454 valve spring rotators/ shims

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garym
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454 valve spring rotators/ shims

Post by garym » Sun Jun 10, 2018 8:40 am

I am in the process of changing a cam in my 84 chevy C-30 truck.I have a comp cams towing cam .504 int .514 ex . After pulling the valve covers off the motor I saw that the intake valves have the valve rotators as well.I know that on my other truck that the rotators were on the exhaust valves only.I called comp cams and they did not know a lot about my problem and said that I would have to order 8 more spacers for the intake, but the 4779 spacers will not fit over the intake valve guide, so I used the intake stock rotators.I bought the 911 valve springs that comp recommends and the installed height is between 1.850-1.865 .So my question is will the stock intake rotators work and be OK or should I get another set of the 4779 comp spacers and enlarge the hole so that these spacers will fit over the intake valve guides? Any help/advice would be great.
THANKS garym

rp930
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Re: 454 valve spring rotators/ shims

Post by rp930 » Sun Jun 10, 2018 11:14 am

In the old days I’ve seen guys use 1/2” id washers as rotator eliminators.

Seemed to work fine.

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Re: 454 valve spring rotators/ shims

Post by Speedbump » Sun Jun 10, 2018 11:40 am

I, personally, have never seen a rotator fail. In your HD application with moderate lift and spring pressure, I see using them at worst neutral and probably a positive.
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pamotorman
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Re: 454 valve spring rotators/ shims

Post by pamotorman » Sun Jun 10, 2018 12:30 pm

if you are towing or hauling loads GM did not spend the extra $$$ on rotators if they did not think it was necessary

Newold1
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Re: 454 valve spring rotators/ shims

Post by Newold1 » Sun Jun 10, 2018 6:05 pm

With a basic stock BBC -towing with a mild camshaft stay with rotators.

Give Precision Engine Parts PEP in Las Vegas. They will have the rotators in stock that You need and their prices are very soothing.

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Re: 454 valve spring rotators/ shims

Post by Schurkey » Sun Jun 10, 2018 7:02 pm

When I was playing games with L-29 Vortec heads, they had rotators on both intake and exhaust.

The rotators I was dealing with are not flat where the valve spring sits--there was a slight angle. I was NOT comfortable putting heavier springs onto this taper

The standard rotator-eliminator shims dropped right onto the exhaust guides. Half of the intake guides needed some grinding at the base, where the guide transitions to the valve pocket--the radius was too large, and the rotator shim would hang-up on it.

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Re: 454 valve spring rotators/ shims

Post by ProPower engines » Mon Jun 11, 2018 1:01 am

Yes I see that often. I use lots of them and it seems the spring pockets are rarely concentric to the guide.
If needed I just enlarge the spring pocket slightly as well as take the shoulder off the outer edge of the pocket to allow the rotator to sit flat.

Be sure to check retainer to seal clearance as those heads don't allow for much more then stock lift cams to be used.
as well confirm the lobe to lifter bore location is as close to correct as possible.
You may need to machine at least .040 off the timing gear end of the cam to get it closer to right.
I have a comp cam here that it was not done to and it lost 9 of 16 lobes even with all the right lubes and oils and spring pressures cause they were just in the wrong location to start with from factory.Customer did not want to do it and installed the cam anyway. [-X

Some get away with it some don't but its worth checking regardless to improve the cam life.
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garym
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Re: 454 valve spring rotators/ shims

Post by garym » Mon Jun 11, 2018 7:48 am

thank you for all the replies.Idid check the clearance from thebottom of the retainer to the top of the valve guide and I had .700 + so with the lift of the cam I should have.180 + clearance. Thanks again for the input. garym

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