Printable Version of Topic

Posted by: bd1308 Nov 20 2006, 11:36 AM

I found some heads that I think I may purchase, they have dual springs though. Nice stainless valves, but doesnt dual springs put alot of pressure on those valves?

Posted by: URY914 Nov 20 2006, 11:43 AM

Well it sorta depends on the spring rates doesn't it?

Posted by: Brando Nov 20 2006, 11:45 AM

Usually your cam profile determines if you need dual springs or not...

That begs the question -- what else has been done to these heads? And why no pics?

Posted by: Joe Ricard Nov 20 2006, 01:37 PM

You will never rev your motor high enough to warrant dual valve springs.
SO you are just pissing your money away and actually making more internal drag on your motor.

Posted by: Aaron Cox Nov 20 2006, 06:50 PM

the weight of your valvetrain (lifters, pushrods, rocker arms, valve adjusters and lastly valves) along with cam profile determine spring rate...along with desired RPM range....

heavier components and pyscho cam profiles need bigger springs to keep stuff from floating

Posted by: bd1308 Nov 20 2006, 06:58 PM

they look blue in the combustion chamber.

Whatever that means.

If i got them, could I just swap springs out with new other ones?

Posted by: brant Nov 20 2006, 07:00 PM

this is not quite accurate.
its not all about rpm.. more about cam profile combined with rpm.
my old 2.0/4 had and needed dual valve springs, yet I usually shifted at:
6250-to -6500rpm

brant

Posted by: Aaron Cox Nov 20 2006, 07:01 PM

brant, what cam? and what kinda spring pressure?

Posted by: brant Nov 20 2006, 07:05 PM

I don't think my builder would want me to divulge the cam specs...
and I actually don't know what the spring pressure was.

I can tell you that the heads included titanium spring retainers with about 8 hand drilled windage holes in each retainer...

stainless thin stemmed valves of 38/48 diameter.

brant

Posted by: bd1308 Nov 20 2006, 11:21 PM

Guys, Trust me.

I dont NEED dual springs. that wasnt my point. I wanted to know if I could change them back to OE spec.

Posted by: brant Nov 20 2006, 11:26 PM

most likely unless the head was machined to accept them.

I agree though that if someone put dual springs on those heads you should look carefully to see what else they did. Porting is really an art form that can ruin the streetability of a set of heads when "practiced" by an amateur.

brant

Posted by: bd1308 Nov 20 2006, 11:35 PM

The heads are blue


Attached image(s)

Posted by: SGB Nov 20 2006, 11:40 PM

They look pretty Krazee (give 'em a glowstick, everyone loves glowsticks)!
Actually why not try 'em at least. Dual springs might allow you to rev a little higher. Where the magnafluxed- or is that possible with AL alloy heads? They look preety kleen! Really, someone thought it was better.... Are the valves stock?

Posted by: bd1308 Nov 20 2006, 11:48 PM

Well see thats the thing. They were advertised as 2.0 914 heads, but they do not have sodium valves, which means theyre stainless?

Posted by: Brando Nov 21 2006, 12:10 AM

Looks like stainless exhaust valves to me.

Makes you wonder why they didn't install stainless intake valves as well though.

Posted by: bd1308 Nov 21 2006, 12:36 AM

Thats what I was wondering too.

Posted by: messix Nov 21 2006, 12:43 AM

dual valve springs were used to avoid spring harmonics, so insane high spring rates wouldn't have to be used.

new tech springs are better and engineered for harmonic suppression. [beehive valves are an example]

Posted by: Mueller Nov 21 2006, 01:04 AM

Brando,

I'd guess they re-ground the intakes and replaced the exhaust with SS due to either cost ($15 each instead of $80+ each for sodium filled) or that some shops will not touch/re-grind sodium filled valves. Adding new intake valves would have driven up the cost and maybe they had spent too much already....

Posted by: sportlicherFahrer Nov 21 2006, 03:24 AM

Any other pics of those heads? To me they look like 1.7 or 1.8 heads. The spark plug hole angles look off for a 2.0. Looks like they are more upright.

Posted by: Brando Nov 21 2006, 02:07 PM

I dunno, it doesn't make sense to me to spend that money for installing dual springs, new guides for the exhaust valves, new exhaust valves and not spend the extra $50-$75 to do the intakes?

Posted by: Bartlett 914 Nov 21 2006, 03:09 PM

I can't believe thy are 1.7 or 1.8. They do have 3 studs and not 4 stud. Any numbers on the heads? They look a nice find.

Posted by: Joe Ricard Nov 21 2006, 03:17 PM

For some reason I just knew which heads you were talking about.
FYI I passed on them myself. Didn't feel confident about the rebuild.
After listening to JAke and Len talk about how many heads have valve seat just fall out when heated in an oven.

Only heads not suspect are mine. 60K + miles on them and still hanging in there.

But LE 200 heads are the only thing I would pay money for.

And did you notice thatthey are not matching. one is early 2.0L and other is late with a air injection port.

Plus I swear I see a crack originating from the upper right cylinder spark plug hole.

Posted by: Bartlett 914 Nov 21 2006, 03:56 PM

Everyone keeps scaring you about loosing your seats. I don't know it this will hurt them but remove the valves and put the heads in the oven with the turkey on Thursday. 325 350. Then you will know. Then let them cool slowly. Little worried about warping them. Maybe someone else with experience can say. That or just run them.

Posted by: Joe Ricard Nov 21 2006, 07:00 PM

The guys wanted 600 or do dollars for unmatched heads with a bunch of blue shit all over the combustion chambers can't see shit.
no head studs no rocker studs I bet there are no exhuast studs. Not to mention the condition of the exhaust sealing surface.

Still wanna buy them?

Posted by: bd1308 Nov 21 2006, 07:07 PM

I think i'll take my chances with the 'blue shit'

I'll buy them and take them to get looked at.

Posted by: SGB Nov 21 2006, 07:56 PM

I think they are 1.7 heads also, but that in itself may not be deal breaking. $600 is pretty cheap. Cracks should prob be deal breakers though. They are set up for 2.0 intakes, but I dunno - isn't exhaust different also on 2.0? I also think they are mismatched by year, but is that a crisis?

Posted by: bd1308 Nov 21 2006, 08:58 PM

I'm not seeing the whole 'this is a 1.7 head' thing.

call me stupid, but those valves look large. I'll be looking at them this week sometime maybe.

If they are 1.7 heads, then i'll pass.

Posted by: Aaron Cox Nov 21 2006, 11:52 PM

brit,

i have the head tool you use to compress the springs, pull the retainers, and thus pull the valves out...

then you can try and clean up the combustion chamber of blue goo and look for cracks...

if you want to borrow the big head stand, let me know.

AA

Posted by: Type 4 Unleashed Nov 22 2006, 12:24 AM

Is this a Generalized Insinuation, or did you have some one in mind ?

Hey B, spring pressures can also be determined by cam lift, example: Springs will have X amount of pressure at .465" lift, the same springs will have X+Y amount of pressure at .500", have the spring pressure check for the cam you want to run.

Installed height will also determine spring pressure, and as some one mentioned dual springs will have better harmonics than singles.

OH YEA, and those heads look like BUS HEADS

Posted by: McMark Nov 22 2006, 01:35 AM

Those are definitely 2.0 914 heads. They are definitely mismatched (early/late). I'd be worried about the air injection ports in the late head. Could cause problems. The dual valve springs are a waste. The price makes them hard to pass up. The rebuild is definitely questionable. It sounds like they've had about $250 worth of work done to them. I would pass on them and find some cores to send out for REAL rebuilding.

Posted by: bd1308 Nov 22 2006, 07:48 AM

Mark, thats my general feeling.

They're shiney, I'll at least check them out. Good eye on the mismatch, I didnt notice that.

The guy said the blue stuff is gone.

Posted by: Jake Raby Nov 22 2006, 09:22 AM

Carb cleaner will remove the dykem...

Don't trust anything just because it's shiny..

Anyone that "Rebuilds" these heads without changing the seats is not very smart..

more than 80% of heads lose their original seats with flipped upside down in the oven at 400F and just fall right out.. I want to try to rig up a camera to record this and show you guys just how real it is..

The fact that the intakes are reground also tells me that more than likely the stem heights are going to vary greatly between intak ane exhaust valves.. Thats no fun when doing valve train geometry.

Posted by: bd1308 Nov 22 2006, 11:43 AM

Sounds like too many questions for the price to be right.

Last thing I want is to build a engine, and be on the side of the road with nothing.

Posted by: Joe Ricard Nov 22 2006, 02:23 PM

Learning well you are Young Jedi.

Best you could do is make the deal with the guy to inspect the heads and opt for full refund if they are junk. and all the studs must be included.
Have you priced studs yet? Holy crap!!!!!!!!!!!

Posted by: Brando Nov 22 2006, 02:46 PM

Get some inexpensive rebuildable heads, send them to Jake's head guy, pay the $800ish, and you're set.

Posted by: McMark Nov 22 2006, 11:45 PM

In the long run, this is a good choice. Glad to see you looking ahead.