Changing The Valve Springs

[JETURBO]

congrats for giving it a shot dude

[PHANTMXR6]

  typhoon_freak said:

we went to ford and was able to perchase their tool for doing it so will do it again this sunday, thanx for all your input

How much do genuine Ford tools cost??

[01txr]

Matt hope you had the springs installed at recommend heights.

When ever I fit new springs I always check installed heights and adjust

using shims.

And if you have a valve spring tester even better as it can help you to set them

at there correct seat pressure.

One spring may require a larger shim to the next so on.

It all comes down to how well matched and made the springs you are installing.

Your mechanic friend probably had done this hopefully and not just did a swap without

at the least installing them to recommended installed height.

[ebxmple]

Does anyone measure those things?????????????? I could understand if you were building a full race motor but didnt think that was necessary when fitting replacement valve springs as they have been measured and tested when made. Dont know of anyone who replaces them to go through that procedure but if their is anyone please speak up. Have done atleast 20 sets of valve springs whether it be the NIZPRO ones or the Crow ones and havent had any dramas.

[PHANTMXR6]

Yep, and you'd be a fool for not measuring them.

The biggest mistake people make with components is they expect that because they are coming from a reputable company they will be right.

That's the first mistake. Why you ask?

Well for starters yes they should be measured already, but people make mistakes.

Things get missed and unfortunately that's a fact of life.

Also, not every valve spring seat is the same height, hence the main reason for checking the springs and shimming them before final installation.

When the engine is doing 6000+rpm, you want to know that your valve springs are good, especially when you've paid someone to do the job properly.

[01txr]

I have pulled down engines with broken valve springs from people not checking them for installation.

As phantmxr6 mentioned all valves seats will have different installed heights, just think about it

you have a cast head which is machined for the valve seats which are press fitted to head then there is the

machining of the seats and valve, then you have the valve spring foot that is also machined, from there

the retaining clips (Collects) hold the valve stem tapered into the valve spring retainers which also can very

installed height.

so with all those areas there will be differances but no where near as bad now with the quality of manufacture process.

Then pending how good the set of valve springs are you will get different pressure from each spring

at the same compressed height.

On top of that you get people fit large lift cams and dont check the coil bind (The springs being compressed fully)

Eg having 12mm valve lift but only 11.8mm valve travel to compressed spring.

If the spring manufacturer requires say 120lb seat pressure then you need to get this as close as possible

with the 120lb being the minium as anything less will mean poor valve seating meaning that cylinder to

be down on power.

When choosing upgraded camshafts it very important the valve springs are of correct specification to suit

not only for seat pressure but open pressure as that's where you will have valve float if its to soft.

eg you have a large cam that has a power band area at say 4500 to 5800rpm if the springs arn't matched

and they have less than specified open pressure the engine will not develop power in the upper power range

as you will get valve float. on the other hand if the valve spring pressure is higher than specified you may

have the head of the valve part way which is another problem with people fitting big cams with heavy valve springs

without upgrading the valves to a valve made to handle the extra spring pressure.

when buying valve train where possible buy all parts from the same manufacturer as it is all tested to suit,

follow all installation procedures.

Hope I explained this simple enough for anyone wanting to know without being to confusing, it is very early morning.

Any mismatched valve train will end in tears, not only can the valve train fail but if a valve lets go at rpm say good by

to your engine.

Sorry Matt back on your subject, how did you go, did you get them all done yet also I had sent you a PM.

[IH8TOADS]

I have a noise from under the rocker cover following the installation of Nizpro springs.....the car is with the Company that fitted them atm and I demanded a cylinder leakage test be done as I'm convinved this is valve spring related and nothing to do with the fitment of a plenum and turbo mods which I did just after. Get them installed properly the first time and you won't go through the grief I am

[ebxmple]

Well their you go,thanks for the feedback. I guess I am just a "lucky fool" with the 20+sets I have done as they havent had any dramas with rattles,breakages,power or high rpm problems. Will look into it further for specs etc before I do my next set next week as the springs dont come with any info. Whats a estimate time factor in measuring and setting the mentioned things "per spring" and have you measured them before on an xr6t with the head still in the car? Thanks.

Edited 20/05/09 09:01 AM by ebxmple

[01txr]

It is a time comsuming process to measure and check all, there would be a lot of mechanics out there that

will charge you for the labour but may skip in doing the process of checking everything and just fit

the springs, they take the risks if it does fail.

They can always argue the point that you have over reved it, not warmed engine before giving it a

workout, run to much boost etc etc.

Quality springs should always come with a specification, if not the manufacturer should be able

to provide it.

I would never install a set of valve springs if the information wasn't available for the install.

With a standard heavy duty direct replacement spring you may find they come with no installation

specifications as they have been made to fit in as per standard.

In saying that they need to be installed using factory specifications of installed heights.

if you dont bother to set them to spec or check them its the risk you take.

With you having fitted 20 sets you have been lucky, just remember it only takes one bad spring

to fail and worst case your engine is scrap.

I have not performed a valve spring change in a Barra 6 as yet but have done plenty of ford v8's

crossflows, and VW's.

I have my new engine sitting in my shed on a stand and when I get around to doing the valve train it will

be done to spec and nothing less.

I will not be using a valve spring that has no specification supplied.

may I ask what brand springs are you using, have you asked the supplier to supply specification for install.

[typhoon_freak]

I decided to go one step further and purchase the race valve springs not the heavy duty ones.. sorry I will reply to your pm 01txr.