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View Full Version : HRG Derrington Crossflow Head



WhatsThatNoise
04-20-2006, 06:52 AM
https://cgi.ebay.com/ebaymotors/ws/eBayIS...TRK%3AMEWA%3AIT (https://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=4632881697&rd=1&sspage name=STRK%3AMEWA%3AIT)

I have been lusting after one of these original heads for years.

Please tell me this one isn't worth it!

What is the likelihood of a repaired aluminum head lasting?

Grantura_MKI
04-20-2006, 08:53 AM
I was looking at that one for a while. I have stayed away because it looks like the water ports are on there way out. /ubbthreads/images/graemlins/yesnod.gif These heads will take a little welding, but it appears that this one will require a lot.
Cheers, David.

MGAdams
04-20-2006, 09:49 AM
I would really want to have a good look at that one first, and if it isn't too bad, it is presently cheaper than the cost to prepare a new MSX unit.
I already have two .. so likely won't bid, just watching for now.
https://www.imagestation.com/picture/sraid204/pc33b554a89526f1e83a8ea723e26e694/ef591e12.jpg

WhatsThatNoise
04-20-2006, 06:33 PM
I couldn't have a MSX even if I wanted it.

My race group doesn't allow heads manufactured after 69. (& I'm a bit of an originality nut anyway)

I have never tried to repair an aluminum head & don't know what is involved.

Then there is the question of reliability.

MGAdams, What is your experience w/ these items...
Are they the cat's meow or just the subject of folklore?

piman
04-21-2006, 03:00 AM
Hello WTN,

certainly Jaguar XK heads are routinely welded to correct corrosion damage, and I see no reason why the Derrington head would be a problem?
The obvious benefit is the individual intake ports allowing higher performance carburettors like the Weber for maximum power output.

Alec

Matthew E. Herd
04-21-2006, 07:55 AM
But I noticed you're still stuck with the siamesed exhausts. While this isn't a total killer, after all you've made a big improvement in the intake area. However, it's not an upside. I'd be curious to see the differences between two well-tuned setups.

MGAdams
04-21-2006, 08:49 AM
[ QUOTE ]

MGAdams, What is your experience w/ these items...
Are they the cat's meow or just the subject of folklore?

[/ QUOTE ]

I wish I could tell you they are some remarkable improvement, but this is my first and only MGB, so I don't have a non-crossflow experience to compare to, and mine hasn't gone vroom for twenty years, I WILL FIRE-UP THIS WEEKEND. I would think that if MSX is copying, and everyone seems to rave about the crossflow performance, that there must be some sizable benefits with this set-up
Bill Spohn has a lot of research on the HRG heads on his site and maybe he can chime in with the comparison. His site by the way;
https://www.rhodo.citymax.com/HRG.html

jlaird
04-23-2006, 09:22 AM
Alum aircraft engines and engine parts are welded all the time.

DrEntropy
04-23-2006, 02:47 PM
Many a Lotus T/C head, Alfa heads and blocks too.

billspohn
04-23-2006, 08:33 PM
I have run several HRG heads in race cars. In fact the web page cited in that auction is my page:
https://www.rhodo.citymax.com/HRG.html

That was a great price if it was a rare Mk 4 head, a lousy price if it isn't repairable.

Here is a pic of my TVR with the head and Webers:

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

Grantura_MKI
04-23-2006, 09:21 PM
Bill, lose those filters and get some horsepower. /ubbthreads/images/graemlins/savewave.gif I can tell that you all are tig welders and know all ahout hot spots, etc.? To compare an after market head to a Jaguar unit shows a lack of knowing about English castings. Most after market alloy castings are very porious and filled with tin...add in the corrousion= big holes. /ubbthreads/images/graemlins/devilgrin.gif
Cheers, David.

billspohn
04-23-2006, 10:37 PM
[ QUOTE ]
Bill, lose those filters and get some horsepower. I can tell that you all are tig welders and know all ahout hot spots, etc.? To compare an after market head to a Jaguar unit shows a lack of knowing about English castings. Most after market alloy castings are very porious and filled with tin...add in the corrousion= big holes.

[/ QUOTE ]

Filters are necessary on that car as it has no inner fenders. They are filtron foam and low restriction - no doubt replaced by the current owner.

No idea what you are talking about when you mention Jag heads (nor, I expect, do you). HRG castings are very good, show no more corrosion than any production alloy head and certainly have no problem with holes.

PS - it is 'porous', not 'porious' and 'corrosion', not 'corrousion If you hurry you might still be able to get your money back on that dud dictionary you bought.....

TypeRboy
04-24-2006, 01:28 AM
[ QUOTE ]
[ QUOTE ]
Bill, lose those filters and get some horsepower. I can tell that you all are tig welders and know all ahout hot spots, etc.? To compare an after market head to a Jaguar unit shows a lack of knowing about English castings. Most after market alloy castings are very porious and filled with tin...add in the corrousion= big holes.

[/ QUOTE ]

Filters are necessary on that car as it has no inner fenders. They are filtron foam and low restriction - no doubt replaced by the current owner.

No idea what you are talking about when you mention Jag heads (nor, I expect, do you). HRG castings are very good, show no more corrosion than any production alloy head and certainly have no problem with holes.

PS - it is 'porous', not 'porious' and 'corrosion', not 'corrousion If you hurry you might still be able to get your money back on that dud dictionary you bought.....

[/ QUOTE ]

Ouch.. That even hurt me. I think I'll keep my two cents on this subject to myself, which is a shame really, cause I thought we wanted to encourage posts and discussion, not discourage them.. /ubbthreads/images/graemlins/grouphug.gif

WhatsThatNoise
04-24-2006, 05:53 AM
Oh well....I didn't feel comfortable bidding w/o a closer examination of the head.
(I'm going to continue to be on the lookout)

From what you folks say, I take it that aluminum heads can be relied upon after repairs.

I'm wondering what the difference in performance is between a race prepped MGA iron head & a HRG.

Also, who is the best race preparation, head specialist.(cast iron head)
Prather...Fab-Tek....APT....or ?

Grantura_MKI
04-24-2006, 08:39 AM
I have worked on cars with those filters in the past...they went straight in the bin. As for the the quote " a car with no inner fenders"...I have restored many Granturas, Vixens and Griffiths and they all where fitted with inner fenders except for the hack jods.
I have vast experience welding British alloy. Jaguars are the at the top of british build quality and there castings are far better than aftermarket pieces. Try welding a TVR rear up right some time.
As for the spelling bit...Thanks for the help, but you would be mutch better of if you knew more automobiles, there care, maintance, and restoration methods.
This is what I love about this forum...most think they know, but will not listen to someone that has been there done that.
Cheers, David.

billspohn
04-24-2006, 08:50 AM
"Also, who is the best race preparation, head specialist.(cast iron head)
Prather...Fab-Tek....APT....or ?"


I'd probably say Prather, given his consistent success in SCCA, although there are many producing heads including those in the UK, and it is hard to separate the competent from the charlatans. I suggest that you contact a couple of current MGB racers and get their reading on it - they'll be more up to date than I will - its been a few years since I have run a pushrod in anger - I'm too busy with Twincam engines.

The HRG doesn't necessarily give more outright flow than a fully prepped SCCA cast iron head - if you think about it, you are only using the siamesed port for one cylinder at a time, and it is bigger than a single HRG port. What it does do is handily exceed output of a more normal cast iron head.

On SUs, a Derrington head will produce up to 16 BHP more than a cast iron head using the same cam and carbs (obviously the intake manifold must be different). In 'tuned' engines with Webers, compression, cams, the benefits are much greater.

In short, you can eliminate one of the greatest hurdles in MG engine prep, that execrable head design, by using the Derrington head, and take the uncertainty out of what you will get for your dollars. They also look neat. I've run them in MGA and TVR and still keep one on a back-up engine for my Twincam.

PS - sorry if I kicked the puppy, but he was blathering on about seemingly irrelevant matters (or if he has something to say, concealed it rather well).

Hey Grantura Mk1 - I know having Volkswagen suspension on both ends can skew your view of things. ;-) If you have anything to contribute to a discussion of Derrington heads, don't let me scare you away!

BTW, several racing organsisations do not allow new alloy heads, only old ones, so you may need to find one like the one just auctioned.

You can, I believe, use modern repro intakes, so twin SUs or Webers are no problem.

billspohn
04-24-2006, 09:10 AM
[ QUOTE ]
I have worked on cars with those filters in the past...they went straight in the bin. As for the the quote " a car with no inner fenders"...I have restored many Granturas, Vixens and Griffiths and they all where fitted with inner fenders except for the hack jods.
I have vast experience welding British alloy. Jaguars are the at the top of british build quality and there castings are far better than aftermarket pieces. Try welding a TVR rear up right some time.
As for the spelling bit...Thanks for the help, but you would be mutch better of if you knew more automobiles, there care, maintance, and restoration methods.
This is what I love about this forum...most think they know, but will not listen to someone that has been there done that.


[/ QUOTE ]

Uh David, I can understand you being ticked at me dismissing your post as off topic (and badly spelled, but that is admittedly a cheap shot), but why do you assume I have no experience with British cars?

In fact I have been racing and building them for over 30 years, have owned around 100 of them myself and continue to play about with several.

Right now the stable consists of a stock 1962 MGA deluxe coupe, an MGA Twincam race car, a tricarb (my conversion) MGC, a 1957 MGA with Fibrefab body that I am rebuilding, a 1971 Jensen Interceptor, a 1965 Jensen CV8 with sixpack, a 1969 Lamborghini Islero, and a 300 BHP 1988 Fiero.

I have had a fair bit of experience with aluminum heads in that bunch as well as in the previous 90 or so cars, thanks.

The shortie filters (which need to be replaced regularly)were used on the TVR because there isn't much clearance between the footbox and the intake with Webers on it. The inner fenders had been removed to make servicing easierwhen I was using that car as a development mule for my Twincam engine and needed access to various bits - the inner fenders were preserved and are now in Holland, no doubt attached to the car again, and running around the European tracks.

You are right about TVR rear uprights - I removed the 'ears' that stick down - the ones that weren't already broken off from hitting things on the road, machined the bottom smooth, and welded on a tube of alloy to take a 4130 steel tie-bar - a much better set-up and one that served well in many years of racing.

Much of the problem with alloy heads is owner caused - not using antifreeze accounts for many broken heads I've seen. We've saved several heads with that sort of problem by stitching them up again - unless the cracking is internal in an area you just can't get to.

And as for porous castings, we've seen more probems in things like my Lamborghini than many British cars. The intake manifolds on some of the Lambos (not mine, thankfully) and the magnesium Campagnolo wheels have a reputation for leaking. HRG heads, however, do not.

Take a look at the attachment - it is my TVR, arrived in Holland, with the new owner's kids helping wash it from several years of storage grime. Cute kids!

MGAdams
04-24-2006, 02:09 PM
[ QUOTE ]
Much of the problem with alloy heads is owner caused - not using antifreeze accounts for many broken heads I've seen. We've saved several heads with that sort of problem by stitching them up again - unless the cracking is internal in an area you just can't get to.

[/ QUOTE ]

So Bill ... now I am curious about the lack of antifreeze ... are you talking just a typical frozen and cracked head or something else from using just water? The vintage rules for VARAC don't permit you to use antifreeze, so I am just using water and a waterpump lubricant.

Mike Adams

billspohn
04-24-2006, 02:45 PM
[ QUOTE ]

So Bill ... now I am curious about the lack of antifreeze ... are you talking just a typical frozen and cracked head or something else from using just water? The vintage rules for VARAC don't permit you to use antifreeze, so I am just using water and a waterpump lubricant.

[/ QUOTE ]

Well basically anything that keeps the engine from boiling will preserve the heads. Antifreeze is one of the easiest for elevating boiling point, but I know some organisers do not allow it (always a sore point with me when they often DO allow motorcycles with open chain oilers to race...)

Fitting a modern shallow throat inlet on an old British radiator will allow you to run a modern high pressure cap (I run 15 psi and on the street up to 25 psi) which should keep you clear of problems. I've cracked a Derrington head before but from running out of coolant, by way of a bad cap. By the time you notice a problem....

I am not sure about things like Water Wetter - I think they work, but haven't personally examined any objective tests. If they do, that may be another way to protect the engine.

I've moved my thick core radiator on the race car into the nose as far as it will go and ducted it, and now have trouble getting it UP to temp, so am not overly worried about overheating.

I am using a really nice alloy crossflow rad in my Jamaican project that I hope will keep things sufficiently cool.

https://www.rhodo.citymax.com/i/non-rhodo/engine2apr15.jpg

https://www.rhodo.citymax.com/i/non-rhodo/radiator.jpg

WhatsThatNoise
04-25-2006, 01:48 PM
Bill,
Kent Prather was my first choice except he didn't have any 1622 heads.
He said if I found one he would do it up for me.

APT said they would sell me one but, only if I bought the fully race prepared one ($1,600)

Fab-Tek said the same thing as Kent.

Guess I'm gonna have to bite the bullet.(I simply must have the head w/ the 16 on it)

Here is a pic. of my little Brother's Vixen.(w/ a really hot Kent X-flow)
https://i50.photobucket.com/albums/f312/dlg208/tvr.jpg

billspohn
04-25-2006, 09:20 PM
You do know that the 16 head is identical to the 18 head (valves, chamber size) except for the '16'?

I'd grind the '18' until it looked like a 16 or grind it off and defy them to tell the difference, or grind it off and put it back with weld as a 16 (you need a steady hand!).

If you are desparate, I still have the original engine from my TVR but I wouldn't want to sell the head without the engine.

I had a rare factory TVR Weber manifold that some twit had bored a hole in - I plugged it with JB Weld and you can't tell the difference - right through one of the 'TVR' letters

https://www.rhodo.citymax.com/i/non-rhodo/tvr2.jpg