Valve gap grows on my 74f rebuild (1 Viewer)

[rsbcruiser]

My valve gap is loose everytime I check it. I have adjusted out 0.020" since rebuild. I have adfusted the valves maybe eight times now. Forget your first thought. I ran and set valves for years with no problems. 74 f has all new (or rebuilt) valve train except pushrods. Lifters are Man-a fre cheapies. I almost sent them back because they look cheesey compared to stock with serations on pushrod contact area and smaller cup. Downey torque cam and Downey springs. Jim "just say yeah" (thanks Jim) says gap is same as stock. Pushrod tips were ringed but not worn thru hardening. Checked oil, no metal there since rebuild. I suspect rods are wearing into new contact surfaces. Any other ideas? Suggestions on what to do? Gap growth has decreased but has not stopped. I know, I know, hit my head into wall, was just trying to pinch pennies. man those things are expensive to rebuild! Hindsight says I should have gone for all new, no skimp but that is hindsight isn't it?

 

[Degnol]

Cam and lifters are wearing in, too. How many hours or miles since rebuild?
Did you break in cam and lifters? Run at 2000-2500 rpm for 20 minutes?

GL

Ed

 

[Trollhole]

I'm thinking wear in. But is this the same engine that has a crack?

 

[grant5127]

How many miles or time usage between adjustments?..is there adequate oil flow throughout the rockers...

 

[rsbcruiser]

Degnol, Broke in for maybe 10min at 2000, changed oil. Motor has 3000 miles now. Trollhole, yes it is the cracked block. Crack is tiny though, maybe lost sip of coolant since rebuild. So far, it looks as though it might be fixed, block sealer and JB Weld on exterior with no metal work. poor old motor had even worse than me (hard to imagine) mechanics in past. Wow! some people need to ease off the copper coat applications. Wad as big of my fist made it 8 years down there before I dropped pan. It dropped a main cap finally. On and on I mean buy a torque wrench.

 

[rsbcruiser]

Grant5127, she has maybe 3000-4000 on her some har and I do mean hard off road, 3 days. All rocker holes are squirting with very little seap from rocker bearings, Those puppies were dead nuts 0.0004-0.0006" one a little loose at 0.001" Have not yanked rocker to check. Do you think I should. Toy bearing in there.

 

[grant5127]

Yep, I'd inspect the rockers and shaft just to make sure whats going on.........

 

[Degnol]

Did you retorque all the rocker shaft supports? Maybe not the correct terminology, but you know what I mean. Poser always begins with that when "running the rack"

GL

Ed

 

[grant5127]

"running the rack"

That brings back fond memories of my Diesel Days....

 

[Degnol]

That brings back fond memories of my Diesel Days....

Whole different meaning for me, but hey


Ed

 

[rsbcruiser]

Did you retorque all the rocker shaft supports? Maybe not the correct terminology, but you know what I mean. Poser always begins with that when "running the rack"

GL

Ed

No I didn't, sounds like a good idea, I will take rocker off, inspect and then torque, hope no damage there. spent 150 bones on damn rod of steel with a couple of holes. and those rocker bearings aren't the funnest to do, let me tell you. Thanks

 

[Degnol]

Probably no need to remove it, just torque back to spec. You said it was getting oil. This is not my original idea, Poser turned me on to it and I had completely overlooked it. Do you use a "go,no-go" feeler gauge? Makes it easier/simpler.

Ed

 

[grant5127]

Loose rocker supports are usually noticeable at a glance with the engine running, especially #4, there would be excessive oil leakage at the base and decrease in flow to the remainder.....

 

[rsbcruiser]

Loose rocker supports are usually noticeable at a glance with the engine running, especially #4, there would be excessive oil leakage at the base and decrease in flow to the remainder.....

Now that I think about it, I checked torque on the shaft mounts a couple times. I might yank that sucker anyways, to check my work on the rocker bearings. I used an old reamer on them. Seems to be a place to start. I didn't set the valves for a thousand miles or so now, when I was doing it all the time it seemed to settle down some between settings. Funny but in a way the motor seems to run better a little sloppy on the valves.

 

[Degnol]

Funny but in a way the motor seems to run better a little sloppy on the valves.

And far less likely to burn an exhaust valve, too.

Ed

 

[Degnol]

Here is a pic of a "go-no go" feeler gauge. If you want to set your lash at .008" select the .007-.009. The tip is .007 and the body is .009, so when the tip will fit and the body will not, in theory you are right at .008. Hope that makes sense

Ed

 

[rsbcruiser]

Much sense. Funny, I've been dinking around with this plus years doing precision measurement for $ and ya know either I've never seen them before or never paid them no mind. I like how they can be seperated like regular feeler gauges. Going back in there. Though I'll have you know that this violates one my tried and true landcruiser rules. If you don't look, its' not broke. How do you think I got into this mess in the first place?

 

[rsbcruiser]

Here it is several weeks and maybe 500 miles. The valve seem quite since the last setting. I just did a compresion and leak down test.

DRY WET % Leak
1 150 152 20
2 135 148 55
3 140 145 50
4 150 155 55
5 155 155 35
6 150 160 55

Grim to say the least. I will have to pull the heads for sure. Lots of air coming from everywhere. I'm thinking the bottom end might be okay.

 

[grant5127]

Grim to say the least. I will have to pull the heads for sure. Lots of air coming from everywhere.

I think so.......

 

[IDave]

I had problems with expanding valve lashes on a head earlier this year. It turned out there were a couple of issues, different valves. One was a cracked valve stem seal (new, aftermarket) that caused the valve to stick partly open. The other was a stuck lifter (and worn down cam lobe associated).