ptuomov

Here's another valve spring question. Many thanks for everyone who's helped me greatly already!

Question / request 1: Could everyone fill in as many of these as they can for stock '87 S4 valve springs:
- Outside diameter of the outer spring: mm or inches
- Inside diameter of the inner spring: mm or inches
- Maximum coil bind (basically at what height the spring locks): mm or inches
- Recommended install height: mm or inches (a guess is intake 35.5+0.5 mm and exhaust 34.5+0.5 mm)
- Max safe lift assuming installed height of 35mm: mmor inches
- Load @ 35mm installed height: lbs
- Load @ 23mm height: lbs
- Spring rate: lbs/inch
- Spring weight: grams

I searched the forum and found some indications, but nothing conclusive beyond the recommended installed heights.

Question / request 2: If I were to increase the installed height of the '87 S4 valve springs, while keeping the seats and valves exactly the same, just by letting the springs expand a bit, how would I go about it? How much could I gain by not useing the washers? Are there alternative spring plates? Alternative retainers? Etc.

The purpose of these questions is to help me find alternative siffer springs for the s4 head. In case I find anything, I will share my findings with the board, of course.

Many thanks in advance.

Rob Edwards

Tuomo-

I have a set of used 91GT springs and can measure the dimensions. I will measure them tonight if no one else answers first. I don't have a spring dyno, however- can't help you with the force questions.

ptuomov

Thank you very much Rob.

Rob Edwards

Tuomo-

Here are some of the #'s you seek. These springs are 19 years old, no guarantee they have the same free length they did in the 28th week of 1990...


Outside diameter of the outer spring: 30.27 mm
Outside diameter of the inner spring: 21.85 mm

- Inside diameter of the outer spring: 22.66 mm
- Inside diameter of the inner spring: 16.29 mm

-Free height of outer spring: 44.27 mm
-Free height of inner spring: 37.03 mm
- Maximum coil bind outer spring: 21.15 mm
- Maximum coil bind inner spring: 16.44 mm

The upper washer is 30.00 mm in diameter, and 9.75 mm in maximal thickness. Measured at the outer spring perch, it's 1.91 mm thick and 4.68 mm thick at the inner perch.

The lower washer is 31.90 mm in diameter and 9.52 mm in maximal thickness. the outer spring perch thickness is 4.32 mm and the inner spring perch thickness is 6.95 mm

I can weigh the springs in my lab tomorrow. I dunno about the rest:
- Recommended install height: mm or inches (a guess is intake 35.5+0.5 mm and exhaust 34.5+0.5 mm)
- Max safe lift assuming installed height of 35mm: mm or inches
- Load @ 35mm installed height: lbs
- Load @ 23mm height: lbs
- Spring rate: lbs/inch

Vilhuer

Nominal upper washer outer spring perch thickness which is used in measuring spring installation height is 2.0-2.2mm.

Nominal lower plate outer spring perch thickness for '87-95 928 is 4.5mm. 928 S3 and 944 S2 use 1.5mm thick plate.

Valve spring installation lenghts for 944 S2 springs are 38.0-38.5mm for intake and 37.0-37.5mm for exhaust springs.

968 use same 1.5mm thick plate as '85-86 32V 928 and same 38.0-38.5mm intake and 37.0-37.5mm exhaust spring installation lenght as 944 S2 but 968 valve springs have much longer free lenght and little thinner wire diameter IIRR.

Vilhuer

Also one thing which is good to remember is that '85 32V 928 has different valve springs than '86 MY 32V. '86 MY yearly changes document has details of differencees like 40.0 vs 43.5mm outer spring free lenght etc.

Rob Edwards

FWIW, for the 91GT springs, here are the weights:

Outer spring: 38.04g
Inner spring: 16.03g
Lower spring washer: 28.04g
upper spring washer 18.69g

ptuomov

Rob , many thanks for the spring dimensions.

I have been trying to look for light and stiff single beehive springs for '87 s4. Based on Rob's data, here are two candidates. These are probably not appropriate for a street car since the pressures at installed heights are very high. However, the racers out there might find these springs useful if boosting and revving the engine like the madmen they are.

Option to research 1:

http://www.pacracing.com/Beehive_Spr...Set_of_16.html

Single beehive spring PAC-1223
Outside diameter: 1.105 inches
Inside diameter: 0.742 inches
Maximum coil bind: 0.900 inches
Recommended install height: 1.470 inches
Max lift: 0.500 inches
Load @ 1.470 height: 90 lbs
Load @ 0.970 height: 252 lbs
Spring rate: 324.0 lbs/inch
Spring weight: 37.6 grams

Based on Robs data, these would fit based the diameter. The bottom washer and top retainer might have to found / acquired / machined.

My elementary calculations say that at 35mm = 1.38 inch installed height, these would give about 119 lbs force when installed and valve closed. The max lift within the specifications at that installed height would be about 0.41 inches. 0.41 inches I think is large enough for the stock valves, because the curtain area is already at that point large relative to the valve throat area. If the springs fit and can somehow be easily installed at say 1.40 inch installed height, they would be within spec for the 928 Motorsports s2 cams with 0.428 inch max intake lift.


Option 2:

Endura-Tech springs
Part Number: ENV MGT-4V-D

OD: 1.142"
ID: 0.835"
VC Load: 119# @ 1.330
VO Load: 306# @ 0.840
Lift: 0.492"

Warning: Item is currently out of stock.

Can't actually find a way to buy these.

The research continues.

ptuomov

Does anybody happen to know what the S4 valve keeper angle is? By keeper I mean the two pieces that fit together and "keep" the spring retainer and the valve together. The angle that I am interested in is the angle of the cone that this keeper forms.

ptuomov

How is this defined? Is it the height from where the spring ends to what?

blown 87

my understanding is that Crane closed it doors this week, due to the economy, and the issue of replace cams under warranty that all of the cam manufactures had to deal with that was found to be a oil problem.

ptuomov

http://news.google.com/news?ned=us&h...s+closes+doors

Crane Cams shuts down, workers laid off

By JIM WITTERS
Senior Business Writer

DAYTONA BEACH — Crane Cams, a 56-year-old auto parts manufacturer, closed its doors this week and laid off its employees, a worker said today.

The news took Volusia County’s top economic development officer by surprise. City, county and state officials were working with Crane Cams and officials from its New Jersey parent, Mikronite Technologies, to keep the company open and in the community.

“We were trying to help them through this transition,” said Rick Michael, Volusia County economic development director. “They were considering a transfer of ownership. We were not expecting any closure.”

An automated voice mail system at Crane’s plant on Fentress Boulevard announced at midday today the company was closed and suggested calling back during business hours, 8 a.m. to 5 p.m. A call to Mikronite’s New Jersey offices produced similar results. Six cars sat in the parking lot early this afternoon at the local plant, which employed 220 just three years ago.

Inside the lobby, a reception desk sat empty. A call from the lobby phone got an answer from Dennis Burgess, who declined to comment and said no one at the plant could provide information.

In the parking lot, 14-year employee Ronald Dorn was leaving the plant for what he believed was the last time

He said workers were told during the past week that layoffs were likely, but he didn’t expect the plant to close.

Mikronite received approval in 2006 to receive tax rebates from the state and the county amid discussion about moving its New Jersey operations here. But the company ended its contract with the state in 2008 due to nonperformance, Michael said.

“Crane has gone through a series of small layoffs recently,” he said.

Crane Cams and Crane Technologies Group were founded by Harvey J. Crane Jr. in 1953 as Crane Engineering Inc. in Hallandale. The company is well known in high-performance and racing circles for its line of camshafts and engine valve train components.

In 1979, Crane Cams became an employee-owned company. Some operations moved to Daytona Beach in 1981, with the remainder of the operation and employees relocating here in 1985.

Mikronite, an industrial technology firm, bought Crane in 2006.

In March 2007, Mikronite sold its property on Fentress to STAG Capital Partners of Boston, then signed a 10-year lease.

blown 87

I am going to send my heads back to the machine shop to have them check the installed height and pressure in the next 2 weeks.

I can get all the information from a stock 87 s4 head for you.

With the exception of what the installed height and spring pressures were before they did the heads.

So what you need to know is are they the common 7 degree or 10 degree or some weird angle?

Is this correct?

ptuomov

Exactly. I am rooting for the standard 7 degrees! ;-)

What would also be useful is an estimate of the height from the top of the spring to the middle groove of the valve when the stock retainer is installed on stock valve using the stock keeper/collet/lock.

Out of curiosity, did you just have a standard valve job done or did you go crazy with the heads?

Tuomo

blown 87

I had enough left on the valves and seats to do a five angle job, but other that that, new guides and a 50 RMS surface they are stock.

I just could not find the info for height and pressure when I had them done, they are close, but I want to be sure they are in spec.