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Need help with 512 Stroker please

K-chai

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Hi
Me and my friend are rebuild a440 with 512 stroker kits. We use speed master cylinder head. After the we finished the rebuild we ran engine for 100miles and the pushrod was bend spring valve was broken. We recheck in the Speed Master cylinder specifications. It said "oiling type : through pushrod,but what we use is a normal pushrod.
Anyway after we remesured the pushrod length with the adjustable pushrod. We found out that the length of the pushrod is 0.15 longer than it should be.
So what do you think is the reason of this broken engine? Too long pushrod, no oil through pushrod. or both?..
Help us please
Best regards.

1614239585280.jpg 1614240247515.jpg 1614240208465.jpg 1614240199137.jpg 1614239880435.jpg
 
Well, to start yes they are both incorrect and need to be fixed. If the cylinder heads have no provision to oil the rocker assembly , the oil through push rods must be used. The push rods should also be length correct to get the geometry necessary for your combination. I know Melling quality for oiling system components but, push rods have not been their specialty. Choose your components wisely!
Mike
 
Well, to start yes they are both incorrect and need to be fixed. If the cylinder heads have no provision to oil the rocker assembly , the oil through push rods must be used. The push rods should also be length correct to get the geometry necessary for your combination. I know Melling quality for oiling system components but, push rods have not been their specialty. Choose your components wisely!
Mike
Thank you for your reply, but actually the cylinder head do have a hole. What do you think .. or just follow the specifications

1614253145372.jpg
 
Did you measure the valve to piston clearance? Do your pistons have valve relief cuts? 440'
 
You do have the valve relief cuts in the pistons. Do you have solid roller lifters or hydraulic? Camshaft specifications? 440'
 
There are lots of things to take into consideration.

Pushrod length needs to be measured. With a hydraulic cam you need to use a solid lifter of the exact same height of the hydraulic one you will be using.

Pushrods, whether you need oil through or not, need to be compatible with the lifters as well. Some lifters don’t have pushrod oil through capability.

Verify piston to valve clearance. Are the relief cuts in the pistons big enough for the valve head?
 
Which piston did the valve hit? What damage was done to the head and valve? 440'
It’s possible the pushrods are too short. Maybe it came out of the lifter? Maybe it rubs on the head and caused it to come out or deflect and then it came out. But I agree, if it contacted a piston there will be a definite witness mark.
 
Check that the pushrods are not hitting the cylinder head pushrod holes. There appears to be wear marks in the center of the pushrods?
That might be side-loading the pushrod cups, causing the cracking.

With a hydraulic cam, I would think spring bind and retainer to guide clearances should be OK, but it's best to check.

I use SmithBrothers push rods. If the pushrod holes don't fit a 3/8" pushrod and you don't want to enlarge them, I have used the 0.083" wall 5/16" pushrods with good results on large flat tappet and Roller hydraulic cams (usually around 250 @ 0.050" duration, 0.600+" lift, <6,500 RPM)
 
That head is designed for rocker shaft oiling. There is some Chevrolet information on the sheet because if you notice it also says for "center and perimeter" valve cover mounting. It doesn't require pushrod oiling. I've had that head in my shop. Look closely at the pictures on the website and you can see the oil holes through the head.

https://www.summitracing.com/parts/sdm-pce281-2153
 
Hi
Me and my friend are rebuild a440 with 512 stroker kits. We use speed master cylinder head. After the we finished the rebuild we ran engine for 100miles and the pushrod was bend spring valve was broken. We recheck in the Speed Master cylinder specifications. It said "oiling type : through pushrod,but what we use is a normal pushrod.
Anyway after we remesured the pushrod length with the adjustable pushrod. We found out that the length of the pushrod is 0.15 longer than it should be.
So what do you think is the reason of this broken engine? Too long pushrod, no oil through pushrod. or both?..
Help us please
Best regards.

View attachment 1074732 View attachment 1074733 View attachment 1074734 View attachment 1074736 View attachment 1074737
Hello Mopars don't oil through the pushrods, my guess would be that you bottomed out the valve spring. Check the installed height. Since you only bent one pushrod you need to concentrate your effort on that cylinder.
 
Looked at the pushrods again and the bent one looks like it would be longer than the others if it was straight? It also looks like the cup is different than the others too?
 
Hello Mopars don't oil through the pushrods, my guess would be that you bottomed out the valve spring. Check the installed height. Since you only bent one pushrod you need to concentrate your effort on that cylinder.
Agree this is a good possibility. This also is based on your cam lift and when your springs bind. This is another area to check.
 
That head is designed for rocker shaft oiling. There is some Chevrolet information on the sheet because if you notice it also says for "center and perimeter" valve cover mounting. It doesn't require pushrod oiling. I've had that head in my shop. Look closely at the pictures on the website and you can see the oil holes through the head.

https://www.summitracing.com/parts/sdm-pce281-2153
I use this roller rockers

1614394277404.jpg
 
Pull the head; it’s gotta come off anyway.

Maybe you through a rod; doesn’t sounds like it & shouldn’t have, but who knows

Maybe the valve spring was faulty; had a defect and failed.

Maybe springs are not correct for the cam

Either piston hit the valve while the cam had it open and that bent the pushrod

or

maybe the pushrod came off after the rocker after spring failure and moves under the rocker at the rail and had nowhere to go when the lobe came round

or maybe some other way

either way the piston hit the valve to cause that and/or the pistons hit valve when the spring failed

You need know the whole picture of what’s wrong, before trying to figure out what caused it

The head needs to come off to inspect the extent of the damage to the piston and valve

do that and let us know what you find

edit:
maybe the engine fairy god mother saved you and there was no piston valve contact; but you still gotta pull the head to check right?
 
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