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what fuel mileage

Old August 25th, 2016, 06:40 PM
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Eric I have 8 "hg @850 and 14"hg @3500. Mechanical timing advance is 17* @850 and 32*@3500 and 35* @4300.
If I am reading the article by Lars correctly and understand it I need a Vac canister that gives aprox 14* Vac advance @ 3500 rpm . Am I understanding this correctly? So am I correct that I want a canister that has 14 as the last 2 numbers. The original NON adjustable canister that was installed is a 516-10. I believe that it should give 10* advance on top of mechanical. Is my ASSumption correct?

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Old August 25th, 2016, 08:08 PM
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I've ordered a vac advance stop. I'll update all after I get it
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Old August 26th, 2016, 05:57 AM
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which one did you order?
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Old August 26th, 2016, 08:59 AM
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Eric I ordered the MSD 84281.
I also rechecked Vac with a different gage this morning which I believe is more accurate and I got better readings with only minor flux at idle maybe 1/2 "hg @ idle + 10"hg and 17"hg at 3000. My max mechanical advance was 31* at 3000. I still cannot take the car for a ride as the city just this morning put down another layer of tar and rock. I'm hoping to get it out this weekend.
The car is very hard to start this morning till I spray a little carb cleaner in the carb. I think possibly my carb is leaking fuel down over night, so I guess a carb rebuild is in the near future. What overhaul kit would you recommend? It's been close to 35-40 years since I've rebuilt a carb but as I recall it aint brain surgery

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Old August 26th, 2016, 09:16 AM
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Thats the one I put in my distrbuter, set to 11. You can see if there is fuel before starting by moving the throttle to wot and see if there are 2 solid streams spraying in there. Set you adjustable vac advance so that it brings all 11 degrees at idle. Make sure it is connected to manifold vacuum.
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Old August 26th, 2016, 11:05 AM
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Eric... Dist Vacuum is taken from the center port in the photo, directly forward of the gold painted metal tube which is brake booster Vac. Is this correct for manifold Vac?
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IMG_0763.JPG (1.43 MB, 11 views)
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Old August 26th, 2016, 11:17 AM
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All three of those taps are for manifold vacuum.

- Eric
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Old August 26th, 2016, 11:27 AM
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That's what I thought. other Eric has mentioned that my advance readings sounded as if I'm using ported Vac for advance and I wanted to be sure as it's been many years since I've worked on an Olds 400 eng.
I have mostly worked on Chevy 350 engines in the last 20 or so years.
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Old August 26th, 2016, 01:43 PM
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As stated above, I think its just that the advance cans are setup for higher vacuum than your engine produces at idle. Most engines tune about the same no matter make.
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Old August 29th, 2016, 10:10 AM
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Good morning (other)Eric and Eric
I got my Vacuum advance stop installed this morning and I want to see what you guys think.
With No Vac advance timing is @ 17* @ 625 and 20* @ 3500. With Vac connected I have 18* @ 750(where RPM climbed to w/Vac connected and 39* @ 3500 and no additional rise in timing @ 4500.
Seems to me that I should have more Mechanical advance than what I'm getting. What do you guys think.
Car was no start this morning till I squirted carb cleaner in carb then all was good. I do not have any squirt of fuel into carb till after 1st start. After 1st start it starts fine without any carb cleaner. I have a carb kit on order.(Standard Motor products 635B)

On 2nd check aprox 30 min later I got the following: idle @ 700 rpm timing @ 16* and 20* @ 3500.
Connect Vac idle rises to 850 timing @ 20* and 47* @3500 and [email protected] @ 4700
Can/is the Vac stop messing with my mechanical advance

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Old August 29th, 2016, 10:33 AM
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I think you'll be happier with the mechanical maxed out at about 35 degrees at 3,000 or 3,500 RPM.

That's awfully little mechanical advance.

I've been staying out of this, as Eric is doing such a great job, and has more time than I do right now.

- Eric
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Old August 29th, 2016, 11:47 AM
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well guys on the 3rd check I got some different readings. I removed the dist cap and rotor and found that the "hook" on the back side of the Vac stop appeared to be just touching the pickup coil, removed stop and filed down hook a tiny bit and got clearance. Put all back together and got the following @ idle(725) No Vac 18* 31* at 3500. With vac advance still 18*@idle( Now 825)and 39* at 3500 and 41* max @ 4700 rpm
Other than the advance stop touching the pickup coil, I dont understand why I get different results almost every time I recheck timing. Mechanical advance seems to be much better now. During this entire process, I have not adjusted timing by moving the dist and idle speed is left where it was in previous attempt
Eric< I sorry that I'm taking up so much of your time cause I know most people don't have enough of it. and I really do appreciate all your help
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Old August 29th, 2016, 03:25 PM
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Its not a problem, time is free. I had to place a washer under the advance limiter to raise it up to clear. Yours may still be hitting something. It has 4 stop settings, I used 11 degrees, so what ever setting you use it should equal it + the mechanical . When you do your rpm vs advance notes, please use the same rpms to verify with and w/o vacuum readings.
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Old August 29th, 2016, 03:52 PM
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Originally Posted by My2nd 69 442 View Post
.... I dont understand why I get different results almost every time I recheck timing.
One possible explanation is that the outer ring on your balancer is slipping due to the elastomer being all old and dried. I've experienced similar symptoms.
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Old August 29th, 2016, 04:21 PM
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Eric When I document advance at different idle speeds than without Vac advance it is because that is where the idle goes when I connect Vac advance hose and I can not turn it down even if I turn the idle screw out to the point that it is not touching the idle stop. I have a carb kit ordered and expect it Thursday.
I sure hope that I dont introduce any additional problems when I rebuild the carb
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Old August 29th, 2016, 04:23 PM
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Brian I have marked the dampener on the inner and outer ring and I do not see any slippage and I have run the eng up as high as 4800 RPM
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Old August 29th, 2016, 04:38 PM
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Make sure your choke linkage is not hanging up and overriding your curb idle screw.
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Old August 29th, 2016, 06:34 PM
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(other) Eric The choke as been disconnected by the previous owner and I see no place that it could be binding. The plate stands straight up and down. Once I remove the carb for rebuild, I'll see if anything internally is possibly binding. The heat riser appears to be mostly complete, but is not connected to anything
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Old August 29th, 2016, 06:49 PM
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There may still be the stepped choke idle linkage engaging.
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Old August 29th, 2016, 08:02 PM
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I'll be sure to check the entire choke system tomorrow. Most all of my checks have been done from the driver side so l may have missed something wrong with the choke
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Old August 30th, 2016, 06:01 PM
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(other) Eric & Eric. Today I carefully looked over and lubricated all the choke linkage and I don't find anything at all that is possibly keeping the idle from coming down below 750-800 when Vac advance is connected.
The fast idle stop does not engage till I manually move the choke linkage to full choke and it releases when i bump the throttle linkage. Also, once again I had to use carb cleaner in order to start on the initial start of the day. After the 1st start, it will start fine on repeated starts and I do not see any squirt of fuel at WOT prior to 1st start. Is there any fix (other than complete rebuild) to fix what is apparently the fuel leaking down internally? If possible I really don't want to completely tear the carb down.
Thanks for any advice you can give
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Old August 31st, 2016, 06:35 AM
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One more thing to try to get your idle lower. Disconnect the throttle linkage from the carb and see if that's whats holding it back.

Are you pumping the gas pedal once before initial start? Have you checked if there is 2 solid streams of fuel while looking down inside the carb before initial start?
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Old August 31st, 2016, 09:51 AM
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I was finally able to get the 442 out and drive it this morning and it ran pretty darn good.
Ran AC with no problems. I have not rechecked timing with and with out vac advance connected. I will do that a little later this morning.
Eric yes I have ran engine with throttle cable disconnected and had no real change from what I have previously posted and yes I have tried 1 pump of the gas pedal and still no squirt of fuel even after several pumps.
This morning I hit the carb with a small squirt of carb cleaner and it started right up. I had to play with the gas pedal for a minute or two before it would idle on its own. After that it ran fine. I think that I will leave well enough alone for a while and move on to my dead Tach.
Thanks for all of your and others help
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Old August 31st, 2016, 09:57 AM
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If it has no fuel after 1 day then its time to look inside the carb to see where its going. I'm glad its running well.
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Old August 31st, 2016, 10:37 AM
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What would be the most likely issue with the carb? Maybe the needle and seat?
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Old October 23rd, 2016, 01:22 PM
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Guys I'm very sorry that I forgot to update this post.
I did rebuild my carb with kit and jets and needles from Cliff Ruggles.
Car started on 1st attempt after carb reinstalled. Minor adjustment of the idle mixture screws and all seems to be good.
I have not done any more with timing since the car is running great.
Tach issue corrected with new wire from dist to gauge.
Thanks to both Eric's for all your help .
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Old October 23rd, 2016, 02:41 PM
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I read through this quickly so for give me if I missed this. If the cam was degreed wouldn't that effect the timing ?was,the cam timing advanced.
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Old October 23rd, 2016, 05:37 PM
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Glad you got it running well!

In never hurts to dial in the rest of the tune-up settings, though.

Well, almost never.

- Eric
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Old October 23rd, 2016, 06:12 PM
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Railguy
I wish I could answer that question. The cam was installed 2 owners ago and I dont have the specs used and right now I'm not willing to pull the front end apart to find out.
Eric
I'm changing plugs and a new compression check next week and then I will go thru the timing and mixture settings to the best of my ability. Choke appears to work good at this time.
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Old October 23rd, 2016, 07:02 PM
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Glad you got it Jerry.
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Old October 23rd, 2016, 07:13 PM
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Originally Posted by Railguy View Post
I read through this quickly so for give me if I missed this. If the cam was degreed wouldn't that effect the timing ?was,the cam timing advanced.
Railguy
If I am understanding what you are asking, then no, the ignition timing is completely independent of the cam timing. Ignition timing is relative to the crankshaft/piston position (i.e. top dead center).
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Old October 23rd, 2016, 08:33 PM
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Originally Posted by Fun71 View Post
... the ignition timing is completely independent of the cam timing. Ignition timing is relative to the crankshaft/piston position (i.e. top dead center).
BUT, the distributor is driven off of the rear end of the camshaft, so if the cam timing is changed, and the spark timing is not readjusted, the spark timing will change.

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Old October 24th, 2016, 04:23 AM
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Originally Posted by MDchanic View Post
BUT, the distributor is driven off of the rear end of the camshaft, so if the cam timing is changed, and the spark timing is not readjusted, the spark timing will change.

- Eric
That's what I was thinking. If you have timing set at 35 then you advance the cam 5 I would think it would move the timing to 40 so to get 35 you would need to set the timing at 30. Right?
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Old October 24th, 2016, 05:21 AM
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Well, you need to reset the timing back to wherever it was before (and then possibly tweak it, to better take advantage of the new cam setting), according to the pointer and the balancer marks.

- Eric
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Old October 24th, 2016, 07:56 AM
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Cam timing has nothing to do with ignition timing. Cam timing related to when the valves open and close and will move the power curve up or down. Ignition timing has to do with when to light combustion in relation to a complete burn.
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Old October 24th, 2016, 08:08 AM
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Yes, but.

If someone degrees his cam, and resets it to a sightly different position vis a vis the crank, and leaves his distributor alone, then his ignition timing will have changed as well.

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Old October 24th, 2016, 08:26 AM
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Yes, however again, the cam controls valve timing, the distributor controls spark. Two completely different functions.
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Old October 24th, 2016, 09:23 AM
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Originally Posted by oldcutlass View Post
Yes, however again, the cam controls valve timing, the distributor controls spark. Two completely different functions.
Yeah I guess you're right tdc is still tdc. I f timing I 35 and you advance valve timing 5 it will de 40 should read 40 with a timing light .I stand corrected .
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Old October 26th, 2016, 01:58 PM
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Well Guys I got to a little playing with my 442 today. 400 CID G block w/HEI ignition
Changed plugs R 45 S gaped to .045 an did a compression check as follows
#1 148 #2 145
#3 140 #4 135
#5 140 #6 145
#7 140 #8 140

Checked/Set timing to 14* @ 650 28* @3600 No Vacuum
26* @ 700 & 46* @3600 with Vacuum connected 1* timing increase at most above 4000.
Does anyone see any issue with what I have or any suggestions to improve performance
Thanks,
Jerry
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Old October 26th, 2016, 02:02 PM
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I would set the total to 32-36 instead of 28 as you now have it. You are not maximizing performance with the total set that low.
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