Subtopic	Posts		Updated
	Headers	1		02/07 10:21pm
	Rear brake options	1		02/06 07:42am

By Tom (24.71.223.140) on Tuesday, February 05, 2002 - 06:25 pm:

I have been looking at all my engine parts carefully as I put it back together. It's a EB2 stoker. I've notice my intake manifold has smaller ports than the intake on the head. Would it surve any purpose the match the 2 up in size. Would I get better flow. What about my exhaust? should I be polishing my exhaust port for less carbon build up. There seams to be alot of talk about what is better.

By Todd (63.50.56.114) on Wednesday, February 06, 2002 - 11:48 am:

On the intake side, you want them to be identical. Don't go hogging the ports out, they're pretty good on their own with some minor clean-up. The exhaust works well with the port being smaller in diameter than the header opening. The physics are too much to get into, but it sort of prevents waves from going back through the head.
Is the car a racer, streeter, or both?

By Don (209.181.52.20) on Wednesday, February 06, 2002 - 06:23 pm:

The intake manifold port being smaller is very good this helps prevent reversion. leave it alone!
There is a flow loss called "expansion loss" spend your time doing a bowl blend. Or send me the head and I will do it for you resonable.

By Tom (24.79.34.159) on Thursday, February 07, 2002 - 03:34 am:

Can you explain to me bowl blending? I've done a little polishing and porting on some of my motorcycles, bowl blending is a new one to me.

Thanks for the info on the intake I will leave it alone. This information your giving me is really helping.

Can you suggest an easy way on removing the piston pins from the rods? It looks like I will be need to make a Jig and then us the press at work. I tried one with out a jig and damaged it.

By Don (209.181.52.51) on Thursday, February 07, 2002 - 06:08 am:

Take the pistons and rods to a machine shop. They need to be heated as well as pressed to come apart.
I will try and find a article on bowl blending and smoothing the short turn on the net tonight. You realy need pictures to understand what needs to be done.

By Tom (24.79.34.159) on Thursday, February 07, 2002 - 06:32 pm:

Don
I did some research on bowl blending myself, and I now understand bowl blending. I can find nothing on smoothing the short turn.

How much bowl blending should I do?

Should I do both the intake and the exhaust?

There are some very sharp angles in this area, should they all be smoothed out?

This is one of the articles I read on bowl blending.

The bowls are the tight radiuses port areas located just before the valve heads. The air/fuel is forced past this area, smoothing out casting flash radically improves overall flow through this tight area. Blending the bowls involves recontouring the tight port runners and providing a smooth transfer area between the port and the seat. This is a good bang for the buck

I'll see what I can do about some pictures.

Thanks for your help. Its to bad you do not live in Calgary.

By Don (209.181.52.18) on Thursday, February 07, 2002 - 07:49 pm:

The short turn is the floor of the port when it makes a 90 into the valve bowl.
Common BIG mistakes are to grind down the hight of the short turn, or to lay the radius back too far.

Stick your finger from the valve bowl along the short turn into the port. Feel the sharp edge?
blend the edge into the bowl starting on the port floor and blending into the port. DO NOT REMOVE MUCH MATERIAL!. If you spend more than 5 minutes
doing the bowl and the short turn your taking out too much. I can do it all in about 2 minutes
80 grit Hard rolls with a few mandrels are what you need for the intakes. You can polish the exhaust if you wish after working them with the 80 hard roll. Use a air powered die grinder. A little grease on the hard roll makes a smoother finish. Dont use Carbide burrs right now, its too easy to take out to much too fast for beginers.
Remember we are looking for fast small ports not big lazy ones.
Also the combustion chamber may have some sharp edges around the valve seats, smooth these too.
Finish with a 3 or 5 angle valve job from you fav machine shop.

By Don (209.181.52.23) on Thursday, February 07, 2002 - 08:05 pm:

I tried to take some pictures of inside the port but no dice. I did get a shot of an eb2 head and marked the sharp edges in the combstion chamber. Dont touch the valve seats. A old valve put into the chamber helps if you slip.

By Don (209.181.52.23) on Thursday, February 07, 2002 - 08:08 pm:

EB3 head
see how much deeper it is and the chamber is kind of oval instead of round due to the bigger valves

By DON (209.181.52.34) on Thursday, February 07, 2002 - 08:40 pm:

Here is a crude drawing I stole off someones web page. I marked the short turn and bowl of one side of the head

By Anonymous (209.240.222.131) on Thursday, February 07, 2002 - 10:49 pm:

I saw a header for a 75 civic cvcc 1500 on ebay.Will this fit on a 78 civc cvcc 1500?

By mike adams (206.58.33.68) on Thursday, February 07, 2002 - 11:29 pm:

No, The 75 has a unique head design that later years don't. In short it will only fit on the 75, which is why it's so hard to find headers for the 75. Now there have been two on e-bay in a week. Contact the seller, he may have some for later models, or know where to get them.