Head work

kiwi60 · Post by **kiwi60** » Sat May 09, 2009 9:50 pm

I need to have the valves and valve seats re-ground to get them in good condition for racing (not just lapped in) and I got to thinking, between Lyle and I we have 100 valves that could probably use some attention and at $750/head, this get just a little on the expensive side so...

Has anyone been cutting thier own valve seats (5 angle cut) and grinding their on valves, and if so, what tools did you use?

Did you grind or cut the valve seats?

What set up did you use for doing the valve faces?

Lyle and I can access a fully set up engineering workshop (mills, lathes etc etc), and having a go has never slowed us down before.

Any ideas?

spook · Post by **spook** » Sat May 09, 2009 10:04 pm

I'm looking at buying cutters Kiwi, I don't think grinding seats is really as good an option as hand cutting. Valve faces though can only really be ground, any good quality automotive facing machine should do... providing you can find Collette's small enough to entertain the valve stems. I know Steve at FZroadrace over in pommy land used to resurface and reface. I have have found this site, but I'm sure there are many more. Seems we are traveling in parallel universes..(lol)

http://www.cylinderheadsupply.com/nesmdicubo.html

kiwi60 · Post by **kiwi60** » Sat May 09, 2009 10:08 pm

Code: Select all

Seems we are traveling in parallel universes..

Indeed it does

spook · Post by **spook** » Sat May 09, 2009 10:22 pm

I just added the link.. So far the only bike work I've had to pay for, or have done for me, is the re-boring of the R5 cylinders. I like developing the skills and knowledge, that allows me to do it myself. Not to mention the savings. I also have a number of heads here that need work. I think I will leave boring and balancing to the pros, though, intend to do pretty much everything else.

Yoniboi · Post by **Yoniboi** » Mon May 11, 2009 5:57 pm

I had a head done by Len at the Cylinderheadshop while he was still in Lincolnshire (pommyland). I understand he's since moved to Ireland.

He does 5 angle cuts, and maintains that only a handful of people in the world have the machinery to do it.

He may have done a fabulous job recutting the seats and fitting new valve guides but a) he charged 700 quid for 8 valve guides, 20 seats re-cut and 20 valves cleaned which I thought was a bit steep, but more importantly he also scratched the living hell out of the gasket face and then refused to acknowledge that it wasn't like that when I took it to him. It took a 0.5mm skim to get it flat again, and he refused to pay the 25 quid it cost to get it done.

Anyway, that off my chest, and like I said, he reckoned that outside of certain race shops (Ferrari racing, Nascar teams etc) that nobody else had the equipment to do 5 angles on such small valves.

John

stan · Post by **stan** » Tue May 12, 2009 2:15 am

i don't mind a bit of head work

stan

Post by **Hooligan** » Tue May 12, 2009 2:25 pm

i recall john posting about his experience with len.

can anyone explain here what portion of the valve is ground? i have some kit intake and exhaust valves for the project, all brand new, but the kit manual refers to grinding the shafts and a portion of the funnel prior to installation.

kinda confused on what's involved there, but i am assuming grinding 360 degrees of the valve shaft to match guide dimensions? correct? way off base?

kev123 · Post by **kev123** » Tue May 12, 2009 5:12 pm

i maybe able to help, i'll ask my mechanic. I am sure he did one for his race 0w01

spook · Post by **spook** » Tue May 12, 2009 6:41 pm

Hooligan wrote:can anyone explain here what portion of the valve is ground?

Hooli, the only grinding as such would take place on the valve face, if for instance it had a slight irregularities due to pounding the seat over a period of time. Ideally when rebuilding an engine, you would use new valves such as the kit items you have and as a result no grinding is required. Pretty much all valves have a face angle of 45 degrees. Any removal of matereial from the valve face and the valve seat cause the valve to 'recede' into the head affecting gas flow, valve clearance and valve spring tension. So ideally use new valves (pre-ground)

The kit manual suggests as you mentioned "grinding" of the valve funnel, this refers to removing some material to 'waist' the valve and improve gas flow past it. This has nothing to do with re-conditioning valves and valve seats as is being discussed here.

The following pix shows a three angle cut from the YZF750 o-haul manual.

So in the case of valve seating... the face of the valve is ground to an angle of 45 degrees, the seat is then cut with a minimum of 3 angles in this case 20-45-60 degrees. The main reason the 20 and 60 degree angles exist is to adjust the position and width of the valve seat. The valve seals against the 45 degree section.

In a 5 angle cuts, you would add a say 10 degree cut at the top at (a) and a 70 degree cut past (c) These cuts have nothing to do with valve sealing, they just provide better flow for intake and exhaust gases, in the same way that waisting the valves does.

MsHap · Post by **MsHap** » Thu May 14, 2009 3:59 am

I was thinking about doing one of Jello's myself.
I am just afraid because it kinda feels like more art then science and I am not artistic.

I really want to do what one of the other members here had done and replace the centre intake with and exhaust plus the polishing and really match those intake pieces.
I had a friend over a few months ago and he builds car engines for fun and the first thing he said was wow those intakes are rough and he was feeling the seam where those bolt to the head.

I never really noticed before but it seams sloppy now.

I want to send the extra set of cams to megacycle too so I would need a head that has the proper spings or retainers or whatever they require.

Jello already has all titanium bolts.

I wish I had help. I was driving home the other day after dropping the kids to school and there was this guy working on his car and 2 other guys were there elbow deep in whatever the problem was.
I never have help. I am always the only one and I have to fix everyone elses cars and bikes too. It sucks!

spook · Post by **spook** » Thu May 14, 2009 12:23 pm

There is no art in it really MsHap. the book (service manual) explains pretty well what you need to do if the seat present here or there on the valve. You should have a go. The hand cutters are a good investment

I wonder how much extra hp the center inlet valve mod makes?....

The kit manual goes into cleanning up intake and exhaust channels, its on the pommy site, and is a good read in general.

Help...lol.

Doing this stuff is like moving house... You find out who your friends are... that is, if you didn't already know

keep smiling!

stan · Post by **stan** » Fri May 15, 2009 3:14 am

Umm...........i might be moving house, real soon like

stan

spook · Post by **spook** » Fri May 15, 2009 4:20 am

Don't you go bloody well moving on me Stan! Just imagine leaving cold gloomy Victoria for sunny warm Queensland... What are you thinking old man?

And yes if you so foolishly succumb to the temptation of warmth, blue skies, err, blue tee-shirts, red hair, missing teeth... Well... I'll miss you... but not as much as you will miss civilization

The kids will enjoy music lessons at their new school.... I look forward to coming up to visit and having the kids get out the banjos, and play uncle Ralph a tune.....