Stuart
Senior Member
Posts: 169
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Post by Stuart on Dec 20, 2004 22:31:31 GMT -4
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maritimedragracing
Junior Member
Associated Member
Racing under the Poverty Line
Posts: 42
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Post by maritimedragracing on Dec 22, 2004 9:26:07 GMT -4
Home head porting - yet another "old wives tale" My advice would be the less "porting" the better. I have read that larger and especially smoother ports sometimes only kill torque.(the boundary layer theory) Also the majority of flow improvements from porting come only above .600 valve lift or over 7000 RPM or with the installation of larger valves. The best job you can do on your heads is to blend the sharp edges and port match them. Leave the major grinding for someone with a flow bench - without it you're only guessing.
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Post by Road Rage Racing on Dec 22, 2004 16:09:47 GMT -4
One thing to remember with porting is that SHAPE is more important then SIZE. There is a lot of HP to be gained or lost with the wrong contours. I'd go with what Don said, clean up the ports abit and do some port matching.
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Stuart
Senior Member
Posts: 169
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Post by Stuart on Dec 22, 2004 22:42:21 GMT -4
I agree with both of you...I'm not going to open things up too much, I'm mostly blending everything and removing sharp edges. The big thing is to remove the thermacator bumps in the exhaust ports, they kill the flow in SBF heads. I ported the E7's on my roller 5.0, it made a noticeable difference and I didn't go over kill on them either, I didn't even touch the intake ports or bowls on those heads. I'm just going to blend the intake bowls and ports and remove casting boggers. I think the whole polishing thing is kinda pointless in my rpm range. The SBF intake ports aren't that bad from the factory, a little blending is all they need in my opinion. I'm not going to touch the intake guides at all. A flow bench would be nice if I was trying to make some serious HP. ;D ;D You can see the bumps I speak of in the head on the left. Here's the basic finished exhaust port minus the thermo bumo and sharp edges. They are slightly bigger than stock. I raised the roof a little and widened them slightly. I didn't touch the floor other than to remove casting boggers. The short turn radius is kinda important to leave alone on these heads.
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Post by Road Rage Racing on Jan 1, 2005 4:02:02 GMT -4
Nice Work! ;D
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Stuart
Senior Member
Posts: 169
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Post by Stuart on Jan 2, 2005 8:42:12 GMT -4
Thanks , I gotta do a small repair to the engine mount on my compressor this morning but then I'll be back at these heads to try and finish them off. The heads are dead straight, I glass beaded them as you car see, do I need to have them planed for the smooth finish or will they seal ok to the head gasket with the glassbeaded surface texture?...I have a $100 machinist's straight edge to check blocks, heads and etc for straightness. ;D
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Post by sam on Jan 2, 2005 9:12:29 GMT -4
Myself I like to have a machined finish, have the heads been plained before, you can gain compression by decking the block and plaining the heads also by chooseing the right head gasket . But getting the block decked is money well spent because no matter what you choose to do in the future that step will already be done and will only help with any future mods that you choose to do. ;D
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Stuart
Senior Member
Posts: 169
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Post by Stuart on Jan 2, 2005 22:06:44 GMT -4
We are not looking for any big compression gains as we will be running pump gas for now. Basically we're just trying to save money where we can to get this thing running for this summer....My wife is expecting in July so the budget is a little tight...LOL
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Stuart
Senior Member
Posts: 169
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Post by Stuart on Jan 4, 2005 22:35:11 GMT -4
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Scott
Senior Member
ohhh SNAP!!
Posts: 116
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Post by Scott on Jan 8, 2005 23:59:38 GMT -4
Look nice man!
Im just about to tear my heads off and send em to armstrongs. My car smokes at high rpms and when you first start it after it sits for a while. has a rebuilt 302 done .020 over. about 50k on it since the rebuild. So it has to be the heads.
Stupid cars ;D
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Post by Site Admin on Jan 9, 2005 9:16:59 GMT -4
Smoking after it sits a while is likely valve seals and/or worn guides but I suspect the high RPM smoking is caused by something other than heads.
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Scott
Senior Member
ohhh SNAP!!
Posts: 116
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Post by Scott on Jan 9, 2005 13:13:03 GMT -4
yeah..thing is it had new valve seals put in a few years back, cant see them going so quick. but ya never know. i thought of blowby, but d**n, it has less then 3% leakdown. Like the threads of the sparkplugs and the tips get all oily too. So its coming from somewhere..lol Drives me nuts as i just put the motor in the car cause of worn rings. and im just where i started..
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Post by Site Admin on Jan 9, 2005 13:57:53 GMT -4
High RPM causing excess oil under the valve covers being sucked into the intake through the PVC valve perhaps?
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Scott
Senior Member
ohhh SNAP!!
Posts: 116
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Post by Scott on Jan 9, 2005 14:41:42 GMT -4
Thought about that. So i installed a filter too see how much oil was being sucked through. there was some. So i installed a oil seperator. looks like this it traps some oil, but it still smokes. Dunno..stumps me. I bought the short block used from a buddy, but with low kms. his car never smoked. put it in mine, and smoked from day one. Frustrates me..lol Maybe we should make this a different topic..lol dont want to hijack a thread ;D
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Stuart
Senior Member
Posts: 169
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Post by Stuart on Jan 9, 2005 20:35:23 GMT -4
Nah, don't worry about it, I love a good Ford discussion. ;D I bought a 94 roller 5.0 HO for my 63 for $1000 2 years ago. It had 70,000km on it and it was still showing x-hatch. It doesn't smoke under hard throttle unless you get on it hard in 1st or 2nd gear and then let off it immediately. I taped my runs at the track last summer and I never saw any smoke for the entire runs. I ported and rebuilt my heads myself (except for the machining). I used the stock style valve seals and my guides were tight. I never touched the short block at all. So far, the engine runs great and it only uses a little oil if you drive it to Liverpool or Debert and back from Halifax....it runs 3000rpm at 60mph on the highway so a little oil burned off should be expecxted.
I've got one of the 351W heads finished and I've got the second E5 head a little over 1/2 done. I try to pick away at it for an hour or two in the evenings when I can. I won some brand new 1.94/1.50 chevy valves on ebay for $26 so they will likely be going in the E5 heads unless I find a better set of heads this winter that I can afford - read very cheap or free ;D.
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