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Author Topic:   Snapped Push rod, Have you seen this?
Flanndad
Member
posted October 01, 2003 07:02 AM
Number 4 cylinder intake, Lifter out of bore, pushrod snapped in half, guide plate slot expanded.
Number 4 cylinder exhaust, snapped rocker bolt, rocker laying on it's side, pushrod ok.

Took off intake, and half of the pushrod no where to be found.
Plan on pulling oil pan tonight and looking for other half.
Do you think it could of fell thru the lifter bore and made it to the oil pan?

Friday night at the track it did backfire 3 times coming out of turn 4.
I got off of it drove it to the pit's felt low on power, when I got home I drove it into the garage also.
So I think the cam and everthing is ok.


racer17j
Member
posted October 01, 2003 05:24 PM
you might as well pull the head while your at it sounds like the valve hit the piston when that lifter popped out


istock59
Member
posted October 01, 2003 08:07 PM
More than likely your half a pushrod is in the oil drain back hole at the back of the block. I lost a pushrod down that hole this summer. After a lot of trial and error (and cussing) I was able to fish it out with a magnetic pickup, without taking the intake off.

I'd do a leak-down test on #4 to see if a valve is bent before I'd pull the head. Never know, you might get lucky!

FWIW, Moroso makes a $25 metal tray that fits in the lifter valley that holds the lifters in, keeps them from jumping out when a pushrod/rocker/stud breaks. Cheap insurance, IMO.

[This message has been edited by istock59 (edited October 01, 2003).]

66jj
Member
posted October 01, 2003 09:24 PM
sounds like you didnt adjust lash on number 4 properly or tighten the locks...

intake was ran loose for a while and slotted the guideplate, then finally the pushrod fell out of one end or the other and broke, it probably came out of the lifter end and the valve hit.

the other rocker just fell of and didnt break anything.LUCKY!!!

tilley88
Member
posted October 02, 2003 03:34 AM
JUST FELL OFF?


flanndad#17
Member
posted October 02, 2003 09:31 AM
I was running poly locks, and they were tight, the lash was good the week before.
Part of the rocker stud is still stuck in the poly lock.
After talking to my engine builder, we're going to put it back together without removing the head, and trying it.
He believes the pushrod half is in the oil pan, so we are going to install a strong magnet on the outside of the oil pan.

Just going to keep my finger's crossed

Wallydog9g
Member
posted October 02, 2003 12:22 PM
why chance blowing your motor, its simple to pull the oil pan and then you can check out everything else while your under there... rather be safe than sorry


flanndad#17
Member
posted October 02, 2003 12:24 PM
Hey istock59, you were right, it was in the oil drainback to the right of the distributer.

Guesss I don't have to install that magnet.

istock59
Member
posted October 02, 2003 12:33 PM
Cornering forces seem to natural throw it back there. Now imagine trying to fish that out of there without taking the intake off! LOL...

Glad you found it! Much better than the magnet solution.

MEANGENE83
Member
posted October 02, 2003 09:32 PM
Been down this road many times, the reason the intake pushrod broke is because the exhaust rocker stud broke first, and without the exhaust opening the cylinder pressure has nowhere to go, so when the intake is trying to open against all that air pressure it breaks the pushrod. I think the solution would be a stud girdle or 7/16 studs. But what I do is cuss about it and put it back together the same way it was,lol. What brand of poly lock have you been using? I use pioneer and when they break off the top of the stud it leaves enough thread to use a stock rocker nut for a temporary fix, but I'm not sure if the fact that it puts so much pressure on top of the stud is what is making them break. Any opinions on this or cheaper solutions? It seems like I break one stud a year and there is no rhyme or reason to when it happens.


way2fast
Member
posted October 02, 2003 11:47 PM
carefull how much torque you put on the set screw of the poly locks. I used to really crank them down and had the same problem, dosent take a lot.


flanndad#17
Member
posted October 03, 2003 08:17 AM
I'm thinking their were cranked down to tight, because I put the polylock in the vise And I can not get the allen screw out.
I even busted one allen wrench trying.

I'm going to mention this to the guy who put them on.

I had extra rocker bolts from a old set of heads, but i did put on a old rocker bolt.

MEANGENE83
Member
posted October 03, 2003 09:31 PM
I've always turned the set screw in and then tightened the outer nut to 30 ft lbs. I didn't think you could get it tight enough with just turning the tiny set screw for it to not vibrate loose. I didn't think 30 would be too tight for a 3/8 stud. More opinions?


Rvarc
Member
posted October 05, 2003 09:51 PM
if you have your screw-in studs surface in a valve grinder like the ends of the valves you'll not need as much pressure on the allen screw to lock the poly's.It sounds more like you may have had a bent push rod give them the roll on glass test and toss any that don't pass use good aftermarket rods Most of the push-rod brakage that I see takes out the next rod too.


Flanndad
Member
posted October 06, 2003 06:22 AM
They were the good push rods, comp cams .080 wall type.

I'm leaning towards meangene's comment on how it got broke.

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