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Author Topic:   what breaks first?
BK19
Member
posted August 11, 2003 09:09 PM
i have been having motor problems the last one #1 and #8 rods broke and cam was in 6 pieces the latest one on sat night the #6 rod broke and the # 7 was twisted and the cam was in 4 pieces this was just in the parade lap my question is what breaks first the cam or the rods thanks



sdhnc29
Member
posted August 11, 2003 09:13 PM
The rod breaks and hits the cam . Why are you breaking rods ??

Steve

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Hendren Racing Engines
Rutherfordton , NC
(828)286-0780


BK19
Member
posted August 11, 2003 09:36 PM
i wish i knew i have never had any motor problems until last year, i have been racing 7 years and blew my first motor last year and i just keeps going and going i am baffled,, yes i build them myself


goinrcn44h
Member
posted August 11, 2003 09:59 PM
Are the journals that hold those rods all burnt and black? and is there bearing pieces all over, or are they ok in color and just flat break?
44H


BK19
Member
posted August 11, 2003 10:02 PM
this one was fine in color,the bearing was broken up, the last one was black and the bearings were flat

[This message has been edited by BK19 (edited August 11, 2003).]

sdhnc29
Member
posted August 11, 2003 10:31 PM
Sounds like the first one was caused from lack of oil . Where exactly did the second one break ? And what brand of rod was it ?

Steve

------------------
Hendren Racing Engines
Rutherfordton , NC
(828)286-0780


BK19
Member
posted August 11, 2003 10:45 PM
the second one broke above the journal and on each side where the bolts go sort of splitting it and the bolts fell out they were just reconn rods,, the first engine when it went had 50 pounds of oil press when she went and it was ful of oil before the race


goinrcn44h
Member
posted August 12, 2003 01:36 AM
amount of oil and pressure isnt likely the problem. Purely as a stab in the dark, I would guess bolts possibly, too much or too little clearance, I would guess its somewhere in there though
44H


Stans2411
Member
posted August 12, 2003 05:26 PM
Have your torque wrench checked. You may be over or under tightening the bolts.


towmandan
Member
posted August 12, 2003 06:11 PM
What kind of rpm are turning and do you have a good correct balancer on this engine..Towman


BK19
Member
posted August 12, 2003 08:20 PM
had my torque wench recalibrated and this was the first motor rebuilt with it, stock 350 crank with stock 8 inch balancer and flexplate last motor had a stock distributor the latest one had a brand new dui racing distributor if the wrench is still off i will be mad the mac tool guy comes tomorrow i just got it back 2 weeks ago -----almost forgot 6200 pms except on the parade lap when this one went was about 3000 and only ran 5500 in the heat race

[This message has been edited by BK19 (edited August 12, 2003).]

outlawstock17
Member
posted August 12, 2003 09:11 PM
sounds like fatigue to me. most remanufactured rods have over 100,000 miles on them. they can't last forever.


hamer36
Member
posted August 12, 2003 10:09 PM
what bearing clearances are you running? I run .002 on rods and .0025 on mains. Replace rod bolts with GOOD ones (ARP)


BK19
Member
posted August 13, 2003 05:40 PM
i found the problem!!!! it was the D*** torque wrench we did a test in front of the mac tool man today, which was who sent it in for reclibration well we put a bolt and a nut in the vice set 2 wrenches to 40 pounds i tightened it first then the other one and his clicked right away then we set them to 70 and tightend it with the other one first this time, then with mine, well mine turned it a 1/2 turn more before it clicked!!!! the mac tool guys eyes about fell out of his head and i was very po'd to say the last

[This message has been edited by BK19 (edited August 13, 2003).]

hamer36
Member
posted August 14, 2003 10:14 PM
make it a practise to unscrew the wrench when you are done using it, and only use it on engines. I won't even loan mine to anyone!


BK19
Member
posted August 14, 2003 10:18 PM
i always back the wrench off and have never let anyone use it


SLEEPY GOMEZ
Member
posted August 14, 2003 10:47 PM
Check August 03 Stock Car Racing page 62 for an article on how to check your torque wrench. Simple and cheap. SLEEPY


norightturn
Member
posted August 15, 2003 08:02 AM
That's another reason you dial bore check your rods and mains torqued down. Odds are you would have caught the problem had they been properly checked....an ounce of prevention.


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