gt40 running rough

So I found this when googling the issue. Someone else was saying there car will only idle at 60 degrees timing.

#16
B4Ctom1's AvatarB4Ctom1 , 02-20-2002 09:55 PM
during a bench race session of car builders and racers I posed this question in the form of a pop quiz, "when you try to start a car and the thing will not run without a bunch of advance and the timing light reads like 50*-60*, what is generally the problem?" I got a resounding answer of, " a dist that is 'stabbed' 180* out." when I posed the question of the timing light reading and why it reads that way I got everything from a, "it just does..." to a, "when the earth's orbit..." ps: no prob 87_ta, its cool

Here's at idle it's about 40

https://youtu.be/5ZPowF2gn1c

Here's at 3k rpm

https://youtu.be/nIEjp8G5vwI

i took it out saturday and it ran pretty good. i was out there for about a hour and had no issues. pulled hard off the line, i filled up 1000 pounds of fatsack and it would still pull out of the water with no issues. i dont know maybe i put the f150 balancer back on the engine would i should have put the gt40 one on so its throwing the marks off

i really try to stay out of shops, but i have heard good things about them

Mike9812121298 wrote: So I've messing around with it this morning. I moved the timing down to 5 ran sluggish. Tried 10 a little better, tried 15 a little better, I kept moving it up until 35 and now it revs up and doesn't bog down. It sounds like it's running good. I've been reading that it shouldn't even run at 35. I must of installed something wrong when I put it back together? I checked for tdc and it lined up with the balancer marks

Back on the 17th you mentioned that TDC lined up right so it's not a balancer issue.

What's your timing if you check it running down the lake at 3000 rpm or so?

Or better yet, what is it at every thousand RPM running down the lake?

I think those timing numbers under load every thousand rpm's will be really useful to figure this out.

Key words here are..................under load

So before I went out I moved the timing back to 10 put the spout back in, rev up in the drive way and it sounded good. Took it for the water test and it ran good. I don't really know what changed from last time trying to run at 10 compaired To now. Prob screwed up the engine in the process. It ran good on the water but I noticed oil psi was dropping at idle to 10 or so. I'm gonna swap out the oil and filter tomorrow and see if that helps

From and old thread when I was doing some prop testing.

The GT40 is pretty conservative with ignition advance.

Timing

No load                                   Running on Water

700rpm             8 degrees                         700rpm             8 degrees
1000rpm     11 degrees                         1000rpm     11 degrees
2000rpm     20 degrees                         2000rpm     27 degrees
3000rpm     28 degrees                         3000rpm     31 degrees
4000rpm     30 degrees                         4000rpm     30 degrees

With the GT40 you can only set the static timing the rest of the time the GT40 ECM adjusts the timing depending on input from all other sensors it has a range of 25 degrees from memory that it adds to the static timing from the table in the ECM.

Base timing per manual is 5 deg BTDC with Spout disconnected and engine at operating temp. I have played around with this and actually have tried other settings up to 10 BTDC. I had mine set to 8 degrees with the GT40 ECM. Tried this setting on another GT40 at GL and could hear a slight ping so set it back to standard.

The GT40 also has knock sensor that will retard timing if detected.

So, a new low pressure fuel pump was the fix?

That has nothing to do with what was going on with the timing, that doesn't change with a fuel pump????

Why not set the timing to 5* like its supposed to be and see how it runs?