Got my engine down to longblock status & got a bit of a surprize

efhughes3 · efhughes3's Garage

I started tearing into my 3.2 that saw an over-rev at the track the other day. After I got the valve covers off, the valve adjuster locknuts for #1 & 3 exhaust and #6 intake were off the studs!

I'd done a valve adjust just over 300 miles prior to the mishap. I'd even double-checked the tightness of the locknuts as I've done on all of my previous valve adjusts, so I was confident in them being tight. This kind of perturbs me. I can maybe see it if one spun off as an error, but to have three "fall off" is wierd. Anyone ever experienced this with an over-rev due to a mis-shift?

I don't know if this is a result of the over-rev, or if it all happened simultaneously as they were not tight enough, and the mis-shift rattled them enough to spin off?

The good news is that I did find all three, two unharmed, one smashed a bit to an oval.

On another note, when I drained my oil at the time of the drop, I had a fair amount of metal filings or a gold color suspended in the oil. Valve guide material? I am having an oil analysis done to see what the metal was.

Next step is getting into the guts.

Candelaria · 04-11-2007, 04:08 PM

You should also check the distributor gear on the crank., Candy.

efhughes3 · efhughes3's Garage

It's all going to be torn down and checked. I just am surprised that these 3 nuts backed out.

len911 · 04-12-2007, 03:43 AM

Been there, done that! I also missed a shift a few years ago, 3-2 instead of 3-4 and proceeded to bend my six exhaust valves. Much to my surprise, one of the adjuster nuts was off... I found it at the bottom of the case... So it does happen. Lou

Jeff Alton · 04-12-2007, 08:07 AM

The adjuster screws can bend easily as well when valves kiss pistons. It becomes evident when you try to remove them from the rocker arms.

Cheers

efhughes3 · efhughes3's Garage

Quote:

Originally posted by Jeff Alton
The adjuster screws can bend easily as well when valves kiss pistons. It becomes evident when you try to remove them from the rocker arms.

Cheers

I noticed that on one already. What's a few more $$??

BTW Jeff, I'm hooking up with Bob tomorrow morning.

Jeff Alton · 04-12-2007, 09:55 AM

Thanks again, I talked with him last night. Let me know if you need some screws, I have some good servicable ones here.

Cheers

Eagledriver · 04-12-2007, 06:52 PM

Actually you don't need an over rev to make the adjusters hard to remove. They seem to stretch when the locking nuts are tightened (maybe too much). The easy way to remove them is to back them out instead of screwing them in. The elephant feet will just pop right off the end.

-Andy

Walt Fricke · 04-12-2007, 08:21 PM

I've had nuts back off due to valves hitting pistons. I think it actually compresses the adjuster enough that the stretch holding the nut to the rocker disappears. After that the nut will spin right off.

How can the adjuster compress up by the nut from a force applied at the other end? I don't know, maybe the threads distort just a little.

And we tend to overtorque these nuts (fearing they will get loose due to our assembly failures). I think this has something to do with the difficulty sometimes encountered in getting the adjusters out, with either the rocker threads or the adjuster threads or both being a bit distorted.

Anyway, I think there is a correlation.

All the more reason to pull the valve covers promptly after any significant overrev, even if things otherwise seem OK.

Walt Fricke

efhughes3 · efhughes3's Garage

Thanks for the feedback, it's reassuring to know this is just another symptom of the over-rev. It just hurt me to think I may have caused a problem with a goof-up on my part during the valve adjust.

Now, I only need to be hurt by my goof-up on the shifting....

efhughes3 · efhughes3's Garage

Almost time to pull the P's & C's....

The two cylinders that had the locknuts spin off are bent. I could shine a flashlight into the combustion chamber, peek in thru the port and see light. But, the piston tops look good.

Jeff Alton · 04-16-2007, 08:04 PM

You are making good progress! Fedex says the tools should be there on the 18th.

Cheers

efhughes3 · efhughes3's Garage

Thanks Jeff, that'll be perfect timing.

Walt Fricke · 04-17-2007, 12:09 AM

Er, you meant the two exhaust valves are bent? The ones which left those marks in the carbon on the piston tops in the picture? #s 1 and 2?

When you get the pistons off I'd especially check the area between the first ring groove and the places where the valve hit the piston. My guess would be that you are OK, but you want to check to see if there is less ring clearance at that spot than elsewhere, due to the side of the piston being compressed. I had that happen. The ring was so tight it was hard to remove. Though if memory serves it was from an engine that had a more serious problem - maybe it was the one that swollowed some carburetor air horn screws and finished the race that way.

Walt Fricke

efhughes3 · efhughes3's Garage

Quote:

Originally posted by Walt Fricke
Er, you meant the two exhaust valves are bent? The ones which left those marks in the carbon on the piston tops in the picture? #s 1 and 2?

When you get the pistons off I'd especially check the area between the first ring groove and the places where the valve hit the piston. My guess would be that you are OK, but you want to check to see if there is less ring clearance at that spot than elsewhere, due to the side of the piston being compressed. I had that happen. The ring was so tight it was hard to remove. Though if memory serves it was from an engine that had a more serious problem - maybe it was the one that swollowed some carburetor air horn screws and finished the race that way.

Walt Fricke

That's what I meant, I don't know what you mean, maybe I wasn't specific? All of the pistons had a bit of marking, but the #1 & 3 exhaust noted at the beginng of the thread are the ones that I can see light thru. Good point about specific attention to the grooves in that area.

efhughes3 · efhughes3's Garage

Got the cylinders off today, the cross-hatching looks good, but their are some visible "scuff marks" from the piston skirts. Nothing you can feel, but it's visible none the less. Is this what you would typically see?

I checked the clearance on the top ring to the groove on one piston, and it was .006", just out of spec. But, the ring is a little thinner too, so when you consider it all, I'm probably on the borderline with regard to ring grooves wear. I'll defer final judgement to the machine shop during inspection.

jpnovak · 04-17-2007, 02:14 PM

Ed, Is that rust/corrosion on your head studs? That might just have been a ticking bomb.

btw, your ring land might be in-spec. Try it with a new ring.

The cylinders look pretty good check for out-of-round and diameter.

I bet I can tell which direction your exhaust valves are bent based upon the nice mark in the carbon on the slope of the dome.

Keep going. Doing great so far.

efhughes3 · efhughes3's Garage

Jamie: That is some surface stuff on the steel studs, but you're right, coulda led to something down the road. The funny thing here is the Dilavar studs look great.

boba · 04-17-2007, 04:17 PM

Ed,

It looks like you dodged the catastrophic over rev. Good for you.
Now starts the slippery slope!!! Just do it.

Regards,
Bob

efhughes3 · efhughes3's Garage

Quote:

Originally posted by boba
Ed,

It looks like you dodged the catastrophic over rev. Good for you.
Now starts the slippery slope!!! Just do it.

Regards,
Bob

Thanks, I do feel a little relief. But then, I look at the parts I've got spread out all over, and think about how many hours I'm going to have in cleaning.......