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03-12-2003, 12:08 PM
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CC Member
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Join Date: Jul 2000
Location: San Antonio,
TX
Cobra Make, Engine: FFR3200, Carbed 351W, IRS, TKO600 RR
Posts: 671
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Not Ranked
UPDATE: Cam Lobes - how fast can they wear...
I got a ticking noise last week in my drivetrain('69 351W /no roller anything). Pulled off the valve covers and everything looks fine. Drove a pretty good bit on saturday and it gets worse and worse. Pull off the rockers on the #1/2 and the #1 intake rocker seems to be abnormally worn on the pushrod side.
So, I think its either a bad lifter or I'm losing a lobe on the cam. How fast can a lobe be lost?
Pulled the pan and intake and one head and I have yet to find anything obvious.....I'll post if I find anything interesting. 
Last edited by stuck; 03-16-2003 at 12:53 AM..
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03-12-2003, 12:09 PM
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CC Member
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Join Date: Jul 2000
Location: San Antonio,
TX
Cobra Make, Engine: FFR3200, Carbed 351W, IRS, TKO600 RR
Posts: 671
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Not Ranked
I guess I can use a dial to check the total lift against one of the other intake valves...? Sound like a plan?
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03-12-2003, 12:53 PM
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CC Member
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Join Date: Mar 2002
Location: so cal,
Cal
Cobra Make, Engine: I used to fix them for a living
Posts: 2,563
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Not Ranked
A cam lobe can go away in a very short period of time. If the lifter does not rotate in it's bore, that lifter and lobe will be wasted in no time flat. You are referring to a worn rocker arm however. There are a couple of things that can cause a rocker to wear, a worn cam lobe is not a cause for rocker arm wear. Incorrect geometry at the rocker, too much lift for the factory rockers will cause biding which will bend pushrods and/or chew up the pushrod cup in the rocker. That's why they sell "long slot" rockers. Misaligned guideplates can cause all sorts of problems. ANyway, I think your problem has nothing to do with the cam, I would be looking at the rocker in question and the valve stem tip. Replace rocker, see what happens.
__________________
In a fit of 16 year old genius, I looked down through the carb while cranking it to see if fuel was flowing, and it was. Flowing straight up in a vapor cloud, around my head, on fire.
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03-12-2003, 12:57 PM
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CC Member
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Join Date: Jan 2003
Location: Southlake,
TX
Cobra Make, Engine: BDR #42, 425HP 347 - NASA TX, CMC #55 Mustang Road Racer - Legends 37' Chevy Coupe #43 Oval Racer - Honda CRF450R(I'm afraid to race it), 95' Black Lighting Daily Scooter
Posts: 599
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Not Ranked
Ryan: A bad lifter can flatten a lobe pretty quick. How many miles on it? Too stiff on springs can flatten a lobe before break-in is finished. Definately sounds like something is too stiff on the number 1. I'm not an expert either but the dial gauge sounds like a plan.
I went through 3 Lunati cams one time that would go flat due to spring pressure but the spring pressure was set to handle the lift of the cam. I just gave up and never used a Lunati again.
Boudy
Last edited by Boudy; 03-12-2003 at 01:02 PM..
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03-12-2003, 01:05 PM
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CC Member
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Join Date: Jul 2000
Location: San Antonio,
TX
Cobra Make, Engine: FFR3200, Carbed 351W, IRS, TKO600 RR
Posts: 671
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Not Ranked
If a valve was hanging up would that cause the cam lobe to wear...? Sounds like it would...
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03-12-2003, 01:09 PM
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CC Member
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Join Date: Jul 2000
Location: San Antonio,
TX
Cobra Make, Engine: FFR3200, Carbed 351W, IRS, TKO600 RR
Posts: 671
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Not Ranked
I have a new rocker, so I guess I'll try it out for a week or two......thanks guys!
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03-12-2003, 02:28 PM
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CC Member
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Join Date: Dec 1999
Location: corpus christi, tx78414 usa,
Posts: 401
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Not Ranked
hey ryan
check your oil filter to see if you see any metal shavings. will look kinda like grey sludge. don't run the engine until you see if something is wearing. see my site for the consequences.
paul |
03-12-2003, 02:31 PM
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CC Member
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Join Date: Jul 2000
Location: San Antonio,
TX
Cobra Make, Engine: FFR3200, Carbed 351W, IRS, TKO600 RR
Posts: 671
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Not Ranked
Hey Paul, What happened to you? Or is this a past experience...
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03-13-2003, 08:35 AM
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CC Member
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Join Date: Dec 1999
Location: corpus christi, tx78414 usa,
Posts: 401
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ryan
nope, that is what is going on right now. my spring break will be spent mostly rebuilding the engine. not what i had in mind.
paul
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03-13-2003, 08:48 AM
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CC Member
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Join Date: Mar 2002
Location: so cal,
Cal
Cobra Make, Engine: I used to fix them for a living
Posts: 2,563
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Not Ranked
He is referring to a worn rocker arm. He has speculated that it is being caused by a flat lobe on the cam. That is most likely not the cause. The problem is being caused at the rocker.
__________________
In a fit of 16 year old genius, I looked down through the carb while cranking it to see if fuel was flowing, and it was. Flowing straight up in a vapor cloud, around my head, on fire.
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03-13-2003, 12:50 PM
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CC Member
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Join Date: Jul 2000
Location: San Antonio,
TX
Cobra Make, Engine: FFR3200, Carbed 351W, IRS, TKO600 RR
Posts: 671
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Not Ranked
Well, the new rocker arm went on and the noise is still there! Guess I'll open her up...
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03-14-2003, 06:45 AM
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CC Member
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Join Date: May 2001
Location: Elgin, Texas,
Posts: 231
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Not Ranked
Bearing problem? Less than a month ago I developed what I determined to be a "rod" knock in My 351W. I found no. 5 and 6 bearings down to the brass. Crank was OK after a little emory cloth work. Rods and crank checked out fine on specs. These were the only 2 rod bearings that looked this way, the rest looked proper. Replaced all the rod bearings with Clevite 77, instead of King bearings. I should have stuck with what I new instead listening to someone selling King bearings! Anyway the bearings failed after 400 very hard break in miles{my fault} Tme motor now has over 600 miles, and has better oilk pressure than in the beginning So I still don't know for sure why this happened!
Ryan, check this out. Without listening to your motor it"s hard to determine what kind of knock it is.
__________________
JustJoe
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