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924RACR · Posted: Mon Aug 07, 2023 7:46 am Post subject: Elgin H Prod cam clearances?

Can't remember who I bugged for this, but don't remember getting an answer... finally installed my Elgin H Prod cam and measured the clearances, preparatory to ordering the Alfa shims to complete the install.

But I saw reference (maybe in the cam docs) about possibly not running stock clearances?

What should I be aiming for, here?

Looking forward to finally having this in the car and running it for the next race (sadly, no, not the H Prod Fest at Mud-O next weekend)...
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

Fifty50Plus · Posted: Mon Aug 07, 2023 9:37 am Post subject:

I just looked through all my stuff from Dema and can't find a recommended valve lash. I seem to recall back when Hayes did the first grinds that he said to use stock lash. That's what I've been doing for two seasons now. I figured out last race weekend that I can go above 7K for shifts 3 to 4 and 4 to 5 and it runs a bit quicker than it did when I was shifting at 6500 (IT-B shift point). Lighter valve train, pistons and rods seem to make a difference and it still can breath at 7K.
Enjoy!
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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 Aug 08, 2023 12:35 am Post subject:

Yeah, I think I'll stay away from that since it's all still stock except the pistons and lifters... hell, my driver doesn't even like to hit the shift lights at 6k half the time!! LOL

Maybe if we get it on the dyno and map it out with the new cam, then we can justify revised shift points.

Do kinda love the durability of the 6k shift point, though, TBH.

Hayes did suggest that I email Dema, so have done so, cross-check what he says...
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

Fifty50Plus · Posted: Tue Aug 08, 2023 5:09 am Post subject:

Last winter I pulled my IT-B engine after 5 years or racing. I stuck in the H-Prod cam to run it last season in the new class but no other changes to the IT-B engine. It ran fine to the end. I'll get around to doing a leak down on it some time this summer but was thoroughly pleased with its performance and reliability over the 5 seasons -absolutely no issues. The new engine (full up H Prod specs) feels slightly better at higher RPMs and my lap times have dropped about one and a half seconds. I was hoping for more.

Then again, I'm 76 yrs old

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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: Wed Aug 09, 2023 12:45 am Post subject:

Went back through the Elgin docs, and I do see both 0.010/0.010" and 0.010/0.012" referenced as intake/exhaust clearances... so think I'll be safe going for 0.010/0.012"... now to get the order in... Centerline's website seems to not be working correctly for using their online shopping cart, might have to ring them...
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

daniel · Joined: 18 Jun 2009 Posts: 677 Location: Sydney, Australia

I run 10/12thou on my race cams, 7000rpm no issues. She is a tad bit noisy though...
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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 Aug 09, 2023 11:13 pm Post subject:

924RACR · Posted: Sun Aug 13, 2023 3:10 am Post subject:

Cam is fully installed and running, next stop racetrack in a few weeks!

Thanks all for the input and support...
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

924RACR · Posted: Tue Aug 29, 2023 12:45 am Post subject:

Cam ran well... but the ignition system is back to being flaky and iffy.

Now looking at that Microsquirt conversion, get rid of these damn misfire issues once and for all, and run better besides!
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

Fifty50Plus · Posted: Tue Aug 29, 2023 1:03 am Post subject:

New cams always wake up other gremlins!

With me it was fuel pump wiring. I believe that in H-Prod we can go full Mega-Squirt and solve both fuel and spark issues. And make it easier and quicker to R&R an engine. But it would probably take a long time to de-bug and make reliable the M-Squirt installation. I'm helping a buddy build an H-Prod 924 and he wants to go the full engine route. I'm not sure I'm looking foreward to it.
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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 Aug 29, 2023 2:27 am Post subject:

I've already done it on my street Turbo, and it was a piece of cake compared to trying to keep the CIS and stock ignition happy. Just a matter of rounding up some of the more particular bits, and doing a good clean quality job of the electrical.

And it fired up pretty much the first time - didn't take much debug. Instantly more reliable...
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

Fifty50Plus · Posted: Tue Aug 29, 2023 8:25 am Post subject:

Dang Vaughan, you're not making this easy for me to ignore....procrastinator that I am.
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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

Mike9311 · Joined: 14 Dec 2004 Posts: 1786 Location: Chicago-ish

Hey Vaughn, did Todd ever build the headers for you? Not sure if I asked this already
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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: Tue Sep 26, 2023 4:48 am Post subject:

No, that's back-burnered for now, too busy with a million other things...
_________________
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: 1786 Location: Chicago-ish