Correct initial timing?

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This is the old-school Direct Connection "Mini-Express" mushroom lifter setup "comes very close to roller cam performance at about half the cost". Originally 316 advertised, [email protected] measured at the cam grinder's, .654" lift with .024/.028 lash. Centerline 107.
I had to have it slightly reground because some of the lobes had lost their taper and wouldn't spin the lifters. It came back as 312 advertised, [email protected], .652" lift with .018/.018 lash. That is actually a slightly faster rate and more net lift :) I put it in at 105.
What website? Hope it's not YB :poke:
 
DrCharles said:
This is the old-school Direct Connection "Mini-Express" mushroom lifter setup "comes very close to roller cam performance at about half the cost". Originally 316 advertised, [email protected] measured at the cam grinder's, .654" lift with .024/.028 lash. Centerline 107.
I had to have it slightly reground because some of the lobes had lost their taper and wouldn't spin the lifters. It came back as 312 advertised, [email protected], .652" lift with .018/.018 lash. That is actually a slightly faster rate and more net lift :) I put it in at 105.
What website? Hope it's not YB :poke:
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No, not YB LOL. I'll post the page when I get a chance. You can't type in all your specs and it shows your lobes and gives all the numbers and such. I *THINK* 12many posted the site in a different thread.

Damn I'm jealous. I should have done the mushroom lifter deal on my last build.

In your case, a 1200 RPM is pretty dang spanky. I've never been bothered by idle RPM. I've had cams back in the day that if you can get a 1500 RPM idle you'd be doing good.
 
bbrroowwnn said:
Wow that is a big cam.....it probably still doesn't idle smooth at 1200
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Video with sound from the rear in post #42. You can tell there's a cam all right. Kind of ruins the sleeper image, unfortunately ;)
yellow rose said:
In your case, a 1200 RPM is pretty dang spanky. I've never been bothered by idle RPM. I've had cams back in the day that if you can get a 1500 RPM idle you'd be doing good.
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I would not be bothered except with a 2.67 1st gear and 3.91 rear, it's idling at about 8 mph. Would be no fun in traffic at all. But I live in BFE and it's pretty unusual not to make a traffic light on the first cycle :)
What were you running, the old R286-500 roller ([email protected], .750 lift)? Those liked a 1500 rpm "idle".
 
DrCharles said:
Video with sound from the rear in post #42. You can tell there's a cam all right. Kind of ruins the sleeper image, unfortunately ;)

I would not be bothered except with a 2.67 1st gear and 3.91 rear, it's idling at about 8 mph. Would be no fun in traffic at all. But I live in BFE and it's pretty unusual not to make a traffic light on the first cycle :)
What were you running, the old R286-500 roller ([email protected], .750 lift)? Those liked a 1500 rpm "idle".
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One was an Isky solid. The 1012C grind wasn't fond of low idle speeds.

I had some Crane grinds in SBC's and such that liked high idle speeds.
 
I never understood how a mushroom lifter gave you near roller cam performance at half the cost?

don't you have to machine the block to accept the mushroom lifter? Then buy the cam and lifters? And all the valve gear? Doesn't seem that far a head in the wash.

It's funny, that thing doesn't sound as radical as it is. Here is mine idling at 850RPM and it's a much milder cam all around.

 
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Sounds like you could use a bit more idle timing, and I bet it'd be happier at 900 or 950 too.

Even though that tagline was from the 1982 D.C. book and probably earlier than that, you have to buy a cam, lifters and valve gear no matter what kind of tappet is being used! Unless it's a very mild build using stamped rockers. The 1.00" mushroom lifter allowed a faster rate of rise than a .904" (and most lobes at that time did not take full advantage of the larger Mopar lifter to begin with). A roller cam is still significantly more expensive than a flat tappet. And have you priced roller lifters lately?? Even with having my cam and lifters refaced, plus the cost of buying it used, I have spent a good bit less than just a set of roller lifters...

The DC Engine bible was wrong about the need for back-spotfacing the lifter bores. Most if not all blocks have miles of clearance to the underside of the lifters. Mine certainly did.
 
If you could cut out the machining of the block it definitely makes sense.
 
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