*350 sbc Valve Ajustment*

After finally finding the PO I'm told the engine in my pickup is a 1971 350 block with a 283 crank making it a 302. My truck was running fine prior to adjusting the valves. I was trying to get rid of a little clatter a couple valves had. I was trying to adjust the valves that I'm assuming are hydraulic by loosening the nut until it clatters, tighten until the clutter stops plus 1/4 more. Just will not run right. I have tried 1/2 more after the clatter stops but it runs worse. I was thinking they may be solid lifters but was told it probably would not have ran tightening the valves down that much. Looking for a little help.

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Originally Posted by zippi

After finally finding the PO I'm told the engine in my pickup is a 1971 350 block with a 283 crank making it a 302. My truck was running fine prior to adjusting the valves. I was trying to get rid of a little clatter a couple valves had. I was trying to adjust the valves that I'm assuming are hydraulic by loosening the nut until it clatters, tighten until the clutter stops plus 1/4 more. Just will not run right. I have tried 1/2 more after the clatter stops but it runs worse. I was thinking they may be solid lifters but was told it probably would not have ran tightening the valves down that much. Looking for a little help.

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It will run but like crap. Try running .008 on the intake and .0012 on the exhaust.

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Originally Posted by NTFDAY

It will run but like crap. Try running .008 on the intake and .0012 on the exhaust.

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Thanks. There is a lot of mixed answers on what they need to be set at from some of the other forums so I think I'll start with .020 and see how it goes.

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Originally Posted by zippi

Thanks. There is a lot of mixed answers on what they need to be set at from some of the other forums so I think I'll start with .020 and see how it goes.

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The setting I gave you are for a 63 "Fuelie" cam I had a long time ago. The most radical I can think of is the 30-30 cam used in the 64 Corvette. I have looked at your post on hotrodders and as usual the so called experts over there are all over the place. Good luck.

zippi;
I suggested you start at ".020", did not say that is your setting, .020 will usually be safe to start as your cam's settings are unknown.
I also suggested you try an "Old time way of adjusting valves with vacuum gauge"; back off till they tick (at idle), tighten/loosen slowly to highest idle vacuum, run the rack (all valves) several times adjusting slightly to get highest vacuum or until there is no change in vacuum readings.
Believe it or not, your vacuum gauge will tell you the valve clearance needed by using the above method then measuring the clearance with a feeler gauge for future.

JMHO; keep in mind by your own words "you have not done this for a number of years", and with the problems you're having, I would not recommend the one revolution (#1tdc - #6tdc) method for adjusting valves (in fact I don't recommend it at all). Use the two revolution method, it assures the valves for the cylinder being adjusted are actually closed.

Further, may I suggest you slow down and try one method at a time, and not combine several different methods together.

Also there is a strong possibility, "Mr. Techinspecter1" was correct when he told you your cam may be going flat. I know it's not what you want to hear, but check your oil for metal (looks like metallic or metal flake paint).

And PLEASE, as you go forward, keep a log of all the details about your car's specifications, motor, running gear, oils, plugs, fuel, exc.. You will appreciate it in a few months when you have forgotten, and the next owner will too.

I agree with Denny. I wrestled with this a long time. Found out of 1,000 videos on you tube, 999 were wrong. The advice above is spot on. One thing I would do and you may not like it, is pull the intake, the push rods and the lifters, check the pushrods for straightness, check the lifters to see if one is excessively worn. I would also check the valve geometry and the rocker arms plus the rocker arm studs. The reason I suggest this is the lack of success you are claiming using reasonable techniques. If something is worn ie cam lobe, push rods, etc. it will never work out. Another suggestion is to look up Blackstone Labs, get an oil sample test kit and send a sample to them. They will tell you straight away, normally in a couple of days, if there is some excessive wear in your valve train or components. The solution to mine was replace the lifters, push rods plus the rocker arms, and rebuild the engine which was full of metal shavings. The advantage was by catching it I was able to not destroy the engine. The rocker arm studs were screw in so they were okay but I did replace the locknuts. At the end of the day the solution was to tighten them more than I thought because of my inexperience. This is just an opinion with an objective to support what the guys above are saying. It was only my experience.

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Ok guys.....here is the update on adjusting my valves. I adjusted the valves per the procedure below. I set both the intake and exhaust valves at .020 cold. I'll be damned if it don't run like it did before I started adjusting the valves. So far I am a happy camper. I let it get a little warm and took it out for a run. I didn't get on it to hard but man does it pull and sound like it did before. When I got back I listened to the engine and like before it has some engine noise which now since I know it's not hydraulic I'm fine with it . I did hear something on the right bank that sounded like an exhaust tic. I'll investigate that further tomorrow but for now I'm satisfied. Thanks for all the input.

Get #1 to Top Dead Center

Exh.- 1 – 3 – 4 -8​
Int.- 1- 2 – 5 - 7 ​
​
Get #6 to Top Dead Center

Exh.- 2 – 5 – 6 – 7​
Int.- 3 – 4- 6 - 8​

i have a 302....all were built with solid lifters with duntof 30/30 cam.....set lash at .030...........i just went thru this on my engine..

I always set then hot.

Wow-----what a read Denny-----------guess as I'm getting older and its harder to bend over those fenders---------come on electric cars!!!!!!!!!!!will we have to check things with a volt/ohm meter??????????????how do we find tdc on electric motors??????

And I used to get cams ground especially for me with the same lobe diameter base circle so I could change cams without having to adjust lash!!!!!!

How did they put a small journal 283 crank in a large journal 1971 350 block

I've built several circle dirt track engines with 400 blocks and early short stroke cranks-one of the most successable combo was 400 block with bearing spacers and late 302 cranks( early smallest diameter were very difficult to access) 4.155 bore with 3.0 stroke--------

also used lots of squirters to cool bottom of pistons--

a mistake in this thread early on about valve clearance--------post #2----.008 and .0012 ( should be .008 and .012)