jerking spluttering vts 16v skimmed gasflowed head. (pics) - Saxperience

spencer_cammedvts · 24th November 2007, 09:11

been a lot of questions lately about porting and skimming so thought it may be relevant to post a few pics up.

Im running 708's. ideally with 708's you want to skim the head so that its a certain measurment. strip the head down and get a vernier on it to measure the thickness of the head. you measure from the face of the head (where you will be getting it skimmed) and the top of the head where the cam ladders bolt down to. as standard this measures just over 135mm. about 135.2mm. on 708's the maximum you can take it down to safely is around 134.7mm (id say)

so if you havnt had a skim before you can take 20 thou off but obviously its less if you have had a skim before. mine now measures bang on after i had it skimmed yesterday. i got 8 thou taken off and it now measures 134.8mm

this will give me a further 4 thou to be skimmed if anything goes wrong again. if anything goes wrong after that them im fcuked lol
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as you can see my head is ported/gasflowed. i did this myself but only as i know a few trade secrets such as optimum port sizes for different sized valves. as you can see in thepics. the exhaust ports are polished to a mittor finish and the inlet are left ribbed. just thought id post a few pics up as pics allways make threads a hbit more interesting.

iv also got a set of brembos on and have just bought the xantia disks off that site provided but iv done a little extra

drilled them out myself. they dont look too bad do they? lol

spencer_cammedvts · 24th November 2007, 09:12

any comments welcome!

jeeves_101 · 24th November 2007, 09:30

looks alright too me mate.

did you do the skimming to, or was that done else where?

Toad · 24th November 2007, 10:08

Nice. Put a new camera down on your xmas list matey.

Looking at those measurements, you really increased those exhuast ports! Impressive stuff.

Did you do anything with the inlet / exhaust ports? Looks like you are still using stock valves, so suppose you didn't widen them at the entrance points... Did you shave down the valve guides?

spencer_cammedvts · 24th November 2007, 10:08

ner i paid for it to be skimmed mate.

spencer_cammedvts · 24th November 2007, 10:14

i know i need a new camera mate. lol its shite! well its good if you can keep it still lol.

yer the exhaust ports are far too small as standard and also its hard to know how thick the walls are between port & water jacket. think it will be ok though. inlet ports arnt too bad as standard, although there isnt much point in opening them op much wider than the inlet manifold

yer i widened the ports at the seat slightly. cant do it too much though as you need enough of a seat to get a good seal. (as you will know mate)

spencer_cammedvts · 24th November 2007, 10:17

exhaust ports are now 39.5mm andthe inlet ports all now measure 48.25mm

AliC · 24th November 2007, 19:32

Good one m8, should help me out when i go to get mine done!

jpsaxo · 24th November 2007, 20:20

Quote:

Originally Posted by spencer_cammedvts

exhaust ports are now 39.5mm andthe inlet ports all now measure 48.25mm

What are they standard?

Good thread mate

spencer_cammedvts · 25th November 2007, 10:55

i did measure them but iv forgotten lol

jpsaxo · 25th November 2007, 11:37

Lol, that no use is it

You going to see how she runs with this head? then get a tweak in the map if needs be?

spencer_cammedvts · 25th November 2007, 13:51

yer gonna get a tweak in the new year mate. xmas is too close now. might see what other performance parts santa brings mee too

*cough*stand alone*cough*

lol

The_Notorious_C_A_T · 25th November 2007, 17:08

Why did you drill your disks bud?

jpsaxo · 25th November 2007, 18:44

Quote:

Originally Posted by spencer_cammedvts

yer gonna get a tweak in the new year mate. xmas is too close now. might see what other performance parts santa brings mee too

*cough*stand alone*cough*

lol

Hate to say "i told you so"

Burnout_vts · 25th November 2007, 19:25

can't see the pic's: ...Burnout_vts, you do not have permission to access this page.....

hmm

Toad · 25th November 2007, 22:28

Nice mate. Good work I reckon.

Dibz · 25th November 2007, 23:05

The work looks good! Shud give some nice gains. I want to get my exhausts ported when i get some headwork but the porting is what costs the big £

Shame i cant do it myself...

AXracing · 25th November 2007, 23:20

You get what you pay for. When you pay £1500 on say a longman race head you don’t get anything similar to what most people do DIY. Even a basic head from a good PSA tuner will have a lot of development gone in to it. Even a relatively skilled DIY tuner with a good basic understanding of what they are doing will be very lucky to get good gains or in some engine they will be lucky not to loose power. Some of the PSA engine for example are odd in that ports were made to large and power is gained from totally reshaping them and actually making them smaller on the head face.

spencer_cammedvts · 26th November 2007, 08:35

after fitting everything any putting it all bakc together again. it doesnt run right! on idle its really wavey and when you put your foot down it pops & bangs & splutters!

it sounds like a sensor problem but which could it be?

Toad · 26th November 2007, 08:45

LOL, endless problems mate! I don't know what to suggest. Have you missed something when putting everything back together?