Here is what is required to get some decent springs on your iron heads if youre looking to take advantage of some aggressive cam profiles. These modifications will allow the use of some very aggressive lobes that traditionally werent used or possibly they were mis-used on our engines because the spring pressures were inadequate. Some figured this out years ago and the performance of their cars reflects their knowledge. First inner spring location is achieved, then guides cut for .500" metal clad seals for inner spring clearance, then assembly with titanium retainers and machined steel locks to leave the most possible room for installed height. We are at the mercy of coil bind and the extra lift is a product of the aggressive ramps. These modifications will set one engine well ahead of another if the turbo and cam profile/timing are in check. Were not talking a few hp either. Increased average cylinder pressure across a broader range without adding in extra overlap down low, more cylinder pressure at low rpm from reduced overlap so spooling is better, and of course huge increases in duration from .200" up which will raise the usable power band. This is what fills the cylinder and makes power. I can provide this service as well as spec cams/springs that will work ideally with these modifications and support the rest of the combo. I can alter aluminum heads for these types of springs also. In some instances for really crazy builds the valves need to be replaced for taller ones to be able to run larger spring packages and avoid coil bind. Pushrods may need to be upgraded and pushrod to head clearance verified. You find out the cam specs after i send you the cam which comes with complete analysis and installing recommendations. So please do not ask for cam specs here.
I'm definitely interested in finding out more about this service(and Cost) as well as having you spec a cam & Turbo combo. Please let me know so I can start budgeting for this to happen in the fall/winter.
Is it best to start with a set of Champion iron heads due to any of the characteristics of the port work that you favor or do you tweak a set. I have read much about the flow @ x lift being more desired. Would we send in our turbo for evaluation as well?
Is it best to start with a set of Champion iron heads due to any of the characteristics of the port work that you favor or do you tweak a set. I have read much about the flow @ x lift being more desired. Would we send in our turbo for evaluation as well?
I don't evaluate cylinder heads flow potential except on my own cars. Champion has very consistent flow. I've seen many other good sets of heads also. You would send me whatever heads you needed altered. You could send in your turbo also. Pm if interested.
Coil bind is when the spring is fully compressed and the coils are stacked. You would see a lot of potential performance with an aggressive cam grind that opens the valves much faster and makes more power. The heads should look very familiar to you.
Its easy to get clearance for .600 lift just by cutting the guide down a little but being able to get a high rate spring on there that can control an aggressive valvetrain is a little more work and you are still at the mercy of coil bind with the shorter valves most heads have. The cutter used to locate the inner spring is a custom piece i had made. All else is straight forward if you have a common .500" cutter and a way to measure the spring pressures accurately. I pretty much use springs that i go backward from my distance from coil bind when making a selection. I always run them tight. The tighter the more stability and spring life.
Good write up Brian! I may have to get in contact with you on pricing and turn around time on this. Had to go with a smaller camshaft for the time being just to get my car up and running due to springs holding me back as we spoke about.
Bison
Are 1.65 RR necessary or can 1.55's work?
and thanks for all of your technical info throughout the years.... can you PM me pricing for this... and IYO is this race only territory or would it just be as suited for a BadAss Street car.
Bison
Are 1.65 RR necessary or can 1.55's work?
and thanks for all of your technical info throughout the years.... can you PM me pricing for this... and IYO is this race only territory or would it just be as suited for a BadAss Street car.
The rocker ratio is used to maximize the potential and prevent coil binding in some instances. It depends on the cam lobe. With the craziest cam id ever spec for an iron headed application or any application that uses the standard length Buick valves a 1.55 ratio is required and the lift would be around .600". Remember we are at the mercy of lift here. Were not necessarily looking to increase lift. We want to increase duration at higher lifts and minimize duration at low lifts. Then its just a matter of timing the ex opening/closing in the correct spot and selecting a large enough intake lobe to support the intended rpm. Youre welcome for the info. As far as saying race only id say no. Using these types of lobes requires better valvetrain components but actually reduces overlap at low rpm comparatively while achieving the same or usually better cylinder fill. In reference to duration @.050" i could spec one with 206 at .050" that will crush the common 212 @.050" that you see frequently posted about and we already know that 212 works really well. The aggressive 206 intake could be run with a larger ex lobe on it to get the EVO sooner and really make some power if the turbo isnt causing a backpressure issue and overlap still will be less. More cylinder pressure for spooling Increased CR always helps push all the crap out of the cylinder too. The ex stroke is very important. Ill PM you the price for the modification.
