Just Commodores Forum Community

It takes just a moment to join our fantastic community

Register

Porting and valves - what should I look at?

Discussion in 'VB - VK Holden Commodore (1978 - 1985)' started by synoptica, Jul 31, 2006.

  1. synoptica

    synoptica Stripping VK - PM me!

    Messages:
    353
    Likes Received:
    8
    Trophy Points:
    0
    Joined:
    Nov 22, 2004
    Location:
    Hawthorn East, Vic
    Members Ride:
    VT povpack wagon!
    Hey guys,

    Got an EFI head I'm about to get reco'd, but the guy is pretty reasonably priced so I'm looking at porting and valve work at the same time.

    I'm looking to maintain 100% streetability as it's my daily and it's not on gas - so it's gotta maintain, or improve on, current economy figures.

    As far as valves go - what should I look at in terms of size, and should I look at both intake and exhaust, or just the intake side?

    Porting is an area I'd like to try my hand at - but given I want a mild port (something just a bit better than a basic casting cleanup job), is this best left to the professionals too?

    Engine's getting EFI gear, and is on a stock bottom-end, with a reco and recurved dizzy and soon will be looking at a custom-grind cam too (again something sensible). I'm hoping for, all up, around 120rwkw out of it at the end of the day, before I go playing with the bottom end and ECU, if ever.

    So keeping all this in mind what're your recommendations?

    Cheers,
    Chris.
     
  2. vkberlina

    vkberlina VK Madman

    Messages:
    3,518
    Likes Received:
    40
    Trophy Points:
    48
    Joined:
    Mar 12, 2004
    Location:
    NSW Central Coast
    Members Ride:
    VK EFI 5L, VK 134 Pack, LX8 Adventra, MF35 & MF50b
    maybe im missing something here, your hotting up a 202 & dont want it to use more fuel, it wont happen :) ESP if your chasing 120rwkw I was pulling those kinds of figures out of my 202 and it used to drink fuel as quck as I drink a beer. Flat out I would get 25L/100, around town I was getting 15-17L/100 depending on how I drove & on a trip around 12-13L/100km.

    Basically if you port out the head with bigger ports & valves to let more air & fuel into the engine its going to use more fuel. A clean out & smoothing of the ports & combustion chambers may help a little.
    Next this with the cam whats the specs of the custom grind? make sure you get valve train to suit the cam else you wont get the added performance.

    Seriously consider other engine options any money you throw at a 202 IMHO is a waste of money.

    cheers
    Scott
     
  3. phat_com

    phat_com VR IS A BEAST WITH NEW V6

    Messages:
    764
    Likes Received:
    13
    Trophy Points:
    0
    Joined:
    Jan 9, 2006
    Location:
    Tuggers (da hood),ACT
    Members Ride:
    VR s2 Acclaim/VK IS GONE :(
    why not just sell the motor and put a vn motor in?
     
  4. synoptica

    synoptica Stripping VK - PM me!

    Messages:
    353
    Likes Received:
    8
    Trophy Points:
    0
    Joined:
    Nov 22, 2004
    Location:
    Hawthorn East, Vic
    Members Ride:
    VT povpack wagon!
    I'm familiar with at least one 110kw example which maintained a very healthy 12/100 about town - had a 60 thou overbore, porting work w/ stock valves and cam work - not sure on the specs of the rest of the valvetrain though.

    So I'm aiming for similar figures - maybe I'm a bit optimistic with 120rwkw.

    Right now, I'm running a stock Varajet with a chrome aircleaner, non-clutch engine fan (bent the clutch fan, had this as a spare) in front of an MC6 on a 3.23 - I'll be ditching the carb in favour of EFI, fan in favour of a thermo... I'll be upping the diff to a less economy-friendly 3.45 but also sticking an M76 in front of it which provides a much nicer spread... there's actually a bit of a gap between second and third with the 3.23 and the M76 - so all up, even if my mods do make the economy suffer somewhat, I'm hoping some of it can be reclaimed through this.
     
  5. synoptica

    synoptica Stripping VK - PM me!

    Messages:
    353
    Likes Received:
    8
    Trophy Points:
    0
    Joined:
    Nov 22, 2004
    Location:
    Hawthorn East, Vic
    Members Ride:
    VT povpack wagon!
    Too much money do to as a manual - I wouldn't convert to auto. Engine + gearbox + diff etc etc, adds up too quickly.

    Plus, I like the Aussie 6 - I want to keep it.

    edit: also, no wiring mods, I've already spent a grand or so on mods and the clutch on this car, I don't feel like wasting that.
     
    Last edited: Jul 31, 2006
  6. vkberlina

    vkberlina VK Madman

    Messages:
    3,518
    Likes Received:
    40
    Trophy Points:
    48
    Joined:
    Mar 12, 2004
    Location:
    NSW Central Coast
    Members Ride:
    VK EFI 5L, VK 134 Pack, LX8 Adventra, MF35 & MF50b
    An M76 wont handle 110rwkw, I didnt get out of my street with an M76 in my car. It would need some serious work to get it to handle the extra power. Your much better considering a T5 out of a V6 commodore or 6cyl falcon or a supra box.
    I doubt a 202 would make 110rwkw without more headwork, it needs more fuel & air into the engine.
    I stongly suggest in considering a V6 5 speed conversion it could be done quite cheaply I saw a written off VN 5 speed with 180,000km on the clock go for around $450, so buying a car around that price I would say for sub $1000 you could have a V6 in the car doing the work yourself.

    cheers
    Scott
     
  7. synoptica

    synoptica Stripping VK - PM me!

    Messages:
    353
    Likes Received:
    8
    Trophy Points:
    0
    Joined:
    Nov 22, 2004
    Location:
    Hawthorn East, Vic
    Members Ride:
    VT povpack wagon!
    I've got a strengthened M76 lined up. Currently handling a very respectable figure that I'll never get even close to... guy's ditching it in favour of a W58 Supra box.

    But also - there's wiring, there's the diff, there's the car taking up space... like I said, I'd like to keep the 202.

    edit: oh and I doubt I'll be able to get the Calais dash happening with the T5 or the VN EFI either... there's just 1000 little things that I'll never realise until I come across them, and probably never get around to fixing.
     
  8. gd81

    gd81 Member

    Messages:
    147
    Likes Received:
    0
    Trophy Points:
    16
    Joined:
    Aug 24, 2004
    Members Ride:
    VE SII Sv6 Manual
    synoptic
    it's all possible.
    My 202 is puting 108 rwkw through a M76 into 3.23 4pinion LSD, the M76 is still holding up fine, most of the time I'm gentle on the box, but when i'm on the track not so kind. ( I do try and be gentle.)
    The only mods i'm running are
    After market Computer, mild cam, roller rockers, hardened valve seats. 2.5" exhaust.
    You should be easily able to get the calais dash to work with the T5, just remove the speed sensor and plug in the vk speedo cable. don't know about the vn efi though.

    Remember it's your car. so go ahead and enjoy it. A lot of people nock the old 202, but a little work and they go alright. besides recently I got 12.5 k's per littre or 8l/100k's on the highway. and the efi makes it quite good to drive.

    edit, my M76 is the VH version which is supposedly weeker again. goes to show if you look after it they can handle reasonably well.
     
  9. synoptica

    synoptica Stripping VK - PM me!

    Messages:
    353
    Likes Received:
    8
    Trophy Points:
    0
    Joined:
    Nov 22, 2004
    Location:
    Hawthorn East, Vic
    Members Ride:
    VT povpack wagon!
    Three's one more reason I want to keep the 202 too - I want to rebuild it (I've got a spare). By far the best DIY first-attempt engine rebuild to attempt - and once I'm done, I'll actually have a use for it...

    So what do you think I should look at, in all honesty, for what I'm after?

    I'm going to have a chat with the cam guy, he's bloody good at what he does .
     
  10. gd81

    gd81 Member

    Messages:
    147
    Likes Received:
    0
    Trophy Points:
    16
    Joined:
    Aug 24, 2004
    Members Ride:
    VE SII Sv6 Manual
    I just went to a local engine builder who had a good rep. (Johny Dyno in Geelong VIC) Told him what i was after and what other mods the motor had, he then recommended a cam, which i took his advice and all is good.
    So Tell your cam guy what revs etc you want the motor to do, then listen to suggestions as he'll tell you what cam to go with and what mods work best with it. i.e. valve springs, how much porting etc.
    If you can afford it go to a wrecker and get a complete delco computer from a VN V6 with loom and sensors, then get the kalmaker software. That way you get a programable efi with thermo fan support. It shouldn't cost to much, as i've heard of some good results from this.
    You willl need to mod the dizzy for this.
    Remember the original control unit for the VK's is analog and can't realy handle many mods.
     
  11. synoptica

    synoptica Stripping VK - PM me!

    Messages:
    353
    Likes Received:
    8
    Trophy Points:
    0
    Joined:
    Nov 22, 2004
    Location:
    Hawthorn East, Vic
    Members Ride:
    VT povpack wagon!
    Yeah I'm interested in the Kalmaker conversion... I should probe Dave for a bit more info on it (he's the guy who had the figures I was quoting - that was pre-Delco too)...

    So get my cam done first ya reckon - or at least detemine the specs I'm after, then speak to Mr. Engine Builder?
     
  12. gd81

    gd81 Member

    Messages:
    147
    Likes Received:
    0
    Trophy Points:
    16
    Joined:
    Aug 24, 2004
    Members Ride:
    VE SII Sv6 Manual
    Determine what you're after first, then get the cam to suit, then build the motor to suit the cam.
     
  13. tigervh

    tigervh SS.....smokin....!

    Messages:
    229
    Likes Received:
    2
    Trophy Points:
    0
    Joined:
    Sep 9, 2005
    Location:
    Newcastle
    Members Ride:
    Tiger Mica EFI VH, VZ SS, XC Barina SRI
    If you're going to do head work yourself, or get some done, I would recommend you get a book called Modern Engine Tuning by Graham Bell, ISBN 1859608663. Most good motoring bookshops will stock it. Hey don't be discouraged from doing the 202, they're not the best engine availiable but they can be made to do some pretty nice things. I'd love to do an EFI one myself. Seriously though ditch the M76, I used to work in a machine shop that specialised in reconditioning and modifying manual and automatic transmissions and have administered the last rites to many of them that have come in as exchanges. The M76 boxes were origionally designed to go behind two litre fours and were later thrown behind sixes towards the end of their model life, simply because nothing else was avaliable at the time. Their components are simply not physically large enough to cope with any decent amount of torque. There's not much you can do to toughen them up. Don't waist your time and money, get a Supra box straight off and you'll never have an issue with it. Go the M76 and I can guarantee the guts of the thing will be laying on the road somewhere after your first couple of drag starts.
     
  14. synoptica

    synoptica Stripping VK - PM me!

    Messages:
    353
    Likes Received:
    8
    Trophy Points:
    0
    Joined:
    Nov 22, 2004
    Location:
    Hawthorn East, Vic
    Members Ride:
    VT povpack wagon!
    Well I just scored the uh... score of the year :D

    Chatting to a mate at work today about the car... 'I've got a rebuilt 202 sitting out back - only went for a couple of months before the car got rear-ended'... a bit of talking managed to convince him to depart of the engine for a bottle (well actually he offered it free, I told him I couldn't take it for free) :D

    TO the best of his knowledge it's just rebuilt to stock specs (well, as stock as you can do for a rebuild) - be interesting to see if it's still a virgin bore.

    Either way - it's mine and it's going in - only problem being an auto - what needs to be changed on them to get them to accept a clutch and flywheel?
     
  15. gd81

    gd81 Member

    Messages:
    147
    Likes Received:
    0
    Trophy Points:
    16
    Joined:
    Aug 24, 2004
    Members Ride:
    VE SII Sv6 Manual
    That's exactly how i got my motor. Stock rebuild with only 9000k's on it, except for gas seats and valves. Still haven't pulled of the head of it yet.
    (Yes you can change valve springs with the head still on.)
    Check to see if the rockers are nice and clean. that should give you an idea of how good a rebuild it was. i.e. if it's all black with little to no build up could be just rings and bearings. but if all nice and clean like new, then it will have been completely done, regrind/replace cam lifters, reface valves etc and maybe with a new bore as well.
    To convert to manual is easy, all you do is get a spigot bush and press it into the back of the crank, then bolt on the flywheel.
     
  16. 9898989

    9898989 New Member

    Messages:
    52
    Likes Received:
    0
    Trophy Points:
    0
    Joined:
    Jul 4, 2005
    Location:
    Tanjil, VIC
    Members Ride:
    VY 'S' Pack '03
    with the spigot bush into the back of the crank... you need to take out the auto bush first, it comes out easy if you use pliars then you can put in the manual bush
     
  17. gd81

    gd81 Member

    Messages:
    147
    Likes Received:
    0
    Trophy Points:
    16
    Joined:
    Aug 24, 2004
    Members Ride:
    VE SII Sv6 Manual
    Learn something new every day.
    as the motor i bought didn't have any bush in the crank.
     
  18. 9898989

    9898989 New Member

    Messages:
    52
    Likes Received:
    0
    Trophy Points:
    0
    Joined:
    Jul 4, 2005
    Location:
    Tanjil, VIC
    Members Ride:
    VY 'S' Pack '03
    sorry to be confusing but in the back of the crank in auto's there is a bush like thing that is in the back...

    It pertrudes out from the crank a bit and is larger than a manual bush but it does come out.. I had this problem when i did my conversion the first time
     

Share This Page