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Piecing together my new 383 SBC


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#26 _HRV74_

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Posted 09 July 2011 - 10:20 PM

For what it's worth, I'm very impressed with the Crane Hydraulic Roller in my 383. (Part number Cranes Cam 119841)
It runs: 234 deg @ .050 on the inlet, 242 deg @ .050 exhaust, 112 lobe sep.

Just some of the other vitals include: 10.5 comp and Trickflow alloy heads with 195cc inlet volume.

You can cruise around in the car all day with no dramas, but the engine had a much more cranky idle before the EFI was fitted. I'm running a 3700 stall which is spot on, but you could get away with a bit less. Made 396rwhp with this cam.

Cheers, H

#27 LXCHEV

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Posted 10 July 2011 - 10:57 PM

Thanks guys, very good feedback. Cam choice is so hard and frustrating! Not something you want to get wrong.

Struggler - your mate with the Firebird is running some bloody good times. It's a fairly aggressive cam.

HRV74 - I like the sound of your cam too - those specs are probably a bit closer to what I've been looking at, but maybe slightly tighter LSA, since I'm coming from my old cam with the 107LSA which I loved. Damn that's some impressive power you're getting out of your weapon too!! I wasn't aiming anywhere near that kind of power, but it just goes to show what these cams are capable of.

My current stall is meant to be a 3200, but with the old engine I reckon it flashed to every bit of 3500, so I think this should work ok with cams in this range.

If I do bite the bullet and go for a roller.... how do I decide between a single pattern grind, and a dual-pattern grind which seems to be both more common and more popular? I recall an old conversation with you Struggler when you commented that single pattern grinds tend to make better power up to 6000RPM, so I've always been keen to follow this path as my car is more about low down power and torque and only part time racing. Decisions, decisions....

PS. Yeah I've heard the Yankee's love their hydro rollers, and they usually know what they're on about. So I think that's a good sign in itself.

Edited by LXCHEV, 10 July 2011 - 10:58 PM.


#28 Struggler

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Posted 11 July 2011 - 08:21 AM

OK, I'll be a little more specific.

GENERALLY, with a SBC with 23 degree heads a single pattern cam will generate more torque below the HP peak. The extra exhaust duration is only there to assist emptying the chamber at high RPM, usually after the HP peak. What the extra exhaust duration does below the HP peak is bleed off valuable torque producing cylinder pressure. Yes you can compensate by giving yourself more static compression to start with.

It is easier to make a decision if you know how much your head flows on both the intake and exhaust.

The cam with the longer exhaust lobe will sound better, this is often a selling point.

GENERALLY I like to use a single pattern cam with a narrow LSA in a performance street engine where maximum throttle response and torque is needed between about 2000-5000 rpm. This works well with any engine that has a good flowing exhaust port, particularly HQ headed 308's.

Again, the cam is only one component in what needs to be a carefully matched combo.

In HRV74's case he has EFI which makes the intake more efficient than if he was using a carby, therefore my generalizations don't apply to his case. As the intake is more efficient it doesn't need as much duration and the wider LSA will give it a broader power curve, not like the peakier curve of a tight LSA cam. His exhaust lobe is not bigger than the intake, the intake is smaller than the exhaust and as such I would expect the engine to make power in a similar range as a cam with 242 @ 050 on both lobes. I hope this makes sense. It really is horses for courses. Personally I wouldn't use that cam in a carbied engine.

And now for the disclaimer.....Please note these are my views only and I'm sure there are people out there that don't agree with them ! This is just what I have found works for me.

Edit PS. Don't be afraid to go slightly larger in a roller grind. The rapid opening lobe will have a smaller advertised duration than a flat tappet cam with the same 050 duration. For comparing a roller to a flat tappet use the advertised duration when considering things like stall speed etc.

Edited by Struggler, 11 July 2011 - 08:27 AM.


#29 _HRV74_

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Posted 11 July 2011 - 07:43 PM

Your thoughts always make for very interesting reading Struggler!

Cheers, H

#30 LXCHEV

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Posted 11 July 2011 - 10:27 PM

Bloody oath they do, awesome education on these forums! Thanks mate. And yes, it all makes sense :)

#31 LXCHEV

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Posted 11 July 2011 - 10:58 PM

Found this YouTube video very interesting... purely cos it's nearly a match to my engine... same heads, same intake.. 10.0:1 comp, with a 750 carb...

Have a look, and check out the HP and torque figures!

http://www.youtube.c...h?v=WVaDuBdqpFw

I looked up the Comp Cams "Big Muther Thumper" cam they used, and it's a dual pattern 243 / 257 @ 0.050 on 107 LSA. Bigger than what I want.. I think...

Their engine has real serious pipes though too. My Tri-Y's are going to hold me back, so I need to choose a cam very carefully to suit my exhaust. It's one thing I can't be bothered changing (and don't want to anyway).

But check out the vid - way cool :)

#32 LXCHEV

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Posted 06 August 2011 - 11:06 PM

Hi guys... another question.... what do you know about SBC oil pumps?

I have bought a new Melling oil pump (standard), they're only $35.

The guys at at the speed shop were telling me about the Melling 'Select' series pumps... said they're around $150, and are a better quality unit. There's a few to choose from, some have slightly higher pressure etc....

Have any of you taken this path, or did you stay with the standard cheapo ones?

#33 LXCHEV

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Posted 06 August 2011 - 11:20 PM

For those interested in some oil pump education, check out this page.... great video which explains the differences between Standard Volume, Std Pressure / Std Vol, High Pres / High Vol etc....

http://www.jegs.com/...751586/10002/-1

I'm seriously considering trying the Standard Volume, High Pressure one (M-55A).

More good stuff here:

http://www.mellingse...onOilPumps.aspx

Edited by LXCHEV, 06 August 2011 - 11:24 PM.


#34 _oldjohnno_

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Posted 07 August 2011 - 08:16 AM

One of the really nice things about the old SBC is the fact that it can be oiled perfectly well with quite moderate pressure. Unless it was some oddball build that had unusual requirements I'd stick with stock volume and pressure. Increasing either or both takes more power to drive the pump (especially noticeable with HV pumps) and puts more load on the dissy gear with no benefit whatsoever to oiling. 60psi is plenty for these engines.

#35 _UCV80_

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Posted 07 August 2011 - 08:50 AM

Std mellings pump will do fine, Not sure if you have chosen the cam yet. But i went with comp cams XE282 solid, has been great for streeting. Worth a look.

#36 _Liam_

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Posted 07 August 2011 - 06:13 PM

I was under the impression if you were to upgrade your Oil pump to go the High Volume pump rather than High Pressure?

#37 _nos 598_

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Posted 07 August 2011 - 07:39 PM

make sure you buy a good quality like arp oil pump drive .

#38 _oldjohnno_

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Posted 07 August 2011 - 08:20 PM

1-Changing to a high volume pump isn't an upgrade, it's a downgrade..
2-An appropriately sized pump can be driven forever by any old stock driveshaft, there's no need for a super-duper ARP shaft or any other flavour-of-the-month item. You could almost drive it with the stick out of a goddamn pluto pup...

Look, people have been building high output smallblocks for over fifty years and they've never exhibited any signs of needing additional oil. Another way to look at it: any reasonably built smallblock can only accept as much flow as can be produced by a standard pump running at around 2500 - 3000 engine rpm. At speeds higher than this the excess flow is spilling over the relief valve. So given that at the normal operating speeds of any warmish engine the relief valve is already going to be cracked open what's the point of making the pump any bigger? Really, this stuff was resolved decades ago...

It's good that suggestions are being offered but it'd be nice if there was some sort of supporting data or logic included to back them up. Otherwise it's no better than what you can hear at the pub, and we know how reliable that is. I'm sorry but I'm old, cranky and tired of hearing the same old crap endlessly recycled...

Edited by oldjohnno, 07 August 2011 - 08:22 PM.


#39 Struggler

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Posted 07 August 2011 - 09:10 PM

OK, here's my 2c.....

Yes the standard pump (M55) is fine. I used a M55A in my own engine as that is what I had in stock at the time. The only difference is the point at which the relief valve opens as OJ states (the M55A has a pink spring). On my engine it was 65 psi and hot idle falls off to 30psi. This is more than adequate. The high volume pump really is a waste of horsepower.

I have to disagree with the OP drive comment. I use the ARP one on every build, if only for peace of mind and the steel collar. As someone who has used a Chev oil pump primer for a few years now and replaced a fair few stripped 308 oil pump drives I honestly feel you need more structural integrity than a pluto pup stick can provide to drive an oil pump at 6000 rpm.

JMHO

#40 _Liam_

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Posted 07 August 2011 - 10:08 PM

1-Changing to a high volume pump isn't an upgrade, it's a downgrade..
2-An appropriately sized pump can be driven forever by any old stock driveshaft, there's no need for a super-duper ARP shaft or any other flavour-of-the-month item. You could almost drive it with the stick out of a goddamn pluto pup...

Look, people have been building high output smallblocks for over fifty years and they've never exhibited any signs of needing additional oil. Another way to look at it: any reasonably built smallblock can only accept as much flow as can be produced by a standard pump running at around 2500 - 3000 engine rpm. At speeds higher than this the excess flow is spilling over the relief valve. So given that at the normal operating speeds of any warmish engine the relief valve is already going to be cracked open what's the point of making the pump any bigger? Really, this stuff was resolved decades ago...

It's good that suggestions are being offered but it'd be nice if there was some sort of supporting data or logic included to back them up. Otherwise it's no better than what you can hear at the pub, and we know how reliable that is. I'm sorry but I'm old, cranky and tired of hearing the same old crap endlessly recycled...


I wasn't meaning any offense mate, was just a general question, and I'm glad you took the time to reply. Appreciate that, thank you.

#41 LXCHEV

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Posted 07 August 2011 - 10:08 PM

Thanks guys. Great feedback.

I'll stick with the standard M55... 35 bucks well spent :)

I've always been anti-high volume pumps, it was just the higher pressure that got me thinking (the pink spring)... but since this is just another mild build with hydraulic cam, I think I'll just stick with the standard spring. I agree, they have come up with a proven pump over the years, so there's no need to go searching for alternatives. Thanks for saving me some cash :)

I have actually already bought a new drive too.. can't remember if it was ARP or Melling, but it's got the steel collar and not the plastic one, so should be fine.

#42 _oldjohnno_

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Posted 08 August 2011 - 08:53 PM

I wasn't meaning any offense mate, was just a general question, and I'm glad you took the time to reply. Appreciate that, thank you.


Sorry about that mate. I don't cope with sleep deprivation very well at all...

#43 _Sandman_

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Posted 19 August 2011 - 09:12 PM

With a 72cc chamber, you'll end up around 9.6-1 cr, depending on head gasket and deck height. For what you want and only that much compression I'd stick with cam around 240*@.050", don't go much bigger unless your planning on a looser converter and low gears.
With flat tappet cams, I prefer solid rather than hydralic. Always make more HP. Sometimes figures can be decieving. ie one cam thats 280*@0", may be bigger than a different cam thats 290@0". Best way to compare them is the difference between the zero figures and .050" figures. Less difference means the valve is opening quicker, so is open further, for longer.
Solid rollers aren't reknown for reliability on the street. Needle rollers coming out etc at low milages.
If you want to go roller for street, hydralic roller is best. Although HP is still similar to solid flat tappet. Solids aren't bad for maintenance if valvetrain is good.
1.6 rockers are good.
My old 383 was pretty mild combo, GM crank and rods, forged flat tops, ported fuellies, solid crane cam, 238/[email protected]". Did lotsa miles on the street with no problems. Ran 7.7@94mph for 1/8th mile in HQ panelvan, which would be a high 11 sec 1/4.

What the others said about oil pumps is pretty right. Chevs have a pretty good oiling system. My old 377 race engine used to run through the lights at 8200-8400rpms and 50psi oil pressure. Went 9 years before I sold it. I pulled the caps off now and then to check bearings, but always fine. Good oil pump shaft for peace of mind. With solid lifters in GM block, I used restrictors in the lifter galleries drilled to 5/64". Don't use restrictors with hydralic lifters, or in Dart or Motown blocks.

Forged pistons are the only way to go!

If your using "I" beam rods with a conventional rod bolt, dummy assemble engine with cam in, then put one piston and rod in at a time with no rings, turn it over and check through the opposite bore for rod to cam lobe clearance. #1,2, 5, 6 are the main ones to watch out. May need to trim rods slightly. If any rods clip your cam, you'll have an engine full of junk before you finish test drive. With bigger cams, I've even had to trim "H" beam rods with 3.75" stroke.

Use a good ignition and you should make 400+HP easily enough and be nice to drive around. Depending on gearing and setup, should run 11's easy enough.

If your going to use studs in the main caps, measure up for round, as studs can pull the tunnel out of shape. For the HP your looking at, you could probably get away with std bolts, or to go a bit better, get some ARP bolts, not studs.
Same with the heads. While studs will clamp down tighter, if you use them, you won't be able to get the heads off in the car. ARP head bolt sets aren't real expensive and as long as head and deck surfaces are good, it'll be fine.

Have you got TriY's or looking at getting a set?

#44 LXCHEV

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Posted 19 August 2011 - 11:15 PM

Thanks for the comments Sandman, great reading.

I should be able to reach 10:1 comp, with 0.005" deck height, and 0.041" head gaskets. I'm still very keen to try a hydraulic roller cam. Leaning towards something around the high 230's / low 240's @ 0.050".

I decided to go with an ARP main stud kit only, but just use bolts for the heads (already have ARP ones anyway)... don't want to muck around with head studs for the exact reason you mentioned.

My engine machinist has fitted the main studs, decked the caps, and bored/honed the main tunnel, so it should be spot on now.

And yep - I'm using my existing Tri-Y's which are 1.75" -> 2" -> 2.5".

Here's some pics of the parts and progress from my LXCHEV Project thread...

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#45 _Sandman_

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Posted 20 August 2011 - 06:12 PM

Looks like you've got it pretty sorted. Good move getting the tunnel honed with main studs. That'll all be good.
Hydralic roller around the size your looking should be fine for what you want and suit how much compression you have. Look on some of the US mailorder sites. Jegs, Summit.
My brother bought a Comp Cam hydralic roller kit for $1000 from Jegs. Has Cam, Lifters, Valve springs, retainers, collets, timing chain set. Bargian!! It will cost you around $1000 for lifters alone in Oz.

Another thing to check that I forgot to tell. Before you start assembling anything, sit you heads on the block and look how the oil drain holes line up. Some heads will half block off the drain holes. Easy fix if you do it before assembly, as you only need to scribe through the head onto the top of the block, then grind out the block so that the drains line up.
If they aren't lining up, and you put it together, yopu can run into oil pressure problems, simply because the oil is not draining back.
Don't forget to check the clearance between the rods and the cam. Looking at those rods, the corners might get pretty close and may need trimming.

#46 _Sandman_

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Posted 20 August 2011 - 06:15 PM

LX. Did you get those TriY pipes made? I'm looking for a set of big TriY's myself. Do they fit good? Better than 4 into 1's?

#47 LXCHEV

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Posted 22 August 2011 - 12:14 PM

Thanks for the latest comments Sandman. We'll be checking all those things for sure.

As for the Tri-Y's, yes they were custom made. They fit awesome, with heaps of clearance around everything, and the best bit is they can easily be fitted and removed with the engine still in place. I think they do rob a small amount of top-end power if compared to 4-into-1's, but for a street car that doesn't phase me in the slightest. The Tri-Y's produce fantastic torque everywhere, by the bucket-loads :)

And also for me, ground clearance is important. My previous 4-into-1's were a real pain in that respect.

#48 LXCHEV

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Posted 22 August 2011 - 12:17 PM

Here's some pics of the pipes:

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#49 _Sandman_

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Posted 23 August 2011 - 01:46 PM

Nice looking pipes. What did they cost to get built?

#50 LXCHEV

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Posted 23 August 2011 - 03:18 PM

They cost me $1200, but that was a few years ago now. HPC coating was on top of that. And it sucks now cos it's all dulled off and looks crap! Next time I will go for the black coating.




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