One of these things is different than the others.....

Davesmopar

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Well I guess it was going to happen sooner or later..... lol

Using your weekend hotrod as a daily driver and playing very hard with it can be costly sometimes...
 

Davesmopar

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And tear down begins.... Replacing water pump, minimum push rod and rocker arm but tinkering very hard about replacing all rockers and push rods just cause I have stressed the hell out of them..... valve covers leaking bad...... All new mounts, engine and transmission..... Probably rebuild or replace the proportioning valve..... Might, just might cam it also.... Ohhh and weld the exhaust...... That is all I can think of right now......

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Duke5A

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What cam and springs are in that motor? Any problems with coil bind?
 

Davesmopar

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340 cam so 268/27? Heavy springs will damper spring.... they will hold .500 lift.....

No, no bind.....

I built this motor back in the 90's
 

Mikes5thAve

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When I bought my 88 it had a dieing engine. It ran long enough to get it home and finally died outside a buddies shop when I was trying to get it home and wouldn't restart. Got it towed home and it had at least 2 push rods thru the rockers like that and an air cleaner swimming in oil from blowby. I bought it cheap because it had a bad engine and I had a 360 to go in it.
 

MiradaMegacab

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I’m assuming the lifter stayed in its bore.
I’ve had lifters pop out of their bore, resulting in zero oil pressure....
 

Duke5A

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MP used to sell replacement stamped rockers that were just a little thicker in the push rod area. I don't know if they carry them anymore though. Last set I bought was 13 years ago.

With the age of the motor I would be worried about the rest of them.
 

Davesmopar

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MP used to sell replacement stamped rockers that were just a little thicker in the push rod area. I don't know if they carry them anymore though. Last set I bought was 13 years ago.

With the age of the motor I would be worried about the rest of them.


Yes I totally agree and another forum member gave me an Ebay link to a company selling rocker arms and shafts for about $140.00 free shipping........
I'm also replacing the push rods......
 

M_Body_Coupe

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So I hate to bring the bad/worst case news, but I had something very similar happen to me once before.

The lifter/cam combo wasn't happily mated, end result in a fairly short order: the lifter face wore the lobe down enough so that the valve no longer opened up, I mean literaly NO LIFT.

I was young, didn't know engine tech, and well, "if it runs rough and pops at idle/low-speed it surely just needs to be spun up a bit harder to cure that little problem"...lol, yeah, that very quickly put an end to my tunning efforts that day. The pushrod went right through the rocker arm, cylinder completely shut down.

This was years ago, I mean probably 20-25 yrs ago.

My point being: if you rotate the engine slowly, does your EXHUAST valve open?

Your INTAKE side rocker arm is what is busted. Assuming your EXHAUST lift is gone that hypothetically would allow the cylinder to build pressure with nowhere for that pressure to go but back up the intake side. On it's own that may not break things in one shot, but repeated over thousands of cycles (as the lobe is ground down) it'll stress the metal enough that eventually it brakes.

Anyways, probably the most weird experience I ever had troubleshooting a problem.
 
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Demonracer

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I have a set of 16 stamped steel rockers I took off a 360, I'll take 30.00 plus actual shipping if you are interested.
 

Demonracer

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Let me know, whenever they let the swap meets start again they will be for sale there.
 

AJ/FormS

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Are you aware that 340 arms are different from anything else?
And that the 340 cam needs 340 valve springs, installed at the 340 spec height.
Ima thinking that your valvesprings lost control and the cam slapped the lifter, slapped the pushrod, and the rocker arm was coming back when POW! they met going in opposite directions.

You can tell the 340 arms by flipping them upside down; they are clearance-ground for the larger diameter 340 dampered springs.

the DC-268/276/114 is a pretty good street cam, in an engine with matching cylinder pressure, and if yours is still in good shape.
 
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Demonracer

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AJ, FYI some of the 360 heads had the HD 340 stamped steel rockers from the factory, not a lot of them but a few. The rockers I have are from a one owner virgin 72 360 that came from a motor home chassis with only 22,000 on the odometer.
 
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