'57 Fairlane HO SBF out of a 1988 Mustang GT AOD trans Edelbrock 600cfm carb Holley Intake Long story short... I have read every thread out there concerning the "correct" timing settings for this engine. Factory setting is 10* BTDC and some folks like to bump it to 12 or 14 BTDC (sometimes more) for performance, until you start to get pinging and then back it off. My problem is, I get some ping even at 10* BTDC using premium gas. I set it at 8* BTDC and the ping is only very slight when I tip into the accelerator at higher speeds. I'm tempted to go to 6*, but I haven't found one resource that has anyone setting it that far from 10*. I know I set the timing set up right when I build the engine and I stabbed the distributor at TDC, so the basics should all be good to go. So, do I just set the timing where it likes to run, ignore where it "should" be and not worry about it, or am I missing something here?
Check your distributor. Sometimes a bad spring or vaccuum advance will throw yout timing way off under a load, causing detonation. You won't notice it when checking your initial timing with the vac hose disconnected.
Do you have your vacuum advance hooked up to a full manifold vacuum, or a ported vacuum outlet? What is you timing at the crank with the vacuum advance hooked up at idle?
check out your carb, might need to richen the mixture up a little bit. how do the plugs look? is it running too lean maybe? small block fords like alot of timing so your situation doesnt sound right.
If the cylinders are carbon fouled, they can be cleaned the old way. At about 2000 rpm, slowly pour about a quart of water through the carb. This cleans the crud off the back of the intake valves and cleans the combustion chambers. Then check the distributor like the fellow above said. That motor should take 12 to 16 degrees of initial, with the vacuum disconnected when you set it.
If you are running the stock distributer and the computer, you need to remove the "spout". It is located in the wiring to the dizzy, a couple of small wires and plug type connector. Remove the plug it is similar to a mini fuse if I remember correctly. Then time it.
check for total advance with and without vacuum advance, late model distributors have a lot of advance built into the mech advance side of the distributor. may need to limit the mech advance part. crane has a vacuum unit you can adjust. you could be over 45plus with initial, mech and vacuum added in.
You need to juice the ignition. If you keep backing up the timing to make up for shit water gas you'll be getting no performance and it will run like a turd>>>>.
I have very similar issues with the engine in my Mustang. It's an 85 flat tappet engine, with an Edelbrock Performer cam, Weiand intake and Holley 600. I have to have mine backed way off too, I'm running an HEI. I've already adjusted the idle and mixture... I'm aiming for new plugs this year (and wires, even though they were new last year). I'm wondering if the "ring" on the balancer has "shifted" some, making it "look" like the timing is off... does that make sense? I know it can happen with other brands of engines, but I've never heard of anyone with a Ford complain of it. EDIT- another thought... with the Edelbrock timing chain, doesn't it advance the timing from stock also? Will that play into timing at the pointer? It's been so long since I've had to deal with this stuff (late models and I work on Diesels) that I've forgotten the "basics" Jay
To answer a few of the questions above: 1. The engine is newly rebuilt (by me) and only has about 1,500 miles on it 2. The distributor is new (just installed last week) and replaces another distributor that was new when I built it. It's a GM style HEI. The one I just installed is a higher dollar one that replaced the $75 Ebay special. One reason I put the new dizzy in because of these apparent timing issues. I even put a new MSD 42Kvolt HEI coil in this new setup just to make sure there was plenty of spark. (insert your comments about how ugly the HEI distributors are here) 3. The plugs are a very nice light brown "coffee with creamer color" when I pull them out to check. 4. Vacuum advance is plugged into the ported side of the carb. Funny thing is, I've been using 7-11 gas the last few tanks because it's right by my house. I filled up with Exxon (93 octane) at lunch today and within a couple of miles it stopped pinging. Could it just be shitty gas at 7-11? I know they're not using Citgo anymore. I'll bump the timing back to 10*BTDC and see what happens. I think it could be related somewhat to the stock curve on the HEI distributor. I found some information on a couple of Chevy forums that talk about the specific of tuning a HEI that might help. If it doesn't ping at 10-12* BTDC then I'll just call it crappy gas and move on.
So, go down in heat range? I am using Autolite 25's right now. Any recommendations for a better plug for my application?
You have to check total timing. I've got a 87 HO in my roadster, I've got the timing set at 15 initial and I get another 20 out of the centrifical advance for a total of 35, I get no pinging, and I run the cheapest gas available. The vacuum advance is hooked up to manifold vacuum and only comes on at cruise for a little more advance and better mileage, and because it's hooked up to manifold vacuum it falls off under a load. If you’re using ported vacuum you end up with the initial timing + the centrfical timing + vacuum advance timing under a load and that is why it's pinging. Gus
We had a stroked big block chev in the shop a while back that had this problem. Everything good and hot ignition as well. Thing would ping if you looked at the gas pedal. So we checked all the sources and opted for a plug change. Lowered the heat range and the pinging was gone. As long as the mixture is right on the carb they should run on the street and not fowl>>>>.
How is your firing order wired? It is supposed to be the same a s a 351W -137, not the 154 firing order like most Fords. It surprisingly will run on either one (ask me how I know) , but not very well if it is wrong. Just fishing there. If you are running the TFI and original dizzy, the set timing connect has to be unhooked. The SAW in the EEC should provide another 20°-22° at WOT, but you have to really need to know what is programed in because the EEC will kick in a little extra over that to simulate vacuum advance at light load. 14°-16° is where I have set about every HO I have tuned for initial with it coming out at 34°-36° at WOT. The original coil harness will be right but if it is a spliced one be sure your polarity is right on the coil. It can ping if it is wired backwards, but will still run. Just some thoughts. I am working on a project to adapt a 2.3L twin plug ignition to a V8 firing waste spark. I have to adapt and shunt an EEC to get advance or key it for full advance (36°) with some kind of MAP reference retard. Still in progress. Fun Fun Fun.
He's running a 600 Holley and Edelbrock intake, so he's probably ditched the EEC system!! cheers Ed N.
It sounds like you have it well in hand. Maybe the vacuum advance is a little slow to drop. Most have an allen screw in the vacuum inlet that you can adjust to make it drop out quicker to take a ping out. Good Luck!
After reading a couple of articles about vacuum advance, I believe that's what it is, too. The stock vacuum advance on the Proform distributor is not adjustable, so I ordered an adjustable one from Jegs this morning. Probably could have gotten the Crane unit locally, but the distributor is a Proform, too, so I might as well keep it all the same. The article I read talked about the vacuum advance accounting for as much as 20-24* at full vacuum and it can be very slow to drop. On the test vehicle for the article, they had to dial it all the way back to about 5* to curve it correctly. They described a ping when you tip into the accelerator cruise as the primary symptom. My gas theory seems valid, too. I filled up with Shell 93 octane last night and I only get a very brief and slight ping right when I tip into acceleration with the initial timing set at up to the recommended 10* BTDC. 7-11's 93 octane was pinging worse with the timing set at 8* BTDC! I'll post an update when the adjustable vacuum advance gets here. I think I'm pretty close to getting this solved. Ideally, I would like to be able to run 87 octane, but I would be happy enough running 89 or 93 with no ping and no performance loss.
Beatnik has it right!! None of this makes a bit of difference if you don't know how much total you end up with. Mark the balancer for 40 degrees or so, rev the motor 'til you pull through the advance, and see where your timing light lands, keep it well under 40 if you have junk fuel. K
I took a two pronged approach to this timing issue today: vacuum advance and temperature control. I've been right on the edge of running hot since I build this engine. Typically, it runs at about 200 on the highway and creeps up over 210 in traffic. I've read some articles that talk about heat and detonation/ping, so I might as well look at that, too. I know the HO 302 is designed to run warm, but it's not even hot in Dallas yet and I'm already running over 200*. So, I installed an adjustable vacuum advance this afternoon. I checked the timing at idle with the vacuum line plugged. It was right at 10* BTDC - where it should be. With the non-adjustable vacuum advance, when I connected the vacuum line, it was advancing the timing by about 22*. I installed the adjustable unit and set it where it was advancing the timing by 10* at idle (using manifold vacuum). 10 minute project - done. I then installed a Mr Gasket hi-po 180* thermostat (PN 4364), filled her back up, burped it and headed out on the road for a test drive. There was an immediate difference in temperature...obviously, but even more than the 15 degree difference in the old and new thermostats rated temperatures. It let it idle in the driveway for about 15 minutes before I left and it never got over 175*. Pretty amazing. On the highway, it runs around 170*. I think the readings are a little low on my cheap Moon temp gauge, but the scale is the same because it's the same gauge that was reading 200+ with the old thermostat. On the timing side, it ran great. Very responsive - no issues at all. I was low on gas, so it was a great time to try out 87 octane and see what happens. I filled it up with 87 octane at Exxon and headed back out on the highway with a little bit of trepidation. To my surprise, no ping/detonation at all! After checking my total timing, I am at 10* initial with another 24* out of the centrifugal for a total of 34*. Seems to be right on the money. I may bump the initial to 12-14* to get a little more pep, but for now I'm just going to enjoy running cool and using the "cheap" gas for a change!
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