VN Production Saloon

[VNracer34G]

Block Prep #1.

Cleaned the block and on inspection decided these are some of the daggiest castings i have seen since first turning a spanner. Time for a session with my leetle freeinnd.

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small wonder these motors strangely eat themselves occasionally as a lot of the flash could be broken off with a touch of the finger, vibrations could do the same onto spinning crank/rods.

Dummied up the rotating assembly and measured the deck heights. Came out between .043" - .045" so even but low. Factory advertised comp. ratio is 8.5:1 but it works out at 7.87:1 which is pretty limp ....... good for huffers and hairdryers.

Going to have .035" milled off the decks and my Machinist Guru is going to scare up some thin head gaskets, i'll cut my own intake gaskets out of .060" material to bring the port back into line, the stockers are .120" but make a good template. We are allowed a max. of 10:1 comp and they can test at the track easily with a 'whistler' so i'm going for it with +.006" subtracted from cold deck height to allow for growth hot so if i get pulled aside for going fast it reads 10.005:1 or slightly less after a race

[Holden202T]

looking good man, got anymore pictures of the heads ported ?

i'm suprised the compression ratio is so low .... factory tollerances obviously not that good

i assume your allowed as much porting as you want by the looks of it ?

it sounds like you'll get a good motor from all the bits

[delcowizzid]

hell yeah good looking porting job there

[VNracer34G]

Thanks guys,

Holden 202 yeah when i get round to shrinking a few more that are clear.......i aint a photographer

As to factory tolerences they allways err on the side of caution and i hear that the S1 motors were actually made in Korea for GMH.

Rules state stock cam lift (why i like your idea of V6 rockers for my mates 3.3) and 10:1 comp OEM parts only, stock computer and commercially available gas - AVgas is o.k for now. no blending fuel and for efi cars stock exhaust till first join.......would love a set of SV3800 headers

[Holden202T]

yeah it ain't easy taking good photos of inside ports and chambers either!

when you say OEM parts does that mean you can use oem parts from one model on another or not ?

if you use the vn rockers on the 202, make sure you get the right length pushrods, its holden 308 i think they are .... if you need more info let me know and i can get parts numbers at home.

[VNracer34G]

Cheers man, i meant to ask before about your guideplates, the pushrod slot looks real wide - optical illusion from angle of camera or do they the ones with a bronze bush in them, sent a shiver down my spine thinking of them........had some on my 186/12port HR twenty years ago developed a clatter shifting to second at 7300 (valve float from sad springs was my soft touch rev limiter heehee ) popped of the rocker cover and found one rocker off the valve tip and working on the retainer - bloody lucky it didn't pop the collets and drop a valve - took both rockers off that cyl and pulled out the spark plug - gutless, chuffed like a train but i bloody well DROVE it home. the bronze bushes were flogged out by the pushrods - might not be an issue with the non-hardened 3.3 pushrods, dunno if the 308 ones are hardened or not but you can tell me easily - run a file over the side of one of yours away from where they run in the plate, if it slides easy its surface hardened, if it bites/cuts.....not.

This is my head on loan to 14G they're Pontiac Turbo Firebird rockers i got given (1.6) and need 7/16 studs for the fulcrum, got a broken set of comp cams ones when a BBC race motor had a failure on 1 cyl - two missing from set gives me two spares likewise the posilocks.

Barbeque & Poncho rockers

12Port rockers 1.jpg (48.29 KiB) Viewed 5904 times

as for the rules its pretty much OEM except wher it states 'make, model & year' the new rulebook is online at www.speedway.co.nz and its not out from the printers yet so big ups to them for letting us have access early so we can sort things preseason

[Holden202T]

yeah hardened pushrods and the bronze guides ... theres a slight polished mark on the pushrods where they run but the guides are nice and close, not much play at all and they've done well over 200,000kms on this head ....


ok found some more pics i had of all this stuff ...

pushrod on the left is 202 and right is the v8 one - this head has the guide plates that the pushrods run directly on!


left is vn v6 rocker, right is stock 202 rocker with an aftermarket pivot - not hard to see the difference in strength of the two.


as you can see geometry is spot on


on the left is the rocker i am using and the right is how they come off v6's


the part number for the pushrods is RP-3164 and thats sealed power brand

when i did a search i found this:

Sealed Power Pushrods Pushrod - Steel - Heat-Treated - Buick - 5 - 16 in. Diameter - 8.693 in. Length - Buick - Ford - Mercury - 231 - 252 - 429

so yeah .... go hard and i'd suggest measuring the length before you buy them, cause depending on your cam and how much has come off the head and block etc you might need slightly longer or shorter ones.

[VNracer34G]

Thanks Holden 202.

I have a slight delay with my motor, bumped into my machining guru last night and got the result of magnafluxing my crank......."more cracks than a classroom at girls high school" his words. He reckons he's onto another couple of possibles but S1 manual cranks are like rocking horse droppings. I'm now thinking i better go through the gearbox that came with the motor to be on the safe side.

[Holden202T]

better hang onto my s1 manual motor then

[VNracer34G]

Yeah man i'd hate to pay the postage from your place to mine

blocks rods etc i have a three sets , coupla blocks etc. gonna find out about the crank snout dimensions are on the GN T type buicks, if i can use one of them i can lean on it with a bit more confidence and they have the same flywheel flange - bolt circle and its OEM