924Board.org

daniel · Joined: 18 Jun 2009 Posts: 670 Location: Sydney, Australia

Hi All
I know a few have gone down this route with custom made valves, so heres my take on it:

Rebuilding the engine in my race car (924 2.0) which currently uses a standard turbo head in a NA application. I decided to get something a bit better. Reading various posts/info and considering I am only allowed a bore at 87.75mm (class rules) I settled early on using the standard valve head diameters of 40mm & 37mm however I wanted a thinner stem to improve flow and reduce weight.
The advice I got was that 6mm may be OK but 7mm will be safe with the cam I am using (peak power 7500-8000rpm). So 7mm it is.

Off I went to a racing head shop that promised me the world and delivered squat. 6 months later I demanded the head back and decided to see what I could achieve on my own. I now have all parts to assemble the head. Cam is a custom grind on a blank & valves & guides are custom made. All other parts are off the shelf from various different motors (some unique to Australia).

The retainers are from a AU Falcon 6 cyl 4.0L.
The springs are a performance version from a Holden Gemini (double spring)
Collets (or valve locks) are from a 1FZ Toyota.

I am going to machine some custom spacers to give the desired spring pressure.

So now I am waiting until next year to have the seats cut, valves finished off and guides pushed in and reamed. I have been told Feb-March so will go back to working on my slide on camper project so I've got somewhere to stay at the track...

Here are the pics:

New intake valve, retainer, collets and solid lifter:

Original intake valve, collets, retainer and Porsche lifter (with adjustment screw).

New valves and old valves:

New guides, old guides

_________________
Over the top of skyline, total brake failure.... hit the wall at over 200 kp/h at the dipper, so anyone who has to brake for the esses is a pussy.
1977.5 Race Car, CAMS Group S Spec
1989 944 Cabriolet

924RACR · Posted: Wed Dec 21, 2022 9:55 pm Post subject:

Very interesting stuff.

What are you doing for valve adjustment, with this different solid lifter? That's a topic I have to address with the Elgin cam still, due to the different base circle... too busy chasing other things at the moment...
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

MikeJinCO · Posted: Thu Dec 22, 2022 12:45 am Post subject:

Two options. If using the stock lifters, I think some motorcycle shims might fit in the 9mm bore of the lifter. I think Ideola figured that out. Independent bike shops probably have boxes of shims around. If using the ACM solid lifters, when I had a reground Elgin cam, I put a Manley 8mm .080 shim upside down on the ACM stem and that put me about mid range for using Alfa 1300(105 engine) 9mm lifter shims. I told Hayes, and Chuck followed him. I believe 50plus has a lot of them or available from Centerline Alfa individually. When we set the head up we assembled it and used something like some .125 stock as a spacer, measured the clearance just purchased what we needed. More accurate than I expected, 7 out of 8 ok first round. Just ground .002 off the end of the valve for the eighth. Commonly done in shops these days to to the vast variety of shims.

Pleasure to meet you in Phoenix, I have a full page of notes.
_________________
Mike

'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild)

daniel · Joined: 18 Jun 2009 Posts: 670 Location: Sydney, Australia

Using 7mm ID lash caps. Available in thickness up to 6.5mm.
_________________
Over the top of skyline, total brake failure.... hit the wall at over 200 kp/h at the dipper, so anyone who has to brake for the esses is a pussy.
1977.5 Race Car, CAMS Group S Spec
1989 944 Cabriolet

Mike9311 · Joined: 14 Dec 2004 Posts: 1678 Location: Chicago-ish

This is really awesome. You are putting a lot of thought and time into this! Oh the endless searching to find something that works. Good stuff!
_________________
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

Fifty50Plus · Posted: Sat Dec 24, 2022 4:56 am Post subject:

I just ran the entire season with the Swedish lifters (8 mm Manley lash cap upside down in the cap) and the Alfa 9 mm lash caps on the valve stems. No problems whatsoever. Building two more H Prod engines over the winter with the same configuration.
_________________
1979 924 NA race car
1982 924 NA race car - Sold
1982 924 Turbo almost a PoS
1981 924 Turbo a real PoS, new engine
1982 924 Turbo nice body, blown engine
1972 911 E race car - going to Vintage
Various 944s to become IT-S race car

924RACR · Posted: Tue Jan 03, 2023 1:38 am Post subject:

Fifty50Plus · Posted: Tue Jan 03, 2023 4:21 am Post subject:

Vaughan, I was looking on the internet for more of the ACM lifters last night and couldn't find their site. I called Mike since he had sent me a set last month when he sold off his 924 stuff. He's looking for his old source and will get back to me. The Manley 8mm lash caps are readily available. As for the 9mm Alfa lash caps, I had to order both a small sizes set a larger range set to get the range that I thought I needed. As I recall, each set was several hundred pieces in incremental sizing. I can't recall which sized set was the proper range but each set was about $500.
I'm at the beach right now but will check when I get home and let you know which set was the right range and where I purchased it.
Setting the proper lash was easier than i orignally thought. I had pulled my IT-B cam out of the head while still in the car. I pulled all the Porsche lifters and one at a time, put in the Manley equipped ACM lifter and an initial Alfa 9mm lash cap. I positioned the Elgin cam over the lifter (just held it in by hand) and measured the lash. I did a little math and by the second or third Alfa lash cap I had the correct lash for that lobe of the cam. I repeated the process seven more times, put in all the lifters, lined up the Elgin cam and bolted it down, installed the timing belt, remeasured (plus or minus a thou) and fired it up.
_________________
1979 924 NA race car
1982 924 NA race car - Sold
1982 924 Turbo almost a PoS
1981 924 Turbo a real PoS, new engine
1982 924 Turbo nice body, blown engine
1972 911 E race car - going to Vintage
Various 944s to become IT-S race car

Fifty50Plus · Posted: Tue Jan 03, 2023 4:32 am Post subject:

I'm in the process of building two or three more H-Prod engines this winter for Hayes, myself and Matti Vilkkila (local IT-B racer convert) with all new parts, lighter rods, higher compression pistons, etc. I have heads at the machine shop now and figure that my initial set up as described above will work even before bolting the heads to the blocks. But when I did it to my well used IT-B engine, the valves were fully seated from running. On initial startup of these new engines, I expect the clearances to change as the valves and seats wear in and a complete re-measurement will be necessary before race ready.
_________________
1979 924 NA race car
1982 924 NA race car - Sold
1982 924 Turbo almost a PoS
1981 924 Turbo a real PoS, new engine
1982 924 Turbo nice body, blown engine
1972 911 E race car - going to Vintage
Various 944s to become IT-S race car

924RACR · Posted: Tue Jan 03, 2023 10:42 pm Post subject:

Cool... if you have that many builds upcoming, maybe some group buys on some of the components for the top end setup?

Definitely no rush, we can catch up when you get back.
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

Mike9311 · Joined: 14 Dec 2004 Posts: 1678 Location: Chicago-ish

https://acm.se/category/760

They must have redid the site. My old link didn't work but their site is still there. I can't read Swedish but my German and some guessing helps

In theory I could make these but gladly they are still there so I don't have to
_________________
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

924RACR · Posted: Wed Jan 04, 2023 12:39 am Post subject:

Mike9311 · Joined: 14 Dec 2004 Posts: 1678 Location: Chicago-ish

Quote "Awesome! Actually they have a button top right corner to translate to UK. "

Hilarious

I had a script blocker on that blocked the UK button

_________________
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

Cedric · Joined: 27 Aug 2004 Posts: 2610 Location: Sweden

Some of us can read Swedish if you need any help:). ACM bought all the stuff that the ol guy Sten parner SPM did, and took up the parts in their store. Hence a name change over the years.

Our Swedish Currency has completely tanked against the gbp,euro and dollar. Enjoy that, while everything i want to buy abroad gets even more expensive:)
_________________
1980 924 Turbo
www.instagram.com/garagecedric/

Fifty50Plus · Posted: Thu Jan 05, 2023 1:02 am Post subject:

Okay, I'm back home and found my info on the lifters and shims.
You all are correct, ACM is the outfit that makes the 924 sized lifter without the Porsche adjuster but the 8mm step inside. Hayes and I put a Manley 8mm lash cap (wear cap part No. 42125 - 8 ) inside the lifter.
We then used Alfa 9mm lash caps placed on top of the stock 924 NA valve stems to get the proper valve adjustment.
I bought two Alfa 9mm lash cap kits (small and large) from Centerline International, 1450 Overlook Drive, Lafayette, CO 80026, phone 888-750 ALFA. Their website is www.centerlinealfa.com. The kit that I needed was the smaller sizes 1500 - 2500 and there are 41 incremental sizes (going up by .0025 per step) in that range. Each size came with 5 lash caps in the kit and looking in my kit, I see that I used caps in the range 1625 - 1975 when I set my Elgin cam in my used IT-B head. Even with a fresh head (minimally cut seats and new valves) I don't think I will ever need to use the larger shims (2525 - 3500).
Centerline told me that they sell replacement shims based on size to keep the kit fully stocked but I haven't contacted them to reorder shims that I used.
_________________
1979 924 NA race car
1982 924 NA race car - Sold
1982 924 Turbo almost a PoS
1981 924 Turbo a real PoS, new engine
1982 924 Turbo nice body, blown engine
1972 911 E race car - going to Vintage
Various 944s to become IT-S race car