Porting!

[Mack]

The blasted intake is a very good finish on the intake and should be fine on exhaust. The theory behind the polished exhaust is to reduce the surface area of the port as much as possible to limit heat retention and recirculation of heat back into the head. This is the reason for the insulated exhaust washer as well and the fine gap between the collar and header pipe. All designed to get the heat to the pipe and away from the head.

Any tool shop with dremel bits will have the cutters. Also the sanding rolls which go on the rubber drum as you say. You will need a pack of them. About $10. Before blasting make sure you take the iregularities out of the port. They are pretty bad.

Don't think you have to finish with the bead blasted port. I think its more asthetic than practical. Many top tuners leave the 60 grit finish.

[noidea]

cool. Well i got my hsc trials this coming week and next so i probably wont have time to get much done... In between studying ill pull the head off my spare engine and see how i go. thanks for all the help :-)... should see about getting this thread stickied.

[noidea]

Got the head off finally. Took the rocker gear and cam out. Whats the trick for the valve springs and valves?

Im taking plenty of pics so when i get some spare time ill make a tutorial.

[Mack]

The springs are really quite soft in these. Just use a tube or long socket to compress the springs while you hold the head upside down. You may have to pump them up and down a few times. The retainers will just drop out.

Make sure you hold your thumb on the valve head to stop it opening while you compress the spring. Also choose a socket large enough to allow the retainers room to fall out.

[noidea]

ill have a crack now, and reply if i cant get it done.

(mack to the rescue yet again lol)

cheers

[noidea]

wow, that was easy. Do they come stock with two springs??? not looking forward to putting them back on lol.

edit instead of another post:
All cleaned and ready to port now.

It looks like someone has done some work to the ports, do they get machined before the leave the factory? Its just the top of the intake port, looks like its been opened up by a big grinding bit the diameter of the port... also is the double valve spring setup stock?

[Mack]

Yep, the two springs are stock. I'll warn you now, the only major drama doin this without a spring compressor is gettin those little barstard retainers back in. It needs great patience or save yourself the drama and when your ready go to any bike shop and get them to pop them in. Its 2 mins with a compressor.

Yes the ports have a bit of machining from the factory at the opening. The ducars I have seen have been opened out wide in this spot but then use a way undersized gasket and block the flow.

[noidea]

yea, thats the same. The intake manifold is nowhere near the diameter of the begining of the port!?

Good news is there definantly alot of room for improvement in the shape and surface of the ports :-)

[noidea]

hey mack,
Got most of the intake port done tonight, definantly more fun than studying!!

All looks good, except i can feel a bit of a ridge after the valve guide on the bend in the port before teh valve seat. from the shape of it it would direct intake charge to hit the valve, is this what we want?

Anyway i took some pics, can you give me some tips on what you usually do this this area, and any other comments on my progress.

area behind guide/infront of seat: http://www.mypicpal.com/jarvie/My%20...s/CIMG2801.JPG

Intake port before: http://www.mypicpal.com/jarvie/My%20...e%20before.JPG

Intake port after: http://www.mypicpal.com/jarvie/My%20...ke%20after.JPG

[Mack]

Is this a Ducar head? The opening to that port looks huge. How wide is it? Does it match the intake manifold?

Well I normally would grind down the valve guide flush but that means breaking through and dealing with that. If you don't want this extra difficulty you could grind it down and leave it 3mm or so proud of the port roof. If you don't want to break through I would not grind any more from the surface leading up to the guide. If you look carefully at the previous pics you will see as regards shape that the standard port is a tall oval. After porting these ports end up a flattened oval or D shape. This will give you a clue as to shape. The ridge your talking about I'm not sure what area you mean.

Also if you are getting the valve seats redone, cool. If your not, then be damn carefull with the tool around those seats. If you nick 'em theyre stuffed.