New cam...loud clacking lifters. ???

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rexduster

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Hi, Hope someone can help. Installed XE268 cam and lifters in a stock 318 with carb/intake. Fired it up for break in and very loud lifter noise...thought they would pump up ran thru break-in. Noise never went away, had small oil leak at back of intake, took intake off found 4 bent push rods and lifters completely pumped up. I ordered OEM pushrods and put it back together, noise still there, very loud clacking lifters. Called Comp Cams, they said to check pre-load, did that, found "0" pre load, OEM pushrods undamaged, ordered .050" longer push rods, took a vacation day today to install them....noise still there...sounds like a diesel idleing!
 
What valve covers are you running? Do they have baffles in them? sometimes the noise can be rockers hitting the baffles.
 
comp cam extreme cams are known for there lifter noise ..they have very aggressive ramps that drop of quick. that is where the noise comes from > that is what I have been told .. I had a set in my 440 with edelbrock heads and it claddered real bad after 1500 rpm . even switched to adjustable rockers......... still........... with no improvement.
won't use comp extreme cams again !
 
They are M/T, all clear inside but thank you for the reply, My friend has a repair business and is very much into muscle cars (has owned two superbirds) he is even baffled, says its coming from the lifter area.
 
^^^ This is true also, I run the HE268 and have the same issue, although it isn't very loud, I can hear it.
 
Thanks for reply's, oil pressure when hot is 20@idle, 40+ just off idle, and up to 60+ from there... timing is right on, starts with a touch of key, idles nicely, sounds great at the exhaust, shafts are correct, ran with v.covers off...plenty of oil @ the rockers...only bent 42 yr. old push rods when first started, both sets since are fine.
 
Agreed. Your valvetrain clearances are wrong.

We need more info on the gear you are running.

-heads
-valve springs
-valve spring retainers
-valve stem seals
-rockers

Some years of the 318 have more clearance in areas than others.
 
rexduster said:
Thanks for reply's, oil pressure when hot is 20@idle, 40+ just off idle, and up to 60+ from there... timing is right on, starts with a touch of key, idles nicely, sounds great at the exhaust, shafts are correct, ran with v.covers off...plenty of oil @ the rockers...only bent 42 yr. old push rods when first started, both sets since are fine.
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Do the valve covers have baffles??? Sorry missed the post above!!!


You might be experiencing coil bind, but it seems it would affect the new pushrods as well.
 
Bone stock '71 318 2bbl. plymouth gold duster to start... no aftermarket engine parts...checked for coil bind today...did not have a guage there so I used a putty knife and at full lift seemed to have plenty.
 
Are you running the recommended springs for that cam? You made mention of cam and lifters, but nothing about the springs.

If you aren't maybe you had some piston to valve contact and that's what bent your pushrods.

There is a recommended spring (901-16) I "think", that is required to run that cam.
 
You may be on to something...these are the original springs, probably old and weak...never read anything about new springs. I'll give it a try!! Thanks for all reply's and FABO...
 
I drove the car again today about two miles taking it really easy... if there were valve to piston issues, I don't think it would stay running.
 
rexduster said:
You may be on to something...these are the original springs, probably old and weak...never read anything about new springs. I'll give it a try!! Thanks for all reply's and FABO...
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I bet this is your issue, gotta change the valve springs, esp 42 yr old ones when changing camshafts! Hope you get it figured out, I used to run this same cam in my dakota back in the day, and I didn't have any lifter noise. I know that cam is small but I still think that its too big for the stock valve springs.
 
Could the stamped rocker arms be causing this if they are original and worn? Also, It's just as noisy at idle...so would this rule out valve springs?
 
rexduster said:
I drove the car again today about two miles taking it really easy... if there were valve to piston issues, I don't think it would stay running.
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I wouldnt be to sure on that. This engine ran for about 50 miles before it got torn apart. Did the same thing your talking about. The guy changed his cam and had issues. .475" lift.
 

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Helped my friend install this cam into a 69 318, had stock flat top piston, with no valve reliefs. The valves were hitting pistons. Luckily we never ran it, found it out during mockup. He wound up going to a comp 256xe.
 
The lift is really irrelevent. It's the duration that you need to look out for regarding valve to piston clearance. The Comp 268 should be fine in that area for a stone stock engine. If I had to guess, I'm goin for coil spring bind, or valve retainer to guide interference. Either of those would cause bent pushrods.
 
Mike Liston, Thank you very much for your time...I'm so bummed out today...spent alot on parts over the winter like water/fuel pumps, tune up parts, gaskets, hoses, dress up stuff...Comp. cams tech line said this would be fine with a stock 318...just check for spring bind...did not have the heads off to check valve clearance...rotated the motor 3-4 times b4 firing and did not feel anything... also... if you read my original post, I added the second set of push rods @.050+ and stayed the same noise level. Would you pull a head off to confirm at this point?? (if so I'll give you my address!) just joking... thank you for your input, Dan
 
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