Mechanical advice requested

[Bowser]

I have a 1987 Class B with a Ford 351W engine with 61,000 miles on it. Compression tests on the cylinders are:
1 @ 130 pounds
6 @ 120 to 125 pounds
1 @ 110 pounds.

Anyone able to tell how long that thing will hold together considering it is older and works like a dog hauling that RV around?

If I have to plan on a rebuilt engine the sooner I know the better. And one other question.

Since I plan on keeping this forever, would it make sense to replace the transmission at the same time I did the engine, when I have to?

Thanks for whatever attention you can give this. I truly have no clue, and appreciate those who do sharing.

[DpDave]

Firtst off, to qualify everything I say, I am not a full time mechanic, but I did work on my own stuff for a long time. (These new diesels have WAY too much stuff hanging on them...)

From your readings it looks like you have one cylinder getting a little weak, but as I recall, 10% or so is not a lot to be concerned with. You aren't far outside of that.
How is the oil pressure and temperature holding up? If all that's there is idiot lights, consider putting guages in, they will give you a more accurate benchmark to go by.

If the transmission is not malfunctioning, I think I would let it ride until you had problems with it. Of course, that depends on how you are using it. If you have a long trip away from home coming up, it may be worth revisiting, if you are with in a reasonable distance of your own mechanic, then maybe not.

I am in the planning stages of an Alaska trip, so before I depart, I will lay in spare parts and make sure all repairs are done while I can get service from folks I know at home. It's hard to get a deal from service people on the road.

Hope that helps, and best of luck with it...

[450Donn]

Until that cylinder dropped to under 80 i would not worry. And personally i would opt for a transmission and torque converter at the same time. Once and done. Then your next. Concern is rear end front end and universal joints

[jofo777]

How was the test done and who did it? There can be a lot of variability depending on how it was conducted. Joe

[wonderer1]

biggest question to how long will it last is. how do you drive?? if you baby it, longer than if you have to be the first one to the top of the hill. then what are you asking out of you motor ?? how heavy are you loaded ?? are you towing anything ??

[Bill Davey]

Your compression test results are within normal expected range. The 125# reading is the theoretical max for a compression ratio of 8.5:1, so you seem to be OK. With only 61,000 miles, and a lot of hard work, I'd be more inclined to suspect leaky valves for the lower reading. Low compression will cause loss of power, but IMO is not likely to lead to catastrophic failure. Keep an eye on the oil level and oil pressure (gauge, not ididiot light) and just keep driving it.

If your're really nervous, have a shop do a leak-down test to determine where the compression is being lost (rings, intake or exhaust valve).

[1ciderdog]

Me, I'd drive that thing till it starts smoking or perhaps do a dry/wet compression test to narrow down the why of the lower cylinder compression. Installing a new or rebuilt engine is a lot of money, time and effort and I'd think you'd want to keep running that engine as long as possible.

[vsheetz]

Your compression test results are within normal expected range.
I am not seeing a problem.

Fix/replace the transmission if/when you have a problem with it.

61k/miles is not a lot of miles.

[Bowser]

THANK YOU ALL! That is exactly the information I wanted, from people I can trust. As a person who does not know much about engines, transmissions, vehicles in general, I can't tell you all how much I appreciate it.

For some of the observations, I'm 72 y/o, drive line a 52 y/o, rather slow, cautious. I love to get behind a truck going at the speed I'm comfortable with and just staying there. I don't know how the test was conducted. I'm old enough to recognize vapor lock, and know the cure for it is wooden clothespins attached to the fuel line between the pump and carb. And that's it.

Thanks again, I feel a lot better about that engine. And the transmission is not acting up, I will change the fluid before any long trip. Once I figure out how to get at it.

Thanks again. You are a super resource that is well appreciated.

[bbeane]

Just drive it keep the oil changed and and don't let it run hot, it will likey run a long while. Keep your $$ in your pocket until it breaks. Same for the transmission. Happy camping.