Mounting af new exhaust valve guides

[Roslin]

Does the new valve guide need to be pre heated before i press them in the head ?

Roslin

[cgarr]

No, but you can warm the head and freeze the guide, that can help but really not necessary.

[john walker's workshop]

always mic the new guide to be sure it is very close to the old one. about 3 hundredths of a mm oversize is normal. you don't want to crack the guide bore. lube the bore and guide with something like WD-40 and run them in. i use a air hammer, gently, and a guide driver bit with a thick flat washer slipped over it that protects the end of the guide.

[88911coupe]

Isn't this something that fits in the "don't try this at home category" and better left to the John Walkers of the world? Not to question Roslin's ability, I'm referring to my own, or lack thereof.
Good Luck

[tony77targa]

Cant seem to find a valve guide driver bit....

[afterburn 549]

for me dry ice is the best friend to install stuffffffff and also, I reheat the heads a couple of times b4 doing the seats so any thing thats wants to get comfortable will do it now so as to keep all things sq with ea other later

[Jeff Alton]

I have built and continue to build motors on a fairly regular basis. When I look at what I pay to have heads rebuilt and then do the math.... I send them out every time. The local big P-car shops and the dealer came to the same conclusion I did. I can't justify doing it myself for what I pay.

Cheers

[john walker's workshop]

i would rather know that the heads are done right, rather than assume. too important of a job, and a lot of work to tear the engine down again if something wasn't quite right. i worked at an auto machine shop in the 70s, and did zillions of heads of all types, so i'm set up to turn them out in a reasonable amount of time. besides, i like doing them.

[tony77targa]

John can you point me in the direction to purchase a guide driver bit ?

[john walker's workshop]

a manual one by K-D tools, #815. 11/32". haven't used it in years, but it works fine. the pic is of a 5/16" unit that is too small for a 9mm guide, but just for reference. correct number though, for the 11/32 tool. i machined my 9mm one down for other purposes.
the airhammer bit is snap-on #PH-86. 9mm. that's my tool of choice. just go gentle on the trigger.
be sure that whatever one you use, to install a thick flat washer onto the shank so you don't distort the top of the guide.

[tony77targa]

Wow ! Thnaks John ! Part numbers with pics ! Great info ...
onto the snap on website...
Tony

[Jeff Alton]

Originally posted by john walker's workshop
i would rather know that the heads are done right, rather than assume. too important of a job, and a lot of work to tear the engine down again if something wasn't quite right.

That is the other reason I send them out! I think Lance has way more experience than I do with heads and will do a far better job at this than I will.

Cheers

[Roslin]

I made this tool to guide the valve guide. sprayed them with WD-40, and heated the heads to 170 deg. Celsius. Used a mechanical press to press them in - this way worked fine

Roslin

[shbop]

I made this tool to guide the valve guide. sprayed them with WD-40, and heated the heads to 170 deg. Celsius. Used a mechanical press to press them in - this way worked fine

Very nice looking piece Roslin.

[garibaldi]

The best way to do it, is send it to someone who knows what theyre doing. But, the technique is this, the old guides should be bored or reamed unitl the walls are thin and the press fit is nill, then drive them out. but.....most people are too lazy to do this, second lazy method, heat the head, then pound the old guide out, third totally idiotic method, but used more often than not...just flip the head on its back, and pound the old guide out with a drift. The last two methods will usually tear a fair amount of aluminum with it, and totally **** up the guide hole. In any case, the guide hole should have a hone run through it to bring it back to round and predicatable size (ie use oversize guides if neccessary...usually are). The hone also removes any high spots on the inner bore of the guide hole. Set the bore diameter, and meaure the interference to be sure its within spec (Its been a while but I want to say .004, I may be off a bit, look it up) Then I would put the new guides in a baggie soaked with STP oil treatment in the freezer, and place the heads on a stove to heat (Or oven whatever)....when I spit on the heads and my spit jumped off, they were ready. I had a custom driver I made out of oil hard tool steel bar stock that had a penis that went a ways down the valve stem hole of the new guide, and then had a shoulder that rested on the mouth of the new guided end. I would dab some STP on the id of the guide bore on the hot head, yank it off the stove, put it on a wood block , side an oiled guide onto the driver , line up the guide in the hole, and tap them home. Youd watch the STP bake out from around the hole and then Id put them back on the stove to normalize then let them cool in air temp. I never had a problem, never "Raped" the guide hole going in, and never cracked a guide boss in the port as Ive seen done all too often by lazy shops that jsut bang them in. Take the time, do it or have it done right, otherwise, who knows what the crush is on the guide, and if the boss cracks, YOU DO HAVE TO FIX IT, and that is a nightmare.