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Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine> Broken inner Valve springs Dart Iron Eagle SS Heads on Chevy 383 Stroker
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Topic Review (Newest First)
01-04-2013 11:54 AM
Hotrod1979 I found a number on the back of my camshaft but can't find info on it..

The number are:

3444
BR300-2H
11-18-02

Does anybody know what kind of cam this is??
01-02-2013 01:26 PM
BuzzLOL .. Try and buy American made heads and parts if you want yourself, friends, and relatives to have a job in the future... and if you want the parts to work well and last...
01-02-2013 12:56 PM
cdminter59
Broken inner Valve springs Dart Iron Eagle SS Heads on Chevy 383 Stroker

The heads are not the best suited for a hi performance 383 engine. I would suggest a head with 195-215 intake runners. Depends on how big of a duration your camshaft has. One way to get a good set of heads is to buy them bare and then have your machinist finish them with the springs for your camshaft. Patriot, CNC Ported Alum. Head, Chev SB, 195cc/64cc, Assm.-Competition Products or Patriot, CNC Ported Alum. Head, Chev SB, 215cc/64cc, Assm.-Competition Products
01-02-2013 03:40 AM
BuzzLOL .. Might call Dart and ask if they had a run of defective dampers... ask them why it broke... I think they take pride in customer service and their products...

.. Didn't know iron Eagle SS heads came that small... stock head size... maybe little better than stock heads... max out about 395 HP?

.. As others mentioned, if the main springs are scratched on the inside, they will fail at that spot and drop valves into the engine...
12-31-2012 08:13 PM
dogwater Spend 160.00 and get some bee hives an be done with it. Theirs no need to use a spring w/ a damper anymore, unless you really like to have your valvetrain work harder than it should. To many "new" springs to choose from these days.
12-31-2012 03:37 AM
Hotrod1979 I won't be racing with the car and I am looking for some reliable horsepower.

I didn't measure the lift yet, but if it's the wrong cam I will replace it

What would be the best cam for these heads in a 383 stroker? And what kind of horsepower will this produce?
12-30-2012 08:03 PM
tresi Those heads are basically a more reliable stock replacement head. Of course it would had more power with a larger runner head. The question is does your combo have enough power to please you verses what you budget will allow. If you're just making a nice ride with some more pep than a stock motor many people will be pleased by a 383 with mild cam and the usual bolt ons. If you will be doing any racing there is a lot of power to be found with larger heads with components to match.
12-30-2012 04:45 PM
Hotrod1979 I checked the heads. They are Dart Iron Eagle SS heads.

76 CC chamber and 165 CC runner.

Isn't this far too small for a 383 stroker??
12-30-2012 12:39 PM
Hotrod1979 Thanks everybody for the advice. I was lucky to discover the broken dampers on time... I will first try to find out what kind of Cam I have got.
12-30-2012 06:57 AM
gearheadslife
Quote:
Originally Posted by techinspector1 View Post
This is the kind of thing that makes you want to go back and beat the snot out of the guy who assembled the heads. He had no business putting his hands on them. Makes me wonder what else is wrong.

thats not really fair, most any thing you'll ever read, only says match the springs to the cam..
tons of guys will buy a cam/lift/springs out of summit, not knowing anybetter,, because nothing they've ever read, said anything about the spring seat.. most times it's coil bind/seal clearance/etc
not spring dia. to spring seat..
only one in the car mag world I ever see say anythign about it was jeff smith..
and face it 75% of the guys in the hobby, car mags are what they read for "tech"
then they do a cam swap.. and because the guy on the tech line at jegs/summit sent him "matching springs" he thinks it's all good..
not knowing anybetter..
12-30-2012 01:53 AM
cobalt327
Quote:
Originally Posted by Hotrod1979 View Post
Thank you for your reply. Looks like the Dart heads are stock. Are you sure this is why these springs failed?

I will take one spring out and do some measuring...

I am not sure what kind of cam I have got..
I'm not convinced that the spring seat size was the cause of the dampers breaking. Might be third or fourth on my list of probabilities.

Not knowing anything more than what you know at this stage (which is limited until you can dig further), I suspect floating or lofting the valves. This can happen even at lower than expected rpm if the springs aren't right for the application, or have a too-tall installed height, or are faulty from the factory, etc. Besides the pounding the springs take when that happens, this also sets up harmonics that can break dampers and springs (spring surge). That has been associated w/dampers breaking, and I have had this happen on engines w/insufficient valve spring pressure for the rpm/cam profile being used. 1.6 ratio rockers can magnify this.

In any event there's MANY things that could cause the damper to break, not just the spring seat size. Even a bad batch of spring dampers can cause it, like I went through with the K-Motion springs I was using a while back. They finally redesigned the damper (has a reverse coil from the old ones) and problem solved.

Spring locators:
I prefer to use an ID spring locator. But regardless of what you use (spring cup or an ID spring locator sized to the guide boss), the spring locator HAS to be a close fit to either the guide boss OD or the ID of the head's spring cup, else you're no better off than you were with no locator, period.

The MAIN thing is to have a spring that's spec'ed for the cam and rpm, and to not exceed the redline. If you can do that, you can leave the locators on the shelf.

See:

Valve spring installed height
Points to check
Geometry
Adjust lifters
12-29-2012 05:01 PM
tresi Since you don't know what your cam lift is you are going to verify that your spring you plan on installing are suited for your cam. If your lucky you might find the manufacture and grind # on the end of the cam. If this info is there it will be a simple manner of contacting the cam manfacture for the correct springs. You will still have to insure that they are intalled at the correct installed height and that you have no coil bind. The retainer to guide clearence should have been checked by the person that built the engine but since you're having problems I'd double check everything.
If you can't verify your cam you'll need a dial indictor and check your lobe lift and mutiplt this figure by the rocker arm ratio to get your vavle lift. By know this and the type of lifters you have ( hyd., flat, solid roller, hyd roller) then you can go shopping for springs.
12-29-2012 04:49 PM
techinspector1 This is the kind of thing that makes you want to go back and beat the snot out of the guy who assembled the heads. He had no business putting his hands on them. Makes me wonder what else is wrong.
12-29-2012 04:08 PM
MouseFink You can see in the photo that the valve spring seats are too large for stock valve springs. A stock single valve spring with a damper is 1.265" O.D. to 1.300" O.D. and those valve spring seats are at least 0.200" larger in diameter.

A spring that dances around on the seat at high RPM due to spring seats that are too large will fail. That is probably the #2 reason why valve spring fail. The #1 cause is coil bind or inadequate assembled height for the valve lift your cam has.

You may have both problems if you do not know how much valve lift your camshaft has.
12-29-2012 02:36 PM
Hotrod1979 Thank you for your reply. Looks like the Dart heads are stock. Are you sure this is why these springs failed?

I will take one spring out and do some measuring...

I am not sure what kind of cam I have got..
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