1981 El Camino

[Maverick]

The replacement carb makes the timing behaviors more sensible. The engine will idle now with 10* initial timing but it picks up 200 RPM and smooths out when the vacuum advance adds about 20*. Idle vacuum also picked up from 15 to 17 in Hg. Mechanical advance adds about 22*-24* for total at 34*-36*.

The idle in neutral has to be 900-1000 to not stall in gear. Even at 900-1000, it stalls if AC is engaged in gear. With the idle that high, and 2.41 rear end, it probably won't have much engine braking around town. There's another reason to get some steeper rear end gears. I didn't expect the 2400 stall Hughes converter to drop RPMs by 200 when put in gear. Don't know whether to blame the converter or idle quality.

I'm beginning to appreciate the advice to focus on total and initially ignore initial timing. I"m thinking ideal might be: total 34-36 (18 initial + 16-18 mechanical) and idle 30 (18 initial + 12 vacuum). To get that, it would need an adjustable vacuum canister (on order form Amazon) and adjustable mechanical advance stop. This is the best idea I've seen for limiting mechanical advance - see Sideways' method. http://www.camaros.net/forums/13-perfor ... vance.html Don't think I'll do Sideway's mod any time soon but maybe someday.

[Maverick]

In replacing the manual choke on the carb to be returned, a vacuum leak is evident in the gasket on the choke vacuum port. Blueprint tech guys thought maybe there was a vacuum leak. I blocked off all the vacuum hoses with no change. Didn't think about the vacuum for the choke pull off that's built into the choke housing till a week or so ago. While swapping the manual choke back on, I looked for evidence of a leak and there it was. Notice the dark path on the port.

I don't remember replacing the cork gasket when the electric choke kit was installed so it may have come that way from the factory. Or, maybe I did replace it and cause the vacuum leak. A new cork gasket is still there in the parts left over after the electric choke kit was installed so maybe that's the original gasket.

Looks like the square cork gasket has to be trimmed to fit over the port. I won't be installing the electric choke on the new carb with it on the engine. Its too hard to see what's going on.

Got the replaced carb ready to go back to Blueprint. They provided a shipping label and sent the new carb out with no invoice and no means to charge me. I'm pleased with the tech support and customer service,

[Maverick]

Note to self: Carb, tracking number 1Z 777 520 90 4751 2077, was returned to Blueprint arriving 7/7.

No decision yet on how to get the advance curve set right. This https://www.msdperformance.com/products ... arts/83653 would be great since it has mechanical advance stop bushings and, presumably, adjustable vacuum advance. There just has to be a less expensive way.

I could set total at 34-36, use the adjustable vacuum advance to set initial plus vacuum (i.e., idle timing) at 18 or higher but that puts initial (off-the-line timing) at around 12 which I think is not enough for the best low end torque.

WXO dropped off an old HEI distributor for me to experiment on. Might try to fashion an adjustable stop for it and, if successful, do the same for the dist that came with the 383.

WXO also dropped off the 6/17 issue of Hot Rod Magazine with a very good article on carb tuning on a 383. Lots of things are explained in the article, such as WHY hotter cams take more timing and how carbon-ed up plugs can indicate either too lean or too rich.

Since I'm putting more advance in than recommended, I'm concerned about detonation at WOT. MSD previously made a knock alert kit https://www.summitracing.com/parts/msd-8964/overview/ but it's discontinued. (Wonder if people were to claiming the knock alert kit didn't warn them and blaming MSD for engine damage??)

Found this http://www.viatrack.ca/ and it's on the way. It will use the '83 El Camino knock sensor, Standard Motor Products KS2. (Already had ordered it thinking I'd try to get the knock sensor to make "clicks" in a radio.) The KS2 screws into the SBC block drain plug. The KS2 and its pigtail are waiting to be installed. Boris Mohar, borism@sympatico.ca, builds and sells the Knocksense kit.

If money were no object the EC would have the more tuneable QuickFuel 750 carb that's on the Continental, an MSD ignition box with programmable advance curve, and an MSD distributor. I should buy some lottery tickets.

[Maverick]

This might get me admitted to the Cheap Bastages club it if works. Need to limit the mechanical advance to keep total in check with as much initial as the 383 seems to need. A 10-32 screw fits nicely in the holes on the plate and limits the weight travel. One side of the screw head is ground down to the diameter of the thread and a cam shape goes around to the original diameter on the opposite side of the screw head to provide for adjustments. A nut under the plate secures the stop cam. There's room for a lock nut on the screw that will be added when adjustment is final. Some clearancing of the rotor may be required to fit over the screw head.

First try will have the stop set for maximum travel.

Tomorrow, when the neighborhood is at work and school, I'll see what that does for total advance.

[Maverick]

Clearanced the rotor for the new stop screw.

Initial timing was only set at 9* BTDC and total was 30* with the new stop screw set to allow new max advance. Moved initial to 11* BTDC and total was 32*. Close enough for government work.

Then, the MSD whiz bang HEI module failed. Put the module that came with the 383 back in and it runs again. Think that's enough frustration for today. Maybe I'll get the MSD module ready to return.

[Maverick]

The MSD HEI module went back. Hope they do the refund.

I bought an MSD 6AL-2 ignition box. The stronger, multiple sparks helped when the Maverick objected to idling in gear it and it helped the 383 too. It idles OK now in gear with reasonable curb idle. It also provides a rev limiter (actually TWO rev limiters). Lost that function when the MSD HEI module failed.

It still idles too slow, or even stalls, when the AC is turned on. Guess that's normal. Holley sells an idle solenoid to kick up the idle when AC is on. I'll call them and ask which bracket goes with my carb. Pretty pricy at near $100 for the solenoid and bracket but it should do the job. And, I won't have to implement my hair-brained scheme to put a vacuum switch in the compressor power supply, switched by ported vacuum to turn off the compressor when idleing.

I'm also working on electric releases for the tonneau cover latches. Found a pair of universal door lock solenoids for $10 shipped. Now a pair of adjustable pull rods are needed to install them. The adjustable rods will no doubt cost more than the solenoids. A quick test indicated the solenoids are strong enough to release the latches.

Got my "two steps forward" today!!!

[Maverick]

Got the Holley AC idle solenoid but when I tried to put it in it's place, the upper radiator hose was in the way. I never liked that hose anyway. It runs sideways from the thermostat housing over the valve cover, squeezed in between the AC compressor and the oil fill cap.

Before:

A guy on the El Camino forum suggested a hose ("It is an upper hose for a 1990 Suburban 1500. Carquest E71973") that goes forward from the thermostat housing. Fortunately, I already had a swivel housing to point the hose forward.

After:

That picture shows the hose before about 8" was cut off the engine end to make it work.

With the new radiator hose, the AC idle solenoid goes on.

The solenoid was adjusted so, idling in gear, no RPMs are lost when the AC cycles.

But, even with the replacement Holley carb, MSD CD multispark ignition, and AC idle solenoid it STILL doesn't run smoothly except under heavy throttle. Guess its time to do a compression check.

[Maverick]

Got the electric releases installed for the tonneau cover. Picked up two generic door lock solenoids from ebay for $10 shipped. Set them up to pull the levers on each side to release the cover.

Previously, the tonneau cover was opened with a strap hanging over the tail gate that pulled the tail gate release lever on the inside of the tail gate to get access to the levers that held the cover down. Didn't like the strap hanging out.

10-32 threaded brass rods with helm joints on the ends connect the solenoids with the levers.

Works great. New tips for the soldering gun will arrive tomorrow so I can finish the wiring and mount the push button behind the driver's seat.

Still trying to sort out the poor idle. I think there must be a vacuum leak somewhere although I've checked and found none. Reason I suspect a vacuum leak is only .020" of the transfer slots are exposed with the idle at 800-900 RPMs. Seems like it must be getting air from somewhere. WXO is coming over tomorrow the help check my logic.

I removed the carb to check the transfer slots exposure expecting to find too much of the slots exposed and found just the opposite.

[Maverick]

WXO came by with another Internet carb tuning video that took quite a different approach. First, it said to set the throttle blades so the transfer slots were "square" as opposed to the .040" suggested by the video I was viewing. That made the .020" exposure of the transfer slot more reasonable since the transfer slot is only .024" wide. That disabused me of the notion that there had to be a vacuum leak.

Second, it said to start with the idle mixture screws out 2.5 turns where I was starting with them out 3/4 turn. We took the screws in to about 1.5 turns to get the best vacuum reading.

The new approach worked well. Its idling and running much better. Not perfect, but much better. Total timing was 41* with initial at 21*. That was backed off to 36* and 15* I thought I'd connect the vacuum advance to ported vacuum to get advance only at cruise but for some reason ported vacuum is getting vacuum at idle. So, now the plan is to connect it to manifold vacuum and adjust the max vacuum advance down to 5*. That will put idle back at 21*.

AFR is still too rich on idle and cruise. The #72 jets had already been replaced by #70s and #65s will go in today.

[Maverick]

#65 primary jets didn't lean the mixture enough. #60, 61, 62 and 63s were ordered from an ebay seller that lets you choose any sizes for 8 jets. I'll install the smaller jets and see what happens but based on my limited experience, it doesn't seem that a 383 CI engine should require jets that small. I'm wondering if smaller jets will be masking some other issue. Comments, anyone?? Only idea is maybe the power valve is leaking? I did notice a wiggle in the power valve stem when the jets were changed. I'll replace the power valve next time the jets are changed. Float levels are correct.

WXO took Fred32 for a short ride with some "one wheel peel" after which Fred32 suggested the rear tires should be swapped, side-to-side.

Autometer tach and speedometer are on order.

https://www.summitracing.com/parts/atm-1476

https://www.summitracing.com/parts/atm-1478

The 3 1/8" gauges should fit nicely in the gauge cluster. Speedo will replace the broken original speedo and the tach will replace the on again/off again clock. A new cable will be required to replace the destroyed cable with the GM push-on connector at the head.

[TireSmoker]

65 jets on a 400+ HP 383 sound suspiciously lean to me, especially after coming down from a 70 jet -- changing 5 number sizes is supposed to be a BIG change. The more important question is, how does it drive with the 65s compared to the 70s? Changing power valve not a bad idea, especially if you have a known-good spare.

-Dave

[Maverick]

Not a big change when going from 70s to 65s. After the timing & idle mixture adjustments WXO and I did, and going from 72s to 70s, the plugs went from very sooty to charcoal grey. Haven't checked the plugs with the 65s but the AFR meter still reads rich except at WOT. That's what made me question the power valve seal.

The spare carb parts include some slightly used power valves.

[Maverick]

Got the EC to Henry's yesterday for the dronectomy. Got about 3/4 of it out. Moved the needle from "obnozious" to "Tolerable". When the floors are repaired, it'll get some good sound insulation on the floor and the whole back side of the cab. I suspect the rear surfaces of the cab are acting like a drum and passing the sound in.

We then headed up to my favorite photo site at a boat launch on Falls Lake and got some pictures. I'll get a large print to match the large prints of the Maverick and Lincoln taken with the same setting. Also the National El Camino Owner's Association, which owns the EC Forum, has been PLEADING for pictures for calendar(s). Decided to oblige them although mine's not yet a calendar girl.

WXO came over today to continue the tuning. We replaced the somewhat wobbly 65 power valve with less wobbly 65 from the spare parts. Also replaced the 14X3" air filter, that seemed to restrict flow and reduce AFR by .5, with a 2" from spare parts. A 14X3" K&N is on order from Amazon.

Runs better each time we work on it. It's getting close and maybe good enough. I'll drive it for a few days and see how it goes.

[Maverick]

14X3" K&N air filter installed. Headers loosened, dropped down, and massaged to get 1/4" clearance with the right lower A-frame. Relay installed to avoid starter solenoid's current thru the ignition switch. Hope that will eliminate the occasional failure for the starter gear to engage the ring gear. Wires to the starter rerouted a bit to get good clearance from the headers. High Temp RTV applied to the 1/8" aluminum header gasket in hopes it will seal up the small leaks.

Next task is the Autometer tach and speedometer. I need an 84" speedometer cable from the TH 350 to the 5/8" screw-on, rather than the GM push on, connector at the head. There is, no doubt, one for some application that would fit. I sent a query to a custom cable maker but I'll see if I can somehow find a standard one that fits.

Edit: Ordered a custom speedo cable from a shop in California. $60 shipped. Hope it's right.

[Maverick]

Got the Autometer tach and speedometer installed to replace the non-working clock and broken speedometer. The 3 1/8" gauges fit nicely where the original gauges were. Also installed blue LED gauge lights. Pictures aren't great because of reflection off the lens but it all looks pretty good.

Haven't tested the speedometer yet but everything else works. Custom cable fit well. The contacts for the ammeter were cleaned and treated with conducting grease. Loose copper ribbons at the gauge connector were glued down with conducting glue. Volt meter is reading accurately for the first time.

Its drivable again.