Hi, im feature to a new build soon and im wonder is it better to change the valve guides on my Evo 5 during the build?

Any idea how to remove and install the old and new guides?

Thanks

 

Search is your friend

https://www.evolutionm.net/forums/ev...tml?styleid=23

 

that should be sticky on exactly how not to do it. driving the guides out like that galls the guide walls. the new guides will leak oil through the sides of guides when done like that. proper way is to drill the guides with core drill bit.

 

Let your machine shop take care of it for you and yes if you have a car with a lot of miles do it. I am assuming with an EVO V that fits the bill.

 

Funny thing, that's how most shops change them.

I have built a few hundred 4g heads, never had one leak oil around the od of the guide.

Maybe I am just lucky.

But you are correct that there is a chance that it can happen.

Also, you can gall the guide bore on the install if you are sloppy about it.

 

Thank you very much Guys for your advise.

 

of course thats how most shops do it. its 20 times more time consuming to do it the correct way. I dont buy for a second you have done 200 heads with good success. you only have to do a handful to find out the hardway the guides will leak.

 

Oh I remember the first 4g head I changed guides out in back in '92, I totally junked the head and had to get a customer a new casting. I was also a first year engine machinist apprentice.

But I learned from that bit of experience.

If you are a moron about using the guide driver yes you are correct about tearing up the guide bores.

Over the years you get the "feel" for what you do, So after 20 years of doing this kind of work, I have a good idea of what I am doing.

Yes, there have been times I have had to shell drill the guides out.

But for me changing out guides in 200 plus 4g heads, well you might not want to believe it, but that is on the low side.

There is always more than one way to skin a cat.

I commonly have in stock 20-30 4g heads in the shop.

 

I have read your post for years and honestly I have always enjoyed reading your advice,experience and opinions.
That being said , it confuses me that you consider this method of R&R a sure way to cause guides to leak on alloy heads even though it is common practice .
The head will tell you if you need to drill them out almost instantly.
I am very surprised that you would be so against this method but in the same breathe not send your rotating assembly for balancing or intentionally install unbalanced assemblies.

Still love your posts .

cool shots.
what brand head facer you running ?
What brand valve spring installer ?
here in Aus/Nz they run a Ford 4.0l (AU) because of the length of the guide I always end up drilling them out. If they are being replaced with bronze/bronze alloy forget about just driving them in.
I tend to remove the interference of the guide that protrudes in bowl, heat,liquid nitro etc

I've never had issues with 4g's but I have seen the guides bend same with RB's.

Do you charge the customer for the extra time if you have to drill them out ?
We charge by the guide so it tends to be uneconomical to drill 16 guides out and if we charged by the hour I think most people wouldn't bother.

7th year still never seen a guide leak from this process , I personally wouldn't put a number on how many heads but I imagine another 13 years from now I still won't have seen it

Thanks for the healthy discussion fellas

 

Bcity, I run a Comec Auto I1000 CBN/PCD surfacer. Best money I have spent. It is made in Italy and runs about half the price of a DCM.

My head shop is a TnS System 2000, another great machine, one of only a couple that use a digital level system , and not a bubble level.

For a spring compressor I have tooling that fits in the TnS to compress the springs for install. Works good for the 5V VW 1.8T heads too.

 

bogus obviously rebuilds heads with $$$ in mind. he is not doing it how it should be done for costs reasons. while most oil transfer through side of guide will be minor, I have seen it bad enough the cylinder heads had to be taken back off. I couldnt care less if you have bogus do your head work. but I wouldnt send mine there.
http://www.jackstransmissions.com/pa...-guide-removal

 

Not to veer to far off topic but I just had my gsc valvetrain installed and I put all new gsc valve stem seals in and along with the old valvetrain and oem valve stem seals I found 1 what I think is a valve lock

It's like a two piece cone about the size of a finger nail made out of metal. I am worried they forgot to put this one piece back in OR it was from something else and just fell in my box....

All of the valves and the rest of the valvetrain seems to be installed correctly I'm just wondering that this piece is...I'm 90% sure it's not a valve guide.

 

Yes I do.

But drilling the guides out has it own set of dangers that can damage the guide bores.

This pic is pulled from the link you posted.


If you look at the guide I circled in black, notice how the guide is cut down the side.

Good chance the cutter got into the guide bore.

A simple leveling issue can cause a misalignment causing the cutter to get into the bore.

So no 1 method is best, It is up to the machinist and his experience to decide what method will be best for the head casting.








It could be a spare valve lock. look at the top of the spring retainers and check to make sure you have 2 locks in each.

A pic of the piece would help ID it

 

You don't NEED to change guides unless they are worn out, cracked, or leaking.

 

Why didn't you just post the link to begin with ?
Negative nancy
Why would I send my head to another machinist ? when I am a machinist.
Also the picture shown has a fixed head drill which is useless for clevos and chevs( just off the top of my head)

If you are going to drill them out, I would use a Serdi( or something similar) and core drill with at least 0.010" either side (0.020 total) stopping 0.040 before the bottom of the guide removing the possibility of side wall damage.
Leveling issues, casting issues, guide material issues, the list goes on and on with any technique chosen thats what experience is there for

Tototally agree nice spot on the guide