Topic: Cast iron guides for 5mm valve stems?Fix: back to stock thickness 6.6mm stem valves, cast iron guide

[PeWe]

I'm looking for a cast iron alternative to replace bronze guides for 5mm stem valves.
-Anyone that know an alternative that can work?

CBR1100XX (Superblackbird) has guides with 5mm ID but hardly around 12.07mm OD on photos I have seen.

The ported K6 head I have need a few new guides so finding new  guides will ensure the longetivity.

[Tintop]

PeWe a number of versions offered by Cycle X - http://www.cyclexchange.net/Engine%20Parts%20Valve%20Trane.htm   Not what your looking for?

[PeWe]

I think all their guides are for stock sized stems, 6.5mm.

The 5mm conversion kits have bronze guides.

I have thoughts to ask CycleX about  guides for 5mm stems.

[754]

Skinny vakves are a racing thing, so are bronze guides.. i think they are less prone to sticking, scoring, and galling in higher temperatures. You have to decide which you want..
 A fast motor with shorter life.... or a stock motor  that you will find boring, but will last longer than some of us got left in life..

[RAZZ]

Skinny vakves are a racing thing, so are bronze guides.. i think they are less prone to sticking, scoring, and galling in higher temperatures. You have to decide which you want..
 A fast motor with shorter life.... or a stock motor  that you will find boring, but will last longer than some of us got left in life..

What is it Neil Young singes.. , "It's better to burn out than to fade away."


Sent from my iPhone using Tapatalk

[MRieck]

I think all their steel guides are for stock sized stems, 6.5mm.

The 5mm conversion kits have bronze guides.

I have thoughts to ask CycleX about steel guides for 5mm stems.

I have spoken to Kenny about this Per.

[PeWe]

I can get both if not always riding it too hard
Current 392 head has stock guides (slightly modified), a little bit smaller in,  kpmi 33.5mm and 28.5mm ex. No dyno yet.

Another older looking K2 head with 34mm F2 in valves using lash caps since stock F2 in valves mushroom very quick, especially in a K head,
kpmi 28mm ex. Also stock guides.  This head gave 100whp last year.

It would be fine if longer living guides should be availabe for the kpmi 5mm stem valves. Their surface look like the other kpmi valves my other heads have.

I know that shiny stainless valves needs bronze guides.

So before restoring that head with 5mm valve guides for 67mm CR12.5:1  pistons that will fill the chambers better, a good idea to look for longer lasting alternative.

[PeWe]

I think all their steel guides are for stock sized stems, 6.5mm.

The 5mm conversion kits have bronze guides.

I have thoughts to ask CycleX about steel guides for 5mm stems.

I have spoken to Kenny about this Per.

That sounds good!
Any ideas from him?

I will not be surprised if they can provide a steel guide like their other steel guides but 5mm inner.
Finding another engine's stock guide for 5mm valves will most likely have too small o.d.

The engine build will use CycleX rods.
CycleX steel guides for 5mm stems will match!

[MRieck]

I think all their steel guides are for stock sized stems, 6.5mm.

The 5mm conversion kits have bronze guides.

I have thoughts to ask CycleX about steel guides for 5mm stems.

I have spoken to Kenny about this Per.

That sounds good!
Any ideas from him?

I will not be surprised if they can provide a steel guide like their other steel guides but 5mm inner.
Finding another engine's stock guide for 5mm valves will most likely have too small o.d.

The engine build will use CycleX rods.
CycleX steel guides for 5mm stems will match!

They are really no problem to manufacture it's just the fact you have to buy a large quantity. It would be nice if they were more popular.

[PeWe]

I think all their steel guides are for stock sized stems, 6.5mm.

The 5mm conversion kits have bronze guides.

I have thoughts to ask CycleX about steel guides for 5mm stems.

I have spoken to Kenny about this Per.

That sounds good!
Any ideas from him?

I will not be surprised if they can provide a steel guide like their other steel guides but 5mm inner.
Finding another engine's stock guide for 5mm valves will most likely have too small o.d.

The engine build will use CycleX rods.
CycleX steel guides for 5mm stems will match!

They are really no problem to manufacture it's just the fact you have to buy a large quantity. It would be nice if they were more popular.

We are not talking 8 or 16, its hundreds, right?

Finding another engines guides for 5mm valves  with thick outer diam as 12.1 mm or more that can be modified to fit is difficult too.

Or if Superblackbird's  (CBR1100XX) cheap steel guides fit the valves, an outer guide (bronze?) fitted in head before mounting the guide.

Make hole conical so the outer bronze sleeve cannot  fall inwards despite crimp fit. Or a little bit wider at top only, it must be material in head.

Held in place by shim washer under spring.
I think I have to order one of each to check.

Might cost too much unless the guy in nearby shop will do some of it  for fun before retire which soon will happen.
The CBR guides cost less than half than CB750 stock guides.

[754]

 You want a straight hole, dont screw  with that..
 Turning fatter down, or turning down a sleeve pressed over, is a fairly easy lathe job...just make sure your centering stub is dead nuts  running true.l

[PeWe]

You want a straight hole, dont screw  with that..
 Turning fatter down, or turning down a sleeve pressed over, is a fairly easy lathe job...just make sure your centering stub is dead nuts  running true.l

Thanks for the tips Frank.
I'll not do the job if it will happen
An experinced guy used to port and restore heads since the mid 70's. Plus all other engine jobs.
He might have done something similar before. I have to check with him.

[bear]

I know this goes against what would be normal practice and I'm certainly not advocating this set-up for anyone else but I used to run S/S valves with cast guides. No valve stem oil seals though.
Never had galling issues but it must be remembered that my motor's where raced with a 9krpm ceiling.
I just thought I would add this to the discussion.
I am not saying that my set-up should be considered for normal HP applications.

Cheers,
Brian

[PeWe]

Brian, it smoked a little extra after throttle off-on without seals, right? 
I'm sure it smoked anyway.
Good to know though. Stanless valves vs cast iron guides.

I have got info locally here about ev bronze sleeves.
Sleeves needs to be at least 2mm thick, a flange at top.

5mm cast iron guides are  10mm, not less which ends up in 14mm instead of ~12.07mm. Guide hole in head not to be opened more.

An alternative is to make own in cast iron.  Machine time might be high.

I'll see what it can cost if the shop has time.
It might be worth some to achieve 2-3 times longer life than bronze. 
As long as not overheating which has quickly killed stock guides with valves for me before.

EDIT:
I have just talked to the mechanic. It is not that easy to buy only 1/2-1 meter of a cast iron rod. Machine time to make 8 guides at least 4 hours.
He had done inserts before in GSX heads when increasing valve size by spreading them apart (Prostock bikes). Then drilling holes in head bigger, insert with guide hole for valve displaced.

He thought they have KPMI 5mm bronze guides in stock.
 Ideas about making ex guides ends less sharp, the lower inside hole a little bit bigger the first mm to reduce heat killing the guide. No valve/guide contact there.

Maybe find thicker/wider/deeper lash caps too. From other bikes.

This with correct jetted carbs will make a longer life.

My guides had a hard life with to lean and way too rich most of the time. Dyno time will reduce cost and durability, thats for sure!

Important notice.
The bronze guides are not worn enough to remove head for.
Not good enough to not replace when apart. I'll update when fixed. All are not bad.

[MRieck]

I think all their steel guides are for stock sized stems, 6.5mm.

The 5mm conversion kits have bronze guides.

I have thoughts to ask CycleX about steel guides for 5mm stems.

I have spoken to Kenny about this Per.

That sounds good!
Any ideas from him?

I will not be surprised if they can provide a steel guide like their other steel guides but 5mm inner.
Finding another engine's stock guide for 5mm valves will most likely have too small o.d.

The engine build will use CycleX rods.
CycleX steel guides for 5mm stems will match!

They are really no problem to manufacture it's just the fact you have to buy a large quantity. It would be nice if they were more popular.

We are not talking 8 or 16, its hundreds, right?

Finding another engines guides for 5mm valves  with thick outer diam as 12.1 mm or more that can be modified to fit is difficult too.

Or if Superblackbird's  (CBR1100XX) cheap steel guides fit the valves, an outer guide (bronze?) fitted in head before mounting the guide.

Make hole conical so the outer bronze sleeve cannot  fall inwards despite crimp fit. Or a little bit wider at top only, it must be material in head.

Held in place by shim washer under spring.
I think I have to order one of each to check.

Might cost too much unless the guy in nearby shop will do some of it  for fun before retire which soon will happen.
The CBR guides cost less than half than CB750 stock guides.

Per...like 500 pieces.

[PeWe]

I think all their steel guides are for stock sized stems, 6.5mm.

The 5mm conversion kits have bronze guides.

I have thoughts to ask CycleX about steel guides for 5mm stems.

I have spoken to Kenny about this Per.

That sounds good!
Any ideas from him?

I will not be surprised if they can provide a steel guide like their other steel guides but 5mm inner.
Finding another engine's stock guide for 5mm valves will most likely have too small o.d.

The engine build will use CycleX rods.
CycleX steel guides for 5mm stems will match!

They are really no problem to manufacture it's just the fact you have to buy a large quantity. It would be nice if they were more popular.

We are not talking 8 or 16, its hundreds, right?

Finding another engines guides for 5mm valves  with thick outer diam as 12.1 mm or more that can be modified to fit is difficult too.

Or if Superblackbird's  (CBR1100XX) cheap steel guides fit the valves, an outer guide (bronze?) fitted in head before mounting the guide.

Make hole conical so the outer bronze sleeve cannot  fall inwards despite crimp fit. Or a little bit wider at top only, it must be material in head.

Held in place by shim washer under spring.
I think I have to order one of each to check.

Might cost too much unless the guy in nearby shop will do some of it  for fun before retire which soon will happen.
The CBR guides cost less than half than CB750 stock guides.

Per...like 500 pieces.

Thanks Mike,
OK, I'm up for 8, 16 with reserve
484 left...

[754]

1/2 hr per guide , spunds a bit slow.
 I made a cast iron lifter sleeve about 3 inches long.... had to buy 6 ft of material.
 The material you need is cheap.... small diameter.

[PeWe]

I let the shop have a look on the head today.
All guides need to be replaced. The tips are OK, the upper part of guides another thing.
Holes between 5.04- 5.09mm.

The rocker arm movement bend valve sideways and cause wear.
5mm setup is much flimsier than a 6.5mm you hardly bend sideways with your thumb as a 5mm setup. The spring do not need to be heavy for those light valves either.

Dohc with vertical guides must last a lot longer when using bronze. I guess these guides are made of C630.
http://www.nationalbronze.com/C63000_Nickel_Aluminum_Bronze.php

If it is  like Ampco45.

A lower lifting less agressive cam might add a longer life. Like a KHD I have on the shelf.  Those rounded mouse ears must match CR12.5:1 pistons.

Oil with lots of phosphorous and zinc must be vital here with metal contact.

The first break-ins used not good enough oils with low amount of lubing additives (ZDDP).  Simple Castrol minerals 10W-40 followed by 20W-50.
Not only flat tappets here, bending valves in guides too

[754]

Small gains on those stems, a tradeoff in reliability... if you want long lasting , think conservatively.
 I sold many ROWE AMPCO 45 Guides for mostly street Harleys , dont recall anyone complaining..

[Old Scrambler]

Per................Ferrea makes 5.5mm valves in many varieties including hollow-stem. I use their bronze guides but all exhaust because they are shorter and allow for longer 'lift'...........Stem-caps snap on .............Prelude car valves can be cut to desired length for use with bee-hive springs and optimum spring pressure for desired cam

[PeWe]

The  last year dyno guy had good experience of Ampco 45 guides.  Long life guides.
Also for HD since he worked mostly with HD. Porting, boring and general run better tune on dyno.  He has a dragracing history, also Harley. The Harley heads might have another guide angle?

It seems to be the stem flex that wear the guide quicker.
Cams used:
- DP315 not that high lift with 0.3mm valve lash.
- RC295 profile most of the time with higher in lift.

5.5 mm stems can be an alternative. Hollow stems?
Are they stiffer?

Lash caps open up for cutting the stems to correct lenght.

All valves look good, only guides that need to be replaced. Seats hopefully OK with another guide change. 3rd change.

- Any good link where to find the valves and guides, Dennis?
34mm In, 28mm Ex .

[Old Scrambler]

https://www.ferrea.com/about-us

Take a look at Honda Prelude valves for starters.............those guides snap into a CB750 head...........I used 35 x 31 sizes but 34mm intakes are on the list......you may have to do some hunting to find the 28s.........

[PeWe]

Thank you very much for the valve info.
35 and 31mm valves sounds large if used as is and not cut down.
F2 head?

Update:
Old guides removed. Really worn guides at top.
As Frank wrote earlier Racing application, not street.

Light valves for max rev, not longetivity.
Too worn in the wrong end to blame heat, fuel etc.
Cast iron is probably not enough for flexing 5mm stems getting a longer life in a CB750 with valve bending rockers.

Plan to return to stirdy 6.6 mm valve stems.
Guide holes in head look OK:
IN  12.07mm
EX 12.08 mm
OS guides needed.

A little bit more looking for alternatives going back to 6.6mm stemmed valves.

*** I checked with CycleX. ***
- CycleX cast iron guides, thickness 12.09mm. Update: Measured ther recieved cryo treated guides, 12.11 almost 12.12 mm so they will fit!
Cryo treated or not.

They claim that their stainless hard chromed valves works with their cast iron guides ( or bronze).
IN 34mm, EX 28mm that match the seats.

Springs, retainers, keepers adds on too...
Their set with hardwelded rockers might be too tempting.
This is a better priced alternative that hopefully will work better in the long street run way beyond the speed limits!

[Old Scrambler]

Yes, F2 head.................on 62mm bore...........

Ferrea has numerous other stem sizes and blanks............They feature a quite different angle at the valve to seat area. I especially like their quality and their bee-hive springs with small Ti retainers. Spring pressure is lower which means less 'oomph' is needed to begin the opening process and should help to keep things from 'bending' 

[PeWe]

Yes, F2 head.................on 62mm bore...........

Ferrea has numerous other stem sizes and blanks............They feature a quite different angle at the valve to seat area. I especially like their quality and their bee-hive springs with small Ti retainers. Spring pressure is lower which means less 'oomph' is needed to begin the opening process and should help to keep things from 'bending' 

Really good alternative to be aware of. A complete valve-spring setup in various configurations, stem sizes.

The Kpmi 5mm conversion kit has also softer springs when valves are lighter. Still a bender. (Guides shot after 25.000 km, valves look OK though)

Bee-hive springs even softer I suppose. I understand now why they are needed.