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gerg

2V Head Refresh

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Engine uses oil and smokes too much, especially for 70,00 km.

 

So... heads are off, have been stripped and inspected.

 

7ada84a6d942597be1da076f449dc4cc.jpg1) Engine is pretty clean inside, probably because it's always getting fresh oil from needing to top it up

 

b4908feac143c9060f9a65bbaf899223.jpg2) Oil deposits in exhaust port

 

3cdefa6b764e244828ca572440abd1d0.jpg3) Chambers were all like this. Plugs fouled but somehow ran fine (the MSD probably helped)

 

4723905776f4ef039070106fba7750ab.jpg4) Weird scoring on one seat, either from new or from the valve face

 

4e255afbdefcdd8143f0453e6e13d72b.jpg5) Seriously crap daggy bits inside the ports

 

01c3f7ced1b59be03fdc6c69283ef9c7.jpg6) Anyone who likes umbrella seals, take a geez at this. Every one was at least split in 3 places, some smashed or missing the tops. I reckon they'd be softer if made from bakelite. At 70,000 km, that is rubbish

 

4b3964ed2a81c205b2c5c5a29066443c.jpg7) My head jig, for both disassembly and porting. The idea is that I can have both heads and all the ports lined up so I can be consistent with each shaping operation.

XPT, deankdx, bear351c and 3 others like this

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29 minutes ago, gerg said:

Lol backyard engineering... You've come to the right place emoji6.pngemoji106.png

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how are the home made aerochamber mufflers going?

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how are the home made aerochamber mufflers going?

Lol.... Forgot about them. If anything, they're a bit tame now. Probably sooted up from all the crap coming out of the motor

 

 

More on that soon, I've got a plan to install a cutout. Thread to come.

 

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CHESTNUTXE and deankdx like this

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Yeah was in a hurry last time i did a cam swap (i'm always on borrowed time) and just slopped on the Threebond without paper gaskets. Worked ok no probs. I've ordered a proper pan gasket this time.

Engine is a bit brownish inside but just needs an oil change.

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Outback Jack likes this

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if you orderd the stamped steel one be carefull as they are sharp as all hell,i use both felpro valley or stamped steel valley work well altho am biast toward felpro on alloy intakes.

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Yeah it will be Fel-pro, everything's coming from Precision International except Crane springs and retainers, which will be from PC Engines.

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Valves look to be one piece (promising) as opposed to the notorious factory 2-piece so hopefully can be re-faced. Might get a back-cut while i'm at it.

Inlet: G223G EV 37030
Exhaust: G540A EV 37036

Anyone recognise these numbers?4d1c9e723e4ca082338083eaddb0e8ed.jpg

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Decided to attack the short turns today, and started on one guide boss.

 

Before & after:300ceefcc0e0968c5d8c29eb8ed79d88.jpg70adb57607386ff0f3abafd7f8d37d31.jpgOk so you can see that the factory port work is disgusting. A sharp ridge pretty much all around the bowl, with a very sharp edge on the short turn, and a big dumb lump of a guide boss, also a dead pocket behind it No wonder they only flow marginally better than a 351W.

 

Now some progress shots:a30c53ba58651154d625f4d87181187c.jpg08e3a0dee0619f92e6423feaf2ffe0d2.jpg9214cf1033cbde5a514f8b2f8b5446a8.jpge583ea826638537c9cef48894a2d9330.jpg8f9e236e8d54346cdbb27565eaa991ec.jpg

 

Did the exhausts too, but hardly worth showing as they only had a slight ridge coming just out of the bowl. Spent no more than 10 min on them and that's how they'll stay.

 

The whole job (8 inlets and exhausts) was only about 90 min. Any more than this i reckon would bring diminishing returns for your time spent.

 

Next is finish the guide boss and copy its shape for all the rest, including exhaust.

 

 

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deankdx, Thom, Valvebouncer and 2 others like this

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are you copying a design/rules/pics from ones that have been done or just cleaning up the obvious flaws from a common sense approach?

i always wanted to have a go at something like this.. should have tried it on the crossflows..always had several spare heads in the past.. might try it with a gemini head yet..

 

gerg likes this

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are you copying a design/rules/pics from ones that have been done or just cleaning up the obvious flaws from a common sense approach?

i always wanted to have a go at something like this.. should have tried it on the crossflows..always had several spare heads in the past.. might try it with a gemini head yet..

 

Bit of both really, I often read myself to sleep looking at this kind of thing, and luckily there are a few folks out there kindly willing to share pictures of their work.

 

I took this on with a general idea of how things should look. However there are things that a camera just can't show, like the transition between the short turn and the port floor, which can only be felt with your finger, kind of like looking for its g-spot lol

 

Give it a go i reckon. Stick to a few rules:

 

* use a decent size compressor

 

* always keep the burr moving

 

* take very small nibbles, not big chunks

 

* repeat exactly the same action for every port. Pretend your arm is a robot on a production line, using your muscle memory.

 

* on a street engine, you only want to smooth, not enlarge. 2Vs are already a bit big for a 302, so going bigger is a step backward.

 

* concentrate on the bowl and short turn. The biggest gains for time invested are made here. Leave the port alone unless you have a whole weekend to spare

 

* it doesnt need to be pretty. If it feels smooth, that's good enough. Your fingertips are your eyes

 

EDIT: also if you have a pressure reg set up in your air line, set it at or below the cut-in pressure of your compressor. The pressure variance between cut-in and cut-out causes big changes to the speed of the die grinder. A reg will keep the pressure (and thus speed) constant.

 

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XPT, CHESTNUTXE, bear351c and 1 other like this

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ol'm8 down at the machine shop has done a million clevo heads over 40 years and he showed  me something i had never seen b4 on a set of 2v c/chamber experimental heads ,he cut the fkn head in half just to see how much he could take out of the turn b4 hitting the waterjacket,there is more to it but ,all this was done for stock car racing where the rules are very strict what can be done,no aftermarket alloy hot shot heads ,after all the work was done then some welding was needed for some reason,this head was only cut just to see what could be done when rules apply to gain a little more hp,i should get a picture next time im down there but he is very secretive ,he also uses a smaller exhaust 1.60

gerg likes this

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Sectioning heads has been done since Noah was a boy. I'll bet a lot of aftermarket heads were develloped this way to eliminate all the trouble spots on factory heads.

Some pics off the web that I've been using for reference:a58b2afe11751ac46479c8e059b57ca4.jpg62230560adb134971c98ef087c9fd38f.jpg

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Yeah plenty of meat there but what i found was that the more you removed, the more you had to blend in and there's a point where you just cant get the grinder deep enough to blend what you've taken out. You could probably get in there with a skinny grinder and/or a long-shank burr, it i have neither.

I could cut further into the short turn but blending that would mean going halfway up the port, which would take cubic amounts of time i don't really have. It would also add port volume and reduce velocity, exactly what I don't want to do.

I just want to keep it simple. I know that what's done is going to be a definite gain (cant get worse), but when you get into professional grade porting, it takes decades of experience and flow benching to know what to cut and what to leave. You can do more harm than good without these elements.

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CHESTNUTXE likes this

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Nice work there, Gerg.  Another reason why i put pics up on the Nugget heads, just so others can see a basic idea. Always hard to explain these things.

Good explanation as to using the hand tools, too. (Robot like) is perfect. 

gerg likes this

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Nice work there, Gerg.  Another reason why i put pics up on the Nugget heads, just so others can see a basic idea. Always hard to explain these things.

Good explanation as to using the hand tools, too. (Robot like) is perfect. 

Thanks bear yeah i saw your chamber work and it gave me some pointers for mine. Started taking the edge off one to see how it looks.

 

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Man.......look at the restriction to flow, before and after. Nice work.
I might see about getting it flowed if the head reco mob can put me on to someone reasonable. Being Sydney though, they'll probably want you to give up your first-born.

My philosphy is to make the most power with the least amount of cam. I'll keep my current one which is a Crow 204/214, very mild.

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Interesting......  Had a Crow 21666 and valve gear, on my Gas 351, ran sweet as. 
 
Yeah the 666 is listed as an LPG cam, funnily enough

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