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#1
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stock rocker arm strength
Hi guys,
while collecting parts and mocking up my 408cui engine, I thougth about "why not put the big cam into my currently running 360 to break in the lifters?" Cam is a 285XE comp cams 285/297adv 0.545"lift spring required has 400lbs/inch rate. Is this to much springload for stock rockers? If the cam break in goes fine, I´d like to drive a few hundred street miles with that cam in the 360. Will I break rocker arms? Thanks Chri |
#2
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Hmm, are your lifter angles the exact same in the new motor? I doubt it, I dont think it is a good idea to break a cam in a different motor, Why not just wait?
I have a 567 lift cam with stock rockers, so I dont think it will be a problem. I have new ones though, not old worn out stuff. |
#3
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408 block is a 1984 block, current 360 is a 78 block, never thougth of lifter angle yet. If I sweep a lobe, I will not ruin my expensive new parts.
In what kind of vehicle do you use your cam/rocker combo? Thanks Chris |
#4
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stock non-adjustable rockers?
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#5
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Put on a full flow oil filter, like a Fram HP1 for the break in! Even if the cam goes south the rest of the engine (other than the oil pump) will be spared!
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#6
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Yes non-adjustable stamped steel rockers. It´s not just breaking in the cam, it´s also I´m curious how that cam feels like in a 360, compared to a 4
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#7
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No it won't! I have the trail of broken parts to prove it. When all the little metal shavings from a wiped cam are heading down to the oil pan, some of them will get thrown up the cylinder walls via the crank, and then get dragged up and down by the piston skirts...had to bore the block another 0.010 to get rid of the scratches after a flat tappet cam failure.
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#8
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The spring pressures are to much, I would put a crap set of stock springs on for break in.
Forgot to write that earlier. I would just get a cam for the 360, you will end up liking it as long as it is a manual or a big stall. |
#9
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Quote:
The 408 is going to make SO much more torque it wont feel the same the 408 will make peak hp at lower RPM compared to th |
#10
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big block hyd rockers pushrod spear, sb not as much though crud ratio.
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#11
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http://www.molyslip.com/Products/MolySlipE.html
Or http://www.hughesengines.com/Index/p...p?partid=23942 Or http://www.schaefferoil.com/specialty/132.html Or Put stock rockers on 408 if you have 1.6 ratio Or Use stock springs on 408 for break-in period. |
#12
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Thanks for your replies!
Chris |
#13
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Also use a break in oil, or oil additive. There have been alot of cam failures since the zinc (ZDDP) was lowered/removed from current oils. You don't want to wipe out a expensive cam.
STP oil treatment has a good amout of zinc in it. Royal Purple also has break in oil. And I believe Comp. Cam's has a additive for cam break in. |
#14
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Quote:
Well it worked for me, but then I only put 50 miles on it!!! Not a scratch anywhere! Nothing gets past the filter. And my dealership GAVE me the replacement mopar cam. Do you understand what a FULL FLOW FILTER IS??? Apparently You must have run it to destruction before you knew what was wrong. Not everyone would wait that long! You shouldn't make this kind of statement if you have not done it!!! Why do you think racecars run full flow filters, for the added cost? |
#15
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Quote:
Do I under stand what FULL FLOW FILTER IS...eh, yeah. Do you? They have been around since the 1940's... So please don't tell people that if you use this Super-de-duper filter that it will magically save you're engine from a cam failure. That would be a completely illogical hypothesis. BTW, I caught my wiped cam lobe within minutes and it still did a lot of damage...good job on catching yours in 50 miles. You da man! |
#16
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ha ha ha ha ha
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#17
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Hi all,
I've been running the "stock" Mopar performance heavy duty stamped steel rockers arms with the Hemi springs (> 300 lbs open pressure) in my 440's for three race sessions (one with the 509 Mopar cam, one with the 480 Lunati cam), without any breakage or excessive wear problems. I just make sure that the engines are warmed up thoroughly before any race. Oil pressure is >72 psi at 1000 RPM at 185 t0 195 degrees F. Use 15/40 wt diesel engine oil or 20/50 wt Castrol GTX. I think the limit on the stamped Mopar Performance rockers for small or big blocks is probably the "509" cams. My recollection is that only the later (like 1971 and after) production rocker arms were equal to the "heavy duty" ones. The rockers in the '60s were not as heavy duty, hence the bad reputation for "push rod piercing". (Why are the Mopar springs so darn expensive today ! I can't believe that the "933" springs are over $10 ea ! The "848" springs are $18/ea) Mark Henesian |
#18
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Quote:
Apparently You Do Not understand oil filters. A lesson for you. A standard oil fiter only filters between 10 and 20% of the oil at about 2 to 3 microns in particle size while bypassing 80 t0 90 % of the oil unfilterred. A full flow filter bypasses no oil while filterring at 10 to 20 microns, thereby allowing no large particulate past the filter. I have seen many engines turn out like yours also, needing Complete remachining after cam failure. I only had to wash mine out with solvent. Absolutely NO bearing shell or cylinder damage (not even a hairline scratch). Just a new oil pump, camshaft and lifters, and of course a new FULL FLOW oil filter. But I guess YOU will call this luck! ha ha ha. I hope many with new builds are following this thread so they may possibly be saved some possible expensive grief. No magic, just filter facts not to be disregarded by fiction! Now what is that saying "he who laughs last, hmmm?" |
#19
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What do you do when the FRAM goes T-up????
Cut some of them open after use and you will never say the name again around a good motor. |
#20
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Thanks for all your input. Actually the question is "will stock rockers handle a decent cam and springs?". To find out, I will put a decent cam into my 360 and see what happens. I can have the rockers crack-checked for free, I will cut a 360° groove into the #5 cam journal to make sure lots of oil get to the rocker arms. Running outer springs only for break in and first street miles. Then, with dual springs, fully ported 587 2.02 heads, air gap intake on a 10:1 360, I´ll let her ri
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#21
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STOP
There's plenty of oil up top already and more oil won't keep the rocker from braking if it's a load issue. |
#22
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I wouldn't drive it after cam break in without first putting the inner springs back in.
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#23
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Look the real deal is you'll probably only get around 1.4 ratio with those stamped paper weights, so make more hp, save yourself sum grief and pick up some 273 iron adjustable rockers or after market rollers.
just trying to help..... |
#24
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273 adjustables are just as inaccurate. plus more things to go wrong.
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#25
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really?
They worked fine at .620 lift and 9500rpm at el cajon speedway....... have fun breaking parts. |
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