CB Ultra Mag head, snapped spring

[Stefan Rossi]

Hello, need some advice, again...

Ive just stripped, inspected and replaced a broken pick up pipe on my 2276. Ive put one head on already and upon leak testing the other head for fitting I noticed this....



Can you see the discolouration? Looks like maybe heat damage and the spring got brittle? Tight valve? I just did the tappets at 002" before 1000 miles at spa the other week... Spring snapped is No4 exhaust...

Does anyone know if the valves fitted in Ultra Mags are VW OD or Chevy OD? Im sure they are VW OD? I want to replace the spring but not sure which set to buy, don't want coil bind ect ect... CB site says they are dual super rev springs but they don't actually have them advertised? I dont know if they are their VW650 springs or their 1491 - Dual Valve Springs

I want to buy the correct springs or even better springs but not sure which ones. There is a set of GB273A springs for sale on VZI but cannot find any info on these on GB's site?

Also I'm right in assuming I should take the other head back off and replace all 8 springs at the same time?

Thanks, Stef

[Torben Alstrup]

Ultra Mags come with 1491 springs.
I believe the only version that is standard supplied with VW650´s are the Utra Wedge.

Do you have an FK 40 series cam in there ?

T

[Stefan Rossi]

Sorry, my cam is fk89

Stef

[Torben Alstrup]

Do´nt be  I was just curius.

Check your valve train geometry. just in case.
You might have overreved it or just had a bad spring.
T

[Andy]

I am in the middle of repairing my 044s,at the moment.

I was told the CB1491 springs that come with the heads are good for 0.520" lift.

I think too much lift and the age of my springs were my problem so I am going to use the CB1493 '650' springs.

To use Chevy springs, I believe you have to fit longer valves, I stand to be corrected though.

[nicolas]

i would replace all the springs just to have a new staring point. if these springs were already used in a different engine (different cam) i would change them anyway as i believe the spring 'set' themselves to the cam they have to work with.

[ED2.4]

Hi,
it's not a new that 1491 springs are not recognised like a top notch product ...here ,we systematicly swap them by others each time on 044 heads,too much trouble/issues on HiPo engines with them,
change all of them for a proven set of springs like vw650,Bugpack 4047,etc...Berg are good stuff but they have a very long coil bind length (about 24mm)

[leec]

When I bought my wedgeport heads from CB the springs fitted gave me no where enough to run the FK87 I wanted to run and needed mods. I understand that you should never just bolt on heads and assume they will work but why can't CB supply these heads with proper springs (top quality) as it would be a fair assumption that if you buy Ultra mags/wedgeports that your lift at the valve is going to be more than an engle 110!

Lee

[Stefan Rossi]

Thanks for all the replies. Ive checked all geometry and its all fine, they open the valve okay without coil bind. I guess one just got weak and snapped or maybe I messed up on that tappet clearance. 

Either way from what ED said ill change them all out for some vw650's.

To run chevy LS1 springs I'm pretty sure you have to modify the head to take the larger OD of the chevy spring...

Stef

[richie]

I would put CB vw650's in there,I dont know how you manage to get those springs[1491] to work with a fk89,thats way to much lift for them in my opinion,you can set the 650's up to a max 630 lift and I usually see about 600lift with a fk89 and scat rockers so add a shim under them on 044 wedgeports

cheers richie 

[Stefan Rossi]

I have 5 shims under the rockers. They are CB rockers if I remember correctly. That setup has been working fine for the last 4000 miles. Spring just got weak?


so 650's, one shim, check geometry, should be good to go?

Do you stock these springs richie?

[richie]

I have 5 shims under the rockers. They are CB rockers if I remember correctly. That setup has been working fine for the last 4000 miles. Spring just got weak?


so 650's, one shim, check geometry, should be good to go?

Do you stock these springs richie?

I was talking about shims under the spring base,not under the rockers,with that much shim under the rockers you might have longer than normal valves in the heads,did you buy them new? its not geometry thats the problem its coil bind,those springs[1491] bind at max 0.550lift and even that is tight,unless you have 1.25 rockers or a flat cam I cant see how it would work.

Yes we do stock the 650 springs

cheers richie

[ED2.4]

[/quote]

I was talking about shims under the spring base,not under the rockers,with that much shim under the rockers you might have longer than normal valves in the heads,did you buy them new? its not geometry thats the problem its coil bind,those springs[1491] bind at max 0.550lift and even that is tight,unless you have 1.25 rockers or a flat cam I cant see how it would work.

Yes we do stock the 650 springs

cheers richie
[/quote]

+1 , 5 shims under the rockers ,you have a geometry problem(too long PRs?) ! or like Richie said some longer valves (LS1 or T4 valve ?)

[Stefan Rossi]

Okay i will measure my pushrods tomorrow.

What are the length of the VW valves compared to Chevy LS1 valves?

I will remove them and measure them tomorrow too and let you know, I got the heads from america and was told they were off the shelf Ultra Mags with the CNC porting and matched IDF manifolds. which Iv'e since changed for IDA ones.

How many shims do you guys usually run under the rocker shafts?

Richie I will hopefully order some springs off you plus my clutch and line lock stuff near the end of september 

Stef

[ED2.4]

Okay i will measure my pushrods tomorrow.

What are the length of the VW valves compared to Chevy LS1 valves?

I will remove them and measure them tomorrow too and let you know, I got the heads from america and was told they were off the shelf Ultra Mags with the CNC porting and matched IDF manifolds. which Iv'e since changed for IDA ones.

How many shims do you guys usually run under the rocker shafts?

Richie I will hopefully order some springs off you plus my clutch and line lock stuff near the end of september 

Stef

Hi,
T1 valves are 112mm ,T4 (8mm) 117mm, and if i remember well LS1 are 118mm ,
the less shims under the rockers the better,usually one shim ,the thickness of the shims is determinate by the good geometry,
in some case it's the opposite ,you must removed beef on the rocker boss to have a nice geometry ,it depends of parts

[Stefan Rossi]

Just measured the valves they are 112mm.

The pushrods are 282mm

What is my problem? Are the push rods too long?

Stef

[Stefan Rossi]

Going to make an adjustable push rod and cut my pushrods to the correct length.

stef

[ED2.4]

Hi,
check the rocker position at mid lift,pushrod must be straight with the rocker adjusting bolt and the the other rocker end must have a good position on the lash cap,
it's not a rule of tomb but one way

[Stefan Rossi]

I checked this before and all seems good? 90 degree angle. Rocker arm is straight. also i have plenty of threads left for the nuts. Pushrods need cutting down i think...