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Internal engine mods what to do

1K views 33 replies 10 participants last post by  PaulF 
#1 ·
well i was going to get my flywheel lightened but if they have the crank they can balance the lot and lighten for £80 i didn't originally intend to touch the bottom end.
so while its off what else can i do
Should i replace the shells?
shot peen the rods?- what is this?
i looked at forged pistons

Set of 4 Corsa 1600 16V Omega forged pistons, high compression with valve cut outs, price includes VAT (£361.70 + VAT) £425
i don't think this is a cost effective mod

Headwork is on the cards as well as an sbd exhaust
basically i was tying to do it on a resonable budget - not cheap not expensive

cams?

throttle bodies are on the cards in the long run but not as yet
basically i want do as much as a can for a resonable outlay

what are the do'sand don'ts of engines no real experiance with
them.
 
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#5 ·
you'll need to pocket your pistons to be able to use high lift cams as there is hardly any clearance in these engines, if you get omega pistons they come pre pocketed so you can run whatever cams you want, when you get your tbs you will want to do this, trust me!! the heads dont need too much work either, i got 202bhp with waisted stem valves and stock casting!
as for your crank you could get it nitrided for extra strenght but usually a balnce and some heavy duty bearings from sbd does the trick, rods are fine to 9000rpm
 
#7 ·
rod bolts, get some arp ones, have your valve guides checked, they were a weak spot other than that not alot! apart from the long inlet tract, which you can chop and change to get the filter on the other side but its hassle for no real gains, unless you go the mantzel route. how fardo you want to go? past 8500 rpm the rear main oil seal isnt too great, speak to sbd, they really are the daddies on this engine, although steve will try to sell you lots of tempting but pricy bits!! :)
 
#8 ·
also being as you are in manchester, you should speak to dave at bat motorsport in liverpool, hes probably the closest bloke to you that has good knowledge of this engine, i got my tb kit from him, he rallys a corsa 1.6 16v with 230 bhp and kevlar wide arches! www.batmotorsport.co .uk or 0151 709 8585
 
#9 ·
will do :)
Was looking at a blystein head but can i get hold of him can i feck
I know he does big valve heads and i assume he changes the valve guides and valves rather than reworking the old valves
but i keep getting a BT woman asking to leave a message
 
#10 ·
bill is very hard to reach, he was back when i did my 8v head. on the 16v you dont need bigger valves, they are already 88% of the area of the 2.0 xe, getting waisted stem variations will help flow and be lighter, which is a good thing, you just need to get it flowed a bit, if you go for mad enough cams you will need to remove a small bit of the casting to clear the lobe but you definitely need pocketed or omega pistons if you go there! i run cams with about 11 mm lift from sbd, but there are milder ones available that suit standard pistons, get vernier pulleys too if you can
 
#11 ·
May get in touch with paul ivey on the wasted stem valves - hes aprently very good

I know there is a trade off in cams
drivabilty v's peak bhp but are they really worth going for a wild cam rather than a mid range one
obviously the origainl is designed for mums down the shops etc but are they a good trade off?
 
#12 ·
the original cams are great actually, lots of torque but you have to think what you want from the engine, if you want to get more than 170bhp you will need some fairly lairy cams and pistons but if you dont then go for somekent cams with standard pistons, speak to dave, he knows the options better than i do!! before i forget, you must buy sbd cambelt idlers, they are steel with proper bearings that you have to press into place when you get them but are safe to 10000 rpm+ and after all the horro stories i've heard about these failings the extra cost is worth it, vaux do know do a later spec idler which is supposed to be better but the sbd ones are virtually bombproof!
 
#15 ·
region17rc said:
vaux do know do a later spec idler which is supposed to be better but the sbd ones are virtually bombproof!
The new Vaux ones are made from a softer plastic which stops them from shattering, but it means that they now wear out quicker. (As I found out when I had mine done last week!!)
 
#16 ·
-shot peen the rods?- what is this?
They blast the surface with shot, this puts a compressive stress into the surface which helps prevent cracks from forming. Not necessary for a 7750rpm engine.

i looked at forged pistons Set of 4 Corsa 1600 16V Omega forged pistons, high compression with valve cut outs, price includes VAT (£361.70 + VAT) £425
i don't think this is a cost effective mod
I came to the same conclusion with the 2.0 16v pistons.

You seem to be doing all the right things. The smart move is to only change/improve things that need it.
 
#17 ·
region17rc said:
you'll need to pocket your pistons to be able to use high lift cams as there is hardly any clearance in these engines, if you get omega pistons they come pre pocketed so you can run whatever cams you want, when you get your tbs you will want to do this, trust me!! the heads dont need too much work either, i got 202bhp with waisted stem valves and stock casting!
as for your crank you could get it nitrided for extra strenght but usually a balnce and some heavy duty bearings from sbd does the trick, rods are fine to 9000rpm
Wouldn't risk rods at that rpm. As for the heads not needing that much work, have to disagree. When I had my head re-worked, the peak flow at maximum valve lift was increased from 70 to 91 cu ft per minute.
 
#18 ·
hi andy, we met at corsa vs saxo day, how the car?? only said that about the rods having spoken to mantzel about them, they regularly do this amount, not even bothering to change the rod bolts!!!!!!!! mines been revving to 8500 with standard items for two years now with no ill effects, as for the head, do you have the later head with the triangular shaped inlet ports? these may be different to the early spec head i have, bill blydenstein told me not to bother with too much work on it, thats where i got the info on the valve sizes from, and i'm making 204 on a stock head
 
#19 ·
How ya doin! Yes, I do remember. Good to hear from you again. You probably haven't heard then that my Corsa was nearly written off by some moron in an old Clio last October. But the good new is that his insurance have stumped up for everything and (when I had an independent motor engineer's report done) even agreed to have the car reshelled! :)

Needless to say, I've taken the opportunity to start again - the car now has a full 16-point welded in cage and will be totally stripped out. There'll be a few other trick bits on her too and with around 80kgs weight loss, should be a bit quicker!

You're right - my head is the newer Ecotec version, but I believe the main difference is the EGR casting in the exhaust ports - these have been machined out on my engine. Rods and pistons are very strong as stock items, but personally I think 8,500rpm is right on the limit and I still wouldn't really want to risk it over 8000rpm!

I think there are gains to be had on the head, but ifn you're making 204bhp already, you've obviously got a good example. What sort of peak torque are you making, because that's where the extra headwork might show? I currently make just over 145ft/lb at around 6200rpm.
 
#23 ·
yeah, i'm only making 132 at the same sort of revs, sorry to hear about the brash, good to hear its meant a cool rbuild though! going lightweight myself on the nova, got some carbon fibre doors and plastic windows, looking for a bonnet and tailgate now, might go for fibreglass, dunno? just had to change my fuel pump, the standard one gave up the ghost on the rollers running fifty psi, got a sierra cossie one as my mapping guy reckons they're bomb proof, did you have any fueling probs? my fse regulator turned out to be pants to, got a weber one now, again on advice from my mapping bloke
 
#24 ·
region17rc said:
yeah, i'm only making 132 at the same sort of revs, sorry to hear about the brash, good to hear its meant a cool rbuild though! going lightweight myself on the nova, got some carbon fibre doors and plastic windows, looking for a bonnet and tailgate now, might go for fibreglass, dunno?
sorry to hijack here but a quick question bout the doors. whats the quality like on them?what do they come with? cheers

oh yeah www.motorsportdirect.co.uk for fibrglass goodies for the nova

thanks

rodgerq
 
#25 ·
the doors are great, better in quality than i thought they would be, you need to drill the holes for the lock mounts but the hole for the key part is already there, you also needto add the hinges and plastic windows as there is no provision for a regulator to be mounted, though you could if you put a frame inside the door but i'm going light, plastic windows it is!!!!!
they come in a gelcoat (what they coat boat hulls with) to ease the painting process and eradicate ripples, lookon www.novarally.com for pics and info
 
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