push rods rubbing???

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Meet-Joe-"Dart"

Meet-Joe-"Dart"

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Hey guy's haven't posted in a while(busy moving to Burnaby)
Anyways my 360 is almost finished, but the pushrods are rubbing. Eddy magnum heads on a 360 block(1970) flat tappet cam. We tried a 1.6(prw) rocker and a 1.5. -the rods rub inside the heads(in the rocker holes) The parts store said to buy Crane magnum rockers($598.00) the shop suggested machining out one side of the heads to get the clearance we need. Any thoughts, anyone build this combo?


Many thx!!!:scratch:
 
Haven't done it myself, but I've read about it. You do indeed need to wallow out the pushrod holes. You can do it with a die grinder and rasp. It will work, and won't cost any more than the abrasives.
 
I can't see how different rocker arms will make any difference at all since the pushrod location is in the same spot. Sounds like the auto parts store just wants to sell you a set of expensive rockers. I helped a buddy build a 418 and we used Eddy heads and ran into the same problem with them rubbing and used a die grinder to open up the pushrod holes so they cleared.
 
fishy68 said:
I can't see how different rocker arms will make any difference at all since the pushrod location is in the same spot.
Click to expand...

Yeah that's what the machine shop said too. Ok I'll probably get them to go ahead and grind em out.


Thx:cheers:
 
hi, I've had to open up pushrod holes on LA heads, I put them in my milling machine and ran a end mill cutter down the holes, elongated them, much more professional and less time involved. plus I could measure how much I moved them. just food for thought,
 
if you have adjustable rocker arms there should only be 2 threds sticking out the top. otherwise your pushrods may be to short throwing of your rocker gyometry causing the pushrods to rub the pushrod holes. unless you have some huge cam with oversize pushrods they shouldnt rub. I had the same problem before on my 340 build. I bought a adjustable pushrod checker to determin the right length pushrod then bought a cut to fit set from mancinni racing and built them myself, or you can order a set already made from smith bros. pushrods.net
 
Don't run the motor if the push rods are even within .030-.040" of the head. Chances are they will flex and rub under load, especially if you have a big cam and stout springs. My last set had "some" clearance under static conditions but this is what happened to this set of T&D rockers. Every intake push rod had a similar wear mark when the heads were pulled. This time I made sure there was a good .100" or more clearance.


SDC12033.jpg

SDC12064.jpg
 
perfacar said:
hi, I've had to open up pushrod holes on LA heads, I put them in my milling machine and ran a end mill cutter down the holes, elongated them, much more professional and less time involved. plus I could measure how much I moved them. just food for thought,
Click to expand...

That's a great way to do it, if you have a milling machine. But I kinda doubt very many mechanics have one. I'd sure love to have one. Their generally found in shops that deal with doing more than just the average 1 per year job. Not knocking your post so please don't take it that way. Just stating my observations on what most garages have.
 
Took care of mine with a die grinder followed by a sanding wheel. 15 minutes per head.
 
had the same prob but mine was a la motor, the 1.6 cleared better than the 1.5, took a drill bit and ran back and forth where it was hitting slow but it worked, kinda of whallered it out, then changed cam and ended up taking the nemt size drill bit in small increments and drilled the whole hole out till it cleared , it didn take much, maybe it helps:D
 
1977 360
deck milled, its been like 20 years ago and i cant remember if it was .040 or .060 off the block and I took .020 off the head. to get 9 1/2-1 to 9 3/4-1 compression

so now I have a blown head gasket. I had the heads resurfaced. after putting the heads on, I noticed the pushrods are rubbing. a couple already had slight rub spots.

the question
can I use a die grinder on the holes with out taking the heads back off, if I'm careful about keeping the grindings out of the engine

also a while back I saw pushrods that had a thinner diameter where the pushrod went through the hole. any input on these
 
I don't think I would grind them with the heads on the engine. Metal shavings in the engine, not me.
 
I thought in might be a bad idea. these head gasket will have the shortest life i'v ever seen
 
.........There was a debate on here as well as other forums about reusing the head gaskets as long as the motor wasn't fired.........I was surprised to learn that many ppl do that.........I don't.........kim..........
 
SnowDrifter said:
1977 360
deck milled, its been like 20 years ago and i cant remember if it was .040 or .060 off the block and I took .020 off the head. to get 9 1/2-1 to 9 3/4-1 compression

so now I have a blown head gasket. I had the heads resurfaced. after putting the heads on, I noticed the pushrods are rubbing. a couple already had slight rub spots.

the question
can I use a die grinder on the holes with out taking the heads back off, if I'm careful about keeping the grindings out of the engine

also a while back I saw pushrods that had a thinner diameter where the pushrod went through the hole. any input on these
Click to expand...

I wouldn't even consider grinding with them on the block. You'll never get all the tiny bits of metal back out. As for smaller diameter pushrods, if your running a small cam with stock'ish valve spring pressure you should be ok, as long as your not talking dinky 1/4" pushrods. If you have any kind of performance cam with upgraded springs small diameter pushrods could deflect causing you to lose lift and duration. They may even deflect enough to rub when the engines running. What diameter pushrods do you have now and what size are you considering?
 
Pretty much running the same setup. 91 LA block with Eddy Magnums. I have 1.6 rockers. When I had the heads done, Hughes Engines cleared out the pushrod tunnels because they knew they would be a problem. Dave Hughes said that if you wrap the pushrods with 1 layer of masking tape and the tape doesn't tear when turning the engine over by hand, your good to go, which was the case. It is pretty hard to get a wire gage down in there to check the clearance about the periphery of the rod. As Fishy said do not attempt to hog out the heads with them on the block, you're asking for trouble. Go to smaller diameter rod?.......IMO...don't! I have about 2000 miles on engine and no issues.

Also, on the head gasket, many pro's and con's. I reused mine after torqueing and checking for clearances. As long as not heat cycled (started and ran) should be fine. I am running about 10.6:1 comp. and again no issues. I would suppose that if you are getting into high critical squeeze that it would cause me to rethink that.
 
oldkimmer said:
.........There was a debate on here as well as other forums about reusing the head gaskets as long as the motor wasn't fired.........I was surprised to learn that many ppl do that.........I don't.........kim..........
Click to expand...

Yeah........as long as you haven't heat cycled them , you should be fine.
Unless you have MLS gaskets........then you can re-use them as many as 4 times based on reports from the field.
But with regular gaskets , if you haven't run the motor all you have done is compress the gasket to it's compressed thickness. It will still seal when re torqued.
 
my push rods are 5/16. i think the tapered ones i was thinking about are larger and tapered down to 5/16 or 3/8 so that would not work for me.

maybe someone should come out with off set rockers. or off set rocker shims

so now i need to decide. grind or shim????????????????????????????????
think think think:banghead:
 
I had to grind a pile out of my Indy heads to fit my 3/8 pushrods, easy enough to do, just time consuming. Grind a bit out, clean em up, put on motor, check clearances, remove, repeat untill you are happy. Get a burr for aluminum, metal one will plug up easier. Try not to get aluminum to hot, I used a drill because an air diegrinder was too fast.
 
I've reused the std 8553 fel pros before, no issue. The heads were torqued, not fired.

If you use a carbide burr, Take PB blaste/wd40 and fill the cap with some. Dip the burr in the fluid to keep it cool and from loading up.

Ede heads + roller lifters usually = grind time in pushrod holes
 
SnowDrifter said:
my push rods are 5/16. i think the tapered ones i was thinking about are larger and tapered down to 5/16 or 3/8 so that would not work for me.

maybe someone should come out with off set rockers. or off set rocker shims

so now i need to decide. grind or shim????????????????????????????????
think think think:banghead:
Click to expand...

You can't shim anything to get clearance. Think what'd happen, you move the rocker arms to make the pushrods clear and what have you done? You've moved the rocker arm tip either off the valve tip or way off center which = way bigger problem than the pushrods rubbing. No rocker arm will change things if their made right because all locate the pushrod in the same place. That's a part of geometry that if properly designed is a constant. Grinding is the only correct way to do it.
 
fishy68 said:
You can't shim anything to get clearance. Think what'd happen, you move the rocker arms to make the pushrods clear and what have you done? You've moved the rocker arm tip either off the valve tip or way off center which = way bigger problem than the pushrods rubbing. No rocker arm will change things if their made right because all locate the pushrod in the same place. That's a part of geometry that if properly designed is a constant. Grinding is the only correct way to do it.
Click to expand...



off set shims i could see. with the rockers i was thinking the valve side would remain the same but the push rod side if extended i don't know maybe .03"-.04" (just a number) the push rod could be moved a little. although the rocker ratio would have a slight change.

Ok is this right
mill the block or head, the push rod stays the same angle. but as the head is lowered towards the block the hole moves towards the push rod. why,
because the push rod angle is not the same as the angle of the hole.

also would that mean because the push rod is not in-line with lifter, lifter cup and the rocker arm cup. the angle of the push rod would change if the distance from the rocker to lifter was changed?

does this pic make any sense. the dashed lines are where things would be after milling block or head
 

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maybe i better go to bed. my head is spinning and i pulled half of my hair out think about this.
 
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