Need help, advice with my 318 build

[RustyRatRod]

Wow, ok. Bit harsh there, I never thought installing a 4 degree advanced cam in a straight up position would get a "never in a million years" or "That's the stupidest thing I ever heard" response. I have read you can usually go 4 degree off the cam card either way for tuning. And that 4 degrees advanced is usually the sweet spot, so it is usually best to degree to the card.

I agree that the OP should pick another cam preferably something with a wider LSA, but they posted that they wanted to keep that cam, trying to give suggestions. If I was way out of line I apologize.

No. I didn't say you were stupid. Just the idea of retarding a camshaft to reduce DCR. If that's the case, simply choose a "smaller" camshaft.

This is exactly why I recommended the camshaft that I did. It can be installed probably down around 100* ICL and will get the best of both worlds. That cam is plenty big enough to pull like gangbusters on the top end and advancing it more than the suggested 4* will bring back the low end torque.

But of course, as usual, my recommendation fell on deaf ears. That's cool too.

 

[nm9stheham]

So I'm trying find that sweet spot just in between stock and ported.

With mild port work, you aren't in any serious danger of doing too much. As I have been taught (and again, I am not an expert on this), concentrate on the bowl below the valve, and any other area that are rough and that narrow up. Get a good multi-angle valve job with a steep angle cut below the valve area.

Windage tray is something that might be thinking of also to make it more efficient?

Windage trays give most of their benefit at higher RPM's.

Have some more grind questions about the combustion chamber. You don't want to have any sharp edges in the combustion chamber as those gets hotter? Is it alright to just smooth this edges? Going to buy a plexi glass and CC my heads soon and then I will find out where I'm going to be more exact where my compression will be. So if the chambers are to small the smoothing of the edges will lower my compression. Not going to touch the quench area I rather take material in the chamber. My second question about the chambers is it ok to grind it a little further than smoothing the edges and shape the non quench are to the cylinder shape or does that edge doesn't effect the combustion process?

I would smooth the outer edges and then smooth the combustion chambers all over with a rough grit sanding drum if I was doing anything to them beside removing material for the compression ratio. And be aware that most of the time, the chambers are larger than published. I would not bother with matching the size of the combustion chamber to the cylinder.

 

[nm9stheham]

Regarding 302 cc's a book will say 56 - 65, ours measured at 62 after a light chamber clean up.

Good real-world data is always appreciated.

 

[Coronet 500]

Ran this on Camquest just for comparison purposes.

XE 250 H = 285hp, 375tq.

265 DEH = 308hp, 368tq.

XE 256 H = 297hp, 375tq.

Their cams, their program, argue with them if you disagree.

 

[toolmanmike]

Polish the chambers to help ward off detonation.

 

[nm9stheham]

Ran this on Camquest just for comparison purposes.

XE 250 H = 285hp, 375tq.

265 DEH = 308hp, 368tq.

XE 256 H = 297hp, 375tq.

Their cams, their program, argue with them if you disagree.

What is missed is the breath of the torque curve.....that is what your butt feels.

 

[Coronet 500]

I think 9.5 - 9.75 in a car is fine. We went with 8.5 based on our machinists recommendation, it's in a truck that we do work and towing with it.

 

[Pompis]

Sorry for a very slow reply. But I have been busy lately.

I'm done with the grinding the ports. I have left some polishing of the exhaust ports and maybe the chambers. Have cc one chamber at 61cc. But I'm little worried that I removed little to much at the "short turn radius" at my exhaust port. Since It's good to have material left there for the seat because it gets warm there. Didn't remeber where I read it and the whole info at it either. What do you guys think based on my pics at the exhaust port?

Didn't remove to much at the valve stem guide.

This is what I ordered from ebay to help me reach in the ports. I ordered the whole set. They aren't the best but for the money they are really good for what i used it to. And you can port a set of heads with them if you want to they will last. It will loose some "teeth's" even if you are careful and takes it slow and the finish aren't the best but that's maybe because the long shank makes it shake and jump easier. I cut mine shorter so they reach just enough for what I wanted. I also had some better burrs to make the ports smoother.
http://www.ebay.com/itm/1-4-Shank-6...hash=item3f4f93d8d8:m:mvARkyXiaj0_U7w3zU7xwrQ

Have also begun with building headers.

Made two forming dies from aluminum. I first press the tube in the vice so it's fit in the forming die, then I press the tube in to the forming die in the vice. When the tube reach the "bottom" I use some rounded bar and hammered the corners so the tube fitted nicely at the corners.

I also opened the flange so the tube would fit in the flange port opening. It didn't fit at all the flange port opening was to small.

When I opened the port opening at the flange I made it in the direction so the exhaust will flow smooth at the roof at the port but made so I got a anti reversion dam at the outside and bottom. In the middle is where it will be flow restriction. But that's better than before I opened the flange up. Because if I have jammed the tube in there it would be even more restriction than now.

This is the bent tubes I'm going to use. The material I going to use is 0.1" thick. So it will not rust away as fast as the most headers that's made of exhaust tubing thickness.

 

[Pompis]

I have looked at the Lunati 10200702 cam as a possible cam to change to if I'm not satisfied with my current cam. Have looked at the XE 262 and also the 265 DEH as RRR suggested. But think the Lunati seems the most appealing for they are designed to work together with the .904" lifter diameter.

I didn't buy the XE 250 cam for this engine build. I bought it as a replacement for the stock cam but I never installed it. So I'm going to try it at least. And I like all the suggestions and stories about your engine with different cams and parts you built.

Some more progress on my short header build.

I had to cut and hammer both pieces to make them fit better together.

The passenger side almost done. Going to make a collector that I will weld a 2.5" v band flange to.

First tube at driver side.

 

[aaronk785]

Get a real 904 lifter design. Summit has howards cams. PART NO.711381-10 208-214 at .050 479-494 on a 110 lsa. Howards makes top notch stuff. Could run comp cams 901 springs cause you probably wont see .480 at the valve.