Noise after Cam Install
Thread Starter
On The Tree
iTrader: (15)
Joined: Mar 2003
Posts: 163
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From: Sanger, California
Noise after Cam Install I was wondering if anybody's valvetrain got noisy after going from a stock cam to an aggressive cam? My car never made a ticking noise when it was stock but now there's ticking in the motor. The ticking gets more rapid the higher the RPM but gets quiet at idle. It almost sounds like a bent pushrod but I replaced them with hardend pushrods when we rebuilt the motor and I havent abused the motor yet. It has about 1100 miles now since we rebuilt the motor. Is the ticking noise normal? My mods are in my sig
Launching!
Joined: Nov 2002
Posts: 296
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From: NY
Where did you here this? I wasn't told to shorten the pushrods on my f11 cam. Most run the stock length with a cam change unless heads are milled.
Originally Posted by Larry
The problem is the base circle is smaller on high lift cams. Shorter pushrods are almost always needed if you do not mill your heads.
Originally Posted by SloppyRob
Where did you here this? I wasn't told to shorten the pushrods on my f11 cam. Most run the stock length with a cam change unless heads are milled.
There is certainly some tolerance in required lifter preload but if you reduce it much the lifters will get noisy. This is why so many complain of a noisy valve train after cam install.
Launching!
Joined: Nov 2002
Posts: 296
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From: NY
If the base circle is smaller wouldn't you run a longer pushrod if any?
Originally Posted by Larry
Measure the base circle of all the aftermarket high lift cams and you will see what I'm talking about. With a smaller base circle you will get less lifter preload.
There is certainly some tolerance in required lifter preload but if you reduce it much the lifters will get noisy. This is why so many complain of a noisy valve train after cam install.
There is certainly some tolerance in required lifter preload but if you reduce it much the lifters will get noisy. This is why so many complain of a noisy valve train after cam install.
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What the hell ... I have never ever heard anyone say anything about this.
I was under the impression the louder valvetrain was do to the lighter valvetrain components one usually installs with an aftermarket cam, and the higher lifts involved in the aftermarket cams.
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What the hell ... I have never ever heard anyone say anything about this.
I was under the impression the louder valvetrain was do to the lighter valvetrain components one usually installs with an aftermarket cam, and the higher lifts involved in the aftermarket cams.
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Originally Posted by Larry
The problem is the base circle is smaller on high lift cams. Shorter pushrods are almost always needed if you do not mill your heads.
I just recently installed a FMS F11 and I have the "sewing machine" noise that everyone has heard of for the last coulple of years with cams of these specs, if different length pushrods were required to lessen this sound I would think that this would be informed to all that purchase cams with these specs?
Originally Posted by SloppyRob
If the base circle is smaller wouldn't you run a longer pushrod if any?
Originally Posted by ss rally red
I just recently installed a FMS F11 and I have the "sewing machine" noise that everyone has heard of for the last coulple of years with cams of these specs, if different length pushrods were required to lessen this sound I would think that this would be informed to all that purchase cams with these specs?
I really don't think a lot of the guys selling cam know to tell you this.
Anytime you change cam, heads or whatever that might change geometry, you need to check to be sure the rocker tip is moving on the center of the valve tip and the proper preload is adjusted into the lifters.
Launching!
Joined: Nov 2002
Posts: 296
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From: NY
I dunno man, i think the sewing machine noise is caused by the valves opening and closing fast. I've yet to see someone sell anything above a 7.4 pushrod so I definitely don't think they're necessary for a cam swap.
Launching!
Joined: Nov 2002
Posts: 296
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From: NY
Well I was reading a few days back and saw that the stock pushrods are indeed smaller than the 7.4. I believe they are about 7.35. So by running 7.4 you are running a slightly longer pushrod to account for the difference in base circle with the new cam. Oh, and my cam install went well and i have no real valvtrain noises besides some soothing machinery moving type sounds (best way to describe it) 
Stock push rod = 7.375". If you change the cam only, the base circle is .030 smaller so to get back to the exact preload you would need a 7.405". Since there isn't one, most people go with a 7.400" which is fine. Now if you have heads and cam you would need shorter push rods depending how much they were milled.
On The Tree
Joined: Aug 2003
Posts: 123
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From: Las Vegas, NV
One noise I noticed after doing my cam swap was that my injectors were all making loud ticking noises... I found it was the injectors by listening through a small tube around the block. Doesn't seem to hurt performance and it sometimes goes away if I throw in a bottle of techron.
