924Board.org

endwrench · Joined: 07 Dec 2002 Posts: 1631 Location: Victor, Montana

Martijnus, I was under the same illusion as you as to how the shims worked until I talked to Min about his setup. The shims actually go on top of the valve rather than the top of the lifter like most stock setups I have seen. I'd like to see a picture of both the shim and the underneath of the lifter.

Todd
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'79 924NA. Rebuilt 9.5:1, MSDS header, Mega Squirt Injection, MJLJ-EDIS Ignition, 1.6L Whipple Charger and Intercooler, 10lbs Boost, 944 Trans, Custom HD Clutch.
"simsport" said....superchargers are better than turbos its official!....

dpw928 · Joined: 02 Nov 2002 Posts: 1860 Location: owasso, ok 74055

The 924 head isn't like the VW and Audi versions in that there is no retaining wall for a shim on top of the lifter. That's why the shim/adjustment point must be between the valve stem and bottom of the lifter.

If someone is going to produce an aftermarket lifter, why not go hydraulic like on the 928?

Dennis
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81 931 5 sp
78 928 5 sp Silver
78 928 AT Euro Black

bass gt · Posted: Thu Feb 21, 2008 1:06 am Post subject:

Dan,

This may come as no suprise to you, but i have these piper followers in my engines. Regarding the Q as to the worth of fitting them, i believe they are worth it for several reasons.
1) Much lighter than the stock item.
2) Much lighter than the stock item. When i say lighter, i really mean lighter. From memoery, the weight of 2 stock followers is equivalent to all 8 piper followers. There really is a noticable difference in the engine with these fitted.
3) Better performing, due to the weight issue.
If you are fitting a new cam, i think these are essential. Why wreck a good cam with suspect followers?
Now, i have had a couple of sets from Piper, and both came with the shims. 6mm is ideal, and a good engine shop will have plenty of scope to machine these down.
Now, i have had no problem with Piper, but one batch did take in excess of 3 months to arrive!! So perhaps Arrow are the better bet. Arrow are a superb company, they supplied my steel rods. The items would be faultless from them, and well worth the extra couple of $ in my opinion.
Now, if your next question is about dry sump pumps, i know all about those too

Steve
_________________
Front Wheel Drive is the Devil's work.

bass gt · Posted: Thu Feb 21, 2008 1:06 am Post subject:

Dan,

This may come as no suprise to you, but i have these piper followers in my engines. Regarding the Q as to the worth of fitting them, i believe they are worth it for several reasons.
1) Much lighter than the stock item.
2) Much lighter than the stock item. When i say lighter, i really mean lighter. From memoery, the weight of 2 stock followers is equivalent to all 8 piper followers. There really is a noticable difference in the engine with these fitted.
3) Better performing, due to the weight issue.
If you are fitting a new cam, i think these are essential. Why wreck a good cam with suspect followers?
Now, i have had a couple of sets from Piper, and both came with the shims. 6mm is ideal, and a good engine shop will have plenty of scope to machine these down.
Now, i have had no problem with Piper, but one batch did take in excess of 3 months to arrive!! So perhaps Arrow are the better bet. Arrow are a superb company, they supplied my steel rods. The items would be faultless from them, and well worth the extra couple of $ in my opinion.
Now, if your next question is about dry sump pumps, i know all about those too

Remember. Build it once. Build it right

Steve
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Front Wheel Drive is the Devil's work.

Min · Posted: Thu Feb 21, 2008 1:50 am Post subject:

bass gt · Posted: Thu Feb 21, 2008 1:57 am Post subject:

Min,

The shim sits in a tube in the underside of the follower. The tube then slides onto the valve stem, hence setting he clearance. Simple really.

Steve
_________________
Front Wheel Drive is the Devil's work.

dpw928 · Joined: 02 Nov 2002 Posts: 1860 Location: owasso, ok 74055

ideola · Joined: 01 Oct 2004 Posts: 15548 Location: Spring Lake MI

Regarding ARP, I have no doubt about the excellence of their product. However, I am concerned about lead time. They haven't made these before, so it would be a completely new R&D effort for them, and guess who gets to pay for that

Also, it only adds to the lead time...by the time we ship them a sample, give them the 4 week lead time they need, and wait for them to be shipped back, we're talking a minimum of 6 weeks. That puts me into June before I can get send the head to Eurorace. I don't want to wait that long if I can avoid it.

For point of comparison, here is the response I got from Nick Frazer at ARP:

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11723 Location: PacNW

Plus, hydraulic lifters need an oil galley in the head to pressurize them.
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

Martijnus · Joined: 29 Dec 2006 Posts: 2019 Location: Netherlands

bass gt · Posted: Thu Feb 21, 2008 3:38 am Post subject:

hydraulic?? why??for what advantage?? hydraulic lifters are for ease of maintenance, not performance. the weight addition is horrific
really, once you take the time to measure up the cam to follower clearences, machine the shims, fit them, you are set. Period.
Anyway, if you have your smarts about you, you get the shop doing the head work to do this as part of the job. because, it goes without question you are having the ports matched, the valves upsized, a 3 angle valve job, new guides blended into the throat wall ect....
Re the followers, Piper are the naturalchoice, as they are an item they make, but the lead time can be very long. They told me 2 weeks, then another, and another. Turned into 3 months. i guess it depends where in the production cycle you land. But with a group buy, perhaps they will push them through asap. however, the Arrow price is better than the piper i think.
Also, when upgrading these followers, don't skimp and fit the stock springs. a) these will be 30 years old and prety tired b) once you up the boost and rpm, they just are not man enough. Put one on a spring gauge, and then do the maths re boost ect. Go for double springs, no doubt.
really, the efect on the engine is quite remarkable. it seems much more responsive with just the valve train upgraded.
So Dan, welcome to the thin end of the wedge. I remember being there once. Worse than a crack habit i think!!
Oh, BTW, i had my car runing N/A the other week. All this lightening work seems to have a result. The car wont idle below 1400 rpm, and it's a pig to move at slow speed. Revs flare and die, clutch(AP 6 Paddle) is a pig, but give it a sqirt, and

Really picks up, and revs Soooo cleanly. Sounds the nuts, if i say so myself!!

Steve
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Front Wheel Drive is the Devil's work.

ideola · Joined: 01 Oct 2004 Posts: 15548 Location: Spring Lake MI

Min · Posted: Thu Feb 21, 2008 5:10 am Post subject:

the real problem for me is when we run in our brand new integral cam, we have to run different valve lash than when the thing is finishing being run in. So we'll have to set the valve lash ourselves.

Min
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Custom means it didn't come from a box.
1980 n/a with EDIS and Megasquirt II Injection. 7 different colors and counting.

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11723 Location: PacNW

So, about the valve replacement. . .I thought 931 valves were special material and/or fill. Will the Eurorace "big valves" be similarly made? I have a spare head I am interested in sending off.
_________________
Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

bass gt · Posted: Thu Feb 21, 2008 5:23 am Post subject: