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Author
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Topic: Thoughts needed on setting lifter preload with my XE-274
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69Cat
Journeyman Posts: 97
From: Sask., Canada
Registered: Apr 2002
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posted 08-01-2006 02:12 PM
 
I beleive I have gotten a decent break in on my 351C with this Comp Cam hyd, all valve train stuff is new Comp Cam. Its pretty noisy when the oil is warm though. Also, vacuum is around 9" at 850 rpm and timing is 15 deg with no vacuum advance hooked up so that should be in the ball park. If I pull a vacuum plug the engine speeds up so I don't beleive there is a vacuum leak.I set the preload to 1/2 turn, maybe a little less so it was around 0.025" when I assembled everything. I did this with each piston at TDC of its compression stroke so I didn't use the text book procedure. Question is: Comp recommends preload of 0.030 +/- 0.010 so that would be 1/3 to 2/3 of a turn for preload as one turn is 0.050". When do you use 0.020 and 0.040? One will hurt vacuum and one will quiet it down it seems. I saw an old post where one person stated that Comp Cams recommends 3/4 to one turn of preload with the XE cams - is that true? I'm going to check my preload before I put any more run time on this engine so let me know what I should shoot for. I'll use the text book procedure for this upcoming check. Thanks guys,
Ken
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Moneymaker
Administrator Posts: 29200
From: Lyons, IL, USA
Registered: May 99
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posted 08-01-2006 02:47 PM
After break in I like to pull one valve cover at a time and set them running hot.
Loosen each (quickly to avoid a mess)one at a time until it clicks then tighten until quiet.
Repeat proceedure on the other side.------------------
Alex Denysenko
Co-Administrator and Moderator NHRA/SRA member and licensed Superstock driver
NHRA and IHRA SS/LA & SS/MA National Record Holder '00,'01,'02,'03,'04 &'05
First NHRA & IHRA 289 automatic Superstock Mustang in the TENS 06-99
First SS/MA in the TENS 04-03
IHRA division 5 Superstock Champion
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28 The Barry of BarrysGrrl Quote #1: "I never met a magazine mechanic I liked."
Quote #2: "Make sure brain is in gear before engaging mouth!"
Quote #3: "If you can't run with the big dogs, stay on the porch!"
www.moneymakerracing.com
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70rancheroGT
Journeyman Posts: 48
From: Durham, NC
Registered: Mar 2005
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posted 08-01-2006 04:34 PM
Are the lifters standard or anti-pump lifters? On my 351-C, I run 1/8 of a turn. I'm using lifters I got from Reed cams, they are anti-pump lifters that can be run at zero preload. I measured about 0.010" at 1/8 turn.It is pretty noisey. I have tried adding preload and it's still noisey. My lobes aren't as aggresive as the XE lobes, I've heard they make a lot of noise. FWIW, I've heard MANY people complain about the cleve having a noisey valvetrain when converted to fully adjustable. It's been hashed and rehashed a bunch over on the cleveland forum. Most just say it's the nature of the beast. Many ideas as to the cause. The lifter galley is the last to get oil, so some think the lifters don't get enough pressure at idle. I've thought about it a lot and I think it has to do with the canted valves. The pushrod is not traveling in the same vector as the lifter and I think the pushrod motion causes the rocker arm to twist. I think the noise comes from the rocker sliding back and forth on the trunion and hitting the c-clips. Just another guess Run as little preload as you can, it will rev higher. I think Alex's procedure will get you the minimum preload. I think it will also demonstrate that its not preload that is causing the noise you hear. Good Luck,
James
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69Cat
Journeyman Posts: 97
From: Sask., Canada
Registered: Apr 2002
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posted 08-01-2006 06:08 PM
Alex, I just don't have the heart to get oil all over my newly painted engine, engine bay and ceramic headers. Now, if I was working on a tractor at the farm that would be a different story! lolJames, the lifters come with the cam in kit form so I assume they are not anti-pump up. I'll re-adjust to 1/3 turn preload. I have the occassional tick occuring at different locations in the valve covers so I would say preload is OK though things are still wearing in. The noise I am hearing is most likely the lifters on the lobes but I still want to double check things. Oil pressure is 45lbs at idle, tops out at 65 lbs at +2000 rpm using a Stewart Warner mechanical gauge. My screwdriver-oscope (you know - the screw driver handle to the ear) tells me the noise is in the lifter valley as it is louder when I move from the valve covers towards the carb. I've got some Pioneer rocker studs on order that are 1.94" long which I will install at the same time in place of the 1.75" Comp Cams.
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mustangboy
Gearhead Posts: 1343
From: Ont, Canada
Registered: Mar 2002
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posted 08-01-2006 11:18 PM
69cat just cut the top out of an old valve cover and you won't have any mess.I've set mine using this method many times.------------------
68 J-Code,Sprint,306 4 speed,4.11s 13.69@101...............
66 coupe 289 4 speed, 3.20 cruiser http://mustangsandmore.50megs.com/MembersPics/mustangboy.html http://mustangsandmore.50megs.com/MembersPics/mustangboy2.html
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69Cat
Journeyman Posts: 97
From: Sask., Canada
Registered: Apr 2002
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posted 08-02-2006 01:08 AM
Thats a good idea. I'll set them cold for now and then dig one up to modify for another day.I'm pulling my intake tomorrow. I see the rubber seal at the back split lengthwise so I'll replace the front and rear seals with a thin bead of silicone. Thats the first time that happened. It will give me a chance to check the lifters for peace of mind.
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DutchD58
Gearhead Posts: 142
From: West Milton, OH
Registered: Jul 2000
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posted 08-02-2006 03:06 AM
FWIW, I have this cam in my 351W (Trickflow heads, Scorpion roller rockers, etc), and I pull roughly the same vacuum @ rpm.
I run the CompCams Pro-Magnum lifters with mine and they suggest .006"-.008" pre-load, warmed up, with those lifters. It pulls to well over 6K with no problems, but there IS a little valvetrain noise. Not much though, and certainly nothing the exhaust can't drown out!  Kevin
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69Cat
Journeyman Posts: 97
From: Sask., Canada
Registered: Apr 2002
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posted 08-02-2006 10:10 PM
Well this sucks, I found that a lifter on #7 cylinder is wore down about 1/8", all other lifters are excellent. Visually the cam lobe looks not bad and certainly isn't scored up but when I shine a flash light across the front of the lobe I can see a little bit of a wave. So, is it possible to replace a lifter in such a case and see if it gets chewed up? Or is changing the cam and lifters the only smart thing to do? I wouldn't mind running it for the next two months to see how things work as I will get maybe 100 miles on it. I dipped the base of the lifters in cam lube, pre-lubed the engine, static timed it and filled the carb with gas so it lit up in the first rev of cranking, used diesel engine oil, GM EOS and had good oil pressure. The only hick-up was I had the rad cap off watching the coolant start to circulate then the thermostat opened fully and the high volume water pump shot a gyser of water out the open rad so had to shut it down to clean up and top up. Lesson learned regarding the HV water pump.
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