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906 heads- valve locks

Ray70Chrg

Ray70Chrg

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I believe the 906 heads on my 383 magnum are all original. I want to change the springs, keepers, and locks along with cam and lifters. Are the original locks just 1 groove items or are there additional grooves that can't be seen inside the keeper? Thank You
 
The original locks were NOT 1 groove. They were a combination or 2 groove & 4 groove, intake & exhaust. Aftermarket valves generally have single groove locks.
 
your new springs may take different retainers unless you are say going from a standard spring to a HP spring with dampner
new cam
check your retainer/ keeper distence to valve stem seals, which you will need new also
why change the locks unless you are going up in spring pressure?
which if you are going for around 480 lift you will need to cut your guides down for clearance and cuton seals, especially if going dual springs
what year 383
parts may have changed on late 383 when they went to lower compression
This has ever had a valve job?
 
I am planning on lunati voodoo 703 cam & lifters with the recommended 73815 springs. This is a '70 383 engine. I suspect some engine work was done in the past but don't know exactly what. The engine was originally painted orange but at some time was painted blue. Before I order the springs I need to know what retainers & locks to order. The springs I'm ordering are very near the pressures of what the 70 service manual says. My question is do you have to disassemble the lock and retainer to see if there are more grooves on the valve stem. As it stands right now I only see the top of retainer and it appears to be one lock. I plan on using the valves that are there since the compression test came out good. Thanks
 
Ray70Chrg said:
My question is do you have to disassemble the lock and retainer to see if there are more grooves on the valve stem.
Click to expand...

To know for sure just remove a valve spring and check.
Would be an expensive and time consuming lesson if you had the wrong parts in house when you start the job.
Get yourself a valve compressor, put cyl #1 at TDC and remove a retainer and see what you got.
Not only could it be the amount of grooves, but also the type of groove.
Some cuts are "square" and others are "round", although i am pretty sure you would need the round version.

If you are buying a valve train kit you should be ok, but if you decide to hand pick springs, locks and retainers make sure the lock and retainer have the same angle, either 7* or 10*.
7* is what you want, 10* is more for extreme cases.
 
Hello Wietse. I,m impressed. 4am and you're on the site. Thanks for your advice, as you can tell I'm new at going this deep into the engine. Just trying to take advantage of the very few discounts available this holiday weekend.
 
Ray70Chrg said:
4am and you're on the site.
Click to expand...
Bear in mind i am in a different time zone.. :D
Regarding taking advantage of the sales going on this weekend i guess you could buy the camshaft and lifters already if you know what you want/need and as they are the most expensive parts you need, you can score the best discount.

Not long ago i also replaced locks, retainers and springs and i used the below spring compressor.
This thing works very well and can be used with the head installed on the engine.
com5324-jpg.jpg

You bolt this arm in place of the rocker shaft and use that as a pivot point.
Use the original bolts but use some washers to level the tool out as the bolt holes are different depth's.
For removal of the locks a magnet is your friend here, they are small and easy too loose.
When installing new springs you need to play a bit with the tool to get the spring retainer in the right place to install the locks, but you will find out yourself once you get to it.

Just for a reference in case you need it:
1) Set Cylinder #1 at TDC
2) Remove the rocker shaft from the bank by loosening the bolts and lift it out of the way as an assembly.
Store the rocker shaft assy and push rods in the order they came out of the engine to avoid mixing it up or losing/misplacing something.
3) Install the tool over the cyl #1 valves and set it on either valve spring retainer and push down. You will see that the valve hits the piston after a little spring compression, a little "tap" from a small hammer will help in loosening the taper between the locks and retainer without putting too much force on it. (piston is not a steel vice you know) :D
Now you can push the retainer further down until you can pry out the locks with a small screwdriver or keep a strong magnet near them and you got them.
Slowly release the spring tension and now you can check all parts.
Whatever you do....DO NOT CRANK THAT ENGINE.....your loose valve will drop down and then you got a serious problem.:eek:
 
Another thing to consider since you are replacing the lifters.
The lifters you are going to use could be of a different height compared to what is in there now, this affects the push rod length and, assuming you are using stock stamped rockers, you might need different length push rods.
Maybe some guys who know what lifters will work with this setup that avoids the need of new push rods.
 
Wietse, Thanks for all the great info on this topic. I'll be busy now ordering all this stuff.
 
Ray, if you're using the existing valves, be sure to pull both an intake and exhaust to check how many grooves your valves have. If you get the Lunati cam, you may want to go with the kit, cam, lifters, springs, retainers. Then do as wietse said, check what length the pushrods need to be. Good luck.
 
Are those 73815 dual valve springs? (Lunati website has them listed as single and dual springs?!) If so be aware your valve guides O.D. will need to be cut down and positive seals installed as umbrella seals will not fit...
 
73815 springs are single spring w/damper and the springs that are installed also have damper. I don't know if these are original springs or not. I do know that at some time before 1992 the engine was removed from the car, work was done to it and engine was painted blue. There is plenty of spots where the original orange paint has come through. It's all a mystery and that's why I'm replacing as much as possible short of lifting the heads. The engine seems to be around half the power it should be. Thanks "62" and "66".
 
Last edited:
Without lifting the heads
that's the easy part
"The engine seems to be around half the power it should be."
what's your compression?
 
Hi Wyrmrider. You gave me some good advice about a month ago on this car and lead me to using Lunati voodoo cam. I'm looking to use their kit for the 703 unit. As I told you then the compression test on this engine was all cylinders arournd 170 psi except one cyl was about 155.
The reason I am avoiding taking the heads off is I know damn that I'll use that as an excuse to replace the intake mani. get into porting the heads if not replacing the heads and since I only have the block left I may as well take it out and paint the engine bay and of course put in a disc brake system that I always wanted. I am trying to keep ME away from myself.
 
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