Hi guys

I recently bought a 1978 f800 dump truck with a 477. The truck runs but has a loud knock. I also have pretty good oil pressure. The questions I have are as follows

1. Is this motor worth fixing in the first place (or can I even get parts for it)?

2. Is there any other ford truck motor that will bolt in to replace my motor? (I have access to a 391 and am somewhat familiar with the FE.)

My original intention was to make a trailer out of it.

Thanks for your help
Mark

 

how many miles? How hard has it been driven do you think? Whats the overall rating of the truck? 1-10 1=junk 3=well used 5=average wear 7=pretty decent shape 10=excellent?

1978 F-250 Ranger Explorer 4x4
351M, C6, Np205, D44, D60 4.10LS

Drive It Like You Stole It!!!

 

I would guess that it has 146,000 miles. It is in pretty good shape, probabally a 7 or 8. It has been a city truck since the mid 80's. One of the landfill guys that used to drive it told me that the transmission has been recently overhauled and so had the motor. It has a new radiator and many of the belts and hoses appear to be pretty new. He thought that the city had spent around $13,000 on it in the last seven years. He didn't seem to know what caused the knock. He also said that it drank alot of gas.

My dad thinks it has a broken piston.

any ideas would be helpful

Thanks

 

Sounds like a piston skirt or wrist pin. Does the noise occur at engine speed or half engine speed?

Could it be in the valvetrain?

 

I have only started it two times. Each for just a few seconds. It has a very loud knock at regular idle. I have not tried to rev it up any higher.
I have a buddy who also thinks it may be a wrist pin.

If it is just a piston can I hone the cylinder and replace the piston?

Will I be able to tell which cylinder is bad with a compression tester?

Thanks

Mark

 

A compression test might not show you anything. Try disconnecting spark plug wires one at a time and running it. Sometimes with no spark the cylinder with the problem will not make noise. Be careful, and don't try pulling wires while it's running.

 

What happens to a wrist pin anyhow? Do they break?

I am also wondering if anybody has ever driven a truck powered by a 477. What kind of power can I expect?

Thanks

Mark

 

well I finally dropped the pan and found out it was a rod bearing. The bearing was completely gone. The journal is worn pretty bad, like .040 with a caliper. Does anybody know how much I can have the crank turned down? I also need to know what the original rod bearing diameter was. It was stamped and had been turned .020 already.

Thanks

 

I dont have any experience with the SD series engines, but a normal crank having been turned .020 already and then throwing a rod bearing would be junk.

 

My dad had a 477 in an F-880 Tandem axle grain truck. he could put 30K on it and it would get where you wanted to go, just might take awhile. It had a 10 speed fuller, and it would turn 3K at 55. Didn't matter if you only had 5K lbs on, when you were loaded, even a little bit, you used every gear in that tranny. running down i-75 to the grain elevator and back ~30 mi round trip, using the "georgia overdrive" on the one hill that would maintain 55 MPH, the truck got 2 MPG. It was a good ol truck though. If you could find a crank, I would stick it in there, it would be worth fixing, if you could pay the gas bill.

 

Thanks for the input. That is not what I was hoping for, but what I expected. I did find a crank. I just started to reassemble the motor today. I am currently waiting for rear main seals.

 

I have everything back together and have been driving the truck for about six months now. I am very happy with the motor. I have put about 1000 miles on it and have been getting 4-5 mpg. If anyone is considering buying or rebuilding one of these motors I would recommend them to go for it. I would also like to see someone put one of these in a pickup. I realize that it would not be easy or practical but it shure would be neat. Thanks to everyone who helped me along the way.

Mark

 

With today's gas prices, that's gotta hurt.

Glad to hear you got it running. Does it have good power?

 

It's no diesel but it's got pleanty of power for what I need it for. The most I have carried is 7 tons of distillers grain feed and had no problems cruising along at 50 mph. I was paying $90 per load to have the feed delivered and now it cost me $30 in gas plus my time. So even at $3 per gallon I am still saving money. Plus it is a good excuse for me to own another ford.