Head upgrades

[losh1971]

I think some head work will benefit low and top end. Given it probably has some miles on it the valves would benefit from a valve grind plus something shaved off to also help get some more compression. I am considering a cam with stock lift but some extra duration. But that will depend on if I do the work or the garage does. I want the mech to disco the balance shaft like I requested but he failed to do during the overhaul. I reckon even just stopping the engine having to turn it will actually increase HP, even if only marginal. On a race bike we take off any gear that the engine spins, plus we reduce any weight that we can that the engine needs to drive, even dropping down a chain thickness to help HP at the wheel. Not sure if same applies to cars but on bikes any weight the engine is not driving is equivalent to 100x that in actual weight. so essentially 10 grams off the crank is equivalent to a kilo on the bike frame, IIRC.

 

[vc commodore]

Honestly Losh, I'd be thinking long term on what you actually want in the end....You've been talking S/C....Do you want S/Cing, or naturally aspirated....By thinking long term results, it will enable you to do thinks once and not throw money willy nilly on patch up areas.

ie, Heads/compression....Shaving heads, porting heads are done to suit what you are going....S/Cing requires less compression, therefore the heads only need a skim....Bumping the compression, means more shaving.....Then you have the porting to suit what you're chasing.....Get the lot done all at once....Saves too and froing to the machine shop.

This is just the start....Also don't think I'm having a dig at you.....I'm thinking of long term and the all mighty dollar that's involved....Unfortunately people get sucked into one area, spend coin there and all of a sudden, they need to upgrade that area to suit the next step they take.....

Worth considering

 

[losh1971]

Honestly Losh, I'd be thinking long term on what you actually want in the end....You've been talking S/C....Do you want S/Cing, or naturally aspirated....By thinking long term results, it will enable you to do thinks once and not throw money willy nilly on patch up areas.

ie, Heads/compression....Shaving heads, porting heads are done to suit what you are going....S/Cing requires less compression, therefore the heads only need a skim....Bumping the compression, means more shaving.....Then you have the porting to suit what you're chasing.....Get the lot done all at once....Saves too and froing to the machine shop.

This is just the start....Also don't think I'm having a dig at you.....I'm thinking of long term and the all mighty dollar that's involved....Unfortunately people get sucked into one area, spend coin there and all of a sudden, they need to upgrade that area to suit the next step they take.....

Worth considering

Yeah and this is what I need advice on. I definitely want to upgrade the heads that's on the cards. But what I do to them I really don't know. I am pretty sure a reshape of the valves and seats is a no brainer, as is some mild porting. I don't really know how much to shave off the heads I wouldn't know if 10 thou is a lot and yeah I want to keep my options open that if I decide I want SC then I can. I may be happy enough with the head upgrades and will stay N/A, especially with some 3.45s and a shift kit.

 

[afstruct]

Honestly Losh, I'd be thinking long term on what you actually want in the end....You've been talking S/C....Do you want S/Cing, or naturally aspirated....By thinking long term results, it will enable you to do thinks once and not throw money willy nilly on patch up areas.

ie, Heads/compression....Shaving heads, porting heads are done to suit what you are going....S/Cing requires less compression, therefore the heads only need a skim....Bumping the compression, means more shaving.....Then you have the porting to suit what you're chasing.....Get the lot done all at once....Saves too and froing to the machine shop.

This is just the start....Also don't think I'm having a dig at you.....I'm thinking of long term and the all mighty dollar that's involved....Unfortunately people get sucked into one area, spend coin there and all of a sudden, they need to upgrade that area to suit the next step they take.....

Worth considering

Yeah and this is what I need advice on. I definitely want to upgrade the heads that's on the cards. But what I do to them I really don't know. I am pretty sure a reshape of the valves and seats is a no brainer, as is some mild porting. I don't really know how much to shave off the heads I wouldn't know if 10 thou is a lot and yeah I want to keep my options open that if I decide I want SC then I can. I may be happy enough with the head upgrades and will stay N/A, especially with some 3.45s and a shift kit.

It's a daily save , save ,save= keep the exhaust and fit / mod a l67 .
In a daily this type of supercharger = a grin from ear to ear )

 

[losh1971]

I'm having fun working with the L27. At this stage I am happy to keep going with it for a while. I have my eye on a SC14 which I should be able to fit myself. I'm just waiting for the price to be at what I feel it's worth. So far full kit with brackets is $500 but it was $800 a few weeks ago. I'd be comfortable at $300 that way if I decided to never fit it I won't be much out of pocket.
I still have to think if I want to sacrifice economy for a few extra KW. The heads and re-gear will only help economy, I'm pretty sure so it's a no brainer.

 

[Hivisibility]

Dpepends on your determination... I know you are in Tassie, but take a holiday to the mainland and grab yourself a L67 and go from there... will be much more value in the medium/long run and reality you just need to change some wiring/Fuel pump and Memcal... and your smile will go for miles. Young fella does this sorta thing drives 28 hours there and back to get what he needs at the right price... makes a few days of it with his lady and mate.. has the best time and has the quickest P=plate car in the area at an all up cost of maybe 7K (VY S_Pac ute in black, 10 psi L67, 5 sped T box, 3.45.... ) He's owned 12 or so commodores since getting his Ls and hes just turned 19...everything he does is done on a budget and usually works out.

 

[losh1971]

So been thinking and I am thinking more about economy over HP. Plan is to still upgrade the heads but go no further on engine mods. I reckon I will get some gains with fresh heads, mild porting and valve reshape. I am pretty confident that I will be happy with the end result.
3.45s and final stage shift kit is on the cards for this year as well. I believe as far as gains and usability go this is around the limit, unless I want to use more fuel, which I have decided I don't. Gonna book in for a shift kit or 3.45s soon as i hear from the trans tech. I'm just undecided on which first. I'm hoping the trans builder might help sway my decision.

 

[losh1971]

Been looking into this some more. I found out that the machine shop I use for parts was sold last year. Good thing is it was sold to a bloke who builds race engines. I had a 2min chat to him and he said he will be able to give me the good info I need before they start the work. I think I will slip the heads off on the spare engine and take them in then have a good chat to the bloke about what he can do in the way of porting. He agreed with me that it would be good to take out less, so I don't lose bottom end to have large gains at 4k.

Still undecided as to when I will remove the heads and drop them off. I have the coin but I don't want to spend it on the ute right now as it will cost me $1500 in parts and machining, plus my new shed is not up and I'm undecided whether I go new shed or keep saving and get a builder to put the house up first and hold onto my current property in case the market takes a downturn. Thing with that is I'd need to lug the engine up home as I don't want to have it outside where it will seize.

Not sure if I will fit the heads myself my concern is trying to figure out the port alignment and getting that right if I shave the heads 15 or 20 thou. Issue will be if the manifold needs shaving and I'm not sure how to get it exactly right as I'd say even from factory there could probably be improvements.

 

[shane_3800]

If you only want to make power before 4,000rpm do not bother with the heads. Just add boost.
Toying with the head flow and cam duration will just move the torque curve forward in the rev range.
You could get a small centrifugal supercharger for not much add a real time tuning connector and 2 bar map sensor and get it tuned.

 

[shane_3800]

https://www.maceengineering.com.au/Raptor-Supercharger-Kit-To-Suit-Holden-VN-VR-V6

Just save up for that.