Pushrods

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twodoorsedan

twodoorsedan

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Hi,i´ve built me new engine for my Dart.
Head are milled and ported,a bit hotter camshaft,Four barrel,headders.
Runs,but with one problem.
Keeps bending the pushrods.Put stock ones in.Since i live in Sweden and have talked to a couple of different shops about harder pushrods,and they can´t help me.
Is there anyone out there who knows where to get hold op some?
Thanks.
Per (from Sweden)
 
twodoorsedan said:
Hi,i´ve built me new engine for my Dart.
Head are milled and ported,a bit hotter camshaft,Four barrel,headders.
Runs,but with one problem.
Keeps bending the pushrods.Put stock ones in.Since i live in Sweden and have talked to a couple of different shops about harder pushrods,and they can´t help me.
Is there anyone out there who knows where to get hold op some?
Thanks.
Per (from Sweden)
Click to expand...

Im surprised nobody has said anything yet but i would recommend Smith Bro's, custom fit and not an outrageous price, though it could be pricey to ship to sweden......

Jake
 
First,you should not be bending ANYTHING with a cam that is a "bit hotter",that is
job number one to find out why.How much lift?With a ported head surely your
machinist would ask that and be sure the retainer to guide clearance was OK for
the cam.Second, exactly how much milling?Antything over .060" TOTAL(head&deck),
will make the pushrods very close to hitting the rocker arm at lift esp. w/extra lift.
You will need shorter ones,mopar used to sell cut to length chromemoly kits,but I
successfully removed the cups from a set of crane CMs and cut them down.It's
not likely you've got a valve/piston interference issue unless you've got long rods
and a much higher piston in the bore.The one thing about slanty's the stock piston
ht. is WAAY down in the bore,even mowing the head& deck usually leaves plenty of
room for xtra valve lift.You shouldn't be running much valve spring load for that to
be an issue either,it would be helpful for some particulars on your components.
Hope that gives you some direction,good luck and keep us posted:coffee2:
 
I had the same issue with mine .040 off the head .080 off the block bigger cam and bent the same ones-get shorter ones made pretty much the only remedy
 
How much did you mill off the head and block? Back in the seventies I milled .100" off a slant six head and used .060" shims under the rocker arm stands to space the rockers up. Direct connection recommended this to maintain rocker arm geometry.
 
Hi! Thanks for great response!
I guess i should try to find out what kind of work that has been done to the head.
I know it´s milled,but not how much. The block hasn´t been done anything about.
If i look at the rockers and the adjustment screw,those screws are all as far as they can go,almost....
I can drive the car for some miles,50 miles was the latest trip before the pushrod gave up.
 
You really need to find out why you are bending the push rods. I have a 225 engine with large valves, head milled .125, a .525 lift cam, single spring with damper, stock push rods, and rocker arm/shaft. Haven't had any problems. Did have to set the spring height, and check for coil bind (close, but just barely OK), did have to shorten the valve guides.
 
Charrlie_S said:
You really need to find out why you are bending the push rods. I have a 225 engine with large valves, head milled .125, a .525 lift cam, single spring with damper, stock push rods, and rocker arm/shaft. Haven't had any problems. Did have to set the spring height, and check for coil bind (close, but just barely OK), did have to shorten the valve guides.
Click to expand...

^^^ I was going to suggest looking at max lift and see what clearance you have on the guides too or check for coil bind. Shimming the rocker shaft sounds like a good way to fix the geometry issue.
 
are the adjust screws almost all the way up or down? new stock pushrods should be strong enough, unless something is hitting or u have too stiff valve springs. are all the pushrods bending, or some in the same location, or random locations ?
 
Hi guys,thanks for all ideas.
The adjustment screws are almost as far down they can be. When rotating the engine,the springs is far from coilbind. The rods has been bent at cylinder 5 and cyl 2,both intake and exhaust. I bought the head on Ebay,years ago,with camshaft,springs and valves.I don´t remember the facts about the stuff,,stupid....
Regards Per
 
Per, do you mean to say that the adjustment screws are turned so that they are down towards the block as far as they can go? With the head milled, the likely problem with the screws should be that they are all the way up, not all the way down. All the way down says that the valves are too short, or the pushrods are too short, or the cam base circle has been underground a lot. What is your total lift at the valve?

Also, you have checked for coil bind but it does not sound like you have checked for clearance between the spring retainer and the valve guide.
 
I made shims from brass stock and shimmed up my shafts.Cheap easy solution.
 
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