Show full size 924Board.org
Discussion Forum of 924.org
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
 Technical FAQ924 FAQ (Technical)   Technical924 Technical Section   Jump to 924.org924.org   Jump to PCA 924 Registry924 Registry

CS Head Build - Bigger Lighter Valves - Process - Progress
Goto page 1, 2, 3 ... 23, 24, 25  Next
 
Post new topic   Reply to topic    924Board.org Forum Index -> Performance Upgrades
View previous topic :: View next topic  
Author Message
Mike9311  



Joined: 14 Dec 2004
Posts: 1678
Location: Chicago-ish

PostPosted: Mon Sep 27, 2021 2:25 am    Post subject: CS Head Build - Bigger Lighter Valves - Process - Progress Reply with quote

For those that don't know already I am building a temporary motor for the Club Sport (Dan's (Ideola's Garage) old car for you newbies). The 2.2L stroker was pulled temporarily.

https://www.924board.org/viewtopic.php?t=31912&highlight=makes+club+sport

Its been frustrating for me personally because I have a lot going on work wise and have to walk away from cars a lot in the past 1.5 years (I also have too many).

Gegge and MikeJinCo have been charting new ground and I have been right there in the mix but waaay to slow. Rasta's words were poignant and on target so here is my attempt at starting the follow through

Yesterday I made a test same for something I have been preparing for quite some time. Its small but oh so satisfying.

The idea for the Club Sport head is to rebuild a badly rebuilt and somewhat ported head I pulled from a crashed car. I can't use the original Club Sport big valve head due to damage (may be usable in the future).

The plan is to remove 800g off the entire valve train Gegge style. 6mm stem 42mm intake / 38mm exhaust. I would have prefred a 36mm for the exhaust but I am looking to use an off the shelf 'super alloy' for turbo use. The option is there though to turn it down to 37 or 36 if needed.

If I can pull it off, I would like to apply a Joakim 1mm head shift combined with a 0.5 to 1mm off intake valve guide for a total unshrouding movement of the intake valve toward the cylinder center of 1.5 to 2mm.

Unlike everyone else I am pursuing lighter pressures because of the tremendous mass reduction of the valves, springs, retainers, and tappets permit this approach. The number one reason being: why beat up the cam when not needed. I am tired of seeing up cams especially the 4th cylinder position so I will be running equal sized oil supply holes from the rail like any reliable Japanese car or supercar.

The valves come with unfinished ends so I can size the length and without grooves so my options were open.

So back to yesterdays test. The stem groove... I machined a 5.97mm "fake" stem and then a groove for a beadloc style of keeper. Man was this oh so sweet success

Fake stem with groove left / actual 5.97-6mm stem right


Retainer with keepers installed. They clipped in so nicely


Lash cap installed... The dust on the spring is indicative of how long this has been sitting on the desk...sigh


I have posted this previously in someone else's thread (Juho I think). Beryllium free copper alternative exhaust seat. Used in all of motor sport but of course I have 'pay up' for all this and the days of a $400 big valve head kit are certainly over. Even the valves have doubled in cost over the past few years. I have have invested heavily in Serdi style tooling as well



Stay tuned... Head fixturing and more testing to follow. Final groove position and overall process are in constant flux mentally so I think I will move to doing an exhaust first because its easier without this offset mess figuring. Its length thats driving me crazy since I have to figure out the spacing of everything (Spring pressures, clearance, etc)
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
Back to top
View user's profile Send private message
MikeJinCO  



Joined: 08 Jun 2010
Posts: 1227
Location: Maysville, Colorado

PostPosted: Mon Sep 27, 2021 1:30 pm    Post subject: Reply with quote

Very Interesting. A much more sophisticated approach than I am taking, but then a turbo motor has a lot more heat to deal with. My small stem valve scheme is basically at a standstill due to the machinist just having too much work and not enough help. I saw him today, we'll get there someday, some how. Our design philosophy is that since the motor is intended to spend 80% of is time in the top half of the rpm range and we know that in that area the valves tend to bounce off the seats in that range we want to discourage that by having a higher seat pressure but do not need a high spring rate as the cam shape is fairly normal. For high grade springs made in the US are really still centered on V8's with roller cams this is basically a contradiction in terms. They typically want over 140 closed and over 400 lb/in rates

The new modern small motors have 4 valve cylinders in the 30mm range with short 5 and 6mm stems, miniature by our old school standards they can get by with much different spring setups.

The stock spring rate according to RC's old threads are approximately 340 lb/in at 63C-225O. We would like to be about 110 closed and 230-250 open or a rate in the 275-300 lb/in range, so no more actual load on the cam, just better valve control. The Ford modular block V8 springs are the ones closest to our needs. The LS springs we found are longer than the Ford ones and in the 330 range a little higher than I would like but my supplier was insistent on not having the thicker spacers needed for the valve seat, for use in a 931 head and not using the rotators. I believe his setups for the 944 and 944T do use the Ford springs, but then the valves are also in the 110mm length range vs. our 133-137 range, a generation advanced design head..

My search engine does not find European or Japanese spring manufacturers and the Netherlands cam supplier CatCam sells PAC springs so I know nothing available to the rest of the world. Ferrera Valve has setups for many non US motors, but you need to find the combination of spring and retainer and seat that will work with the valve stem.

Sorry about the length, but it is a fairly complex subject.
_________________
Mike


'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild)
Back to top
View user's profile Send private message Visit poster's website
morghen  



Joined: 21 Jan 2005
Posts: 8868
Location: Romania

PostPosted: Mon Sep 27, 2021 3:33 pm    Post subject: Reply with quote

Proper stuff happening, I'll need to change the clutch in my 924 and been thinking to lighten up some stuff like the flywheel and valvetrain...so i'll be looking here for ideas and guidance.
Thanks for sharing!
_________________
https://www.the924.com
Back to top
View user's profile Send private message Visit poster's website Yahoo Messenger MSN Messenger
Cedric  



Joined: 27 Aug 2004
Posts: 2600
Location: Sweden

PostPosted: Mon Sep 27, 2021 5:41 pm    Post subject: Reply with quote

Interesting project, it will be interesting to follow the process!
_________________
1980 924 Turbo
www.instagram.com/garagecedric/
Back to top
View user's profile Send private message MSN Messenger
Mike9311  



Joined: 14 Dec 2004
Posts: 1678
Location: Chicago-ish

PostPosted: Mon Sep 27, 2021 11:39 pm    Post subject: Reply with quote

Thanks guys

Ford modular is my way too and I have to see how the numbers work out once I get to details. I never looked at LS options. Just didn't think of it and maybe I should have. There is so much to think about simultaneously. Spring pressure, retainer clearance, guide/seal clearance, and ultimate valve length* with much of it hanging on groove placement which has to be min 0.275" down (so 0.300 inch from tip likely which is what I did here). I am hoping to have shim space if needed. Lift wise I don't have a lot of margin. Essentially 2mm at max in the spring. I'll use the rotators if I can or even design new ones using a thrust roller bearing if I need space.

*Valve length for the most straightforward setting of tappet to lobe clearances. I would like to be in a position to either carefully control tip length to the cam or at least be so close I can lap the cap to size. Worst case is making my own caps which I am comfortable doing. This was a course already charted before me in the Ducati world. The kit I have for the bike has a ton of caps of all thicknesses that can be further fine tuned by lapping. I tip my hat to that gentleman! It was a really brilliant idea

With such a massive mass reduction it will be like I have a stronger spring. Always amazes me how much the top end of the rev range can be lifted by a simple swap to a titanium retainer in a race motor. In this case its -100g per valve parts total (Edit: More like -118 grams per valve in total parts)

To start, I think I will just have to pick an exhaust valve and go from there to see how things stack up. Even if I sacrifice a valve for the test. Exhaust is easier since I can make a straightforward guide. The guide material could be made out of the same material as the exhaust seat but I just went for manganese bronze for the moment. Once I get to the intake, the only valid approach I see is to drill and ream in place to get the offset right where I want it.

I was all over the place with the seat material and almost went with copper impregnated sintered seats but they were hard to get. I still ended up with custom exhaust seats and technically at the highest end of motorsport. I think I am being paranoid about pulling heat from that valve. Its so much work that I just want it to "work" when I am done

Next step is to finalize my valve stem fixture to machine the grooves as well as the head fixture itself for the machines. It looks like I will be jumping between a manual machine and the cnc when it comes to working on the head itself
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
Back to top
View user's profile Send private message
gegge  



Joined: 27 Jul 2007
Posts: 1124
Location: Sweden

PostPosted: Thu Sep 30, 2021 4:15 pm    Post subject: Reply with quote

I am following this fore sure!
_________________
Carl Fredrik Torkildsen

924 turbo -81 Carrera GT RESTOMOD
924 turbo -80 Dolomite De Luxe
924 -85 DP kit, BBS RS, M030 and tuned engine
924s -86 Black on black turbo with Fuchs
Back to top
View user's profile Send private message
MikeJinCO  



Joined: 08 Jun 2010
Posts: 1227
Location: Maysville, Colorado

PostPosted: Mon Oct 04, 2021 10:58 pm    Post subject: Reply with quote

My approach has been to keep the retainer/valve keeper location in a position fairly close to stock to allow easier assembly and disassembly, taking up the extra space with spacers above and below the spring. It will very slightly due to the shape of the retainer. I never thought of the LS spring either as most(there are many versions) have much too high a spring rate.

Not having the machining capabilities of yourself I'm using Alfa 105 motor 9mm shims to control valve clearance. On the 7mm stems I have fixed thickness shims to get out to the 9mm. A less ideal system, but fairly inexpensive and quite easily adjustable.
_________________
Mike


'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild)
Back to top
View user's profile Send private message Visit poster's website
Mike9311  



Joined: 14 Dec 2004
Posts: 1678
Location: Chicago-ish

PostPosted: Wed Dec 15, 2021 12:51 am    Post subject: Reply with quote

MikeJinCO wrote:
My approach has been to keep the retainer/valve keeper location in a position fairly close to stock to allow easier assembly and disassembly, taking up the extra space with spacers above and below the spring. It will very slightly due to the shape of the retainer. I never thought of the LS spring either as most(there are many versions) have much too high a spring rate.

Not having the machining capabilities of yourself I'm using Alfa 105 motor 9mm shims to control valve clearance. On the 7mm stems I have fixed thickness shims to get out to the 9mm. A less ideal system, but fairly inexpensive and quite easily adjustable.


I haven't decided quite yet the location (even though I have been leaning your way) and just recently discovered the type of lock I'm using does not allow for rotation which is fine. Its a firm decision which I need sometimes

Since the last post I have been refining the groove process. First groove was too large. I could tell it was bugging me and a lot of searching finally got me my answer. The radius center is out in space whereas I had it on the surface of the stem in the pic above. It looks correct now and using machinist dye reveals the contact area is also correct. Next will be cutting an actual stem and possibly a surface treatment of the groove.

Now, I've moved on further to the cylinder head fixture. Had a couple of ideas but have been leaning this way. Want to use the month of Dec wisely and get this head near the finish or at least within sight






_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
Back to top
View user's profile Send private message
Mike9311  



Joined: 14 Dec 2004
Posts: 1678
Location: Chicago-ish

PostPosted: Sun Jan 02, 2022 6:31 am    Post subject: Reply with quote

Making progress now that I chose a better direction. This side fit perfectly in all the scanned holes I felt were quality. They are tight to the 6mm screws with no room for error so the head would be true in the fixture or at least close for fine adjustment. One was off but I knew that it would be given its at the edge of the scan. Ample clamp force plus I still can use that hole to add a fifth screw

The other side is still in the CNC. Will be shrinking/press fitting a ground bar into each plate. In CAD, I ran the bar cylinder from one plate to the other through the cylinder head mesh. This way the ground bar ends on each plate will share the same axis in the final assembly. Fixture will allow for guide, seat, chamber, port work, and decking when finished. At least that's the plan


_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
Back to top
View user's profile Send private message
Mike9311  



Joined: 14 Dec 2004
Posts: 1678
Location: Chicago-ish

PostPosted: Thu Jan 06, 2022 12:45 am    Post subject: Reply with quote

The other side. Scan data was really good which allowed for a nice fit to the M8 bolts. Threaded bar ends will go into the large holes later today. Finally will see a start of the fun stuff. I didn't complete the hole by the bar. Too close due to a programming mistake at the CNC. Bar became larger than planned. Not a big deal. The last bolt hole on the one edge also fits. Just didn't carry over enough bolts from the other room


_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
Back to top
View user's profile Send private message
Cedric  



Joined: 27 Aug 2004
Posts: 2600
Location: Sweden

PostPosted: Thu Jan 06, 2022 1:45 am    Post subject: Reply with quote

Will be nice to see the complete fixture, and how you can use it for the future head work.
_________________
1980 924 Turbo
www.instagram.com/garagecedric/
Back to top
View user's profile Send private message MSN Messenger
morghen  



Joined: 21 Jan 2005
Posts: 8868
Location: Romania

PostPosted: Thu Jan 06, 2022 9:33 am    Post subject: Reply with quote

Oh that 3d scan gives me dirty thoughs with mixed parts from other cars
_________________
https://www.the924.com
Back to top
View user's profile Send private message Visit poster's website Yahoo Messenger MSN Messenger
Mike9311  



Joined: 14 Dec 2004
Posts: 1678
Location: Chicago-ish

PostPosted: Sun Jan 09, 2022 3:27 am    Post subject: Reply with quote

morghen wrote:
Oh that 3d scan gives me dirty thoughs with mixed parts from other cars


That's funny I said to myself yesterday once you go down this hole your mind starts to come up with other ideas based on the current success
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
Back to top
View user's profile Send private message
Mike9311  



Joined: 14 Dec 2004
Posts: 1678
Location: Chicago-ish

PostPosted: Sun Jan 09, 2022 3:42 am    Post subject: Reply with quote

Here is the CAD idea I have been developing with a better picture explanation.

I shrink fitted the ground bar ends that will make up this single axis into my plates. Then bolted this up for a test using standard set up blocks. Whats cool is that I can already work from this but will eventually make side stands with adjusters to tweak alignment when I dial indicate whatever surface or item I want to work on (valve guide for example).

Here is a video link as well. You can imagine custom uprights with clamping and other brackets points on the head like an exhaust or intake stud. The bar ends are also threaded for a possible lock stop location

https://vimeo.com/663724137




_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
Back to top
View user's profile Send private message
Mike9311  



Joined: 14 Dec 2004
Posts: 1678
Location: Chicago-ish

PostPosted: Wed Jan 12, 2022 12:47 am    Post subject: Reply with quote

Yesterday I swept the gasket surface after I leveled it off in the short direction using the new pivot system. Its so crazy. From one side to the other its off by 0.0015" inches / 0.0381mm and this seems more so that my 0.0001in indicator is picking up the previous machining lines and general uncleanliness. This means scan to bolt on worked in a way I wasn't expecting. Close but not this close! Over half the distance I couldn't even see any deviation because the factory machined surface was bouncing the needle

The head I am going use has previous work so the next step while fixtured is reaming the guide bores before installing new guides. Exhaust will have the stem bore but the intakes will be drilled once installed so they can be properly offset. Current thinking will be 1mm toward the exhaust valve

Working on an offset bushing to study what it takes to apply another 1mm offset
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    924Board.org Forum Index -> Performance Upgrades All times are GMT + 10 Hours
Goto page 1, 2, 3 ... 23, 24, 25  Next
Page 1 of 25

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group