273 rockers? on 340

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LA340

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Hi all.

After some advice please.
Are these 273 adjustable rockers?
I can see the tops of the lifters and they are hydraulic.
The push rods are ball and cup.

I am thinking of pulling them off to see if they can be shimmed better because some of the rocker arms don't cover the valve stems fully. Surely this is not optimal.
Am wondering if this has been done to make sure the oiling works.
But as I have never seen these Mopar adjustable rockers before wont know how it works until I remove them and inspect.

Question is..... How do I set them up when I put them back together? (adjustments, torque settings etc.)

Here are some pics, Your comments are most welcome so I can learn about them.

First pic shows that the rocker on the left can not go any further to the left so it will cover all the valve stem because the 'retainer' or whatever it is called, under the bolt is stopping it.

Second pic shows that these two rockers can float left or right.... maybe they need more shims on the shaft?

Third pic shows that there are 2 different size 'retainer' things under the bolts.
Is it possible that whoever put them on got it wrong and the 'retainer' should go small-large-small-large-small and NOT large-small-small-small-large?

Thanks
 

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That's your problem, the wider retainer washers don't go on the ends. Starting from either end of the head they should be narrow, wide, narrow, wide, narrow.
 
Thanks for the quick answer rapom65!
Can anyone point me at the correct torque for the bolts? I'll change the retainers over two at a time, that should not upset the rest of the rocker adjustments.
 
Someone more knowledgeable will chime in, but some thoughts for research. I understand there was a 340TA engine with adjustable rockers similar to the 273. If so, jump for joy if that is yours since a rare performance engine. Those rockers are offset a bit from the 273 design, which was because they designed the head for big valves and had to relocate the pushrod holes laterally. I have two 273 engines but don't recall exactly what the rockers look like. Refer to book photos. Don't assume a 340TA since many people have put 273 rockers in later engines. Check your head casting numbers.

Re the "mis-aligned" rocker tips. Seems I have seen this before, I think on my 273. I didn't try to improve the shim washers. It might be intentional, I recall something about that causes the valve to spin slightly each time, which helps with wear. Study before you "fix" it.
 
Easy to tell TA heads, the pushrod holes in the head have literally been "hogged out" to offset them I can't tell from those photos
 
Thanks Bill.
I will take your advice as I am cautious of 'fixing' something that is not broken.

The block is a standard 340 block from 1970 I think... Sure I read somewhere that the TA blocks had 'TA' in the casting number.
 
67Dart273 said:
Easy to tell TA heads, the pushrod holes in the head have literally been "hogged out" to offset them I can't tell from those photos
Click to expand...

Hi 67Dart273.
The holes look like the original, they are NOT offset or hogged out. Standard X heads.
Thanks
 
those are 273 rockers...the TA rockers have offset intake rockers.....
 

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also looking at your pictures...you have X heads...TA heads are not X heads....
 
Thanks All.
I now know they are 273 rockers, anyone got a link to an online service manual for a 273 for assembly (torque settings and adjustment). I only have paper copies of LA engines with standard rockers.
Thanks
Steve
 
the torque on the shafts are the same for all LA engines...whether they are adjustable rockers or non adjustable...the shafts dont know what rockers are on them.


to adjust them....follow the same sequence as a solid lifter cam...except no lash...you will preload the lifter.....adjust to zero lash then add about .020 to pre load....something like 1/2 turn on the adjuster
 
70aarcuda said:
the torque on the shafts are the same for all LA engines...whether they are adjustable rockers or non adjustable...the shafts dont know what rockers are on them.


to adjust them....follow the same sequence as a solid lifter cam...except no lash...you will preload the lifter.....adjust to zero lash then add about .020 to pre load....something like 1/2 turn on the adjuster
Click to expand...


Thanks Tony, much appreciated.
 
LA340 said:
Thanks All.
I now know they are 273 rockers, anyone got a link to an online service manual for a 273 for assembly (torque settings and adjustment). I only have paper copies of LA engines with standard rockers.
Thanks
Steve
Click to expand...

Yup. You can download the 66 FSM in the thread:

http://www.forabodiesonly.com/mopar/showthread.php?t=132309&highlight=manual,+download

I believe this is the manual that you have to "play" with page numbers, as they aren't using factory page no. index.
 
Glad I could help you out. I wrote up a bunch of info for you and then lost my internet service overnight so I lost the whole damn thing. Now that you have access to a manual you have all you need the check out the motor. I would definitely give it an intensive inspection as some one unfamiliar with Mopar motors has been "under the covers". A few things to look for on the rockers and shafts: the shafts have a small notch in one end, make sure they are on the BOTTOM when installed. This is for proper oiling. If they're upside down oiling will be negatively affected. The notch should be at the front of the head on the odd firing bank and at the back (firewall) of the head on the even firing bank. If someone has put in non stock valve springs there is a possible interference point with the rocker. This is just under the arm and may rub on the top edge of the spring/retainer. This area can be ground a bit for clearance. If memory serves me correctly the torque on the rocker shaft bolts is 15-17 ft. lbs. but verify that with a manual.
 
I just looked over your pictures and noticed there are some shim washers installed between some of the rockers. Looks like someone was trying to fix they're boo-boo. On the two sets of factory 273 rockers I have there are no shims, just the wider spacers. I'll post up some pictures for you of how these should look when assembled correctly.
 
Ok here's the promised pictures of the 273 mechanical rocker setup. I just set these on a rebuilt 915 "J" head with 340 springs for illustration purposes. Pic 1, 2 & 3: Retaining bolt "washers" correctly oriented ie. small, large, small, large, small. Notice rocker arms are centered over valve tips. Large spacers are between rockers which are between the retention bolts. No shims really required unless your building a race motor and then you want everything as correct as possible. Pic 4: Notch that I was speaking of. If your shafts are not stock 273 shafts like these they wont have a crescent notch like this but they will have some sort of mark on the end of the shaft. Be sure this is on the bottom when the shafts are installed. Pic 4 & 5: You can see where the rocker body has been ground a bit with a carbide bit to provide clearance for larger valve springs. Go easy and just remove enough so they don't rub, no more. The hole you see in the middle of the ground area is a oiling hole that squirts oil onto the valve tip which is a modification to a stock rocker. There is another hole on the other side that squirts oil into the cup area of the push rod (stock). You will notice the oil hole in the top of the rocker has been spot welded closed. The valve tips in a stock 273 valve train, like on your motor, are splash lubricated by just the one hole in the top of the rocker which I wouldn't rely upon if your going to spin your motor up. I noticed in your pictures that your adjuster screws have a slot for a flat blade screwdriver and jam nut. Those are not standard 273 adjusters like the ones in my pictures. Don't know what to tell you on those, maybe aftermarket? Can someone else provide some insight?
 

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Hi rapom65, thanks very much for the pics and thorough description.
Due to family coming first it probably wont be for a few days to a week that I get the time to have a good look at the rockers.
Knowing what I do now I think I will remove them to have a good look at the area under the arm near the spring to make sure there is proper clearance, and set them up in the correct order with out the shims.
I have no intention of high revs so don't think I need to make the oiling mods.
Will update the thread when I have made progress.

Again, a big thank you to everyone who has helped.
http://www.forabodiesonly.com/mopar/member.php?u=15615
 
Sorry for the slow response, I hope to do the rockers in the coming week and report back.
When I had some time last weekend I decided to do a compression test before 'fixing' anything.
So bolted up a TF904 and starter to the 340 on the garage floor.

Here is what I got :D:D:D.

1 - 230psi
3 - 225psi
5 - 240psi
7 - 240psi

2 - 240psi
4 - 245psi
6 - 240psi
8 - 225psi
 
LA340 said:
Hi all.

After some advice please.
Are these 273 adjustable rockers?
I can see the tops of the lifters and they are hydraulic.
The push rods are ball and cup.
Click to expand...

I know this thread has been inactive for awhile, but can someone shed some light about using the 273 adjustable rockers on hydraulic lifters?

Its been my understanding that adjustable rockers are used only on solid lifters. The 273 rockers look a lot sturdier than the stamped steel rockers on my 318, is there any benefit of switching to the adjustable rockers?

Questions asked by "Not an engine guy", so be gentle.
 
Roger....Adjustable rockers can be used with hydraulic lifters, BUT, stamped-steel rockers can't be used w/solid lifters. Using adj's on hydraulics lets you dial-in your preload precisely, plus you can compensate for a smaller-than-stock base-circle cam w/o having to change pushrods.
 
Roger, they're also useful for high rpm motors, where hyd. lifters might pump up, and actually hold the valves open.
 
65Val said:
Roger....Adjustable rockers can be used with hydraulic lifters, BUT, stamped-steel rockers can't be used w/solid lifters. Using adj's on hydraulics lets you dial-in your preload precisely, plus you can compensate for a smaller-than-stock base-circle cam w/o having to change pushrods.
Click to expand...
but you must use pushrods for the type of cam your running,mechanical cam pushrods are longer than hydros....
 
bad440 said:
but you must use pushrods for the type of cam your running,mechanical cam pushrods are longer than hydros....
Click to expand...

Maybe....I cheated on my first 273 waaayyy back....I put in a 340 cam w/hydro lifters and shimmed up the rocker shafts with a washer to make up for the diff. in lifter height....It worked fine, on the street...I never raced it.
 
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