DOHC EFI modification underway

[davidimurray]

Rapidtornado - Just a word of warning - be very careful with chemical metal. We used to use it to plug empty holes in throttle bodies. However one day, one of our engines started running badly on the dyno. Compression test showed one cylinder was 'ill' on stripping the head off I found a small pellet of something hard, a bent valve and a 'ding' in the top of the piston. After some head scratching and seraching we realised that the pellet was chemical metal that had previously filled one of the holes in the TBs. It had been in there for a couple of years on various engines. After that we always made aluminiun plugs and pressed them into the holes.

[rapidtornado]

OK, thanks for the heads up. My intention is to use thios to get me through the IVA then very shortly after sitch to a zetec, but good to know.

Thanks
Matt

[Eternal]

Fantastic work! Im working on my rb25det manifold atm modding it from a top feed to a gtr side feed. Loads of work and like you need to get it tig'd... just need to do some practice welding on some cast ally before i start anything!

You know what this has inspired me to do it this weekend! nice one mate

[Enoch]

A very timely thread, I am going through a similar process with mine at the moment. I tried to cut one manifold down and duraweld an ally box on to it, that went badly wrong as I could not get enough heat in to the job. I have since acquired a manifold off a Galaxy - it goes down instead of up. I don't think it is going to work though as on the galaxy the manifold incorporates the injector ports, whereas in the sierra the ports are built in to the head. This all means that the galaxy manifold won't seal to the Sierra head. Also the throttle body is different and the manifold has an awful lot of holes in it that need to be filled. I have thought of loads of ways of doing the job but am still nowhere with it. I am having another look at the galaxy manifold today, that chemical metal may be the answer to fill the inlet ports and then reshape them.
Best to all,
Enoch

[ozzy1]

I recall seeing an ad for a product called Lumiweld i think that was used for these sort of things.Think it was in a car or bike mag

[Eternal]

Took a couple of pics to show what im going to do with the gtr plenum and rb25 manifold. the ports on the injector manifold are in a "C" shape but the plenum is in a nice straight line. I think with any kind of manifold mod its important to make sure the air flow is nice and smooth. So what i decided to do is make a set of plates to weld to the injector manifold that will line up with plenum. Then grind down the inside of the manifold to make sure there is a nice flow basicaly porting it.
Im not keen on using those metal glue type things as you really dont want stuff getting inside the engine. Also in the future you might want to turbo the engine and in that case it might blow bits off... well you never know! heh
Anyhow hope that helps you a little.

[rapidtornado]

nice work there.... would be interested to see it when it's finished

[Enoch]

Bought a pot of that chemical metal today and glued a few bits together with it to see how good it was. After it passed the "pull test", the "hit with a hammer test", the "fill it with petrol and leave it for 2 hours to see if it weakens test" and the "heat it up with a blow torch and hit it again" test I can confirm that it is, in technical terms, the mutt's nuts Very impressive stuff indeed. I have since taken my manifold off the car, cut it down and glued on the metal box I had previously made and abandoned. It is looking pretty damn good and for the first time I think I am going to get a manifold I will be happy with.
So thanks millions for the top tip, i will take some photos when it is done. It will sit well below the top of the engine now, the throttle body will exit from the rear of the manifold, the air intake will sit between the manifold and the side panel.
Best to all,
Enoch

[Eternal]

Sweet nice work. Nice to know that stuff is rock solid! I will probably have some uses for it in my build

[Enoch]

I have now got a manifold I am very happy with, it is test fitted in to the engine bay to make double sure everything fits without any problems. I will have to undo my engine loom a bit as three or four sensors are now in a different place but that's only 10 minute's work.
Thanks again to Matt for bringing Chemical Metal to my attention, I had almost given up! I would strongly recommend this to others, it's great stuff to work with and files / sands well while giving an amazingly strong bond to roughened alli.