MGB: A Neck With Bolts, Creating Frankenstien...

With the Halloween holiday rapidly approaching, I figured it was probably as good a time as ever to unveil something we've been cooking up our own secret lab recently.

For those of you who have been following the Jimmy Hilton MSX project here, this will probably be rather interesting.

Now for those of you who don't know, Jimmy sent out a couple of MSX heads to us over a year ago, with the intent on having us pick the best of the two for him to use. Now it just so happened at the time, that we were going through the frustration over the "devil head" scenario (see here: http://www.flowspeed.com/msx-tribute.htm ), and decided there might be a better route than to compromise with either casting. In the end, I specifically chose the worse of his two castings and quickly got to work milling holes in it!

Not too many people begin the process of improvement by making something useless, but we had bigger plans in mind.

Ok ya got me I am all eyes!

A couple of the problems facing the smooth influx of fresh mixture to the engine on any MSX headed affair, are the sharpness of the short side turn and the lack of sufficient port area. Because these heads can only be ported so far before the other side of the port wall is found, and because there is only so much short side turn height to work with as stock, we felt that adding material where we wanted it might better allow us to get the shapes we needed to help the air flow better into the chamber.

To start, we stuck the TIG torch through the holes in the roofs of the port and welded material onto the floor of the port, which would allow us to create a higher and longer (less sharp) short side turn once the porting process began.

Additionally, we added a lot of material to the outer portions of the side and roof walls, so that we could grind well past the original wall "boundaries" without making holes in to the water jacket area. In fact, the roof area no longer had water above it at all when we were done, becoming one solid piece with the valley area inside the rocker box.

After getting material everywhere we thought we'd want it for porting purposes, the rocker box floor, spring seats, etc. are welded back in place.

Looks a little ugly right now huh?

The inlet ports weren't the only places we spent time with the welder, getting the chambers right was a major part of the re-do on this job.

With a stock MSX head, you can just barely get an effective chamber de-shroud profile on the inlet side, where they usually leave you enough material to make a smooth transition off the seat top cut to your lay-back profile. Once you start welding however, you can do anything you want!

Everyone knows I hate rules, so... Why not?

[quote=spikemichael]
Ok ya got me I am all eyes![/quote]

Probably Jimmy too!

Some of these pictures have never been off my computer before now.

At this point in the "show", I think I'm getting a little ahead of myself. You see, I really started this project by only modifying one port first and using clay on the flow bench to get the shapes worked out how I wanted. There were two reasons for doing this specifically.

One was in case I stumbled upon something great, I could duplicate it easily on all the rest without having to go through a lot of (extra) rework.

The other was so I could keep the stock chamber and modify the port side only. In this case I didn't even change the original Pierce valve seat or use a tapered guide. I did that because I've always wondered just how much better one of these heads could have flowed with only a simple change in the port coring, the answer was interesting indeed...

First a port mold photo however, the stock port is on the left with our modified port on the right. Note that the opening location (manifold flange location) has not been altered in any way.

I did this so that Jimmy could bolt any MSX manifold to the head, if by chance a better one were to be found... (but we're already way ahead of ourselves, so let's keep on track!)

Ohy, I am liking this!

Great explanations and VISUAL AIDS!!!

This is great...

i am salivating as if there were brownies in front of me...WITH walnuts!

Here is a photo of the stock chamber with my first "test port" almost ready to go. Yes I filled the big gaping hole at the top of the port with clay before I loaded it up with valves!

I'm not going to post flow numbers at all the lift points in the interest of saving myself a lot of typing, but a stock MSX head flows about 123cfm at .450" valve lift and the port you see above flowed 150cfm, no other changes!

To me that was significant, because it proved that Pierce could have made a head capable of massive gains in performance (rather than mediocre ones) by simply having a slightly better cast shape to their inlet ports. Sad to say, but true...

Here's another view of the original test port ready to flow test, just to prove I closed off all the holes first!

By now, some of you are wondering if all this welding isn't going to wreck havoc on the metallurgy of the original casting? Well, you would be quite correct in assuming so, as it indeed did just that.

Prior to getting started in the head welding business with Jimmy's MSX project, I did my homework and called PBS in southern California to find out what material they were casting these heads from. I pretty much suspected A356 would be the answer and I was right.

The welding rod pictured here is designated 4008 and if you'd like to have a little fun, give your local welding supplier a call and ask them if they can get you some! Assuming they can, it'll likely be in a ten pound box (as seen here) and cost you around $250.00.

Unlike commercially available fillers like 4043, this product is not only the correct chemical mixture to join to A356, it's also heat treatable, just like A356! This means that after all the welding is done, the casting can be sent off and solution heat treated, in order to nullify the stresses imparted in the welding process and at the same time, re-harden the casting.

After all the welding you see above was completed, the head was shipped off to a heat treating company in Portland, where it was normalized and then re-heat treated back to the T6 condition.

We felt all these steps were essential if a quality, lasting product were to be had in the end, and we wouldn't have it any other way. There are a lot of people who weld nonchalantly on aluminum cylinder heads, but we weren't interested in adding unknown variables (like warpage or seats falling out) to an already very extensive project.

OK Soo,My question is,without doing all of the port and combustion chamber work does a stock castiron head on a 78 perform better than an aluminum MX head right out of the box???
Right after I got Mine 78 B I was looking in the Moss catalog and saw these cross flow heads and thought"OOOOHHHH Boy,when I get some money together I`m gonna get one of them bad boys.Maby it`s a good thing I did`nt get some money ahead.
Next question is,Do You rework these heads commercially and what kind of a price tag would be on one???

""
Looks a little ugly right now huh?""""

beautiful scalloped puddles

a pleasure to see

Sean.....Brilliant!

First off, thanks for sharing Sean.

Just a thought. I wonder if once you get it where you want could it be mass duplicated? Cast plugs and make molds for casting or however they do that? That would surely be less expensive than the first one off modification. Like I said, just food for thought.

So you got roughly a 20% increase in flow at high lift, which would be expected any time you make the port bigger. My question for you is this: How does flow compare at low lift, where the vave is just starting to open? What are your numbers at .050", .100", and .200"? Do you see the same gains or better? Or is this just designed to be a race head where throttle repsonse isn't near as important as WOT? What's the goal with this head? Street peformance or track performance? Designed to work with a high duration hp cam or be a torque monster?

Just by looking at your port moulds, I'd guess that the straight bore (not tapered like a typical venturi) I'd guess that your flow suffers a bit at low lift, where you need to get great initial velocity for street performance. By designing a very low volume intake manifold, you could make up for that though. Or maybe I'm not seeing the full picture with a simple "side shot" of the port mould? More info please!!! :D:D:D:D:D

Outstanding! It is such a pleasure to see actual, as work progresses photos, instead of "here is my......" that most folks post up. Sean, this is truly a credit to your skills and expertise. It does make one wonder why these heads were not thought out a bit better from the beginning, especially as the price tag was $$$$$$$ right out of the box and hasn't changed any or the product been improved in all of these years. Thank you for all of your interesting insights Sean.


Jim B.

Congratulatios Sean, that's a nicely done bit of of re-engineering. Now a few questions:

Are these heads still being manufactured?
Would the foundry be willing to modify sand cores or even better sand core molds? Water jacket and/or port?
Would any other pattern changes be necessary to achieve the desired results/
Would the changes envisioned for the ports work well on an as-cast street port head?

Back in the day I was distantly involved with these kinds of mods to sand cores for iron heads which could be raced as stock appearing.

I'll be adding a post in the Motorsports Forum with a reference this thread as it should be of interest to the racers. ( with Sean's permission).

First off, this is 100% a street engine and the ports are being sized appropriately for that! You guys are all jumping way ahead here, but that's good to see. I'm glad there is some interest.

Yes these heads are currently available and yes, with some core changes, they could be cast this way. I'm sure the foundry would be willing to do anything for Mike if he paid them to do it.

Now some more specifics...

Shown below are two of Jimmy's valves, one inlet and one exhaust. I thought it would be fun to make you guys guess the sizes, but I'll be a nice guy in just tell you. The inlet we're using is 1.5625" (stock small-valve size) and the exhaust is a 1.25" valve I made from a standard sized MGB exhaust. It may not be apparent, but in addition to turning the head down to 1.25", we also increased the back angle to 25 degrees for more of a "tulip" shape. The seat angle is also 50 degrees rather than the standard 45.

As a reference to those who don't work on MGB heads for a living, the stock MGB exhaust valve is 1.343" and an early MGA exhaust valve is 1.28". If you look at exhaust valve size as a percentage of the inlet, the stock MGB is about 86%, the MGA valve is about 82% and Jimmy's will be about 80% on the nose. Most successful naturally aspirated engines run valve sizes in the 78% range, so this change to a smaller exhaust valve should not be wholly surprising. Remember that the engine doesn't know what sized valves it has, just how much they flow.

Another advantage to the smaller exhaust valve, is bore clearance. Note that with this sized valve and the roughly .050" overbore, Jimmy won't have to worry about his exhaust valves nearing the block. This is a good thing since he'll have over .450" exhaust lift and the chambers are only about .350" deep.

Now for some finished photos (I hate to jump ahead, but if I don't stop now I'll be on this thing all day!).

Shown here is the final inlet port shape. I did not pour these to find their cc volume, but I can assure you that the cross sectional area is not large, simply adequate to feed the valve/cylinder. Those guides are standard MGB inlet guides which have had a groove machined on the top side for a circlip (similar to Jaguar and other similar styles) to retain them should they ever possibly work loose. In my testing, the fin behind the guide worked even better than I thought it would at helping to smooth the flow of air back past it. That is something you couldn't cast readily, but pretty standard in the high performance porting world.

Last photo for now.

This is of the finished chamber.

In addition to welding a bunch of material around the seat areas so that we could get the wall to continue straight off the seat, we also moved the spark plug into the chamber slightly (so that it's not buried down in a hole anymore) and made the exhaust side of the chamber smaller. This means the chamber is not overhanging the block as much and of course the flow performance is significantly better.

is this PBS Engineering the same outfit that built DSR cars back in the 60s and 70s (and raced an 1100cc Corolla-powered FC pretty competitively in Cal Club)?

Jimmy's gonna have to really start recycling batteries now!

Sean, at the end of the day will there be any back to back dyno testing?

Sean, one more thought b4 I close my pie hole. It's too late on this head but if you do another consider welding in some correctly targeted fuel injector bosses.

Sean.

Thank you for pursuing this project and sharing what you have learn't.

kelvin

Jeff asked if the low lift flow performance was degraded at all during the process? The answer to that is no, though I wasn't particularly concerned with it had it been. When looking at port flow, I try to target valve lifts during which the piston is moving the fastest rather than those lifts where the piston is moving the wrong way. It doesn't take a lot of calculating to see that the piston will be drawing harder on the head at 75* ATDC than it will say, 10* BTDC, so gains made at very low lifts are usually of no value and only serve to increase overlap area, rather than power. BTW, I consider "low lift" to be .200" and less.

Here are flow results from the stock inlet starting at .050" and increasing by that amount each time.

27
51.5
76.5
95
109
116.5
120
122
123

Here are the final flow numbers from Jimmy Hilton's inlet as per above (note same valve size).

28.8
52.5
77
100
121.5
139
152
159.5
163.5

Here are some numbers from a standard ported MSX head I did for a racing customer. Note that the valve size in this case is a much larger 1.665" Ferrea inlet valves.

29
54.3
80
104.3
125.3
141.5
149
155.5
161

As can be seen, the much larger racing valves did improve the flow up to .300" lift, but Jimmy's head took over from there up. Jimmy will also have over .450" of inlet valve lift, so these numbers are valid for his case and again, target the times during which the piston is moving the fastest on the inlet stroke.

While there won't be any back to back dyno testing that I'm aware of, I've been told that there are plans to dyno it.

Kelvin,

You guys haven't seen anything yet! ;)

Sean

[quote="mac townsend"]
is this PBS Engineering the same outfit that built DSR cars back in the 60s and 70s (and raced an 1100cc Corolla-powered FC pretty competitively in Cal Club)?[/quote]

To my knowledge, they are just a foundry down by the Mexican boarder... They cast all of Mike's stuff as far as I know, heads, manifolds, etc.

Sean

There is a PBS that runs a H/Mod in VARA. I believe they cast aluminum DOHC Fiat heads in the 70's. The PBS in Garden Grove MAY be the same place. See http://pbseng.com/PBSHistory.html
http://www.duneguide.com/news/2009/07/pbs-engineering-co-founder-dies-in-sand.html

Great work !!

Picture is of the very back shop, engine development at a major nascar racing company, Richard Childress Racing. I was there for "work"-long story, but we got the great tour. Thought you'd like this. The newer race heads are built with a lot of input from the field. The valve seats are not steel etc anymore. It's some fancy and expensive metal compound that I cannot remember the name of.

Take care, keep going !

Awesome picture Tom! I haven't seen any R07 heads in a finished machined state, so that's pretty neat (check that cutaway!).

The seats they use are usually a copper material alloyed with small percentages of beryllium. I don't use those because with standard steel valves (rather than titanium) they aren't really needed and also because I don't want the beryllium in my life (carcinogen).

Sean

Amazing craftsmanship. RAY

I have 'til now been privy only to a few pics, and all of the flow information. I am now even more in awe, and most of the theory was explained to me along the way. To work with Sean is amazing. His level of work, commitment, expertise, and communication are stunning.

Sean and I discussed this project over the course of a year before he began work. After many conversations Sean new what I wanted, and went to work designing it. Obviously one of the requirements was that it was naturally aspirated with SU carbs. As Sean progressed with his design, a few changes and additions were called for. Communication with Sean always led to more expense, but with the fabulous explanations all made great sense. It is a good thing the project took a year! I have been incrementally paying along the way ;)

What is seen in this thread thus far, is only a portion of the package that FlowSpeed designed. What Sean has yet to reveal is every bit as much interesting.

Fanatastic project and obviously great craftmenship!!! Can't wait to see what else is up your sleeve...

[quote=fast-MG.com]
Sean, at the end of the day will there be any back to back dyno testing?[/quote]

Dave,
I bought an LM1 Wideband sensor to try to get initial tuning close. Beyond that I will go for a final dyno tuning, and try to provide a B series in known state of tune to compare.

The suspense..... :thumbsup:

Ok for the laypeople here.....what is the goal here? Faster street engine at WOT? This all seems like pretty cool stuff but I am not sure what everyone is so excited about.

Thanks,
Marc

Marc,

Jimmy might be able to better answer this, but he told me he wanted to out perform his buddies with superchargers.

So I wanted the engine to definitely have better WOT performance than stock, or even most modified versions.

I think the engine will be surprisingly efficient however.

MY goal in doing this work, was to bring the technology of engine modification for these pieces out of the stone age and advance it up closer to the state of the art. I think we've definitely done that.

I (like everyone else) will be excited to see what this engine can do, because it looks very promising at this point.

Marc,

My hope is that it will have a more predictable/controllable torque range than a blower would have, and to have a more instant response. I also wanted to retain that very free reving feel of a B series in great tune. I also love to hear both the intake and exhaust, and to feel the "groove" that any particular engine likes. I can't wait!

I hope you have more luck with the AFM as a tuning aide than I did, Jimmie. The fluctuations were simply too wild and readings changed too quickly for me to really know WTF was happening. I later tried a convention SUN analyzer and found that also more puzzle than proof. It looked very much to me like the B engine was in a constant state of misfire at idle or low rpm, over 2 grand the HCs started to smooth out (but not the AFM numbers)

Got it close, I guess, with a Gunnison Gastester then a little by ear. Haven;t wanted to touch it since.

Mac,

Since I will be dealing with an absolutely unknown quantity, I can only make some comparative guesses on initial carb jetting. As Sean reveals the rest of this engine equation, you will better see how unknown the start point is.

The only time I have played with the LM1 was on an engine with 1 dead cylinder, and yes the readings were all over the place. The LM1 has provision to program a slower read time, but one must have a 'puter with a serial port to do that. A USB/serial adapter is not regonized by the provided software, no matter what I tried. I need to revive an old laptop with a serial port.

Mac and Jimmy,

I bought an LM-1 a couple of months ago to help me jet the 34/34 Weber on our B. ( I really became intrigued after seeing Jeff use his at MG 2009) Powered it up, calibrated the O2 sensor as per the instructions, put in the tail pipe adapter and away we went. After watching it a little while I was able to see what it was doing and it changed with load and throttle input in a consistent manner. I had been screwing with the jets and had it way rich, down in the 11's at steady cruise. It ran very well but the mileage was down quite a bit from before I started messing with it. By changing the jets a couple of times I got it back to around 13.5:1 a/f at cruise and it drops down to about 12:1 under load and drops down into the 11's under full throttle when the power valve is full open. I still need to change the idle jet again as it is about 16:1 at idle which makes it sound like it has even a bigger cam in it. It has a steady but very lumpy idle.

We tried it on a Healey that was in my friends shop and discovered that each tailpipe gave you a reading for one carb so we were able to set the idle mixtures individually. The car ran great but the a/f was around 11.8:1 all the way from idle to about 3500 rpm just sitting there as we didn't have time to drive it around with the unit hooked up. I think that we will experiment with different needles on his Healey in the future and see where that leads us.

Jimmy, that is interesting about not being able to connect to a laptop with the serial/usb adapter. I bought one but have not tried it out yet, I'll let you know if I can get it to work or not.

Did either or you get your units off ebay? I ask because Innovate has a warning against buying off ebay which leads me to believe that there are maybe some bad units out there somehow. I got mine off Amazon.

Joe

I have been using the LM-1 for tuning my DCOE for a while now and I have not seen the wild fluctuations others have mentioned. I have the unit set for the lowest sampling rate and it is very readable in the car, but the real benefit has been the downloadable AFR graphs. They are very accurate and can help diagnose ignition problems and clearly show problems in transition as well as WOT (they get even better with the RPM converter which allows you to log RPM and other inputs like TPS etc.).
I use a serial connection but I know that there is a lot of good information on the Innovate Tuning Forum about which USB drivers have worked and which haven't. It's definitely worth checking out before you start looking for another computer.
http://www.innovatemotorsports.com/forums/

This is very exciting...an automotive engineer friend of mine (he primarily does cutting edge injector design) looked at the B engine and wondered why the head was not crossflow and why a pretty decent (at least tough) bottom end laboured under such a crappy setup for a head. He was facinated by the SU's - he liked the general simplicity of design.
Give his comments and much of the discussion here, it has always suprised me that someone has not really "gone for it" to solve some of the inherent weaknesses in head, beyond the normal port and polish work. The MSX crossflow seemed like a good start but it stalled long ago for lack of economics or care? Good on Sean (and Jimmy) for going through this. I would love to see this head put together with a S/C to really see some big (and drivable) numbers :-) and even more so, some castings made up so this can be readily available beyond a hand done custom one at a time process.
tc

[quote=TomCarter]
...some castings made up so this can be readily available beyond a hand done custom one at a time process.[/quote]

We are definitely "entertaining" the possibility of doing that.

Sean

Well, now! That is news to stew on. Pretty impressive work. I rather shudder to wonder what similar attantion to my MSX will do to my 401k.

Let me restate:

Fan-frikin-tastic work!

My PLX air/fuel meter was too fast for me to read accurately so a piece of tape over the dial just leaving one decimal point (as in 14.7:1) fixed the problem and its close enough for tuning. I don't know the LM1 readout.

Sean,

I'm curious... it looks like the finished chamber is larger. What was the final chamber volumn and what's the project CR for the head?

Steve

I don't have the specs in front of me, but I believe they were about 33cc's, which is quite a bit smaller than stock. Our target compression ratio is about 9.75:1 for use with his Isky T-32 cam (222@.050 duration on the inlet with .302" lobe lift). His JE pistons have a volume of 16cc's if I recall and mirror the combustion chambers for good squish action at TDC. I did a post on his pistons here: Jimmy Hilton's Pistons

Sean

Steve,

Sean also modified the Titan roller rocker setup to have a true 1.625 ratio. The valve lift will be quick.

It sounds as if Hap has the bottom end in line for about 2 months start date. I can't wait!

I have been using an Innovate G5 analog guage with the LC-1 AFR guage permanently installed in my car. I find it easier to monitor the analog guage than a digital.
(Old Guy!) This unit has helped a great deal in sorting out some problems with my blown 1860. It was bought directly from Innovate but is now also available
through Moss. I am using one of Pierce's 5-port alloy heads with approx 8.8:1 compression. I have only done a bit of clean up on the throats of the head, absolutely nothing like the wizardry Sean is doing. I too am in awe, and wish I had the skills and equipment to do this, or even better, the available cash to have Sean do it for me!
Watching with interest,
Rich

Sean.

Absolute fantastic work, I have always been a supporter of bigger is not necessarily better, and that the quallity of the gas flow and integrity of the mixture reaching the cylinder is more important.

Look forward to seeing the dyno results in due course.

Kevin Jackson.

Sean,,,

Hurry up with your new head! I have a bank of 38mm Mikuni semi flat slide CV carbs I want to mount on one.

[quote="Sean Brown"]
While there won't be any back to back dyno testing that I'm aware of, I've been told that there are plans to dyno it.

Kelvin,

You guys haven't seen anything yet! ;)

Sean[/quote]

I don't know about back to back, but it will if Jimmy goes on with his orginal plan, it will be put on a engine dyno here, I'm building the bottom end for this project (thanks guys) and Jimmy has discussed coming up this way with his carbs, exhaust, an ignition and we putting it on the engine dyno. The boxes are all here, and I have not open any of them yet, keeping them altogether, should start on the bottom end early in 2010. This is Sean's baby, I'm just being trusted to put a bottom end under the whole deal, an honored to be invloved with a such a adventurous build.

Now Sean, if we can talk Jimmy into not requesting the block be painted slime green :)

[quote=Speedracer]

I don't know about back to back, but it will if Jimmy goes on with his orginal plan, it will be put on a engine dyno here, I'm building the bottom end for this project (thanks guys) and Jimmy has discussed coming up this way with his carbs, exhaust, an ignition and we putting it on the engine dyno. The boxes are all here, and I have not open any of them yet, keeping them altogether, should start on the bottom end early in 2010. This is Sean's baby, I'm just being trusted to put a bottom end under the whole deal, an honored to be invloved with a such a adventurous build.

Now Sean, if we can talk Jimmy into not requesting the block be painted slime green :)[/quote]

Hap, I have seen some of your paint jobs! Either don't, or use Duplicolor Green Etching pimer, and Deep Canyon Red.

Sean......from another machinist to another...............THAT IS WAY COOL.............You have some ability..........I wish I could rob some of your skill...

Steve,

Sean also modified the Titan roller rocker setup to have a true 1.625 ratio. The valve lift will be quick.

BREAK

Any further info on this part of the project?

Thanks.

Pat

[quote=neher]Any further info on this part of the project?

Thanks.

Pat[/quote]

Pat,

Sean will have to give the details of the change, but he added height to the bottom of the pedestals and cut the topsides down.

I just posted a few pictures here:

Jimmy's Rocker Setup

[quote=neher]
Steve,

Sean also modified the Titan roller rocker setup to have a true 1.625 ratio. The valve lift will be quick.

BREAK

Any further info on this part of the project?

Thanks.

Pat[/quote]


"BREAK". I love it. :thumbup:


Sean, your posts are always amazing. As someone who's running one of your ported heads, I can vouch for the quality of your work. That's going to be a hell of an engine when Hap puts your work on top of the new bottom end.