383 in work...slowly, but in work

[jgl296]

The last 383 I built was for a 1978 Dodge 1/2 ton short bed pickup. I ended up using 440 length rods with Diamond forged flat-top pistons that have 4cc valve reliefs and .990" (BBC) wrist pins. The block was decked for a true 0.00" deck clearance. I used the new Edelbrock Perf. RPM cylinder heads w/75cc combustion chambers blueprinted to an actual 75cc's This gave me a compression ratio of 9.91:1 with the Cometic MLS head gaskets that have a 4.50" compression ring and a compressed thickness of 0.040". The heads were given a competition valve grind and minor bowl porting. The camshaft I used was a Hughes solid flat-tappet grind with 237/242 @ 0.050" and 0.569"/0.579" valve lift with 1.6:1 ratio aluminum rocker arms. The lift is reduced to 0.534"/0.543" when used with the factory rocker ratio of 1.5:1. I didn't have the engine dyno'd but I couldn't be happier with the engine overall. It pulls hard to 6,000rpm and has far more torque than I expected. If you want something a little racier I have also had good luck with the Hughes solid-flat cams in larger sizes. I hope this info is helpful. I will most likely be running this engine on a chassis dyno some time in the spring of next year and will post the results at this time. Other details for the engine are as follows: MP M1 single plane with carb flange welded-up and modified to match a square-bore, TTI 1 3/4" Headers w/3" full dual exhaust, FAST TBI, Street Hemi 6-quart oil pan w/1/2" pickup, MSD capacitive discharge ignition, 4-speed manual car trans. with Passon overdrive gearset, centerforce dual-friction clutch, 440 Source illet steel flywheel. I think that covers it. Feel free to ask me anything I may have forgotten.

 

[txstang84]

That sounds like a sweet combo, I bet it runs like a scalded dog! That's some great info, thanks! I don't know if I'll swing the extra for the heads, but I am definitely leaning toward the diamond pistons with 440 length rods...I was pretty sure they had a version of them I could use with stock 440 rods, but it's not settled in stone or anything.

I planned on using the 915s I bought off eBay, with some new valves, a good valve job, and some bowl blending. I looked at a few of those Hughes cams too, and they look like good grinds. Especially if I'm dealing with stock heads and less than ideal exhaust ports.

I have plenty of time to work out details...currently all the parts I do have are sitting in a storage unit and I won't be able to really pursue it for another couple years, but I figured a mildly built 383 in his Ramcharger would be a lot of fun.

 

[txstang84]

So, I've been reading a few posts about EDM lifters for solid cams, and the varying opinions on them. Over the past year and a half that I've gathered parts for my 383, the direction of the project has taken a few swerves here and there. I bought a hydraulic roller cam, but likely won't use it in favor of a solid cam (I have adjustable rockers, might as well use them, right?). And that's the focus of my latest curiosity...with a fairly normal solid cam (up to about 250* @ 050"), is there a need or benefit from running such a lifter? I know the .904" tappet diameter allows for quicker acceleration of the valvetrain parts, but since the lifters are only splash oiled plus whatever oozes past in the galleys, couldn't there be some tangible longevity improvements by using such a lifter design, or would I be basically pouring more money into the hole than is justifiable-is it just a piece of mind, warm-fuzzy kinda thing? If there is value-added to this build by using them, I'll happily plunk down the extra, but if it's not useful, then I'll just stick with whatever lifters come with the kit. Next, along the same lines, is there any benefit to running oil through pushrods with a solid cam, and adjustable rockers? Any legitimate disadvantage?

Thoughts?

 

[Abodybomber]

When you start ramping up lift and quicker ramps,usually valve spring pressure goes up. This tends to work the cam/lifter surfaces harder. Not so much a problem with race only,the idling and around town driving hits the cam/lifters hard. Having lost a good 396 Chevy this way(flat lifter),I would highly recommend the EDM lifters and a good ZDDP supply in the oil.

 

[RustyRatRod]

I have the Howards EMD lifters for my 383 and intend to use them.

 

[txstang84]

Thanks guys-I'll likely add them to the list

 

[moper]

What are the specs on the cam? duration at .050 isn't enough. I've never used them and never had a problem but i can see certain scenarios when they would be a good idea. Spring pressures over the nose of more than 400lbs, rocker ratios higher than 1.6, etc. But those are not really commonplace. Depending on the cam and springs you're talking about it's probably got over-the-nose pressures of less than 375lbs. As long as the lifter bores were machined properly and are not worn and you use a good oil I wouldn't expect any issues with running a plain lifter.

 

[txstang84]

Hey moper-good to see you comment on here-I understand the 050 duration isn't enough alone, but rather the cam profile overall and the spring requirements. I was trying to summarize the attributes with your guys' understanding that higher 050 duration will certainly = higher spring pressures, especially with some of the newer grinds that push the envelope of flat tappet, non-mushroom cams.

And while I understand I may not truly need something, if they were to benefit longevity...ounce of prevention type thing.

I was only planning on running a grind like an MP .528" solid, Voodoo, or Howards. And while those cams aren't really that hot, I'll go to my above statement. I understand I can't prevent every contingency, but the price difference between a set of standard solid lifters and EDM lifters is roughly $75-$100 depending on your brand selection...and if that can stave off wiping a lobe I would venture to say the money spent would be worth the piece of mind. I know the lubricants used play a pivotal role and something with zinc/phosphorous has everything to do with it; luckily, there is a dizzying array of ZDDP oils, and or additives from which I can choose. And I may just use those in my turbo'd 4.6 4V build as well.

Now-the other part of that question that no one has touched yet; most of the aftermarket lifters, to include the EDMs, have provision for oil through pushrods...would it benefit me to go ahead and use oil through pushrods at all, or would that take too much oil from the bottom end?

The engine is nowhere near together, hell, it isn't even machined or cleaned yet and it won't be for quite some time...but the more details I iron out now, the smoother this project will eventually go after my retirement from the AF...hence the reason I ask people who build up BBMs...

 

[RustyRatRod]

I would rather have direct oil on the lifters than not. Were they available 30 years ago, I would have used them then. IMO, someone should have thought of this in the industry at the inception of the flat tappet lifter. I have always thought that splash lubrication wasn't sufficient. Now with the reduced and eliminated zinc, it surely isn't. Kinda like a gun. I'd rather have it and not need it than need it and not have it. Since they are available, it's a no brainer.

And about the oil through pushrods, since the heads get oil elsewhere, it's not necessary, but I certainly see nothing it would hurt. I would use a high volume oil pump though. Have you seen the mods on Big Block Dart regarding constant oil to the rockers?

 

[txstang84]

I haven't seen the mods on BBD, but another member recommended I open up the lower passages to 1/2" and I will likely perform the top end oiling mod where the galleys going to heads receive full time oiling...if that's what you were referring to.

 

[RustyRatRod]

The top galleries are what I am referring to. I think that's a good mod.......even though I am not doing it to mine. My engine is going to be 100% street and not see high RPM much at all. Besides, I am using full groove mains and an high volume/high pressure pump so that oughtta be enough. lol

 

[txstang84]

Sounds pretty good to me, Rob.

I honestly don't even know what percentage this thing will ever see of street vs strip, as it's going in my Dad's Ramcharger, but I know I want it to haul the mail-expedited style, and I would think having a screaming 383 in a first gen SUV would be loads of fun. So, it likely won't see the high side of 6k, but depending on my cam choice, how well the heads are prepped and my induction, it'll probably see 6,000 every time it's driven...just because ;)

 

[moper]

"I understand I can't prevent every contingency, but the price difference between a set of standard solid lifters and EDM lifters is roughly $75-$100 depending on your brand selection...and if that can stave off wiping a lobe I would venture to say the money spent would be worth the piece of mind."

This is all my opinon based on my knowledge and experience and I'm sure others' will differ:
You are asigning the blame to the cam lobe and lifter and that is a mistake. The parts on thier own don't cause failure - it's forces acting on them. So while I agree an ounce of prevention is better than a pound of cure - your approach is applying that ounce to the effect - not the cause.
Having dealt with engines that wiped cams for almost a decade now I'd put the failure rate specifically due to the lifter at about 5% with the majority of those being from when the lifters in the late 90s had manufacturing problems. If your engine has big spring pressures (the MP .528 doesn't, but the Lunati might depending), and if you're blocking off the valley for windage, or controlling windage with very tight clearances side and scraper or trays - EDM lifters would be a wise choice. That's because the lobe and lifter are splash fed normally and in those cases you're reducing splash to almost nothing with the goal of controllling losses due to windage - which can be significant.
In most all circumstances - if the lifter bores are sized properly (not worn), and if the lifters rotate properly, and if you run an appropriate oil for the cam choice, and if you can execute successfully priming and starting a new engine instantly, and if you vary the rpms and keep it running so the surfaces can properly seat - then pressurized oil to the lifter face is only an exercise in self assurance. They are not providing anything else for you. If any of those things are not right, the cam will fail even if you dumped a 55gal drum of oil on it while it's breaking in and running.

As far as top end oiling - you don't need anything extra unless you're doing endurance type racing and maintaining high rpm with big spring pressures or high rocker ratios.

 

[txstang84]

I see your point...I truly wasn't attempting to "assign blame" to anything, but I see how it came across that way. I don't believe any of the cams I would choose to require that much spring pressure...but I'll cross that bridge when I come to it.

Would you assert that I'd be wasting my money by purchasing them, or won't gain any benefit?