Hey folks, total newbie here on FTE and also pretty new to actually doing the work on my 1987 E-350 ambulance. I've been handling the electrical stuff and simple maintenance for 10 years myself, but my mechanic handled the yearly tune-ups and keeping her going straight down the road. The Hokie Bus is a football tailgate machine, so she gets less than 100 miles a year which the mechanic says is the main problem ... "it needs more miles"! Well, the mechanic retired and sold his shop to a real estate developer and no-one in town wants to work on an '87 carbureted engine so I'm diving into this myself! My wife hates this idea, but I'm hard headed.

The (short) history on this beast is that it barely runs, we never get it over 35-40 mph and it makes the 3 mile drive to the stadium 6 or 7 times a year plus a few jaunts during the year just to stretch her legs. It has always run a bit inconsistent, sometimes running like a top, other times real rough with lots of backfiring. Tune-ups each year keep the backfires to a minimum, but I lost the mechanic and she hasn't been tuned-up this year. I got her running decent myself until two weekends ago when Hurricane Lee decided to dump 4 inches of rain on Lane stadium here in Blacksburg over a 2 hour period. The trek home after they delayed the game for 6 hours was through puddles of water that were up to 12 inches deep. Needless to say she doesn't run great any more.

I've been slowly nursing her back to health, but something really changed with how the engine runs. It's much harder to start where before it was pretty good at starting (if you knew the right approach), often getting very flooded before coaxing her to life. Power is way down, perhaps 10-25% of normal. I was barely able to get her out of the driveway and onto the street last weekend.

The vibration characteristics are markedly different now too, so we started poking around motor mounts etc and we noticed that (after much research to figure out what it is) the harmonic balancer (vibration damper) seems to be tearing itself apart. In the photo below you can see how the rubber ring is pulling out.

Questions:

1) What are the typical symptoms when a HB gets into this condition? Do you think this could be the cause of the recent degradation in how the engine runs?
2) Like I said, I'm a newbie at the shade tree mechanic thing, am I crazy to try this repair on my own?
3) It looks like it is going to be a real PIA to get the HB out. The Haynes manual says to remove the radiator which I believe since there are only a few inches between the pulleys mounted on the HB and the radiator, not much room to work an HB puller and installer (new tools to me BTW) in. Any recommendations on avoiding removing the radiator and keeping this repair simpler?

I'm going to have to learn about carburetors along the way, so I'm sure lots more questions are coming. I'm eager for advice, please let me have it!

Hokie Ambo driver
1987 Ford E-350 Econoline van converted to an ambulance and then a Virginia Tech tailgate machine for the last 10 years
Unknown number of miles
VIN: 1FDJS34L4HHA99676
Engine: 7.5L 460CI V8 Carb



Harmonic balancer / vibration damper

 

I'd pull the radiator. If you make a mistake with the puller you're likely to damage the radiator, and end up pulling it anyway.

Replace the balancer and a lot of your vibration will be gone. Time the engine with the new balancer (the marks will be back where they should be now).

 

Thanks for the quick reply. Timing ... something else I'm going to need to learn about!

 

The symptom for that balancer being no good is noise and vibration
There is no need to replace that harmonic damper unless the malleable iron inertia ring has slipped
The rubber coming out in one spot is not a problem
Cut it off with a sharp razor blade and move on to the real trouble
Do check the damper ring for being slipped which means a bolt in the spark plug hole
Use the #1 plug for the bolt
Turn the engine both ways until the engine stops and split the difference
I assume it has a 600 Holley on it?
Your mechanic was right
Take that thing out on the highway and run some gas through it
Hit wide open throttle for several seconds and repeat
Go as fast as you dare for as long as you dare
That will give you a decent evaluation of the carb and tune up
Good luck

 

Do pull the radiator to replace the damper
You realize the damper on a 460 has no weight for the external crank balance
That is a weight behind the damper that contacts the front seal

 

that I am purchasing, it looks like an exact match from what I've been able to eyeball online.

 

We have lots of noise and vibration, very different than two weeks ago, but no idea if it is due to the HB slipping. Rubber is coming out at two spots if that makes a difference.

I'm not tracking on your suggestion (I'm a newbie at this) for a bolt in the spark plug hole, what am I trying to check for?

 

Using a bolt in the spark plug hole
You are verifying TDC on the crankshaft and seeing if the malleable iron inertia ring has slipped on your balancer
That looks like the correct balancer