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MG MGB Technical - Special Tuning Cooling trick

Hello all, I'm visiting from the MGA bbs. I have a question I hope you all can help with.

Burgess' book mentions drilling out the 2 rear most waterways in the block as an old special tuning trick to help #4 run cooler. My question is - how does one keep the metal shavings out of the block?

Thanks!
JohnB

John. How to keep metal shavings out of places they should not be is a subject all in itself. I suspect that most people simply drill the holes larger, then have the block hot tanked to clean the swarf (a machinist's term for the filings/grindings/etc. made when a part is machined) out. Using a water hose to flush out the swarf is also a possibility. However, none of these methods works perfectly. And, for the most part, they do not need to. There will not be that much swarf involved and it, in the majority of cases, will not cause a problem. The swarf, being of iron, will rust out over a period of time, is not sufficient to clog up your radiator in any effective manner, and is sufficiently small that it will not jamb up your water pump.

If, however, you want to know the very best way to minimize (you cannot, totally, prevent any shavings from getting into the system) the problem, you may consider this. A new drill bit cuts much better than an older, dulled, drill bit and will make cleaner shavings when drilling. A vacuum cleaner, held to suck the swarf out as it is moved rearwards on the drill bit will minimize the chance of swarf entering the water cavities of the block or head. Grease on the drill bit, and very shallow cuts, followed by cleaning of the bit and re-greasing, will also minimise the chance of a bit of swarf getting into the water cavities. (This trick is also useful when re-tapping the spark plug holes with a 14mm-1.25 tap.)

I suspect that you will have no problems if you simply drill out the holes and flush the system using a garden hose. Using the vacuum cleaner or grease (or both) would almost guarantee that no swarf could enter the block or cylinder head.

All of my cars are daily drivers, sometimes used for long trips. I have not found it necessary to make this modification and, over many years--including some casual race track time, have not found it necessary.

Les
Les Bengtson

So... number four runs warmer, does it... The only question in my mind is - how can I get one, two and three to do the same?

Allen
Allen Bachelder

An idea that springs to mind is removing the rear core plug and placing a magnet in the water jacket while you drill. This could be combined with Les's methods.
David Witham

I've done this.

A telescoping parts retrieval magnet works OK
to pull out small swarfs. It also works to pull out
loose rust in the coolant jacket - especially at
the back of the #4 cylinder. Rust seems to
especially like gathering there.

Of course, you'd have to get a magnet small
enough to pass through the hole you are drilling.

Don't forget to mask off everything else on the
block deck when you do this to prevent stray
swarfs from falling in anywhere else.
Daniel Wong

David. Splendid idea and one I had not thought of previously. As you note, this, combined with my methods, would almost guarantee (no one can provide a complete guarantee) that no swarf would be trapped in the block or cylinder head.

Quite excellent example of either "thinking on your feet" or, "thinking outside the box" as one wishes.

In any event, it is a quite excellent idea. Would require two vacuum cleaners, but most of us have them. One for the house and one for the shop. Combine the two, for this instance, and keep the chance of damage down to about nil.

Do not remember your posting regularly (I have been busy and have not had the opportunity to check as much as I might like). However, based on your insight, please be so kind as to post as often as you are able.

Splendid example of "thinking outside the box".

As my old Colonel used to say, "You done good".

Les
Les Bengtson

Danny. Glad to hear from you. Are you ever going to get off you dead ass and send me a tech article on how to set up the Weber 45 DCOE for the MGB? There is some interest in this type of thing any you seem to be the most competent of us to answer such things.

None of the rest of us are willing to put the DCOEs on cars and none of us seem to have the expertise to do so. Hence, some information would be of benifit to the community.

Have missed your being here.

Les
Les Bengtson

Its funny this topic came up - I just did this to my engine last week. I used two very strong speaker magnets on the block in combination with a shop vac while drilling. I removed the magnet while flushing the block so that the shavings did not drop into the block where they would later wash out to the radiator. The flushing was done through the water pump hole with the back of the block toward the ground.
Jeff Schlemmer

Hey Jeff, com'on over and show me how to do mine.
SF
Dwight
Dwight

Les,
Here one outside the box.
I always place some small, fairly weak magnets around the periphery of the proposed hole to be drilled. As I drill the hole, the swarf is attracted to the surround block surface, and doesn’t fall into the block as the hole is drilled.
After the bit comes through, I carefully remove it, and the swarf either sticks to the drill bit, or to the edges of the hole. Either way, it doesn’t fall into the block.
Using a stronger, rare earth magnet, I place it over the hole and remove the weaker magnets. Lastly, I remove the stronger, rare earth magnet, and along with it, the swarf.
Tadaaaaa! I’m now outside the box.
Richard

Dwight, you don't have an old block like me - yours probably already has the larger holes!
Jeff Schlemmer

HI Les -

Me?... dead ass?

Hardee, har, har!

No, I haven't forgotten about the Weber DCOE
"How-To".

(...and no, I haven't forgotten about the brake master bench bleed "How to" , either.)

As it happens, my engine is completely torn down
and I am also in the middle of refining (and, now
that you reminded me - photographing) my Weber
DCOE setup.

Patience, young Jedi.
Daniel Wong

So, gentlemen all, now that you've captured your swarf, what is current thought on max diameter drill out. This would apply to both head and block holes.
vem myers

While you're at it, tap and plug the middle holes. Forces the water to the back of the block.
Lee Bradley

Reading through the archives, I think 9/16" was the max recommended size to drill out. Anything more than that could flow too fast and not absorb as much heat.

Lee, wouldn't plugging the middle holes just allow the middle two cylinders to run even hotter? I know in motorcycles, the middle cylinders have to be jetted richer to compensate for the excess heat.
Jeff Schlemmer

Lee's comment re plugging some centre holes rings a bell with me, coupled with enlarging the rear, and paying some attention to the flow in the region of the centre exhaust seats.

I understand that it was a factory racing mod or similar. Perhaps the Le Mans or Mille Miglia cars.

I have an article, but it's buried somewhere after our recent house shift.

Cheers
ian F



Ian Fraser

It may have been a factory modification but I got it from Joe Huffaker Sr. Joe recommended tapping and screw in aluminum plugs, machined flush.

Since the holes are between the center cylinders, they disrupt the flow around the top of number 3. By closing those holes you get a smoother flow and the full flow to the rear of the engine.

The factory recommended cooler spark plugs for the middle cylinders because they run hotter. But with today's unleaded fuel and better oils, I run cold plugs, BP8ES, front to rear.
Lee Bradley

You guys know everything. I love this board! I'm quite thankful that so many people are so willing to not only share this type of info, but do it in a way so that it is archived for use in the future.
Jeff Schlemmer

Danny. Just returned home and am getting caught up on e-mail and the boards. You have, already, sent the article on bench bleeding the master cylinder and it has been up, under your name, for some time now.

Please do the DCOE article as time permits. Again, good to see you back more.

Les
Les Bengtson

can somebody print a copy of this article in this site?
Sandy
Sandy Sanders

This thread was discussed between 06/02/2006 and 11/02/2006

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.