Porting

[Jono]

I am going to try my hand at porting a 12G 2940 11 stud head for my planned fast road engine.

Can anyone recommend a decent electric die grinder for this purpose, and a source for the various burrs spirawraps etc?

Cheers

Jon

[In the shed]

Get a Makita one (google it and spend as much as you can afford) for the main meat shifting and a "lidl dremel" for artistry.

You may all laugh, but Aldi/Lidl occasionally do an able die grinder which is surprisingly good. Google should turn this up. Regarding bits, spend asmuch as you dare for starters and let the tool do the work.

[Jono]

..thank you.

I clocked a Makita 400W model with 25k (no load) speed for around £85 on the internet but it does not appear to be variable speed (too much to ask at the price I guess).

I would be willing to spend up to £100 on a grinder (new or used) - any recommendations in this price range? Whilst I like good kit I am probably only going to port a couple of heads (not including the one I wreck ) so I need to keep this in mind.

I agree, some of the Aldi specials are actually great value for cheap Chinese stuff. I have the fake Aldi Dremmel and it's surprisingly good and the compressor I bought around 6 years ago has been an utter bargain (too small to run an air grinder unfortunately).

...and for the burrs etc?

Cheers

Jon

[pad4]

well im going back quite a few years here but my dad (engineer did castings n stuff) would only ever use mounted points (stones) of various grit - never ever would he use the metal burrs and we got some good quality heads using these - he aleays maintained that the metal burs could be to bouncy around if youre not used to them .

i think the stones were all dormer or presto - never any crap

pad

[robert]

try chronos engineering supplies for carbide burrs .

[Ollie78]

Hi, I have 'had a go' at a couple of heads in the past and got some ok for an amateur results , I use die grinders at work for sculpting stone so am quite comfortable using them.
I found it easier to visualise if you have ported head to copy, see if you can borrow one, you can use inside callipers to check.
A word of warning, the fixed speed high power die grinders with carbide burrs are dangerous. I've broken 2 Rupes (Italian brand) 30k grinders so far, a 12mm carbide burr going at 30K takes out the collet on the machine as well as itself if you get complacent or loose your grip for a split second. Its scary stuff, the whole lot literally explodes and most of the part vanish.
I have a 12.5K speed one now and its much more controllable for metalwork. The best (safest) is a pneumatic one but you need a lot of air, failing that a variable speed electric (run one through a dimmer switch maybe).
Go careful, 25K is fast, they go off like a grenade with a massive bang when they jam.
If you really want to do it cheap I have seen people convert routers and use long reach bits.

[Ollie78]

http://www.ebay.co.uk/itm/Metabo-GE700- ... 27d7ee2718

Something like this would do you well, variable speed. Metabo is better than the likes of Makita and not far off brands like Flex and Fein in my opinion. These machines are extremely useful for grinding welds in hard to get to places as well.

[Ollie78]

http://www.ebay.co.uk/itm/Metabo-ge700- ... 1e7fe6b695
Here's a brand new one for auction.

My latest addition is a Chinese copy of this http://www.ebay.co.uk/itm/Makita-Die-Gr ... 2582ba4530
It could be the same machine internally, it has the same casing but its orange and doesn't have Makita stamped on it.
Its quite useable for small jobs, 250W motor, fixed speed 12500rpm, somewhere halfway between the 600-800W big ones and a 125W fairly useless dremel tool.

[Lord Croker]

For re-shaping combustion chambers & opening up ports, I use this mains voltage grinder, shown in the first photo, which is quite powerful & was obtained from a branch of 'Do-It-All' for about £15.

The second photo shows what I use for the inner ports & valve throats, which I obtained second hand & is a superb piece of equipment, (if you see a second hand one for less than £100, grab it!) you will also see a selection of mounted points which I get from my local ironmonger, a cylindrical emery device for polishing, & I have found the best way to get the flat roof of the chamber right, is to cut emery paper discs & stick them to the felt polishing discs that are supplied with most small grinders, using a glue stick. Excuse the mess on my bench, all this stuff has been on the back boiler for a while & I haven't had the time to spend in my shed.

[tedmcedd]

I've used my plug in dremel with very good results....

I can't remember the model, but I will check for you! As far as the tool inserta go, I hjust used the various stones that came with it!
You may also want to rig up an 'extractor fan' I just G clamped a vacuum cleaner to the work bench, as there is a lot of dust!!

Ed.