Disaster...360 Engine blew a connecting rod

[chargerdon]

Expensive day yesterday.   I bought the $250 set of 273 rockers.   When they come in I will borrow my buddys pushrod length checker.   His is a ball/ball end but i presume i can still use it to measure for the new pushrods.   Question:  Ill put one set of the 273's on with the pushrod length checker in place.   How should i "adjust" the rocker to measure the pushrod length?   Count the number of turns to bottom out the adjuster bolt, then back off 50% and use that point to measure or  ?????   

I also bought the A518 overhaul kit off of Ebay $210, it is the one i listed with the raybestos friction plates that supposedly are for high performance applications.   Yes, i have read about the huge spring in the overdrive drum...   Again, my buddy has a press, and ill make a U shaped STRONG tool to put in the press to push down on that tough spring...   When i did my 904 i did the same thing, but, used a 12" 5/8 bolt thru the middle to compress...worked great..nothing like making your own tool with your welder. 

Also, bought from the A518 lockup torque converter, high stall 2300-2850 off Ebay by Torco.   I bought the torque converter thats in the car now with the 904 from them, and have had zero problems with it they do their own rebuilding.   $169 minus 10% coupon is extremely inexpensive....all the ones i looked at on Summit were $400 - $600.    They have already contacted me to make sure about possible weighting..don't need with this engine, and that it does have the offset bolt pattern on the flexplate...  yep...  They said they would ship it on tuesday...   No hurry on the A518 items as that will be a fall/winter project.    Looking at the modified crossmember in the narrative on the tranny swap, it doesn't look that hard to make with a welder...  Heck, that one looks like an overkill in that it is probably twice the gauge of the factory crossmember... 

Gonna be a busy fall/winter..  Too hot to do much here in NC until October.   

Oh one last thing, was doing some checking and noticed that the plastic tube for the mechanical oil pressure gauge had a significant "Kink" in it.   So, spent all morning taking that line out and replacing it with a copper tube instead.   Gauge is mounted in the dash cluster, so had to take that all apart to get to it...  Finished up, and with the new line i'm reading between 5-10 psi more across the entire rpm line.   HOT idle in drive at 700 RPM is now a better 15-20 psi, 2000 rpm now reads around 40-45 psi, and highway driving at 2700 rpm (60) is now close to 50 psi full hot.  Still not great but definitely reading better and in the OK range i think !!   Whew...   Will be happy when the 273's are in so i can quit worrying about blowing another.. 

Thanks again to everyone for the support !!

[Chryco Psycho]

I like to keep the tip of the adjuster in the rocker very close to the rocker arm with only approx 2 threads showing below max
good catch on the oil pressure gauge 

[chargerdon]

Good news and i think bad news.

First the good...the 273 rockers arrived today.   Upon inspection they appear to be in relatively good condition..  no rust anywhere, the adjusters all turn, are very firm to turn,  and the balls all look in good condition.   The pads that goes against the valve stem for the most part look to be in good condition with only 3 of them showing wear that goes across the entire pad.   I think that's ok.    The shafts are all shiny and nearly perfectly round, with 4 spacers for each shaft, good bolts. 

Now the bad..   The shafts are probably only Current std shafts in that they only have the one set of holes, not two, AND they do not have the scour cuts across the holes.    If those scour cuts aren't needed and only 1 set of holes, then i could have used my current shafts and saved $110, as there was a set of rockers for only $139 that did not come with shafts at all.   

Did i get a fast one pulled on me??  Seller said these were from a 273 engine.  Should i be demanding a return?  Should i be complaining to the seller??  If this is what i get item was listed as NO RETURN, then do i need to cut the cross hatch scour cuts into my shafts??   Just let it go as is?  or can i purchase the Mopar Performance Rocker Shafts P4510636 ?? 

Recommendations?? 

To measure for new pushrods, install the set on one head with the adjusters upward until only a couple of threads can be seen right above the ball??  (i have acess to buddys length checker that is ball/ball)  Is that correct?   Or do i have to have to buy a checker that has a cup end?? Then with a adjustable pushrod checker (ball/ball) set to just touch pushrod ball to the adjuster ball and call that zero lash??  Lets say it measures 7.4" for zero lash in that manner.   Then i should order 7.450 pushrods that will give me .050 preload???   

[1 Wild R/T]

Use a dremel with a cut off wheel to make your oil slots.. When done you absolutely must pull the plugs out of the ends of the shafts & throughly flush the shafts, abrasive will find it's way in there & it will fine it's way into the bearings if you don't clean it out...

New plugs aren't hard to source & they are cheap... (Much cheaper than not cleaning out the shafts)

Mostly your description of checking push rod length is good, only thing is you should disassemble the lifter & shim the piece that the push rod mates with solid to the top of the snap ring groove while checking pushrod length...

And yeah, I'd say that was a dirty deal on the shafts...

[Cudakiller70]

I did what Wild is suggesting, putting in oil slot grooves. It was pretty easy. I used tape and hose clamps to limit the length of the banana groove just in case I slipped with dremel . I was afraid of going out past the rocker arms side. Wanted the groove completely covered by the rocker arm. Also I deburred the slot edges. Picture is of the plugs I used. PM your address and I'll put 4 in the mail. They should be easy to get, I think I got em at NAPA.

[Cudakiller70]

I used these instructions from Hughes engines for measuring pushrods. There may be other ways to measure I'm sure. Used this comp cam pushrod checker. Turned out they were a stock length for six pack, from rock auto. Currently out of stock.
http://www.hughesengines.com/Upload/productInstructions/PushrodLengthCheckingMay2014.pdf
https://www.summitracing.com/parts/cca-7709-1/

[1 Wild R/T]

I did what Wild is suggesting. It was pretty easy. I used tape and hose clamps to limit the length of the banana grove just in case I slipped with dremel . I was afraid of going out past the rocker arms side. Wanted the grove completely covered by the rocker arm. Also I deburred the slot edges. Picture is of the plugs I used. PM your address and I'll put 4 in the mail. They should be easy to get, I think I got em at NAPA.

Those are probably what he needs but he should measure cause there are shafts with thicker walls.... I have a set of HD shafts that take 7/16 plugs...

[chargerdon]

How deep should the banana groves be made? 

Is it necessary to shim the lifter??...Intake manifold is on and i do not have a pushrod puller... 

What about the "second set of oil holes"..as i can see them in one picture.   

I think i'm going to contact that seller and see if he wants to "make good" on those shafts and if not file a grievance with ebay.. 

[chargerdon]

Sent contact email to seller and he hasn't responded yet.   Regarding the bananna groves, i'm pretty sure i can do that.   What about the second set of holes??   Are they really needed?? 

Before, i file an ebay grievance with the seller i want to make sure of myself.   Did the "stock" 273 rocker shafts come with the banana groves and extra holes, or were they always added by enthusiasts??   Stock or mod ? 

Read the instructions for Hughes recommended pushrod length checker and i think i understand what their referring to.   If im understanding correctly then using their "adjustable lifters" they have you dial in the preload onto the adjustable lifter first, then do all of the measuring and trial and error to get the maximum lift then take the pushrod length checker length as in as the preload is already in.   Also, their adjustable lifter has no "give" so that your getting accurate measurements always.   I dont have the adjustable lifter, and intake manifold is on and i dont want to mess with the lifters...so, plan on just spinning the engine before i remove my current rockers to get them fully pumped up, and to make sure they are still like that when done with the measuring then add to the checker the amount of preload that i want.     Is that ok ??? 

Now, i have a Lunati cam and lifters in it and Lunati recommends between .020 and .060 preload in their instructions.  Hughes in their writeup at the end specifies between .022-.042 for racing applications, and for street quiet .085-.148.   That is some variation !!   This engine is for street use (with maybe once a year to the strip for a couple of test n tune fun nights..  With that in mind what do my friends here recommend for preload? 

[Cudakiller70]

I had some old lifters and made a fixed solid lifter with preload that my cam manufacturer recommended. In your case use the preload that your cam manufacture recommends.
You can also do Wild's suggestion of using your existing lifter, taking it apart (be careful of the spring clip! I wasted an hour looking for it and ended up having to order some) and shimming with washers to your required preload.
The thing about the Hughes instructions it opened my eyes to rocker geometry. By adjusting push rod length to get max lift. I watched it happen with a dial indicator on the valve. When the length was right, lift matched my cam pretty darn close. FWIW I did every one and they varied a little so I picked an average length and went with that. Don't know if it's necessary to do every one.

[Cudakiller70]

This picture should give you an idea what to shoot for oil hole and groove size. I wonder if grooved shafts were on High performance motors? Like 340 6 pack? I pulled mine off a 273 from a barracuda, no grooves. 

[YellowThumper]

This picture should give you an idea what to shoot for oil hole and grove size. I wonder if grooved shafts were on High performance motors? Like 340 6 pack? I pulled mine off a 273 from a barracuda, no groves. 

I expect all the solid 273 style rockers had the grooved shafts. Stamped rockers effectively have the grooves in them instead of on the shafts.
I ran my setup that way 25 years ago without knowing any better. They galled up bad in short order.

[chargerdon]

Here is the response from the seller:

"Not all 273s had the banana groove shafts. The shafts that are with the set are what came with the rockers when I removed from the engine. I have had rocker sets with and with out the banana groove shafts and have ran them both with no problems. Nowhere in my auction did I say that this set had banana grooved shafts."

So, i guess i'm stuck with them..and will add in the banana grooves myself.   I'm thinking to NOT add in an extra set of oiling holes, and install and run them Until engine warmed up and then remove a valve cover and take a look...make sure the oil is getting everywhere and if it is then i'm done. Reason for not drilling the extra set of holes, is don't want to risk damaging the shafts, and oil pressure when hot at idle is only around 15-20 psi (with the stamped steel rockers) so don't want to reduce any further. 

[chargerdon]

Here i go again.    First i cut into the shaft the banana groves..it was fairly quick and easy.   I did NOT add in the extra row of holes.   I can always add them later if i see after a couple of hundred miles that there isn't good oiling. 

Bought the Comp Cams adjustable rocker length checker with the cup on one end.   

First thing i did was to "set" the depth of the adjusting screw on the 273 rockers so that with digital slide ruler it measured .320 from end of ball to the seat on the rockers.   That was recommended in the Hughes instructions.  (http://www.hughesengines.com/Upload/productInstructions/PushrodLengthCheckingMay2014.pdf
https://www.summitracing.com/parts/cca-7709-1/ ) That shows about 1 1/2 - 2 threads visible on the ball side about what Chryco said to do.   

Now to measure to get the push rod length i started by first running the engine with the old stamped steel rockers in it for about 20 seconds...enough to "pump up" the hydraulic lifters at least so i think.  (yes, i know Hughes instructions and 1 wild r/t both say to either use an adjustable valve lifter or to modify one of mine to be "solid".   Yes, i can see why you do that so that once you have the adjustable pushrod checker in, and rotate the engine to check for maximum "lift" that it doesn't give.)    However, my intake manifold is on the car, and i really really hate to have to remove it to do this checking.   With the rockers adjusting screw set to the .320 depth, put the rockers on and adjusted the adjustable pushrod length checker until the cup "seated" on the ball.  Being careful not to over tighten and push on the hydraulic lifter.  Took it all out, and measured and got 7.25" end to end of cup, or that would be 7.10 to bottom of cup.

I then looked online to see if i could find pushrods that length but the shortest i could find for LA engine with cup was Comp Cams 7692-16 which measure 7.497/7.342 .  That is a full .250 longer than i measured.   So I called Comp Cams tech line support and explained my method of measuring to their technician.  He said that as a Comp Cams technical support tech, that he could NOT say yes, that's good, but, as a mechanic he felt that i probably have it very close.  He said that comp cams does not have a pushrod that length, but, as he often does recommended calling Smith Bros. 

So, i called Smith Bros tech line to find out how much custom would cost me and talked with their technician.  I explained my worry about not putting in a solid lifter to do the maximum lift checking.   He told me..."dont worry about it".  He said that on a Mopar The rocker shaft sets the geometry and that changing the pushrod/adjuster length combos will only modify the max lift by a very small amount..not enough to worry about on a street engine.  Obviously that is way different on a Chevy engine where the adjustable rocker moves higher/lower on the stud based on the pushrod length, and that DOES change the geometry.  Also, the wear patter on the valve stem will not change either by the pushrod/adjuster length combos again because of the fact that the geometry is set on a mopar shaft style.   He said that if i was putting in after market rockers that THEN you have to worry about measuring that stuff, but, not on the Mopar 273 rockers and shafts.   He was quite familiar with them.    He also said that if I hadn't checked for wear pattern that i should do that before settling in on a pushrod length as i might have to put "shims" on the pedestals.   He said that using Mopar original 273's should be right on or very close without modification, but, to check before ordering the pushrods.  Incidently he gave me a price of $190
plus shipping for a set of chrome moly .080 wall thickness pushrods... way more than off the shelf pushrods.  More, than i hoped to get away with..wife is ready to kill me..  Total cost is now $250 + $27.80 (length checker) + $190 plus $13 shipping total $480/

So, this morning, i redid my measurements.   Put the steel rockers back in and started the engine again and ran 20 seconds to insure lifters were fully pumped up.

Then to insure that i was on base circle with piston #1 intake and exhaust, i rotated engine until my
Ignition advance on the damper showed about 10 degrees beyond tdc.  This should put #1 on the beginning of power stroke, and on base circle for the cam lobes on #1.   Felt and the rockers were tight and looked full up on valves.

Removed the old rockers and shaft, put in the pushrod checker in for the exhaust valve.   Marked the top of the valve stem with dry erase,  and bolted the rockers bolted in, and expanded the pushrod checker till it was snug, but not depressing the lifter.     Then i rotated the engine two full revolutions and removed the Rocker assembly and checked the  wear pattern..   It was just slightly toward the exhaust side but within the acceptable area.   Took all apart and again measured the pushrod and it was again 7.25 overall 7.1 to bottom of cup.   I then repeated the procedure using the intake valve and again measured the same..7.25 overall.   Rotated engine and checked wear pattern and it was nearly the same.   Repeated procedure on #5 cylinder.. and got 7.25 and a smidge more.   I realized that each hydraulic lifter after depression did NOT come back up to full pump and that's why i moved to a different valve each time.  I am foregoing insuring maximum valve lift with this procedure, but, according to guy at Smith Bros the variation is very slight anyways and for street use i'm fine.   

Before ordering i am waiting on opinions from everyone here....   Please !!

Oh lastly, i find it amazing that the amount of "preload" as specified in the Hughes instructions ranged from .002-.005 for a racing engine to as much as .145 for a "quiet street application"  Holy smokes thats a lot of variation.   Lunati says between .020-.060.  Tech from Smith Bros said when installing the rockers making sure each is at base circle simply put 1 full turn on the adjuster which should put me in the .040-.050 range right where Lunati recommends.   Comments on this ?   

[Chryco Psycho]

I like less preload , as it is less likely to allow the lifter to pump up & hold the valve open so I would go with the lower amount of preload