is once again firm and not fading.

I'm at a loss as to how the leaky booster could be causing this, but with the new master/ fresh fluid/ no leaks/ firm pedal without booster, I don't see any other root cause of the pedal fade?

 

[Mudder]

The brake booster has gone out. I don't know why it causes the issue but it is covered in the FAQ, and I can't wait to see how the carb goes for you. I was going to go that route but went to EFI before I could.

 

[slimbobaggins]

I just read the two posts regarding the brake booster and idle rpm, sounds about right as far as my idle fluctuation, but doesnt address why I have brake pedal fade with the engine running, and it's fine when off.

One thought I had, was that maybe one or more of my lines is swelling under booster pressure, but without the booster (w/ engine off), I can't generate enough pressure on my own to swell the line, which is why the pedal stays firm?

When I do the MC2100, I will document it on here. Going to order parts this weekend.

 

[slimbobaggins]

MC2100... Need to rebuild it

 

[slimbobaggins]

Got a booster off '90 4runner this morning as well

 

[slimbobaggins]

Got busy at work and havent messed with anything, but finally ordered the LC Engineering Holley 350 -> 22R adapter

 

[slimbobaggins]