Distributor Vacuum

[tls3601]

Thanks, going to round up the missing parts and get back with you about my carb. Jim-Have any '78 Fedral dizzy's for sale??

 

[tls3601]

If my booster was bad wouldnt it want to stall every time I hit the brakes? That is not the case. Spot, think I could JB or weld on the connector when I open up the hole where vac advance connector should be?

 

[FJ40Jim]

Booster badness is a spectrum. It's not perfectly sealed one day, and totally blown vacuum leak the next day. The booster may be starting to leak too much, but not leaking bad enough to stall the engine. Just bad enough to leak the mani vac down to engine stumbly level.

To replace the missing vac fitting, use this:

 

[tls3601]

Use that where mine was cut off? Thanks Jim, BTW is discussing timing nomenclature; 7 deg BTDC-is that 7 degrees "before" top dead center or 7 degrees "below" top dead center? Going to contact my potential parts source for my "missing" fuel vent connections, will update on what I can find soon.

 

[FJ40Jim]

Use that wherever a hole can be drilled & tapped to 8-32. Somewhere on the vacuum side of the canister, possibly right where the original barb is brazed in place.

Yes, 7* Before Top Dead Center.

 

[tls3601]

Jim, "you the man"-thank you. How difficult is it to remove the dizzy to make this fix and then get it put back in the exact way it came out? I am not super mechanical but willing to try. So, by adding 10-12 degrees the new spec for timing would be at TDC(10 deg) or 2 degrees "after" TDC(12 deg), is that ATDC, a for "after"?

 

[tls3601]

With the parts you suggested, you did not mention the blue BVSV, my existing pic shows one of the connectors missing(there are two I believe), do I need that in addition to the cannister+vent valve, VCC on drivers fender and of course mounts and hoses? I might be missing one of the vent lines-going to VCC on other side of motor-drivers side fender.

 

[FJ40Jim]

If an adjustable timing light is available, set the light to 10-12*, then twist the dissy to bring the TDC line to the timing pointer.
With a fixed timing light, put the BB 3/4 of the way down toward the bottom of the timing window.

The emissions drawing for 78 shows the canister purge being controlled by the lower BVSV, which looks OK in your pic. To clean it up nicely, the broken BVSV could be removed & replaced with an allen plug.

 

[tls3601]

Thanks again Jim, I have a guy looking for those parts right now. I believe under the cannister is a connection that runs to a pipe along lower passenger side firewall to nowhere, an outpocketing in the wall. I have a pic of this, this pic is from below-am I right with where it should have a line running off it to the bottom of the cannister?? BTW regarding the timing what do you mean by "BB"? I ordered the vac can fitting-thanks! Also, roughly what is your turn around time on a carb rebuild?

 

[FJ40Jim]

The pipe that disappears into the body x-member is the emergency overflow from the canister. It just goes into the box section and ends.
The BB is the BB on the flywheel that marks 7*BTDC. RTFM for pics & more info.
Way backed up on work right now, prolly 6-8 weeks.

 

[tls3601]

So a hose connects that pipe to the bottom of the cannister I believe? OK, sorry but don't know the lingo for RTFM? Thanks for the info and will give you a call soon.

 

[tls3601]

Getting my fuel vent stuff

 

[cuencanolenny]

Lenny, with due respect, your experiment is not very controlled and therefore not very useful. You are taking a LC with unknown timing settings (you admittedly don't own a timing light or dwell meter) and unknown equipment and you make a modification that results in your vehicle appearing to run better. The only valid conclusion you can come to from that test is that YOUR vehicle appears to run better. If you can verify the timing settings and the carb and dissy you are running, then your experiment might be meaningful to someone other than you.

Sorry for the delay in getting back with you. The dwell meter and timing light came home on Monday, 5JAN15. So yesterday I stopped at the Toyota Parts place here in Cuenca as I wanted new Denso W14 plugs, he had only W20EX-U and said that was for the Land Cruiser. This number would equate to a much colder NGK6 than the NGK4 I have been running, and fouling. I also wanted a side cover and valve cover gasket and they were not available individually but only in a complete kit for $190! No thanks. I'll have to do some more checking on that as there must be a way around his "we make those" scenario.

So yesterday afternoon I started with checking dwell, 23, oops, that is way low. The FSM specifies point gap at .016-.020 and dwell at 38-44 degrees. I had the points set at 18, way off on the dwell. Timing checked a TDC, but the rpm's (by ear) were right at 500. So I adjusted the points with a .012 feeler and got them to 38 degrees, adjusted timing accordingly and adjusted idle speed. Then I plugged the manifold vacuum advance hose back into the distributor, no change in anything. A couple of years ago when awaiting parts from the USA after purchasing this vehicle I ordered a MAF 6-1 header. They had a deal that for another $75 a new points type distributor and I bought it. So I grabbed it out of the box and plugged the vacuum line into it, instantly I see the advance work. So I remove the distributor and replace it. I set the points in the new unit on the bench with a .014 feeler gauge. Installed it wouldn't start, a minor twist of advance and it lit right off. The first thing I checked for was oil pressure, none. So I went through everything again and fired it up and good oil pressure, cold engine so that 40 lbs always looks good, eh? I let it run for a little, rough idle, to warm up. Then I connected the dwell meter and saw that I was at 31 degrees. I adjusted the points with a .012 feeler gauge and got 41 degrees dwell, smack in the middle of the range. I checked and adjusted the timing which changed quite a bit. With timing at the 7 degrees BTDC and idle at 500 I hooked up the manifold vacuum hose. Immediately the rpm's jumped 400 to 900 rpm. I lowered that, double checked dwell and lowered the hood. I took a test drive which includes my mountainous dirt roads, rough pavement and then onto the freeway. Two big thumbs up. Not a single ping, vastly improved low end performance and smoother sailing on the freeway. I love it. So you were correct in that the advance would change the timing, can't tell you how much. On the test drive I thought maybe I should have popped for the advance timing light. I didn't because it is a tractor motor and I would have used the function once, to tell you what it advanced to. Regardless, after adjusting the idle and taking the test drive I would say the information contained in this link http://chevellestuff.net/tech/articles/vacuum/port_or_manifold.htm is validated. I will have to see about these plugs in a few days. I noted when investigating different options (NGK, Denso, Champion) that the NGK plugs will not necessarily be made in Japan. My mechanic pointed that out to me, these Denso plugs were twice the price of the NGK's here, but they are clearly marked made in Japan. The other curiosity in this change of distributor is that my old distributor looks exactly like the pictures in the FSM, however, #1 on the cap (all numbers are on the cap) points at #4 cylinder. The FSM instructions for installing the distributor in a "disturbed" engine direct that the rotor be pointing at the #1 cylinder, which is what I did. Not sure why the discrepancy, but just noting FYI. The new cap(s) do not have any numbers. They are "keyed" to the housing the same as the old with the tang above the vacuum advance can. Which in relation to the dipstick provides a good reference point for adjusting timing as I had to do when I dropped down to sea level and it was pinging like crazy. Bottom line, manifold vacuum to the distributor is good.