351w valve spring help
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Junior User
Joined: Feb 2015
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351w valve spring help
Hi all, I have a 1977 ford 351w out of a 1978 econoline van.
I got a new cam- the summit k4400.
The valve springs I pulled off were quite worn out, so I thought I'd replace them with new ones. I purchased edelbrock#5722, which are non rotator springs.
My motor came with rotators.
Please forgive me, I am naive with valve springs.
Can I still use the rotators with these springs, or should I fork over the money to get new retainers?
The exhaust length, installed, is showing a spec smaller after 1978 than prior to 1978, which Is odd, as my block is a 1977, and installed with the rotators and stick springs, the length is normal within the post 1978 specs, but the retainer won't let the spring be long enough to be normal for 1977.
Are intake and exhaust different lengths for where the keepers seat? Do I need to shim them?
Would I just be better of to use the stock springs?
This was supposed to be a budget build to go into my 1992 f150. Haha
Any help is greatly appreciated!
I got a new cam- the summit k4400.
The valve springs I pulled off were quite worn out, so I thought I'd replace them with new ones. I purchased edelbrock#5722, which are non rotator springs.
My motor came with rotators.
Please forgive me, I am naive with valve springs.
Can I still use the rotators with these springs, or should I fork over the money to get new retainers?
The exhaust length, installed, is showing a spec smaller after 1978 than prior to 1978, which Is odd, as my block is a 1977, and installed with the rotators and stick springs, the length is normal within the post 1978 specs, but the retainer won't let the spring be long enough to be normal for 1977.
Are intake and exhaust different lengths for where the keepers seat? Do I need to shim them?
Would I just be better of to use the stock springs?
This was supposed to be a budget build to go into my 1992 f150. Haha
Any help is greatly appreciated!
Cargo Master
Joined: May 2001
Posts: 3,208
Likes: 13
The lock cut in the valve stem is different on the exhaust valve from the the intake. The springs are shorter. If your cam has much more lift then stock you need to change retainers and springs. I am doing one now and bought new exhaust valves with the lock cut the same as the intake and non rotator retainers. Follow the cam makers recommendation on spring height and spring pressure.
Hotshot
Joined: May 2003
Posts: 11,141
Likes: 25
From: south louisiana
Ford changed the heads in late 77, that's why the rest of the valvetrain changed too. You need springs to match the cam you selected, this is critical, especially for a flat tappet cam. Cam break-in is also something that's critical too, carefully inspect the new lifters to verify the bottom faces are convex (slightly domed) if any are not, toss them and get replacements. Do not use ones you suspect. They're domed on the bottoms to allow the cam lobe to rotate the lifter in service. If the lifter does not rotate, it will wear out the lifter and cam lobe during the 20 minute break-in period. Read up on cam break-in proceedures and follow them to the letter. When you do fire it up, do so with the valve covers off so that you can verify that the pushrods are rotating, they will rotate with the lifters. If any one does not, stop the engine immediately and tear it down and replace the offending lifter. Hopefully the cam lobe won't be toast by that point.
Thread Starter
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Junior User
Joined: Feb 2015
Posts: 67
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Thanks guys! I have new springs and retainers. My heads are already on... do I nees to replace the exhaust valves too, so they are notched at the same height? Or can I just shim the spring so that it is in spec?
Hotshot
Joined: May 2003
Posts: 11,141
Likes: 25
From: south louisiana
Even though the lifters are new, that's no reason to ignore the step I mentioned in examining the lifter bottoms to insure they're machined correctly. That's the reason for many of the cam failures in the past 20 years, poorly machined lifters.
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