535 shortblock tech.

[Brian D]

What is Beryllium, Alex. http://dictionary.reference.com/search?q=beryllium

EDIT- http://www.f1fanatic.co.uk/2007/02/08/banned-beryllium/

[paul burke]

Sorry Andrew, I don't think its on my end, as it only happens when on this site. I get about 40 some odd seconds to write and post before the whole thing goes away and I get logged off.


Paul

[Ken H.]

Andy, you might want to take a look at the Wikipedia reference to Scandium here http://en.wikipedia.org/wiki/Scandium. Nothing derogatory re. Beryllium, but Al-Sc alloys have some very intriguing properties. The Sovs used it in certain structural components in the MiG-29. Drawback is the stuff cost about $75/gram.
But you're correct in that Be is one of the nastier things out there . . . toxic as hell and very difficult to work with.

[Canuck YYC]

Not blaming you Paul - didn't mean to come across that way - IT glitches abound where I'm at much to the dismay and amusement of the IT team.

The Scandium link goes nowhere with the period in the link The
applications section suggests it's not a great strength additive to aluminium outside of heat-affected areas. It is rarer than I assumed after the first link I read from an AlSc vendor talked about it's use in sporting goods. Given it's relative density and strength comparison to Ti (according the Wiki article), I understand why more effort isn't put into generating it. But then, the article is confusing - used on missles to allow them to penetrate arctic ice on launch, but no stronger than Ti. I'll have to read it again.

Brush-Wellman's AlBeMet (40 or 60% Be, balance Al) is 6 times stiffer than steel, and ~the weight of aluminium. McLaren was the first to use it in their F1 engine, in connecting rods. Doing so allowed them to reduce the bore, increase the stroke and still maintain the RPM required to produce peak hp. Shrinking the bore improved the combustion dynamics in the midrange which is where McLaren started spanking Ferrari all over the place. Warren Johnson, IIRC, used AlBeMet-based lifters and pushrods in his Pro-Stock engines until the NHRA banned it's use as well.

As far as being hard to work with - not at all. I've not worked with AlBeMet as you don't want to machine the stuff - it's too expensive (parts are HIP'd to leave minimum finish machining). We process thousands of feet of beryllium copper every year in the facility I manage. It's a pleasure to machine and with basic precautions we have no detectable levels of beryllium or copper in the air of the shop or the blood of the staff (yearly testing). We don't weld it or perform any "dry" work at all - but I can still make valve seats for Ti valves. Poorly handled, like many substances in our daily lives, it is dangerous. Not unlike gasoline come to think of it.

[Ken H.]

Sorry the Wiki link went strange. My exposure to Al-Sc alloys comes indirectly from associates who worked at Lockheed Advanced Projects (aka Skunk Works). In addition to altering properties related to welding, there were some significant improvements in material yield points, or so I'm told. Correct me if I'm wrong here, Andy, but isn't Ti a fairly difficult material to machine? I noticed the inconsistencies in the Wiki article as well...nose cone strength ???
Given the usual performance first, everything else last approach applied to aerospace, I was interested that the Sovs used the alloy rather than Ti. Sc is scarce enough and expensive enough that using it would hardly be on a whim.
Beryllium. I'm aware of it's use as a copper alloy, in medical x-ray applications and its use in nuclear weapons. The latter as it is the best neutron reflector known while it is nearly transparent to x-rays . . .properties which have significance in making fission devices physically smaller and giving more energy yield per gram of active material.
One reason the Rocky Flats facility NW of Denver was closed by the DOE was chronic problems with beryllium dust contamination. This independent from plutonium residues. The USG is still fighting a host of workmen's comp medical claims related to berylosis-induced lung damage, much of this dating back 40 years or more.

But back to the topic, more or less. I haven't found any one good source for doing side-by-side comparisons of exotic materials in automotive applications. I'd love to see some kind of spreadsheet that says, "alloy F has the following key characteristics, and offers the following benefits vis-a-vis these alternative materials (list) in a stated application. It's drawbacks are (list)." Simplistic perhaps, but it would save a lot of time on research. Not eliminate it, but it would sure help narrow the search.

[Canuck YYC]

Indeed. I'd really like to see some parts of F1 un-corked again, get back to driving developments in materials and engines instead of spending hundreds of millions of dollars on aero (boo - boring).

Ti isn't fun to machine - it's hard on tools and it's gummy (and we have no use for it). Inconel is also no fun. We replaced Inconel with our own version of ToughMet (copper/nickle/tin) because you can't thread Inconel parts together without them galling. ToughMet doesn't gall and is...tough along with being very corrosion resistant. I've been experimenting with ToughMet valve guides but it's hard to quantify without a rather precise and effective means to measure FMEP.

Topic...we have a topic? Ah yes...come to think of it, you might want to research ToughMet as a rod bearing material. BW claims it to be the best bearing material on the planet - I'm not sure of that but in a heavily -loaded application like your own, you might be able to meet or exceed the reliability offered by the wider bearing shells with a narrower TM version. Absolute speculation on my part however I'm eyeing up everything that rotates on a bushing or shell bearing as potential candidates for TM-based replacements. Inserts in the cam bores are a very likely target.

[Ken H.]

Ah yes...come to think of it, you might want to research ToughMet as a rod bearing material. BW claims it to be the best bearing material on the planet - I'm not sure of that but in a heavily -loaded application like your own, you might be able to meet or exceed the reliability offered by the wider bearing shells with a narrower TM version. Absolute speculation on my part however I'm eyeing up everything that rotates on a bushing or shell bearing as potential candidates for TM-based replacements. Inserts in the cam bores are a very likely target.

Hmmm. Interesting. I wonder, though if MaBronze might still have some advantages in valve guides where the pressures are lower. Some of the ToughMet literature seems to infer that it has a slightly higher coefficient of friction than MaBronze.
http://www.asminternational.org/pdf/amp ... inodal.pdf
But the material certainly sounds interesting . . . as long as you don't have to eat the fabrication costs. I really like the thought about cam bearings. It's always bothered me a bit that in the S38, the cams run in aluminum journals which are part of the cam tower casting. Doing another engine with all the trick materials has a lot of appeal. What it would cost, I don't think I really wanna know. What kind of power delivery delta there would be is probably pretty small. Longevity? Who knows. Bragging rights? HUGE.

[Canuck YYC]

I don't quite grasp the idea behind the aluminium cam bores either but then these engines do seem to run forever. Might not be a lot of $ return but it would make for a nice repair if you needed.

TM is not cheap - it'd run you ~$120 for the material (less if you can find appropriate tubing) to make the cam inserts and probably the same for machining - they're pretty simple. I'm unfamiliar with the cast bronzes but we do use a lot of C63000 "Ampco" here.

MaBronze? MnBronze? I don't know either - the material of choice for valve guides seems to change fairly often - Al bronze, cast-iron, Mn Bronze...There may not be anything to gain using anything other than the standard offerings.

[Ken H.]

Yah. I referenced the BW website and used their terminology. There I am looking at my posting and thinking, "why am I writing Ma when I know full well it's Mn for the chemical symbol?" Juvenile Alzheimer's??
Cam bearings. Doing a bit of bench racing with the Burkester, I asked, can we use needle bearings here?" "Don't know why not." But then the man comes up with some of the most insane proposals I have ever heard. Insane, but when I do the homework, it's already been thought thru. Scary.

[paul burke]

Ken, you haven't seen my camshaft in a tube for Chevrolets. Isolated from the rest of the shortblock, it has its own oil entry/exit and the cam runs on roller bearings. I am going to use roller bearings on my M30 and move the valve train around a little.

Paul

[Ken H.]

Ken, you haven't seen my camshaft in a tube for Chevrolets.

"huh. huhhuh. I put my camshaft in a tube. heh. hehe. hehehehe."
"Shaddap, Beavis!"

I am going to use roller bearings on my M30 and move the valve train around a little.

I'll bet you will.
More engine porn!

[paul burke]

I might have made a mistake posting about the cam tube thing. O'well it may be old news to some by now.

Paul

[Rich Euro M5]

I might have made a mistake posting about the cam tube thing. O'well it may be old news to some by now.

Paul

I've never heard of it, please elaborate.

Rich

[ElGuappo]

How did this fall so far?
How is this not a sticky?
One of the most informative threads I have ever read here....

[LarryM]

How did this fall so far?
How is this not a sticky?
One of the most informative threads I have ever read here....

I totally agree. In so many threads I see here, someone always wants to take the discussion off-topic and begin debating B34 vs B35, FI vs. NA, etc. Enough already.

This one has been thriving because it has (mostly) stayed on topic, i.e. the buildup of the M30 shortblock. Even though some of it's over my head, I love reading about this hard core stuff as it relates to the M30. I've been learning a lot and have quite a ways to go.

As a way of continuing the thread, I'd be interested in hearing recommendations from anyone in SoCal about a first-class machine shop. I'll need boring, balancing, crank grinding/heat treat, porting & polishing, etc. I've heard good things about Top End Performance in North Hollywood, as well as Ireland Engineering; any personal experiences?

Larry

[paul burke]

My computer glitch is REPAIRED!! Thank God or whoever lives in browser land.

Larry, if you want to get your stuff done for real,

Head Porting - Slover's porting service on sherman way North Hollywood.

Block work - QMP performance in Chatsworth


Does anyone want to talk rod length and its affects on piston speed, intake signal etc.


Paul

[Canuck YYC]

Sure. I downloaded this force calculator from a forum somewhere a few years back. I believe it was a BMW forum of some sort but can't recall. Somewhere I have a tech article about short vs. long rods where the street engine actually had more area under the curve with a shorter rod, counter to common expectations.

[Derchump]

Since this is the short block thread, does anyone want to talk about maximum compression ratio for 91 octane pump gas assuming some chip reprogramming? I'm in the middle of a M30b32 rebuild and I'm trying to make the final decision on pistons. The objective is a streetable motor that will be autocrossed - lot's of low end torque. I typically use a fuel additive for the autocross work and then keep my foot out of the throttle at low rpm for the street time. I'm punching it out to 92 mm.

[patrick]

Sure. I downloaded this force calculator from a forum somewhere a few years back. I believe it was a BMW forum of some sort but can't recall.

Huh. Isn't that interesting. I wrote this in 1998.

http://patrick.my.cape.com/brm/rodlength.htm

http://patrick.my.cape.com/brm/rodratio.xls

[paul burke]

Andrew , Patrick and anyone else with pertinent information/questions, please keep posting here. Its about time we move the BMW thing into a real "hot rodding" format if you will.


Derchump, lets start by addressing what altitude you intend running your engine in, as the compression ratio can be higher at a lower atmospheric pressure.

Paul

[paul burke]

Thrust angles and piston speed are not as much of an issue as they used to be. Understanding how to dampen potential trust loads on cylinder wall and lower structure of the block can addressed with pin placement and skirt design as well as the advent of structural enhancements such as block fillers and main caps held in tension with angular fasteners. The current trend in such apps. as NHRA Pro stock engines, is the short deck short rod configurations that take advantage of the current level of cylinder head/intake flow capabilities.Further enhancing signal with piston speed off TDC , can lead to greater overall acceleration and broader power bands. High static compression ratios (15to1 plus) only add to this by increasing combustion chamber efficiency (less time needed at TDC to complete burn) and earlier stronger signal due to smaller volume at TDC.

Paul

[Ken H.]

Thrust angles and piston speed are not as much of an issue as they used to be. Understanding how to dampen potential trust loads on cylinder wall and lower structure of the block can addressed with pin placement and skirt design as well as the advent of structural enhancements such as block fillers and main caps held in tension with angular fasteners. The current trend in such apps. as NHRA Pro stock engines, is the short deck short rod configurations that take advantage of the current level of cylinder head/intake flow capabilities.

OK. If I understand this correctly, Paul, you're saying that the use of considerably stiffer blocks and newer piston configurations are moving us away from the old rule of thumb that said, in effect, "don't go less than a rod ratio of 1.67."
I'm aware that a lot of BMW engines (M30 and S38) are being built with rod ratios getting down around 1.50. That being the case, what kind of changes need to be made to the intake port design to make best use of (a) stiffer lower blocks and (b)more modern skirt designs?

Regarding the ports, I'd like to see this broken down into several separate elements: overall port volume (and it's relationship to swept cylinder volumes), port venturi area, signal, optimizing Mach index values, valve size, valve curtain area, to name a few. I'm especially interested in venturi configuration, as I believe that there are areas near the bottom of the port walls and port floor where gas movement--both volume and velocity--isn't up to the values seen more central to the venturi.

Back to port volume for the moment. We see things written about "cleaning up the valve bowls." Beyond unshrouding of the valve stems, what happens when the bowl shapes are changed, especially on the "bottom" side of the valve, i.e., downstream from the port floor? Presumably, the bowl cleanup increases bowl volume. What effect does changing the ratio of bowl volume to upstream (above-venturi) port volume have on intake charge delivery volume and more importantly, velocity? I'm assuming for the moment venturi area remains unchanged.

On this topic, I'm aware that back-cutting or putting a waist on the valve stem behind the valve head offers some benefits, as does the use of multi angle seat grinds (duh). But for the moment, I'm curious about what getting busy with a die grinder is going to do.

[paul burke]

Ken, there are two basic ways to increase cylinder head flow.

One is increasing overall area. Although this can increase port flow, it requires a stronger signal to create air movement (velocity).

Second, is to increase air flow by giving air direction. This can be achieved only when understanding the areas of the port that are vital to flow and filling the voids that are not. This can result in a high flowing port that has a relatively small volume. Therefore increasing velocity across a broader rpm range.

One often overlooked area that can have a great effect on port flow is combustion chamber shape and how air exits/enters port.

Paul

[Derchump]

Paul, thanks for the reply. My location is Wichita. From previous posts, I think you are in KC?

I'm leaning toward ~ 10:1. I've been pretty sucessfull in the past with pushing CR and then controling knock with my ear and foot when I'm running crappy fuel. I'm still researching reprogramming the stock 059 DME vs. an aftermarket unit such as Megasquirt.

[Ken H.]

Ken, there are two basic ways to increase cylinder head flow.

One is increasing overall area. Although this can increase port flow, it requires a stronger signal to create air movement (velocity).

Which makes sense in an FI environment where a larger air mass is being forced thru the port due to increased MAP. It also lends credence to using 4 valves and thereby valve curtain area. The other side of the ledger is using a smaller rod ratio, and thus increasing piston acceleration away from TDC. Result: a higher pressure differential between the port and the increasing cylinder volume. Which would also make sense in a NA motor.

Second, is to increase air flow by giving air direction. This can be achieved only when understanding the areas of the port that are vital to flow and filling the voids that are not. This can result in a high flowing port that has a relatively small volume. Therefore increasing velocity across a broader rpm range.

So short of having a fully instrumented head on a very trick flow bench measuring pressures thruout the port tract along with velocities within the intake flow stream, how do we know what areas aren't adding to the desired flow delta?

One often overlooked area that can have a great effect on port flow is combustion chamber shape and how air exits/enters port.

Sir Harry Ricardo discussed the benefits of of turbulence and swirl to intake flow over 70 years ago in his "High Speed Internal Combustion Engine". Ricardo indicated that the patterns of charge delivery had major effects on fuel burn efficiency and limiting of detonation. Step forward to the 1970s and Ludwig Apfelbeck's development of the double and triple hemipherical combustion chambers for BMW yielded major reductions in BSFC. (Reduce BSFC and all other things being equal, you have a more powerful engine.) The ability to utilize incoming charge "tumble" also meant much-improved fuel atomization.
Used in BMW's Formula 2 motors, it yielded significant advantages in power outputs, and lower emissions from reduced HC combustion byproducts. The basic concept went directly into the M10-20-30 series CC layouts.

From this, I'd like to know how much we can improve charge burn simply by alterations of piston squish areas before we have to get into altering intake tract configuration in a significant way. I'll assume that the engineers got it right on combustion chamber roof design.

[paul burke]

Ken,

As to your first point, You are absolutely correct in your analogy.

As to point two, these areas of the port are somewhat predictable if you follow the laws that govern the movement of air. A flow bench can then be used to properly validate ones work.

I recall a phrase I once heard at an engine building conference, "Swirl and tumble can make you stumble". I tend to look at the last point of control when It comes to combustion, this being piston crown (dome) shape as it relates to the chamber and where the heat has concentrated in the chamber. There are many things to be learned on the topic of Internal Combustion, maybe someone else has some thoughts?

Paul

[paul burke]

Derchump, controlling detonation involves more than just static compression. If you can control the running temp of the engine you can get away with even more. I regularly run boat motors at 11.5 -12 to 1 comp. on 93 octane at 150 -160 degree water temp with no trouble. Aluminum heads tend to dissipate heat from the chamber relatively fast so its easier to control . If you are running a stock style camshaft I would stay below 10.5, just remember once parts reach operating temp the compression ratio will be higher ( due to parts expansion or growth).

Paul

[Canuck YYC]

Sure. I downloaded this force calculator from a forum somewhere a few years back. I believe it was a BMW forum of some sort but can't recall.

Huh. Isn't that interesting. I wrote this in 1998.

http://patrick.my.cape.com/brm/rodlength.htm

http://patrick.my.cape.com/brm/rodratio.xls

Seems to me I found it in a discussion about M3 engines but I don't recall. Now I know it's author. Cheers.

[Derchump]

Paul,
I'm obviously using the stock, unmodified cooling system. There is usually a little more leeway with autocrossing because the engine doesn't build any significant temperature with the short 1.5 to 2.5 minute runs. Most of the acceleration is 2500 to 5500 rpm bursts with only 1 to 2 gear changes from 1st to 2nd. I'm working with a local engine builder and will be grinding a cam for that purpose, probably around 270 with around 0.450 lift. Final decision on the cam will come after the pistons are ordered.

[Canuck YYC]

Run-on thought...a short rod will yank the piston away from TDC (and push it up to TDC) quicker than a longer rod, but that also means that for a given crank angle, the piston is farther away from TDC meaning the cylinder pressure generated will actually be lower. To make it work you need a very good head - one who's flow and resultant cylinder fill out-weighs the drop in cylinder pressure under the curve as it were. With lower cylinder pressures you could get away with higher compression ratios I suppose. The slower piston speeds at +/- BDC might serve to reduce the amount of cylinder charge being pushed back into the intake tract.