So, I have a very nice running 2.0, I went through it last spring and its been bulletproof and reliable.
No trouble at all, but lately I've noticed a little more valve clatter. Oil change and valve adjust and its fixed.
2 weeks later, a little valve clatter...valve adjust and..hmm..exhaust on #2 is suspciaously loose. Well, it happens, adjust and on my way.
Another couple weeks and tik*tik*tik...WTF? I go straight to #2 and there it is, a loose .008".
Adjust and I can see that particular adjuster screw is in further than the others.
Not good, but from my experience / understanding the valve seat gets hammered INTO the head and makes for tight valves until it drops out. Engine has about 4000miles, and no other symptoms- no signs of cam wear, haven't pulled the lifter yet but #4 has good/consistant clearance. Adjust screws appear good, no wear.
What do I do?
Bob O

QUOTE (914ghost @ Feb 1 2006, 03:53 PM)

a loose .008".

I thought the spec was .008 on the exhaust?

Well, I've always set mine at a regular .006".
Never had trouble with that....but, even so, the trouble is the clearance is changing rapidly, no matter what it starts at.

Could be a valve seat working its way out of the head. Worry.

The lifter and cam lobe are probably eating each other up. Drain the oil and check the screen for chunks of metal. You may be able to pull the rockers, push rod and tube, then the lifter. If the bottom of that lifter is toast you will not get it out through the hole. It is unfortunatly rebuild time... Sorry...if does come out inspect all the pieces and get new/reground lifter use it and keep a close watch.

Where your lifters out recently for any reason? This usually occurs when two lifters are mixed up put back into the wrong place, Ask me how I know...no don't....

-Mike D.

QUOTE

The lifter and cam lobe are probably eating each other up.

That was what I was thinking, but the clearance on #4 isn't changing at all. Sincle they share a cam lobe I would figure any wear on the cam must effect the other side too?
I pulled the pushrod and let the oil drip out and its very clean, same with the stuff in the valve cover. It's weird enough at this point to freak me out. I hate this shit.
I'll check the screen this weekend.

How many miles on the motor? I thought the rule of thumb is if its made it past the first few thousand miles, the cam and lifter have seated and wont be an issue?

QUOTE (914ghost @ Feb 1 2006, 03:53 PM)

Not good, but from my experience / understanding the valve seat gets hammered INTO the head and makes for tight valves until it drops out.

hammered by what ???

the only thing holding the valve against the seat is the valve spring. i doubt your valve spring is strong enough to somehow force the seat INTO the head.

now, once the seat has worked it's way OUT of the head, the valve & seat can very well make contact with the piston and get hammered into the head that way ...

i'd drop the motor and take the head off and double check the seat ...
Andy

Sounds like a bad lifter to me. I had exactly the same problem. #2 exhaust. Kept adjusting and 500 miles later it's banging again. Fat Performance originally built the engine and replaced the lifter for me and also the valve since the valve stem had been banged on for so long. And yes you should worry.
Cheers, Elliot

Well.."hammered" may not be an appropriate term, but thats what the seat and it's hole look like if they fail.
The hammering comes from the seat being loose and it slightly falls out of its hole, then its shoved back in instantly by the pressure from the spring as the valve closes.
Over and over again at an average of 3500 times per minute and the valve seat fairly quickly eats / taps away at the bottom of its hole in the head. This brings the valve further into the head each time it seats...which is what cause the gap at the valve / adjuster to go away.
The lifTer idea makes more sense, but I'm at 4k miles..and the cam was a regrind, with matched lifters- hey! I'm on a budget!- AND #4 gap stays put.
I'll probably pull it out and screw with it before it grenades.

check the lifter... and if it is messed up or shows ANY wear, don't just replace it and think 'cool', get the cam out too and replace the cam and all the lifters. May already know this, but JIC. BTW, any wear is not good - lifters get kind of a 'pattern' on them that has a rotating look to it, but the lifter should still feel smooth.

as for a few thousand miles being a guarantee on a cam not flattening, that is not always the case. A guy I was just talking to last week just had a tappet cam flatten after 2 yrs of near daily use - don't know mileage but my guess would be at least 10K. Just happens sometimes, though definitely rare after just 20 minutes of good break-in, let alone 2K miles. I would guess it was a bad hardening on a lifter and it just finally degraded enough, and once you start running metal through the motor, more lifters can fail and/or wipe the cam out.

Off the p-car topic, but on the dyno, I have a pretty tight "pucker" going for the first 20 minutes on a small block chevy with a mech tappet cam!! SBCs are just the absolute worse design in engineering history IMO When I ran mine in on the dyno, I was completely nauseated and thought I was going to puke for the first 20-30 minutes!! I''d built well over 500 engines over a 4-1/2 year career at one hot-rod shop alone and only had three cams fail ever - all 3 mech tappet; 2 small block chevies and 1 big block. The BB made it almost an hour

actually... I haven't every messed with a flat four valve adjustment, so bear with me for a minute...

how is the rocker arm mounted? Are they stud mounted? I recall that there are studs in a type 4 head, but never saw the rockers and how they mounted down. I think they were shaft mounts...

If they are mounted one rocker per stud, make sure the stud isn't backing out... I have seen that on other types of engines where there was a press-in stud, and over time and heat cycles, the stud came loose and backed out. THe guy tightened up the rocker, then shortly thereafter same problem and so forth.

Actually, if the stud is backing out near the rocker in question, even with a shaft mount assembly, you would see extra clearance on one valve, but should really see it at both valves; one will just be more pronounced than the other (the one near the stud backing out).

Sounds like you *may* becoming a "Lifter statistic".... I'd pop the lifters out and look at them, if they won't slide out of the bores the lifters are zapping out for sure.

What cam and lifters did you slap back into it.

Lifters and cams do NOT play games fellas- it took me 18 months and almost 16 grand (some of which was donated by you guys- thanks) to get to the bottom of it all. Some issues were the cam and some were with the lifters. Three processes and one radius change has proved t be the answer to the issues.

we have sold 250 cam/lifter sets and only experienced two failures, one of which was the customers fault- he had coil binding valve springs!

BTW- #2 exhaust is the most common lobe/ lifter to fail. dozens and dozens of the issues we have seen have came from the #2 exhaust!