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MG MGA - Moss Crossflow Head

Just a bit of idle curiosity at this stage. Has anyone fitted the Moss Crossflow alloy head? I did not see anything specific about this unit on Barney's site.

With the 1800 engine I have fitted I was wondering if their inlet manifold takes the H4 carbs. I notice in the Moss blurb they refer to the manifold taking the HS6 or HIF44 carbs.

Anyone got anything interesting to say, especially performance, practicality, maintenance etc?

Just toying with the idea as an alternative to the somewhat more expensive supercharger.

Steve

Steve Gyles

Steve

Not really a source of free info but Cameron Gilmore, who is currently doing a milder rebuild of my 1800 engine, has quite a bit of experience with them and getting very high power outputs. See both his web sites and also he was the featured supplier in last months MGCC Safety Fast. He would probably be happy to have a 'free' chat, you can always mention my name as a current customer

The East Neuk is one of our fovourite areas for short A runs. Of course being further up the Forth than Lower Largo we get haar.

Paul

http://www.britishclassiccarspares.com/index_b2b.html


http://www.camerongilmourengineservices.com/Cam_Site/index.html
P M Dean

Steve cc Barney

Thinking again on this I presume the Moss crossflow head is the HRG Derrington design which goes back all the way to when the 1500 A was current, so it is a period upgrade.

I have a copy of Derrington's 1972 catalogue (got by me from them in 1973 as it has a sticker on the front saying prices went up by 10% on 1/4/73). It has pages and pages of data/tests on it including roadtests for ZAs to Bs. In summary it is worth about 12% extra power on an 1800 (23% on a 1500 due to poorer standard head design) but you can double this figure with bigger SUs or Webers.

It cost £120. I fancied one then but that is more than I paid for my first A.

Perhaps I should scan it all and feed it to list/Barney.

Paul
P M Dean

The Moss head is the more "modern" MSX type (not HRG Derrington). Apparently it leaves a lot to be desired with multiple design and manufacturing issues. Out of the box it might be slightly better than a stock iron head,but it needs a lot of special (expensive) porting work to make it better. Even with porting work there are still some significant deficiencies of port design.

Sean Brown at Sean Brown, Oregon, USA, Seven Shop in Oregon, USA, did a lot of well documented porting work in this head. In the end he gave it up as a lost cause and will not work on these heads any more. See here:
http://mgaguru.com/mgtech/power/pp402.htm
Barney Gaylord

Wow. Thanks for that Barney. Rather disappointing report. I wonder if the manufacturers have done any rectification/modification work in the last 5 years since the final report was put together?

Steve
Steve Gyles

Hi Steve

I think Peter Burgess would probably get you close to the crossflow head power with a worked over fast road head

Dominic

dominic clancy

Steve, have you seen the section in britishclassiccars.com and click on the "Performance" heading?

Cameron Gilmour is quoting 185 bhp for his 1950 crossflow rally engine or 145bhp for his slightly de-tuned version. (thats 40+bhp more than mine!)

Apparently he has had lots of experience in this area.

The only worrying feature of the advert for me was the £POA on the price tag!

Wonder how the price would compare to a supercharger?

Colyn
c firth

Agree with all Barney said. I have a lot of experience with the original HRG heads - I guess skilled labour was cheaper in those days because they flowed way better right out of the box.

The reason Sean stopped working on them was poor core stability - he ended up breaking through walls when they should have been thicker etc., trying to configure the MSX to flow as well as it could.


Colyn - you will get better power out of a supercharger without loss of low flexibility than you will by conventional tuning. The old HRG heads are fun though. See my page: http://www.rhodo.citymax.com/HRG.html
Bill Spohn

Hi Steve,

Have a look here,==> http://www.mgexp.com/phorum/read.php?27,2546229

Dominic is working on the same thing. It's not an MGA but the same problems and solutions.

Paddy
Paddy Reardon

I was picking up my rebuilt 3 bearing B engine from Cameron Gilmour last Friday hence mentioned this thread. Yes he has successfully done several MSX heads as Colyn states but they do involve a lot of work, (not an out of box homie). They are a loose copy of the HRG one.


Yes HRG heads were far better but many are now seriously internally corroded. He had one on the bench which he had done a lot of welding but still not managed to rescue it. Seemingly they were/are common on TVRs and I can confirm that my 1963 Observers Book of Autos quotes it as an option giving an extra 18bhp on a 1622 unit.

Paul

PS As I was going to have to do a lift to get the rebuilt engine out of the back of the Focus I decided we would drop it straight into the A. One slight comment it was more difficult than I remember and once complete I realised why, i.e the engine is effectively slightly longer due to the B cast/damped pully rather than the pressed steel one, but it did go in eventually. Now held to gear box by 2 bolts.

P M Dean

I have an MGA which came with Derrington Xflow head. It goes well but the set up does create some problems.
The inlet manifold obscures all the electrics so access to points/coil practically impossible and starter and generator very difficult. I got 123 electronic dizzie fitted and the coil shifted to the bulkhead.You have to have heater tap fitted in line in the hose which not great. Also the heater air intake ran right next to the carbs and I changed it to LH side but deviates over the engine. The thing that worries me most is the thought that I might have to replace the brake switch (which I have to do irritatingly often on my Minors). I can't even see it without removing the manifild/carbs. I would not choose to go down this route if I got another car but use some other method of boosting power.
H L Davy

I did note those issues when I looked under the bonnet of an MGA at a classic car show a couple of years ago. The car in question had also had electric power steering fitted. The engine compartment looked awesome but accessibility to the distributor stood out loud and clear.

Any Judsons going spare Dominic?!!

Steve
Steve Gyles

Judson's are always available, you just have to wait for one to come along. I sold mine recently to someone who wanted one in a real hurry, and the replacement will arrive any day now, completely reconditioned. A tidy profit helped the pain of parting ( I had the new one lined up before I made the sale final)

If you want a Judson, I think I know of one which will be available in a few months.
dominic clancy

Paul, the TVR Granturas had special intake manifolds as well, shorter to clear the inner fender boxes and with 'TVR' cast on them, presumably by HRG. Hard to see but here is a pic.

http://www.rhodo.citymax.com/i/non-rhodo/tvrsmall.jpg

I also used the TVR race car as a mule while developing my 1950 cc Twin Cam - which head do you like better? ;-)

http://www.rhodo.citymax.com/i/non-rhodo/tvrtc.jpg
Bill Spohn

This thread made for some pretty interesting reading, thanks. How are the "standard" aluminum (non cross flow) heads that Moss sells?
Del Rawlins

I have an original HRG- Derrington head on my coupe. No problems with corrosion but metal is "soft" when recently overhauled. General feeling amongst local experts is that this is okay for road and light competition work but maybe a problem for racing applications (blown head gaskets). The general consensus is that all these 60-70s heads are now soft.
A big job to heat treat - needs all steel components removed and then it is reckoned as a 50-50 job. One cylinder head re-conditioner has had success with soft modern MGF/TF heads by pad welding the whole machine face and then machining back to original thickness - this may be an option if head gasket failures become common.
Access to the distributor for timing is possible between the manifold pipes with a long spanner. My distributor is a Scorcher (electronic) so little maintenance required - even so pulling the carbs and manifold is a simple task.
Does anyone have a good cold air box design for twin 45 Webers on a HRG head in an MGA - the stability springs in the foam filters negate the advantage of the installed ram tubes?
Mike


Mike Ellsmore

This thread was discussed between 10/12/2013 and 20/12/2013

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