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GIVE UP T&D

Posted By: 440lebaron

GIVE UP T&D - 10/18/13 05:32 PM

well i now give up, broke another T&D rocker, i am at my wits end, each time right at 2/3 shift, last time i dropped shift rpm from 7000 to 6800 hoping to help, about 10/12 rockers last five years, maybe 30/50 runs on replacements, ex/int any clyinder does not matter, i guess i need to have a "expert" look at my valve train
540 cu stage IV heads .660 roller
on the good side went 8.92 151mph before 1st round and got my entry fee back
Posted By: Thumperdart

Re: GIVE UP T&D - 10/18/13 05:52 PM

Something`s going into bind and or clearance issues come to mind. Valve float maybe? Not set up correctly?
Posted By: B3RE

Re: GIVE UP T&D - 10/18/13 05:55 PM

Quote:

well i now give up, broke another T&D rocker, i am at my wits end, each time right at 2/3 shift, last time i dropped shift rpm from 7000 to 6800 hoping to help, about 10/12 rockers last five years, maybe 30/50 runs on replacements, ex/int any clyinder does not matter, i guess i need to have a "expert" look at my valve train
540 cu stage IV heads .660 roller
on the good side went 8.92 151mph before 1st round and got my entry fee back


To tear up rockers like that you have to have valvetrain issues. PM me if you want it diagnosed.
Posted By: Sammy

Re: GIVE UP T&D - 10/18/13 11:19 PM

T & D's here with sick spring pressure. .896 lift cam shift at 7200 rpms. no issues at all.5 years now.
Posted By: Cab_Burge

Re: GIVE UP T&D - 10/18/13 11:27 PM

When your breaking race parts there is usually a reason thier failing The hard part, sometimes, is figuring out why they broke Now get to work finding out why your breaking them How close are your valve springs to coil bind? How much seat and open pressures are you running now? Which type of T&D rockers are you using, single shafts or paired rockers per shaft? Lots of gremlins out there
Posted By: bigtimeauto

Re: GIVE UP T&D - 10/18/13 11:30 PM

I have the single shaft T&D on my 440-1's. .830 lift 325lbs on the seat and boost on top of that. never had a failure driving it on the street or racing it. Something is wrong in your valve train.

are they hitting the retainer on the inside of the rocker? How much valve clearance? hows the geometry? coil bind? Valve float?
Posted By: dvw

Re: GIVE UP T&D - 10/19/13 01:31 AM

My T&D are used, how old???? .800"@7000 , no issues. Lash stays dead on. My buddy just rebodied his after aprox 700 passes. BB Chevy +1.00" cam lift@1000 psi open
Doug
Posted By: Leon441

Re: GIVE UP T&D - 10/19/13 02:00 AM

I broke one early this year. No telling how many runs they had on them as they came from a NASCAR team form the early 2000's. I had to buy seven used from Ritter because some were mismatched. One of the seven "Dyno time only" broke. LOL

Leon
Posted By: jamesc

Re: GIVE UP T&D - 10/19/13 02:17 AM

not to sound redundant but you have issues that are breaking the rockers. spring surge, insufficient spring pressure, interference of some type. no way you should have that many failures. do you know what your spring pressures are, part number, retainers, spring rate, installed height, open coil clearance?

you need to fill in the blanks and post pics of the failed parts and their installation. unless it's something bizarre it shouldn't take an expert to figure it out, roller valve trains will not live with weak springs.
Posted By: 440lebaron

Re: GIVE UP T&D - 10/19/13 03:03 AM

i have checked every thing 6/7 times, i know i must be missing something, 2/3 sets of springs 2 valve jobs, .663 comp cam (new) open 1.90 680 lbs closed 1.40 270 lbs 1.55 dia spring for clearance issues, no coil bind .100+ clearance custom pushrods adjuster screw right on t&d spec,lash .022/.024 always right on never loose or tight, season over now have all winter
have posted a few times
Posted By: 340man4ever

Re: GIVE UP T&D - 10/19/13 02:31 PM

Posted By: Hot 340

Re: GIVE UP T&D - 10/19/13 02:50 PM

Can you post a few pics of the breakage?
Posted By: BIGSPEED

Re: GIVE UP T&D - 10/20/13 10:00 AM

.100 plus clearance may be the problem coil bind should be set off of net lift at between .060 and .100.Bill C.
Posted By: B1MAXX

Re: GIVE UP T&D - 10/20/13 02:58 PM

Quote:

.100 plus clearance may be the problem coil bind should be set off of net lift at between .060 and .100.Bill C.



I agree.I learned this the hard way. You have to use "all" the spring as stated above. All I did was changge installed height never broke another rocker. I bet if you look at the face of the valve stem that they will have x patterens or shiny all the way around. This evidence of valve float and the "jack hamer effect". When the valve stem and rocker tip crash together the stress on the rocker is multiplied. Like a hammer hitting steel.
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