Hi everyone

I'm preparing to construct the head for the racing "bullett" and am expecting hot parts to arrive soon.

I'd like some advice on the thickness of the head casting on the G150 aluminium head because I'm about to start matching the manifold to it but the twin carb manifold off a Gt, kindly donated by Gt Orphanage, has openings 10mm longer than the inlet ports of the G150 head. They measure 44m long as against 34. I've managed to machine the manifold down by taking material off its face until the difference is 9mm and have worked out that I can raise it against the head so I have to take off 6mm from the tops of the ports which seems quite possible, given the thickness of the head above them and 3mm off the bottom of the ports. This will also help flow in the top of the port and keep the short side turn in the bottom as long as possible.

My problem is:
Taking too much meat off the bottom of the ports worries me as I don't want to hit water channels. Is 3mm within limits? I will also want to "taper" the opening in to about 15 - 20mm into the port, rather than having a steep taper.

I've included some photos so that you can see the longer openings in the manifold compared with the inlet ports in the head. If you look carefully you can see pencil marks which I've made and also feint scribing marks which depict the real measurements needed to match the manifold.
I've also included piccies of the rebuilt SU carbies.

Advice and suggestions much appreciated
YP

The only way I can see for you to check apart from cutting a corroded head apart is to use a feeler wire in through the water jacket hole and see how much clearance you have.
Sonic checking with the same equipment they check cylinder walls and roll cage material thickness with.
Hopefully someone else has more of an idea.

Keep the pictures coming.
It will be interesting to see how much difference there is between this head and the G150 iron head.

Cheers
Rob

i cant help you with your question(s) YP, but i do love your work.
That car will be quite a goer once you have finished it.

more pics, more pics, more pics please.


OZ

Thanks Rob and Oz-T

I have used some feeler wire and think I have clearance but this is my only only Al head apart from the one on the Yellow Peril so I thought I'd be cautious.

I'm with you Oz-T, this is my first big ground up race motor rebuild by myself so I only hope it goes as well as it looks and the theory suggests. I'm stepping into the unknown in many areas.

Will keep you posted and have included a pic of the crank scraper installed. Will it make a difference - I have no flamin idea. My brothers think I must have got bored one day!

Just don't let the Gt Cortina competition get onto it

nice looking engine so far! its a heck of alot cleaner than the lump i have on my engine stand! good luck with the carby set up.

Wicked !!!

Windage tray next ???

Cheers
Rob

Question: isn't the scraper only supposed to be on one side ?
The side going up towards the head.
Otherwise you scrape oil off the crank and it sits above the scraper and runs back ino the crankshaft and rods as they come past the scraper causing drag.
The windage tray also has slots angled against the rotation of the crankshaft to aid in this stripping of the flying oil off the rotating assembly.

Cheers
Rob

Hi RobSA

Avery good observation and one which puzzled me as i was doing it and now that you mention it has made me think some more. When I did one side i realised that i'd need to build up a similar thickness on the other side as well and thought- what the heck! I may as well do it on both sides. I looked at many pics of scrapers and it seemed that some were one-sided and some were two sided. I'm hoping that the holes and slots cut in it will allow oil to drain back into the sump - I'll have to think about the implications of what you're saying. Perhaps i was overcome with enthusiasm and worked faster than I was thinking. Simultaneous fast work and thinking is a very rare occurrence:?

LOL
The two sided scrapers I have seen have holes near the pan rail so the oil doesn't drain back through the rotating assembly (ie American Pro Stock engines, early eighties).
Nice work though
I'm looking forward to more of this build before I pull Bella's engine and get started.
Cheers
Rob

Thanks for the interest RobSA.

I'll keep posting stuff up (not to be confused with stuff ups) regularly. I'm trying quite a few new things with the headwork, within the rules, trying to turn theory into practice which takes quite a bit of nutting out - more planning and sourcing bits than action at the moment. I've been waiting 6 months for some parts and yesterday was told they were being posted that day, so things will start to roll again.

Next weekend I'm going to the historic racing at Phillip Is. and hope to look around and learn a lot of new stuff.
YP

love the effort your putting in mate, nothing like trial and error (although hopefully not too much of the error!) Any chance your heading this way for the historic racing at easter?

Hi Mr Flibbles

Unfortunately I'll be back in Tas over Easter. We are taking the Triumph Stag I restored (big time) for my wife a few years back on a road trip thru inland Vic, NSW and QLD and back to Melbourne via the coast in the early part of April (cheaper than the trip to Greece she wanted After that I'm hoping to have more spare trime to devote to the racing machine.