LOUD lifter (?) clatter???
Thread Starter
Instructor
Joined: Oct 2002
Posts: 103
Likes: 0
From: Crestwood Mo
LOUD lifter (?) clatter???
How can I determine if I'm experiencing a collapsed lifter? I had the car out for a spirited piece of driving and ran the RPM up high enough to hit the rev limiter and immediately began noticing a loud clattering noise from the passenger side head. The car seems to idle / run okay (doesn't stumble or backfire) but still continues to clatter loudly.
Engine is a 350 LT1 with AFR 109 cc heads, 218/224 Comp Cam, new Comp Cam 1.6 RR's ..... no mods to the lower unit.
Any assitance would be greatly appreciated - Thanks
:seeya
Engine is a 350 LT1 with AFR 109 cc heads, 218/224 Comp Cam, new Comp Cam 1.6 RR's ..... no mods to the lower unit.
Any assitance would be greatly appreciated - Thanks
:seeya
Racer
Joined: Feb 2002
Posts: 390
Likes: 0
From: St. Louis MO
Re: LOUD lifter (bogus)
Thanks Bogus - we did exactly that - used a piece of rubber hose to listen for the loudest sound origin and pulled the passenger side valve cover but everything looked okay - I started the car with the cover removed and still couldn't determine where the noise was coming from.....the car ran surprisingly well at idle and at low rpm for some time until the noise suddenly stopped during a short drive.....then the car started running line poopie - wouldn't stay running at idle without sugnificant throttle and had a substantial loss of power at all speeds. I'm about to remove the drivers side cover and inspect there for any obvious problems......still stumped.......... :confused:
Car has 68K on the clock - heads and valve train (cam & lifters) about 100 miles.
[Modified by Topload, 8:07 PM 11/28/2003]
Car has 68K on the clock - heads and valve train (cam & lifters) about 100 miles.
[Modified by Topload, 8:07 PM 11/28/2003]
Burning Brakes
Joined: Aug 2003
Posts: 944
Likes: 0
From: Mesa Az
Re: LOUD lifter (Topload)
My driver side #7 cylinder rocker arm did the exact same thing you are describing. it turns out to be a collapsed lifter. By the time i finally did something about it, i had a slightly bent push rod! Loud clatter means something is violently hitting. try taking rockerarm cover off and starting it up and seeing if the loud clatter comes back. (my L98 did not spray any oil anywhere below about 1500RPM...) I could see mine clattering that is how i diagnosed my problem, lol.
good luck too ya.
good luck too ya.
Racer
Joined: Feb 2002
Posts: 390
Likes: 0
From: St. Louis MO
Re: LOUD lifter (mistaben)
Thanks mistaben - I pulled the drivers side valve cover and found # 3 intake rocker cocked off to the side of the valve stem, bent push rod and collapsed lifter....nutz. Pulled the intake maifold and removed the lifter - sure enough, if I apply just minor pressure to the plunger it will squeeze down inside the lifter body (not a good sign). I'm running the Comp Cams R series lifters and thought these things were bullet proof. Evidently 6K RPM's is more than they're capable of supporting?? Guess it's off to my Summit catalog for a fist full of new parts - thank for the assistance.
:banghead:
:banghead:
Race Director
Joined: Jan 2002
Posts: 12,263
Likes: 86
From: O'Fallon Missouri
Re: LOUD lifter (Topload)
Al, when I initially read this thread, I thought of your car. Little did I know at the time that you were using a ghost writer "62K". :D
Hurry up and get that thing back together, so we can get it tuned.
Hurry up and get that thing back together, so we can get it tuned.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Re: LOUD lifter (Topload)
Here's MY guess on the problem. I think the high revs floated the valves, and allowed the self-aligning rocker to become, un-aligned. With the valve stem riding on the alignment ridge, rather than the roller, things started stacking up. The valve may have hit the piston (unlikely), the spring may have gone into bind, or the retainer may have hit the guide (seal). With the lower spring pressure, due to float or near float conditions, the lifter pumped up, further agrivating the "longer than it should be situation" and bent the push rod. I'd bet the lifter isn't hurt. A couple of things that may help prevent this in the future. Are the valve springs spec'ed for the cam? are they set at the proper installed height? How much lifter preload are you running? The greater the preload, the further the plunger can travel at pump up. Just a few thoughts on the subject. Good luck, and...
RACE ON!!!
RACE ON!!!
Safety Car
Joined: Dec 2002
Posts: 3,655
Likes: 24
From: Charleston SC
Re: LOUD lifter (?) clatter??? (62k)
I had the same thing happen on my L83 and it turned out to be a broken valve spring. I would atempt to adjust the rocker and the clater would persist. Finaly I was adjusting the rocker cold and noticed the valve moving with minimul preasure (Just past zero lash. The good news was it was easy to fix just aplied air to the cyl and changed it on the car. If you have the incorect springs and had coil bind a broke spring is one posiblity.
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Racer
Joined: Feb 2002
Posts: 390
Likes: 0
From: St. Louis MO
Re: LOUD lifter (84LT1)
Thanks for all the assistance - I had AFR upgrade the springs when I bought the heads (they had only been on the car for approx. 100 miles when the problem showed up) so I don't think it's the spring that has failed - but - I'll have a look just to make certain. I'm thinking that the lifter may have been bad from the manufacturer. Close inspection shows that the retaining clip at the top of the plunger is cracked and the plunger is very weak to any applied pressure. All the remaining lifters are rock solid when pressure is applied....after considerable thought, I'm going to put in a new set of standard lifters and go back to the hardened push rods and guide plates and see if that eliminates any further failures........ :confused:
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Re: LOUD lifter (Topload)
and go back to the hardened push rods and guide plates and see if that eliminates any further failures........ :confused:
RACE ON!!!
