engine builders...advice

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SoulSurvivor

SoulSurvivor

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I am finishing off my rebuild of my 69 340 with the installation of new lifters and stainless 273 type adjustable roller rocker and I have just a few questions. When it comes to the adjustment of the rockers..should I soak the lifters first/pump them up or just lube them up cold and drop them in before I adjust? It is a Comp Cams Hydraulic cam/lifter set up. I kind of know how to do the adjustments(hail Mary's combined with lots of beer and crossed fingers) but if you have a tip or two that you can lend I would really appreciate it. Thank you, Doug
 
Hey Doug. Though I'm not a builder by trade, I do not beileve Comp cams wants you to pre-pump up the lifters. They need to be adjusted when the engine is warmed up to operating temps I beileve.

For a ruff dial in, this is what I do. One valve at a time, with the lifter on the base circle of the cam (No lift at all, lifter on the opposite side of the egg shape of the lobe) run the adjuster low and observe the pushrod pushing down on the lifter. The pushrod should push on the top of the lifter down approx. .050.

Gap a spare plug this wide for a general eyeballing quick look so you get an idea of how large this gap is. You really don't want to go to far for start up and hang a valve open, even a tiny bit.

Once the engine warms up, you can adjust the rockers adjuster properly with an ideal amount of 2 - 2-1/2 threads showing I beileve the amount is.
(Sorry, it's been awhile)
Then double check the rockers tip to valve contact area for correct contact and movement on the valves tip.

MoPar has a valve lash adjustment chart that is a sticker and can be put on the fire wall if so desired. It helps speed things up by doing 2 valves at a time per manual rotateing of the engine via the crank bolt with a socket and braker bar.
 
I forget to mention that the engine is still on an engine stand. So I should just button it up and do the adjustments once the engine is installed and running? I was hoping to do it all on the stand.
 
You can do it on the stand, final adjustments in car. Easy to do in car, just takes time.
 
Set them as Rumble says cold on the stand. What do you have for valve springs? Single springs with a dampner (one round spring with a flat inner spring looking thing) or duoble springs with a dampner (look carefully in the coils, you'll see a second smaller round wrie spring inside the flat wound dampner) If you have dual springs, and most modern cam grinds larger than the "268s" take doubles, you need to remove the inner spring frm each valve BEFORE firing the engine. Then replace them after the cam is broken in. Otherwise you run a serious risk of flattening a cam lobe. Also, I think for a fresh start up, I might not go quite to .050, but stay closer to .020, and be ready because they will be noisey and that's ok.
 
Put the valvetrain on before you install the intake.

That way you have a clear view of the lifter when setting preload.

Which cam do you have?
 
I do a half to 3/4 turn after the slack in the push rod is taken up. Done many engines this way. Just make sure the lifters are on the base circle. There is a sequence for that too.
 
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