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MG MGB Technical - Amazing X-Flow Aluminum Head

I am just drooling like a fool and grinning like an idiot. After 3 years stop and go ( I know yall can feel the same pain here) I have just fired up my 1971 MGB, owed ( Freudian there: I meant "owned") since September 1970. This is the 4th and final- man I just turned 54- rebuild. I was determined to do it right this last time. My best guess over the 28 yearsis probably close to a million miles, and I've worn out the other 3 engines, all of which have run like scalded cats.

vic myers

What happened, I hit the return and whoosh the page disappeared.Anyway, then, no new paragraphs.So here I am with some disposable income and a powerful need. I talked to Rog, across the pond, Twist back east, but Doug Jackson in Novato California was the wizard that brought bright white light to my cave.I had been reading back issues of the MG Enthusiast and decided the Ford Sierra 5 speed was the way to go. I checked out Hans in Australia and his superchargers ( way expensive, but my what a beautiful piece of technology).And thats when I started to drool as he "conservatively" rated his power increase to 180 BHP. I figured I could get what I needed for the $3k, do it myself ( I run a seasonal shop in Truckee California), and not have to worry about exotic problems. I was tracking links out here and there, and came across Jackson outside the Bay Area in California. He's a friendly chap and we hit it off. To make this story shorter, here's what we did to have something to bolt the Sierra 5-speed to:

bored 60, flat top forged
Doug's roller rockers
hardened crank, lifters pushrods
Elgin cam 280 duration, about .280 lift
Full balance
Cross flow alum head, 3 waygrind, SU
manifold.
Peco
K & N
25D4 Dizzy with pertronix and 1963vac diaphram

Doug guided and chided me along the rebuild process until what happened next which is stunning. It started right up. I had an extra set of HS4, rebushed, rebuilt, and was outta money, so decided they were pretty close to the HS6 planned and would do for the time being. Immediate objective was to pass smog, which it did no problem, and then Dyno. In Reno Nevada, at nearly 5000 foot elevation, this new marvel, in rareified air, showed over 100 BHP with the x-flow and HS4 at 4200 RPM in 4th gear.
Apologies for the blather, but I am so tickeled with this "new" car. It pulls from about 3500 RPM on up. I've not gone above 5200 RPM's yet ( only 600 miles on the new engine), but one particular day I was at 114 MPH in 5th gear and had plenty of the pedal left to go.
Is there anybody ese out there who can compare notes on the cross flow? Any insights on the heater water control? Did you slice down the carb spacers to get the K&N to fit? What are you doing with the oil filter.... remote or some trick to change it as it is? I went the rebuilt dizzy with electronic igny because I could see no way of adjusting points every couple months. Has your "bolt-on" HP increase been as dramatic as mine????!?. Yep any words, or criticism would be welcome. I am a lonely man up here in the Sierra Nevadas, but with the goofiest grin and just a dribble on the side of my mouth. Cheers, Vic


Vic Myers

Good for you, Vic! So how about giving us some engine specs- modifications (I assume a x-flow head, maybe gasflowed, ported and chambers cc'd?) and performance figures? We never get tired of hearing about hot B engines.
Terry

We just crossposted, Vic. Doug Jackson has a very good reputation around here and your engine sounds great. That 100 HP is at the rear wheels, right? What comp ratio are you using? I know it's expensive but you would probably pick up further significant gains with a couple of Weber DCOEs and they would look and sound terriffic.
Terry

If the oil filter is inaccessible or in the way of the carbs then why not turn it upside down as per the original intallation on the B engine?

Take off the filter adapter and get one of the spin on filter conversion kits intended for the MGA / early MGB - fit this in place of the original adapter and spin on the filter from below.
Chris Betson

I believe the bottom load oil filter from the pre68 US spec cars will interfere with the starter. One would have to change to an after market gear reduction starter--I believe those are shorter, than the pre engaged type. Not positive--any one know for sure???
James Johanski

My 74 GT came with a bottom load filter, no interference issues with the starter. Just about impossible to take it off with a standard oil filter wrench, though.
Marc Deaver

I think the adapter and spin off filter is shorter than the paper cartridge type housing but would have to try it out to be certain.
Chris Betson

I prefer the remote filter before the cooler. Use the early cartridge adpater and cut down the cartridge housing to about 2" and use a 5" capscrew to attach it to the block.
Leland Bradley

Normally the filter is after the cooler in the circuit - I would be wary of putting a remote filter before the cooler because any foreign matter in the cooler could travel directly to the main gallery.

Chris Betson

Chris, interesting point about foreign matter. Do you mean any matter introduced when installing the filter assembly?

Another thought, doesn't warm oil flow better and hold more contaminants in suspension ? I would think that, aside from any contamination from installation, you would catch more in the filter before the cooler has done its job, and prevent the formation of sludge as particulates come out of suspension in the cooler by installing it on the "hot" line.
.

No, I mean any metallic swarf or particles that have lodged in the cooler in its normal mode of operation - ie in line before the filter - the pump can pick these up from the sump and carry them into the cooler where they settle due to the design of the cooler with top entry and exit.

Changing the position of the filter in the line without fitting a new cooler or thoroughly cleaning out the old ( pretty difficult) is risking the particles which would normally be caught by the filter getting into the main gallery and thence to the bearings.

If you don't change the filter often enough the element can get clogged - then a bypass valve in the filter opens and lets unfiltered oil circulate - you would not believe the havoc that this causes to cam and crank bearings!
Chris Betson

I would guess that you would have no objections to having the filter placed before the cooler on installation of a new cooler?
I tend to run the motorcraft filter changed 2500 to 3500 miles depending on operating conditions. Occasionally I will use an AC filter if that is what is available, never a fram.

Vic, I ran a remote filter for 12 years without problem, then age set in and the hoses and adaptor gasket needed renewing. By that time the jeep had been thoroughly stripped of extraneous emmission plumbing and filter access was no longer an issue so I am back to a standard setup. The remote was very nice, it allowed a larger filter to be used which added capacity to the oil system and filter changes were cheap and easy - using an american V8 filter found anywhere in the states. When the engine finally needs rebuilding I will probably re-install the remote kit, but for now I would rather work on my MG.
.

Gentleman;
The adapters for the early cars do foul the late long starter. I went to a gear starter on dee's gt. The Marina bottom load mentioned above would do the trick but only a few 74s came into this country with that adapter. It is rather rare. I have one in my spares. Bob T
Bob Thompson

Hey wait a minute.
Let us not get sidetracked by issues of oil filtration. What about the after-market-super-duper-high-performance-aluminum-cross-flow head which was recently quite controversial? Now I'm as easily sidetracked as the next guy but I would like more info about the head. It has intrigued me since I first learned of it a few years ago. As I recall, not that long ago a contributor made great claims about the performance of the x-flo head but when questioned did not reply. So, Vic, what is the deal with yours? Is it a Pierce unit or elsewhere sourced? Is your's stock-out-of-the-box or did you have it modified and of so, how? What are the valve sizes? Did it require remedial action to get it servicable?
By the way, Bob Thompson: Did you get your's on the road and how is it running? What carb needles in your HS6s did you settle upon? Did you use the Crane cam you were contemplaing? What else did you do to the motor? I've been wondering for a while but have been too lazy to inquire.
Later
Marvin Deupree

Marvin; I'm sad to say it has been done and ready since October. The car is a very long way from being ready for an engine thou. It is tempting to install it in my Gt but nope it's for the car on the spit. So there it sits. I went with the crane cam, and hs6 carbs from a tr4. Tr4 needles. Well it looks pretty sitting in my basement on a creeper. It's hard to get myself to work on my car when i do it all day for a liveing. Bob
Bob Thompson

Hiya

Are the X-flow 'B' heads sold Stateside different from the heads sold in the Uk that look identical to those that are shown on the webpages?
Maybe we just get the reject ones that don't seem to have the valve bowls opened up to MGB size valves and all seem to flow the same as or slightly less than a 12H906 early MGB/MGA MkII head?
They also seem to warp in transit too!
The heads make a nice basis for modifying.

Peter
Peter Burgess

Fellow blather's: Thanx for the dialogue on filters. As Marvin said, hey what about the cross flows?.

Are they all bad over pond? Really, I have never had top end pull like this in any previous MGB, owned or driven. If this is flowing little better than pre-smog heads, then I will be go to hell. I'm not a racer, but do know MGB engine character. Perhaps Jackson's recipe of rollers, Elgin, 60 over flatops( est around 9.5 : 1), K&N, Peco, is spot on for superior performance. I can tell you that pulling from 5000 feet to 7000 feet all the way in 5th gear ( Ford Sierra 5 speed) in little over 25 miles from Reno Nevada to Truckee California, doing ez 70-80 all the way, has me singing the praises.And tat at maybe half-pedal. I've thought the long SU manifold to the x-flow head, ram jets the mix and is extra-effective at altitude. Who knows?

Vic Myers

Hiya

I find it hard to hide my disappointment....here is a chance to produce something we all want, good flow characteristics straight from the box, no fiddling, no messing...lots of power ( for a 'B' series engine).

The mid range power will always be better than a standard B when using a separate inlet port configuration...hence the flying at part throttle and medium rpms.

It seems a shame the flow capabilities of the head as delivered by the makers do not produce what it could with maybe a little more effort.

The best setups tend to run Weber 45s with smallish chokes ( a la Italian style ) which gives bags of mid range torque and very sharp ( almost Gucci :) ) snap throttle response.

Vic, it would be nice if you could give us some bhp @ the wheels figures plus a set of standard MGB bhp @ the wheels from the same rolling road so we can see the sort of power curve you are producing.

Bear in mind we can build a 'legal' standard race 'B' engine that will deliver 95+ bhp at the wheels ( 65 bhp from a standard B) and up that to 112 bhp at the wheels if the race regulations allow the use of a 'tuned' camshaft.....the engine doesn't last too long mind!


No sour grapes are intended re the Ally heads. It is just that I feel our flow expertise shouldn't be neccessary !

Peter
Peter Burgess

Peter - are we just talking bad design or cost concious design here.

I agree, if the manufacturer is going to do it, they might as well save on putting all that metal in, if we are only going to grind it all out 8-)

Or are we, as explained on the thread running re Moss, having to get these small runs made on antiquated machinery in India, etc? Perhaps they can't be sure of the casting quality and therefore leave walls thicker than necessary?

Were Derrington's cast well?

Is the real answer to have a 16 valve 8 port head made for the B? Can 16 valve heads run from a block mounted cam??

I'll have to spend more time sorting out the M16 conversion.......
Chris Betson

Hiya

I assume the Stateside heads are cast in the States.
The original Derrington heads were well casted.
The newer Derrington heads are also well cast, although, I am lead to believe, no longer to be made.

It isn't a matter of hogging loads of metal out, more like the approach to cutting the valve seats, throats and tricky bits around the inserts.

I don't see an excuse for shipping heads that aren't flat and of the correct chamber depth ...unless they are clearly marked 'part finished' etc.

M16 and T16 conversions are 'old hat' as is the 'O' Series conversion.

8 valve engines give the best torque...very important for low revving long stroke-type engines.....viz. 'B' series.


Peter
Peter Burgess

Mr. Burgess,

There's a lot I don't know about hot-rodding motors, but I won't ask you for a whole classroom experience. I am curious though, if you don't think it's too off topic, why is it that "8 valve engies give the best torque?"

Thanks in advance.

Matt Kulka

Hiya

Peak torque and peak horsepower occur at different gas velocities in the ports.....if the engine has to achieve these velocities through larger ports/valve area (eg 2 inlet valves) the velocities will occur at higher rpms...typical multivalve performance characteristics. Bhp dictates top speed and torque dictates acceleration.
As an example... a few years ago we ran a dyno test day for MG Maestros with Rover 16 valve conversions....these all made in the region of 120 bhp at the wheels compared to the 94 or so of the standard 8v motor. Listening to the owners talk amongst themselves was illuminating.....very pleased with top end performance BUT seems a little slower than the original 8v down the twisty country lanes where I test the 'go' in the car! This was the general consensus.

The twin cam makes impressive top end bhp giving 120ish bhp at the wheels at 5800 rpm with peak torque at around 4000 rpm. The 8v has peak torque around 3000 rpm ( approx 74 bhp at the wheels) and gives 94ish bhp at around 4900 rpm. The twin cam only starts to get going at 4000 rpm...when the 8v has already shown the 16v a clean pair of heels! The antithesis of this is that the 16v will eventually drive by the 8v as the top speed of the 16v is slightly higher than the 8v.

Look at the acceleration to 60 times of 16v cars and note that the older 8v version was usually quicker!

If the 16 setup is kept small the torque output is just fine...trouble is the engine will not want to rev! A textbook example is the 1.8 'K' series engine...bags of torque above 2500 rpm.....64 bhp at the wheels at 3000 rpm....breathless above 5000 rpm! This is due to the valve sizing being the same as the 1.4 engine ( The valves look small even compared to say a 1000 cc bike head!)

I hope this helps....

Peter
Peter Burgess

OK - so I suppose this explains why my 1860cc big valve engine has difficulty getting away from a standard small valve?

The answer then is to develop more bhp at lower revs - well without dropping another 4 cylinders under the bonnet - which I what I have done to my daily driver - how else do we get this result?

Is the aim to increase gas velocities in the inlet ports? - this points to milder cams allied with bored out cylinders and a head worked to improve gas flow without increasing port size - even if this leaves the engine "breathless" at high RPM ( which most of us don't use on a daily basis anyway)
Chris Betson

Replying Peter, Marvin: Yes I'm planning a soon trip down to sea level ( San Jose, California) to eyeball and drive a Han's Super Charged MGB. I will dyno the 1971 at Bill's shop and give report.Maybe I can get the stock 1980 down with friend at same time and use its 57 BHP as a benchmark. I feel there will be a measureable output improvement at " 0 " altitude.
Peter- yes, your mid-range power explain due to separate porting makes sense. I like Chris's observation on the breathless glass ceiling though. During normal touring, I'm into 5th rather quickly on the highway, and 5k RPM's would put me over 100mph. From a stop in traffic, and at an advanced age of 54, I just don't wind her up to 5k in first gear anymore.
I assume we have daily drivers out there reading this thread. After all the what-ifs, I'd like to hear some testimonials on the mechanical mods made by the routine daily driver and what worked and what didn't. Or is there another category thread I need to eyeball. After all, what can an enthusiast best do to a stock MGB to produce a good combo of tractiblity and power for a regular, run of the mill ( excusse moi the pun) daily driver?

Where can I go in the States to get the remote filter and setup. No can find at Moss. Thanx, Vic
Vic Myers

Hiya

The standard engine should not be as quick as a properly setup 1860, with big valve head and cam change. Maybe the car wants setting up or the package doesn't quite hang together.

We developed the 'Econotune' spec head especialy to promote loads and loads of torque. With the 1.56" inlet valves it makes around 30% increase at 3000 rpm and 18% at 4800 rpm. The Fast Road head we do makes 25% increase at 3000rpm and 35% increase at 5100 rpm...and will work even better with cam and carb swaps. The 'Econotune' head works best with a standard camshaft and is developed purely for low rpm bhp.....eg put your foot down in top gear up a hill and the engine responds sweetly and doesn't bog down.It is even good for caravan towing!

All in all a tuning package needs to be tailored for the use to which the car is going to be put.

Peter

Peter Burgess

There's a write up on Pierce Manifold's owner's personal B in the May issue of Grassroots Motorsports. Stock looking 70 model with a crossflow head and 5 speed conversion. On a Superflow dyno, went from a baseline of around 85 at the flywheel to over 160 at 8000 rpm. Claims its streetable, but that sounds like a whole lot of rpms to me. Also harder to believe coming from the guy that sells them, instead of a consumer like Vic. I'll be interested to see his results when he gets his motor broke in.
Marc Deaver

"what can an enthusiast best do to a stock MGB to produce a good combination of tractability and power for a regular...daily driver?" Vic: go out and buy "HOW TO POWER TUNE MGB 4 CYLINDER ENGINES FOR ROAD & TRACK" by one Peter Burgess. Absolutely the best $20 you can spend on your B and the answer to nearly all your questions. Also, hang out on this BBS and pay especially close attention to posts by Peter, Chris Betson, and Sean (or Mike) Brown. These guys know B performance like no one else and I, for one, am eternally grateful for their words of wisdom.
Terry

Terry- Been there done that reading cover to cover, now underlined and highlited almost without a break. Had to tape pages back in not long ago. Naively asked yes, but my question was aimed at the DD who can back his observation with experience. As Peter noted his econotune features a bag of low end harummmph. I'm told the HS4 will show better low end work than either the Weber or the HS6 ( those scooting away above 4800 RPm's in measured performance).
Sounds to me like a great DD might feature a 1950 cc, flat top at around 9:1, rollers, lo end cam, minimal overlap, like new HS4, and a Burgess "econotune" head, circa 63 dizzy with vac and pertronix, Peco, K&N, coupled to the 5-speed Sierra which nobody doesn't like.If the bucks were there, I'd think a Burgess magic wand over the x-flow ( given my 3 month experience) would be a jazzy step up. Appears the separated ports really produce starting at 3000 RPM's.

For all: Yep I am anxious to c what a sea-level dyno does say on this screaming x-flow frankenstein I've been talking up. I hope to dyno the stock 1980 at the same time for a baseline comparison and be back at cha. I won't take her past 6500 RPM's though.Cheers all Vic
Vic Myers

Peter:

Our experience with the aluminum head mirrors yours so apparently both derive from the same source.

They indeed need a lot of custom work right out of the box and I agree this should not be the case for an item which sells at so handsome a price.

Will confirm their pre-work flow characteristics are about the same as an MGA/early MGB stock head, perhaps partially because those with which we're familiar come with the small inlet valves as stock items.

The seats we've seen have only 45 deg. cuts with sharp edges and the valves are "out of the box items" as well, with the typical single 45 deg. cut and no evident attempt to reface correctly or lap to the minimal seat work.

The stock ports themselves provide interesting results when probed on the flow-bench.

It's also curious these ports with the small inlet valves are matched with 1 3/4 in. SU's or 45 DCOE Webers.

Respecting flow-testing of the as-cast 1 3/4 in. SU inlet manifold itself, the words turbulence and chaos describe our findings and we've been unable to figure out how to improve matters to any great extent other than design and weld a different manifold.

However, to their credit, these heads do seem to my eye to be presented very attractively in vendor literature.

Best regards,

Mike Brown,
Seven Shop British


Mike Brown

Hey Mike do you have a website??
Greg Wilkerson

This thread was discussed between 07/03/2002 and 16/03/2002

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