Timing

[dobie]

So how important is timing? I got my car back tonight, and there are a few issues. The biggest problem is that the car isn't timed right. Apparently the vaccuum advance I have in my distributor is for an emmisions car. The shop is ordering a correct one, but it wont be in until sometime next week. Until then there is no vaccuum advance hooked up. The car runs fine, but I was hoping to tell a sizeable difference from before. I know for sure that the timing isnt right as when I shut it off she wants to stay running.

Also, I hate mufflers........... The first time I heard it it was thru straight headers. There was a noticable choppy idle. She sounded great!! Now that the exhaust is hooked up, she sounds about the same before the larger cam and headers. Talk about a let down........

One more thing, how the heck do I set the idle? The carb is a 650 DP. According to the on- line stuff on Holley's site, there is a "curb idle" screw and a "fast idle" screw. Which one do I use to get the idle down to 900 rpm? Right now it's set around 1100 rpm.

Thanks!

 

[69hemibeep]

So how important is timing? I got my car back tonight, and there are a few issues. The biggest problem is that the car isn't timed right. Apparently the vaccuum advance I have in my distributor is for an emmisions car. The shop is ordering a correct one, but it wont be in until sometime next week. Until then there is no vaccuum advance hooked up. The car runs fine, but I was hoping to tell a sizeable difference from before. I know for sure that the timing isnt right as when I shut it off she wants to stay running.

Also, I hate mufflers........... The first time I heard it it was thru straight headers. There was a noticable choppy idle. She sounded great!! Now that the exhaust is hooked up, she sounds about the same. Talk about a let down........

One more thing, how the heck do I set the idle? The carb is a 650 DP. According to the on- line stuff on Holley's site, there is a "curb idle" screw and a "fast idle" screw. Which one do I use to get the idle down to 900 rpm? Right now it's set around 1100 rpm.

Thanks!

Timing is huge for performance, so yes it can make the new motor a dog.Use the idle screw in front or above the linkage your cable is connected to, on a 650 I don't remember the position but that will change with timing also! Timing is done first.

 

[dobie]

It's the "curb idle" screw which is on the driver's side, the same as the cable/linkage. The fast idle screw is on the right side of the carb.

So then I probably shouldn't mess with the idle until the timing is corrected then, huh?

Ok.

Thank you!

 

[Basketcase]

you need a set of cut outs on those headers. that reminds me...I gotta uncap those sometime....

 

[dobie]

That's funny, cause I was thinking the same thing earlier tonight.

 

[mcmopar]

Use the curb idle screw to adjust the idle speed. The fast idle screw is used to adjust the choke idle speed. Set the timing first, then adjust the idle speed with the curb idle screw. If the idle speed will not come down below 1100 rpm even when you have backed the curb idle speed screw out you will then need to back off the fast idle speed screw and then adjust the curb idle speed screw for proper idle speed. For further info I'd suggest a good book on Holley carbs to help you make the necessary adjustments. There are quite a few to choose from.
Also - a choppy sounding idle is all well and good but your engine's performance should not be measured by how choppy the idle sounds. A lot of guys buy a cam for the choppy idle and then wonder why the car is a dog. The reason is they have the wrong cam for their combination. Your cam should provide really good performance with your setup. All that is needed is to get the engine timed up correctly. Then you can move on to things like transmission kickdown adjustments and other such things. Trust me - I know this all too well. It takes a little time to get things sorted out and it takes a bit of patience, research and trial and error. Approach everything you do systematically. Start with a baseline and write down your settings (timing, carb settings such as float height settings, idle mixture screw settings, idle speed settings, etc.) Then start by changing one thing at a time. Write down your results - does this change seem to help or hurt the car? Make notes and be as specific as you can. You are not running a stock engine anymore so will will need to make adjustments. Use your engine's stock specs as a point of reference but be aware you will need to make necessary adjustments. Now is the time you really begin to learn about engine performance! Be studious and soon you will find your car's "sweet spot."

 

[SomeCarGuy]

What shop did what to your car? The vac advance has nothing to do with setting the timing. I would be looking over the "work" they did. If it is running after you shut down the timing is way off.

What mufflers you running? You can get a pretty loud set to do what you aree wanting.

What cam are you running?

 

[dobie]

Well, the shop did a lot. Install cam, headers, new milled 906 heads, fuel pump, rear main seal, etc... When I went to get her, they were outside adjusting the timing. The owner told me that the vacuum advance I currently have is for an EGR car. With that vacuum advance, it would be at 20 deg advanced. According to him it should be no more than 8 deg advanced. :huh: I really have no clue, obviously.

The mufflers I have are Flowmaster 40 series. 3 inch headers into 3 inch collectors into 2.5 pipe with turn downs.

The cam is a Comp Cam XE274H. .488/.491 split profile lift. This was the biggest Comp recommended when I called them with my specs for the car.

At this point I'm more concerned with the engine install work. Right now I feel that the install was done right. This shop/owner comes highly recommended. The sound I can fix later with other mufflers or the cut-out trick. Timing can be adjusted too. The thing I'm most pissed at right now is that they totally misaligned the hood. I can't open it without wrenching off the hood latch......... :brickwall: At least this is a perfect time to ditch the hinges and put the pins on.

 

[SomeCarGuy]

Get a light and fix the timing. IF the Vac advance causes tourble, just plug it off. You do need it, but not jst to get by. The timing is retarded if it runs on like that.

Flowmasters should be pretty loud but i you don't like that, I would suggest some sort of chamber mufflers.

 

[dobie]

Right now the vacuum advance is plugged off. Hopefully we'll get it sorted out next week or the week after. I guess I'll have to live with things muffler wise, especially if Flowmasters are fairly loud.

Oh well.... Next week maybe.

Thanks!

 

[mcmopar]

Since your vacuum advance is plugged off try 32 degrees at 2400 rpm and then set it back down to 900 rpm and give it a try. Usually these wedges like up to 36 degrees at 2200-2600 rpm but starting a little low won't hurt. It may, however, cause hard starting, especially when hot, and may also cause some pinging and run-on with 93 octane pump gas. You'll have to experiment a bit to nail it down but at least this will give you a starting point.

 

[moparmoose3]

i have the next step bigger cam in a 440. i believe it's the XE285HL all i can tell ya is i know it has 545 lift and 241/247 duration with hooker super comp headers with 40 series flowmasters and trust me you can hear the chop. mcmopar has the same cam as you and he has magnaflow mufflers and his sounds great. even runs good too, so play with the timing some more. also something to consider too is the coil. i had a brain fart one time and hooked the pos and negative wires to the coil backwards. it'll still run but it will cause you some problems. just go over everything. you'll find it sooner or later. just get the timing right. then adjust the carb. . that's the best i can tell ya. been there, done all that. mine isn't an eddy. mines a 750 holley.

 

[Plymouthfan]

If you're going with the Mopar Performance dizzy, here's some info I came across... trust me, it's accurate. I've been chasing timing bugs for a long time. Mine pings when I get on the throttle no matter what my timing is or whether my vacuum advance is plugged....

Mopar Performance Distributors


These distributors are not ready to run out of the box. They have an extremely light set of springs that will bring your timing in at about 1600 RPM and unless you have a 4000 stall convertor and 4.10 or better gear set in a 2600# car your timing is way to early and will cause detonation.

They are a pretty decent distributor and with the proper curve and phasing they work pretty good and can be used for most applications from an almost stock to 11 second bracket car after they are set up properly.

 

[dobie]

Right now the distributor I'm using is a NAPA one. I had a MP one, but something internal broke. I can't think of the proper name right now....... coil gap, or something like that. The thing you have to use a brass feeler gauge to set........ :crazy:

 

[Basketcase]

I drove myself about nuts chasing the pinging on mine when I got it. A mechinac buddy figured out the engine had some bad lifters, lo volume ones at that. we swapped in the hi volume from my 440, and the pinging went away, but the car would run like crap under load. took off the mSD coli and put a stocker on, end of troubles. Better get that thing straighted out by Thursday Steve! :drive:

 

[dobie]

Well, I really wish I could. I work though Mon and Tues 7a-7p, then Wed 8a-5p. I won't get the chance to get back to the shop until Thurs afternoon or evening. Then back to work Friday.

 

[Basketcase]

better catch some 24 hour flu.........
maybe Dave can look at it when we're up there.

 

[dobie]

I'm hoping that maybe the vacuum advance part will be in Tuesday sometime. I forgot when I typed my last post that Tuesday is my short day. I'm actually off at 3pm. Also, depending on what time you guys get up here, I may have a chance to take it first thing Thursday morning at 0800.

Here's hoping.............


:cheers:

 

[Plymouthfan]

Oh yeah, make sure you also check it with the vacuum connected! With the vacuum hooked up, your timing should be around 54º I have an article at work on timing cars with vacuum advance. I'll double check it today to be sure. I had to make changes to my vacuum canister with an allen wrench.