1966 427 solid Lifter valve lash adjustment

[Gerald C.]

I recently purchased this solid lifter car. I hesitated to buy the car because it is a solid lifter motor and I understand that the lifters have to be adjusted every year. I wanted to avoid that task because of my lack of knowledge to do that.. The seller (a good friend and a gearhead) told me that he set the lifters with a zero lash so the lifters do not have to be adjusted.

The more research I do, the more I don't see a zero lash adjustment to avoid the annual adjustment. Can someone comment on this statement for me?

Thanks

[Joe L.]

Re: 1966 427 solid Lifter valve lash adjustment

I recently purchased this solid lifter car. I hesitated to buy the car because it is a solid lifter motor and I understand that the lifters have to be adjusted every year. I wanted to avoid that task because of my lack of knowledge to do that.. The seller (a good friend and a gearhead) told me that he set the lifters with a zero lash so the lifters do not have to be adjusted.

The more research I do, the more I don't see a zero lash adjustment to avoid the annual adjustment. Can someone comment on this statement for me?

Thanks

Gerald------


A zero-lash adjustment on this engine (or any mechanical lifter engine) is a very unwise thing to do. I would not even consider it.

[Gerald C.]

Re: 1966 427 solid Lifter valve lash adjustment

Joe,

That's the result I'm coming to after my discussions with others. If I had known that I would have to do the annual adjustment, I probably would not have purchased the car. However, It is a great looking and driving car. If I keep it next year, I'll have someone do the annual adjustment.

Thanks,

Jerry

[Gerald C.]

Re: 1966 427 solid Lifter valve lash adjustment

Joe,

One other question.....Is there a straightforward "guide" for a novice to follow to set these clearances and what they should be?

Jerry

[Joe L.]

Re: 1966 427 solid Lifter valve lash adjustment

Joe,

One other question.....Is there a straightforward "guide" for a novice to follow to set these clearances and what they should be?

Jerry

Jerry------


Yes. The 1967 Chevrolet Service Manual includes the complete procedure and the clearance specifications.

[Gerald C.]

Re: 1966 427 solid Lifter valve lash adjustment

Thanks Joe. I'll give it a shot!

[Carl N.]

Re: 1966 427 solid Lifter valve lash adjustment

If they are set right you may be able to go several years w/out adjusting. If you ride it hard and put it up wet you may be adjusting every other race night. Not hard to do at all. If you can get someone that has experience running the valves have them teach you how. Best to allow couple of hours the first time. You need the engine hot and may want to do one side then put cover back on and warm it up and do other side. IMO the best way is with engine hot and running at slow idle. Messy but IMO the best way. I use a set of clips to prevent oil from soaking everything. You can purchase from Jegs or Summit on line. May be some u-tube videos showing how. Just take your time and see if someone with experience can mentor you and it does not need to be a Corvette - the 427 can be in any vehicle - nothing special about the Vette when it comes to setting the lash. Do not zero lash it or you may ruin the valve train and possibly the entire rotating assembly !

[Michael G.]

Re: 1966 427 solid Lifter valve lash adjustment

Before you start adjusting anything, do you know for 'a fact' which or what cam is in the engine. That info will have a direct effect on what specs you'll use to make your adjustments. As has been mentioned the cam can be adjusted with engine warm, probably the not the path most would take due to mess. I've adjusted most all my solid lifter engines cold with good success. Depending how often and more importantly how many miles driven per year will determine when the cam will need adjustment. It's not a mandatory a cam will need yearly adjustment, other factors are involved.

[Joe R.]

Re: 1966 427 solid Lifter valve lash adjustment

Joe,

One other question.....Is there a straightforward "guide" for a novice to follow to set these clearances and what they should be?

Jerry

Jerry,

Hopefully Duke will chime in here soon. I have seen him say that with a cast iron block and heads there is no reason to set the lash hot. Also, look on the net for the Hinckley-Williams valve adjustment procedure. Make sure you get the latest version. Lash is not very difficult to set.

Joe

[Duke W.]

Re: 1966 427 solid Lifter valve lash adjustment

Adjusting mechanical lifter clearance on any Chevrolet pushrod engine is simple. Search the Web for the Hinckley-Williams valve adjustment paper. READ IT THOROUGHLY, multiple times. Make sure you get the latest revision dated September 2008. Earlier superseded versions are still around.

The tops of the clearance ramps (assuming the OE cam) are .012" above the base circle, so the "theoretical" cold adjustment should be .012(1.7) = .020. Certainly the rocker ratio varies with valve lift, but I don't have a reliable set of data that shows the variation. The L-78 recommended lash is .020/024", but this was increased to .024/.028" for the L-72. I don't know why, but it violates the principal that lash should be taken up before the end of the constant velocity clearance ramp, so I recommend .020/.022" for now. The extra two thou on the exhaust is to allow extra valve stem expansion, since the large exhaust valves likely runs hotter on a big block than the smaller exhaust valves on small blocks.

Write the lash sequence on a tablet This will allow you to check off each valve as it's completed so you can keep track of where you are in the sequence. I also recommend checking actual clearnace before you adjust to see how far they are off. You'll also have to make some marks (temporary to permanent, your choice) on the torsion damper at 90 degree intervals. You can measure the circumference with a tape, and then use a piece of masking tape with the quarter-distance points marked and wrap it around the damper.

Extreme accuracy is not necessary, but be within about 5 degree. The zero mark on the tape should be indexed with the damper notch. Make sure you install it in the correct direction. The engine rotate clockwise viewed from the front. If the designated rockers are both loose at each indexing point, you got it right.

Glue the new gaskets to the valve cover, then wipe down the bottom gasket surface and head mating surface with silicone spray lube. This should allow the covers to be removed one to two times before new gaskets are necessary. Carefully and evenly torque the bolts to the CSM spec. in a couple of increments to avoid warping the cover, which will cause leaks. Also, retorque them at least once or twice, after a few thermal cycles.

The recommended adjustment interval is 12K miles, so if you do the job properly, you likely won't have to do it again for several years.

Duke