Old 454 Motor Question

[maxazillion]

Have a question for some of you old motor gurus. I finally did a compression test on my 1971 454 and got the following readings:

#1-137 dry, 140 wet
#2-135 dry, 140 wet
#3- 50 dry, 50 wet
#4- 150 dry, 162 wet

Do you think this is a candidate for a complete valve job? Or do think it would be better to just fix the #3 valve? I know a complete engine rebuild would be the best fix but really didn't want to spend that much money on it. Thanks for any advice.

 

[tractorsam]

That looks like it could be valve related but you wont
know until you pull the head. If you pull the head and find
a valve problem, fix it and put it back on. If not, keep
going. Only one way to find out.

 

[Janicholson]

The low cylinder might take a new valve or seat or both. the remainder should be surfaced and all guides checked. assessment of cylinder ware is also a good idea. Jim

 

[504]

Gut an old spark plug and weld a nipple in it to fit a
male end from your air hose and use it to know where
the air is going. Then you can tear it down with some
knowledge of the problem.

 

[teddy52food]

Could be camshaft rounded out. If the leak down test doesn't show anything, look at
the cam.

 

[rustred]

Thats a funny question ,I have yet to find a machine shop
that will only grind one valve in a head, and I dont
recommend it anyhow. Do it properly. Unless of course its
a backyard job and you talk the guy into it.

 

[DR. EVIL]

Dad traded our old 1960 Chevy 6 cylinder 4-speed 3/4 ton step-side pickup for a really sharp turquoise & white 1967 F-250 Camper Special, 352 V-8 and FMX automatic trans, power brakes & power steering, but no air conditioning. Somehow a tune-up was written into the deal and of course the dealer forgot to tune the F250 up before Dad came to pickup his new truck. Dad left to do other errands and the F-250 went into the shop. The Service tech did it right, did a compression test on each cylinder, and one hole was low. Dad comes back and the salesman says Dad should take his new truck home, and bring it back when he can leave it most of the day.
They pulled one valve cover and cyl head,and the intake manifold of course, and ground one exhaust and intake valve on that head. New head gasket, intake manifold gasket and exh manifold gaskets. The valve covers on the 352 V-8 extended over onto the cylinder head, made them more difficult to eliminate oil leaks but at least it idled smooth. I was about 17 when Dad got that truck, and I didn't mind chasing parts or hog feed with that truck. My future brother-in-law would call my Dad about one morning a month to ask if I could give him a ride to school and pick-up some lumber for his FFA Ag project. We had that '67 pickup for about 3 years, it was the last thing sold on Dad's quitting farming auction in mid-December 1972. Later, about 1975 Dad bought a '67 Dodge pickup, about the same color turquoise, but no tu-tone, 225 slant-6 and 3-on-the-tree, and was a gutless thing, and didn't really get any better mpg than the F-250 did. And pretty sparce interior compared to the Ford. I bought a new 2018 RAM 1500 5 years ago, they've really improved their pickups!

 

[caterpillar guy]

I don't by the valve deal. Since the compression didn't change on the one cylinder. I'm guessing the rings,cylinder,gasket, or piston is the problem not the valves. though since you have to pull the head to see. I would tip the head on it's side and pour water in the ports and see if any leak water if they do they need attention as well.

 

[rustred]

what about the other 4 cyl's ? you can roll the engine over with the valve cover off and check your cam lift. you cant check rings if the
valve is not sealing, thats a useless test. you will not get your answer till the valves are all out and inspected. the rest could be worn
and due. whats your engine miles?

 

[Jim Becker]

I assumed he was talking about an International 454, not a Chevy 454. There isn't another 4 cylinders.

 

[rustred]

makes sense now.