9 replies to this topic

[Willybum]

This may seem a silly question but while re-grinding the valve seats on my 1275 leaded head and seeing some crud/roughness in the inlets, I began to wonder if I could perhaps buy a 'port polishing kit', or even something less sophisticated, and improve flow... has this been done before? Obviously I couldn't expect the same improvement possible when done professionally, but would this be worthwhile doing?

Oh and maybe I should say hi! I've just bought a black 1977 1275GT (without the runflats!) which has been dry-garage stored for the past 25 years and rust-proofed from new...to cut a long story short, there is very little to do (certainly next to nothing cosmetically/structurally) except pop the head back on the block and some little fiddly tweaks here and there. A steal for £500 ) Maybe I should post some pictures on the 'projects' forum?

Will

[Bungle]

yes a bit of home porting does work

get your self a copy of david visards yellow book as it will tell you what and where to grind bits off

[dklawson]

Just a minor point here...

Yes, you can buy DIY kits for porting a head. Over here such products are sold by Eastwood. I believe most Eastwood products are carried by Frost in the U.K.

Polishing is an overused term when porting a head. Most sources ( I believe this includes Vizard ) will tell you that you don't want to actually "polish" the ports. A certain amount of roughness is necessary and a perfectly smooth port may reduce the horsepower developed.

Most texts like Vizard will walk you through how and where to open the ports up for increased flow area and reduced drag. Do not simply buy the tools and use them without consulting a book on A-series engines.

[Willybum]

Thanks guys for pointing me to a book on my shelf! I have Vizard's book on 'Tuning the A-Series Engine' and didn't think to tap into that comprehensive source... I have started reading it (and what a fascinating read it is!) but haven't got to the port chapter yet. I shall have to get reading )

While I have your attention, and to avoid cluttering the forum with lots of new topics, are there any suggestions you have to 'enhance' the GT? I'm not talking modifications, due to insurance purposes, but perhaps certain things that a 30 year old car would benefit from, such as cleaning here, scrubbing there, conversions (halogens, etc.).......? It's running an alternator, I have an electronic ignition which I plan to install, and I plan to fit wheelarch protectors and Waxoyl everything...but is there anything else?

[TWICEmonkey]

I won't say too much because I've never tried it, but my mate did the same for his Cooper MPi and it added about 10bhp. He's quite a good mechanic though (he works for Carlin Motorsport) and knows exactly what he's doin. He just takes out a dremel, sticks on his headphones and away he goes for the day.

I'm gonna get him to do the same to my head when I rebuild my 1098

[dklawson]

A Dremel? Oh God that would take a long time. This is a task better suited to electric or pneumatic die grinders. To reach deep into the ports you'll also need some extended shank burrs and polishing points. Almost all of those I've seen are 1/4" (or 6mm) diameter and too big for a Dremel.

If you're looking at other things to improve the reliability of your GT you may want to go through the brakes and rebuild them as a mater of safety and install the braided flex lines. Other than that, clean all the electrical connections and grounds so the electrical system is equally reliable. I'm sure others will have additional suggestions but I'd focus on brakes and electrical improvements based on what you've already done.

[davexdavexdave]

pictures of this little beast please.

[Willybum]

Thanks for everyone's help on this! I've decided to keep things simple for now, due mainly to lack of time (and partly due to Dad putting the head on before I had a chance to fiddle with it!).
I'll be posting a topic in Projects soon, pictures included...

[Willybum]

Topic created in Projects if anyone's interested in having a gander.

Cheerios,
Willy

[TWICEmonkey]

A Dremel? Oh God that would take a long time.

It takes him a day to do a head, he says...but he says that, so long as he's got music playing through some headphones, he "finds it relaxing...almost tranquel" (his words not mine).

Plus he's a perfectionist, so he doesn't mind taking time on something if it means that it'll be perfect that way