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Clevo120Y

Chris's crossy head

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Well I have the pleasure and opportunity to develop a head for Chris's Cortina, already a very serious engine and produced very good numbers already. He sent the head and aussiespeed manifold down and I run some flow tests and took some pics for comparisons of before and after work, the head had already been ported by someone else and I was keen to see what he had done, the port flows OK but I'm very confident of finding some good gains throughout the lift range.

The valve sizes in the head are 1.84in intake and a 1.6in exhaust and we will stick with those sizes, unfortuanetly the valves and springs in the head weren't what he was told they were, the valves in the head were an EVL 3 groove item for both the intake and exhaust and the spring pressures were measured at 114lbs seat pressure, Chris was told differently and lead to believe he had better quality items installed, also the springs were installed with a flat washer shim which I don't recommend, either an internal or external locating unit should be used. The valve seats are a form I personally wouldn't use, they are a 45 seat with a radiused bottom cut, I prefer multiple sharp angles for better fuel atomisation and flow at the valve seat so this will be recut also.

 

Intake Flow figures for this head are

 

50                   28.37

100                 58.21

150                 92.13

200                 117.51

250                 143.38

300                 166.34

350                 181

400                 193.51

450                 198.82

500                 203.6

550                 199.19

600                 198.18

650                 196.5

 

The main problem with the results are they start to fall over well before Chris's cam lift of 600thou. As I said the results are OK but not as good as I was expecting before I got the head. The Exhaust port is untouched but I will do a little work in there also. The other things that let the job down is poor match porting to the head with both the thermal insulator and also the gaskets hang in the port etc etc, it's just little details but they are the things that matter to me that show pride in a job. Anyway that's the past and we are looking forward with a few upgrades with the head and work on the manifold as well as a new set of headers :)

Here are some pics of the head and I will start work on this in the new year.

 

SAM_3188_zps210bb113.jpg

SAM_3187_zpsdb03b45e.jpg

SAM_3179_zps44a333a4.jpg

 

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Good thread bro...Good to see the approach of your quality control.Chris's engine did make some very serious numbers which shows the promise in the 250 aswell so your work will only compliment that.

 

Have you guys settled on a cam and style yet...IE roller or solid?

 

Keep the updates coming and good luck with the rest of the work.

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That valve seat is a joke in a performance application.  anyone who is anyone knows that the valve seat is where the most gains in airspeed are had.  The head seems to have had a lot of work on the high speed side but the mark from the gasket shows that there is a big step on the low speed side - I like a step there but only about 1mm.  that looks to be 2mm or it could just be that the gasket is not locating properly on the port face. 

The cross sectional area just past the bowl looks out and the short turn doesn't look that good - bit hard to tell from the photos.  The flow figures are also not that impressive - but that could also depend on the money outlaid for the port work and I guess that is what is important to remember here. 

I don't know what the head cost or what the design brief was so I shouldn't sledge to hard BUT simple things like valve spring locators, correct valve spring tensions, valve seat cut, 'port matching' and giving the customer the parts that they paid for SHOULD be a given. 

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Good read those number taken  at 28 or 32?

Its amazing how much numbers can be made with such a basic head 

I got told by who that has not been named that he did 340fwhp with a head that flowed 2cfm more then a standed head. funny most engines get there numbers out of a good heads these engines make numbers just cause they look cool in cortinas :D

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That valve seat is a joke in a performance application.  anyone who is anyone knows that the valve seat is where the most gains in airspeed are had.  The head seems to have had a lot of work on the high speed side but the mark from the gasket shows that there is a big step on the low speed side - I like a step there but only about 1mm.  that looks to be 2mm or it could just be that the gasket is not locating properly on the port face. 

The cross sectional area just past the bowl looks out and the short turn doesn't look that good - bit hard to tell from the photos.  The flow figures are also not that impressive - but that could also depend on the money outlaid for the port work and I guess that is what is important to remember here. 

I don't know what the head cost or what the design brief was so I shouldn't sledge to hard BUT simple things like valve spring locators, correct valve spring tensions, valve seat cut, 'port matching' and giving the customer the parts that they paid for SHOULD be a given. 

 

I can tell you now that head cost me $1950 plus parts and 2 date it owes me $3500 and thats with 2 different people working on it not just one. I am extremely saddened by wat it flows but I should say I have always known they were multigroove valves but I was under the impression I had 1.86in and 1.56 ex.

The work Shaun is doing now coupled with all the new valve train will make it an easy $4500+ Head but with the power it made before coupled with the new work it shall be singing. A big thanks to Ando76 as well who is providing help and advice in the background.

Sly im gonna stick with the same solid cam. I really loved the way it drove and sounded before. Hopefully the EDM lifters will help it last this time around.

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Um I don't know what to say to that Chris except sorry to hear.  At least this time around it will work and with the Isky lifters you will have great, consistent oil pressure and no worn lobes.

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Um I don't know what to say to that Chris except sorry to hear.  At least this time around it will work and with the Isky lifters you will have great, consistent oil pressure and no worn lobes.

 

Perfect thing to say dude. For an engine that has made the power it has the only thing that has let it down is consistent bad oil pressure. Hoping for an engine that lasts more than 800kms this time which is its record not to mention the looks it gets from 60k cars that get blitzed lol

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Those numbers are pretty good up until 0.5" lift and with a basic tidy up will be even better (compare the 0.35" lift with some others here). Value for money may be questionable, but don't be too disappointed Chris.

 

Also remember that the cam should lift beyond the peak head flow figures (because you are not at max lift for long) otherwise your cam is too small.

 

The step at the bottom may be fixed by making sure the manifold is all the way up when you bolt it on. I wouldn't be taking too much material from that area, you'll end up with massive ports for little gain.

 

I am sure it will come out great.

 

If you guys get 212@0.5" without a big cross-section and can maintain it to 0.6" it'll be a weapon.

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your spot on Matt re Cam and peak lift and not destroying the low speed side.  Clevo120 got 212cfm @500 with his speedway head (xflow porting thread) so I'm sure his rework of Chris's head will go as good if not better. 

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Thanks guys, if the port doesn't go 212+ I would be very disappointed. My approach as always is looking for port stability, I believe that when a port is stable the flow figures will follow. Also I personally think that attention to the manifold will be the big payoff. I will be starting this head just after new years and I will keep you guys updated.

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Hoping for an engine that lasts more than 800kms this time which is its record not to mention the looks it gets from 60k cars that get blitzed lol

Fingers Crossed its a constant runner after this and no need to do any rebuilds.

I do about 800km's a week in my Cortina. And this fastest/reliablest/daily driven Cortina award that i been carrying is getting bloody heavy. Come take it off my hands Chris.

 

Mine let me down a bit today, heater core went and spilled coolant all over the road in Mandurah. whipped out screwdriver and plumbed the in/out hoses into each other.. and looped the heater onto itself. slipped into supercheep for coolant. and hey presto problem solvered. Dont even know why i plumbed the heater into the equasion.. i never used one in my life in a Cortina.

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Fingers Crossed its a constant runner after this and no need to do any rebuilds.

I do about 800km's a week in my Cortina. And this fastest/reliablest/daily driven Cortina award that i been carrying is getting bloody heavy. Come take it off my hands Chris.

 

Mine let me down a bit today, heater core went and spilled coolant all over the road in Mandurah. whipped out screwdriver and plumbed the in/out hoses into each other.. and looped the heater onto itself. slipped into supercheep for coolant. and hey presto problem solvered. Dont even know why i plumbed the heater into the equasion.. i never used one in my life in a Cortina.

Challenge accepted Tim LOL when you eat Chris's dust then I can do the work on your new setup to catch up again hahahaha

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So out of interest I flow tested the thermal barrier spacer from aussiespeed that goes between the head and the manifold, 215cfm it flows at 28in, this is great for everyday to mild engines but starts to be a restriction when you start chasing more power, I will be opening it up just slightly to flow a bit more but still keeping the airspeed up, the trick is to open it just enough to flow enough for the purpose plus a little head room, the joys of having a flow bench, I can open it up to flow 230cfm without making it too big. I will be doing this for both Chris's and Slydogs spacers. I know that Slydogs was used on another engine and would have been a restriction to his head flow figures.

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so how much material will you be removing from the high speed side of the spacer - my guess would be .040 - 060" and probably .020 from the low speed - but I'm just an amateur without a flow bench.  lol.  keep the posts coming. 

What is the diameter of the port of the spacer out of curiosity???

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