I was looking for info on dual springs for my valves, as well as seats for smaller stem diameter the SS valves use. I came accross this place. These look really interesting. Dual vlve spring, SS. I don't know price yet. I guess they are rebuilds. Anybody familiar with this outfit? I am really interested in SS valves anyway, and dual springs. Et voila, here they both are, with guides no less.
Hmmmmm.....

Type Four Head
German Auto Heads Feature Our Chromoly Seats, Silicone Bronze Guides, Heat Treated Keepers, Chromoly Retainers And Chromevanadium Valve Springs. All The Heads Feature Stainless Steel Valves.
21-0426 Type IV 48 x 38 Dual Spring (each)
071-101-061D Stock W/F-Ports (each)


SACO page with type 4 heads

I posted this question at Pelican and havent recieved any response. Maybe I need to find a bug forum?

48x38.... would love to see that flow chart!

Never bought from them, never used them..

jake, please go into a little more depth with your reply with regards to the flow rate and the 48, 38, vavles.

kevin

The charge developed by the 48mm valve (and huge port that normally still isn't 48mm)fills the cylinder to the point that the 38mm exhaust valve, nor the exhaust port can operate at 75%-80%...

We have seen this so many times on the flowbench and in engines... My 2600cc engines get no larger than a 44mm intake, and hardly any intake port enlargement, just some shape work.

The 48x38 valves actually hurt the engine. Using a 48x38 valve arrangement I have seen flow numbers through the intake at 225 CFM, while the best exhaust port work would only flow 140 CFM..

More intake charge requires more exhaust charge! If you get less than 75% out of the exhaust of what enters the intake you are losing power... Consistently a smaller intake valve and port has made us more power. Thats why my 2270 C makes more power with 44x36 valves with a split duration cam than a 2600cc engine from another reputable shop that swears by 48x38 and straight pattern cam.

Bigger is NOT better.... Hell my 3.0 only has a 52mm intake valve.... Wait till you see the numbers from those heads! on the first try we got 76% of the intake out of the exhaust!

well put. thanks.

Thankks so much Jake. I sure hoped you would chime in on this topic. I don't intend to enlarge the displacement of my 2.0 at all. I don't even know the size of the stock valves I've got. Can you tell me what size you might typically recommend for a car with a slightly more aggressive cam? It's a Webcam- the "street" grind is all I remember. I think it has a bit more duration and a little more overlap than the stock cam, but not a whole lot. I've got 40 IDAs too.

is it the 494? I've got that one and am very happy with it.

MAybe, but I doubt it. I confess, it is the hydrualic one. I've really been very pleased with it. I'm not gonna go past rings and heads this winter when my kids learn all about 914 engines with me.

Can't beat 42x36 if you are not doing any port work... We flowed a set of stock 2.0 heads last Friday and they were 80% right off of a 50K mile engine.. I stay 42x36 till we reach over 284 degrees of duration @ .020 or go above 9.5:1, or break 2100ccs as a general rule..

Jake-
Thanks again for sharing your experience with me. Thats great.