924Board.org

[PORSCHEV]

I was driving the 924 last night and was getting really tired of the way the car would buck and chug when crusing. It would only seem to do it when you were just touching the throttle. Under load it was fine. But under deceleration it would chug...buck..then smooth out. It was terrible at 2500 rpms /80-90km. It would buck every few seconds if you didn't hold the throttle just right.

I thought it smelled a bit rich when sitting at idle..so I already had suspected that the timing may be out a few degress. I backed off the distributor retaining nut...run the car up to 2500 rpm's and moved the dizzy until the engine smoothed out...tightened up the nut. WOW..what a difference! It idles at 1000 rpm on the nose and pulls alot harder on the lower rpm's. NO MORE BUCKING or chugging.

Now I just have to set the cam followers and see if that smooths out the engine a bit more as well.
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1976 924
5 lug conversion, 17'C2 wheels,custom body work,327 vette engine.

1978-#53 "D" track racer.

[koolkarateguy]

Timing is amazing. I had to crank mine over about 6-7 times before it would finally catch. Kicked the timing up a degree or two and it smoothed her idle out and she starts on the first turn of the key as well as stopped the bucking and chugging. Mine used to buck and chug as well before I fixed the exhaust, seems the car works fine with straight pipe , but when the muffler is hooked up and there is the tiniest leak anywhere in the exhaust ,it plays havoc with the engine.
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1979 N/A 924

[924RACR]

LOL... you know they now make instruments called timing lights, you can measure AND accurately adjust the timing?!?
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[PORSCHEV]

I'm old school.... I used to use a timing light all the time and found where it "should" run and where it runs best were often different.
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1976 924
5 lug conversion, 17'C2 wheels,custom body work,327 vette engine.

1978-#53 "D" track racer.

[Ozzie]

I found my car was rattling under load, sounded like marbles.
I had the mixture right, timing right, etc.
Just richened the mixture a little and now gone.
Doesn't have the rich fuel smell though so I'm happy.
It was just the smallest of tweaks too.
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Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

[PORSCHEV]

Where is the mixture setting..is it on the throttle body? What is the best way to play with the settings? I read in the hanes..but they really try to make it complicated with tools to read from the o2 sensor and a remote tachometer...blah blah.
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1976 924
5 lug conversion, 17'C2 wheels,custom body work,327 vette engine.

1978-#53 "D" track racer.

[Ozzie]

The mixture setting is on the fuel dist between the boot and fuel lines.
You need a long 3mm allen key to put in the hole and locate the screw head.
CCW is leaner, CW is richer, and a minor 1/4 turn makes a big difference.
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Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

[PORSCHEV]

Thanks Ozz.. I am going to try and lean it out...still smells to be running rich.
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1976 924
5 lug conversion, 17'C2 wheels,custom body work,327 vette engine.

1978-#53 "D" track racer.

[fish62570]

Im jealous fellas! I read these and it makes me want to drive. I can't wait to get the beast running and apply what I have been reading to my soon to be peach. By the way Porschev, you have a couple beauties in your stable. I had enjoyed your website about your rebuild and would love to borrow some of your upgrade ideas. Unfortunately it would be the cosmetic approach do to time and cashflow, but what a machine. Well done! Then to top it off, the red rocket is a marvel too!! If the old saying about a bird in hand is followed, what would two in hand be?
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924 work in progress

[PORSCHEV]

Thanks for the kind words fish...... don't get discouraged about your project. I did mine as I could afford it...you can do the same.
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1976 924
5 lug conversion, 17'C2 wheels,custom body work,327 vette engine.

1978-#53 "D" track racer.

[924RACR]

[koolkarateguy]

Well, I'll have to agree with Porschev on this one. I have a timing light and an engine analyzer and what is factory spec and where it runs right can be two different things. What you must remember is that these are for some of us 30 year old cars with vacuum systems that are questionable or totally not working. Mine doesn't even have the vacuum amplifier anymore ( I got it this way) So for a factory fresh (or recent engine) I'm sure all the timing marks work great !! But I'm not going to put up with chugging or worse, pinging if advancing or retarding my timing a few degrees fixes it. Besides, my '79 N/A doesn't have an interference engine so there is going to be no harm running it out of spec. I'll know if it isn't working right because performance will suffer. My 2 cents.
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1979 N/A 924

[924RACR]

And how do you measure it without a timing light?

I'm on the record nearly a decade ago (search the arcihves) as noting that about 6 deg or so works real well as a baseline... decidedly not factory. Also quite measureable... with a timing light.

Don't guess - it's a great way to destroy a head and/or pistons.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[koolkarateguy]

I didn't say anything about measuring, if it's not factory spec there really isn't any point. I don't care what it measures as long as it's running well. If it measures in spec and pings like hell ,I certainly am not going to keep it in spec just because "the manual" says it's right. Not sure how I'm going to ruin pistons and heads this way. If you leave it in spec and it's pinging, you'll destroy your valves along with other head damage. My car works fine, I played with the timing until it worked right for my particular car. And that's all I really care about .
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1979 N/A 924

[augidog]