TangoMan
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| posted on 12/5/07 at 07:39 PM |
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A good days work!!!
I spent around 4 hours today with the die grinder.
Throats nicely opened out and tidied up. It wads surprising how poor these were as standard. I have blended in the ports and polished the exhaust
ports to help reduce temperatures but the inlet is staying largely standard except for the area around the separator and the entry into the
throats.
A bit more work required to finish off and then grind in the valves and skim the head ready for refitting with Piper cams.
The headgasket was not good and the valve seats had seen better days so I am hoping for a good improvement.
I will them have some standard 2.0 cams for anyone running standard 1.8 cams and looking for more power.
Summer's here!!!!
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DarrenW
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| posted on 12/5/07 at 08:01 PM |
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Sounds great Steve. Some sensible blending in has got to yield some improvement. I reckon its going to be a strong engine - should yield some good
power and torque. Cant wait to hear what its like.
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rustybits
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 posted on 13/5/07 at 02:35 AM |
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Don't polish too much though Tangoman. Remember the laminar flow theory.
The big hammer artiste formerly know as skodaman
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zetec
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| posted on 13/5/07 at 06:32 AM |
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I'm going to order my Piper 285 next week, will be interesting to see how well our DIY porting works!
" I only registered to look at the pictures, now I'm stuck with this username for the rest of my life!"
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TangoMan
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| posted on 13/5/07 at 06:48 AM |
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quote:
Originally posted by rustybits
Don't polish too much though Tangoman. Remember the laminar flow theory.
The inlets will stay rough to assist with fuel atomisation at low speeds but the exhausts will be polished as this should reflect heat back in and
also reduce carbon buildup. Not that I expect much of this with a well set up system.
It was nice to see that my Megasquirt setup was very good as the valves and chambers were a nice light brown colour and consistent across each
cylinder (except for the plug on the cylinder that was making friends with my cooling system.)
Darren, I am only doing it to lead you along the same path. Another benefit of the Zetec is the ally head is much easier to work on than the
pintosaurus.
Zetec, make sure you check the cams in the head before fitting the followers. Dusty on here had a problem where the lobes were fouling the head so he
had remove some of the casting. That could have been disasterous to the new cams had it not been spotted. When you see the steps and sharp corners
left in the ports and throats from production you will feel an improvement in flow should be easy.
Summer's here!!!!
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Browser
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| posted on 13/5/07 at 08:34 AM |
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How rough was the standard head? I'm only asking as I've got a Zetec to go in my Velocity and am debating whether to bother lifting the
head off or just leave it standard, get the car on the road, then start mucking about (possibly even get a spare head ).
Are you planning to re-profile the valves at all? I know it's a lot of extra work but you can gain more low-lift flow by grinding/cutting the
back of the standard valve heads to a shallower angle and waisting the stems of the inlet valves. I'll try to find some diagrams to show you
what I mean. It's fairly easy and it'll complement the head mods you've done.
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TangoMan
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| posted on 13/5/07 at 02:19 PM |
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The standard throats are very restrictive and have lots of mismatch between the various casting and machining are.
I will have the inlet valves cut back with a 30degree angle but will leave the exhausts and the stems as they are thin to start with. I would rather
keep relability than chase a couple of extra bhp.
I will find out if it was worth the effort when it goes back together in a couple of weeks.
Summer's here!!!!
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