69 slowmaro

[Audrey]

Some of you may know I purchased a project car a while ago. I'll document any progress here and ask for help as well since this car has one of those carburetor things I'm not familiar with. Below is the breakdown of the car and what it had when I bought it.

1969 Camaro 388 c.i.

350 Small block w/400 steel crank @ .060 over cylinder bore, all solid roller motor.
11.5-1 Compression Ratio (runs on 93 octane)
Weisco, Forged Aluminum, Domed Pistons attached to Eagle H-Beam Connecting Rods/Internally Balanced Steel Crank with Fluidampr Balancer
Aluminum, Air Flow Research 220 CNC Ported Heads/Stainless Valves
ARP Main and Head Studs
Crane Cam solid roller Cam/Lifters = 118531*
Harland Sharp Roller Rockers
Powder Coated and Ported Victor Jr. Intake Manifold
Holley 750 double pumper w/ Electric Fuel Pump
Large 7 quart oil pan and many other powder coated parts/brackets.
Hooker SuperComp Headers to 3.5 inch exhaust with Dual Flowmaster Mufflers
400 Turbo Reverse Manual Valve Body Transmission w/Custom 10” TCI Torque Converter Matched to the engine, trans, gear, and weight of the vehicle. B&M Shifter.
Twin, Oversized, Electric cooling fans/3 Core Aluminum Radiator.
MSD Electronic Ignition, Distributor and wires.
Auto-meter Gauges – 12 Point Roll Cage/w full tub and front wheel Line Lock.
15x15 rear, 15x3.5 front, Weld Draglites
Dana 60 Rear End, 4.88 Richmond Gears, Strange Axles with 3” studs. Coil over adjustable rear shocks.
Painless Wiring electrical system/ Battery disconnect.
Harwood 12 Gallon Fuel Cell

[Audrey]

First problems
1 - high idle to keep it running, even after warm up. Cam spec's aren't small and there is little to no lopieness to the idle. My old 355 had a 230-244* dur cam in it and it loped heavily at 1000-1200 rpm. This one doesn't and idles high, attempts at lowering idle result in stalling. I've checked the floats, they're just a hair low than perfect. I've messed with the primary idle screw but it seems I'm either dealing with it stalling in Drive, or idling at 2k rpms in neutral. So stepping on the gas and break at the same time seems to be the solution. Not ideal, and generating more heat in the tranny.
2 - overheating. Too much old antifreeze and no thermostat in the motor resulted in water pump cavitation and no circulation. Drained coolant, replaced with water and additive 'water wetter' also installed 160* stat. Helped a lot, but still 'overheats' at highway speed. Just takes longer now. Car is turning 3000-3500rpm at moderate highway speed 50-60mph.
3 - battery charging issue, replaced alternator w/ 100 amp version, seems to be working but losing a couple tenths of a volt going from the rear dual mounted batteries to the volt gauge.
4 - spark advance at idle is 22-24* BTDC. Not sure what it is at full advance or if it's locked out. On the list. But I'm used to 12-14 at idle, then 33-36 at full advance (3000rpm and up). It does occasionally get hard to start after driving. There is no start retard on the ignition box. Might upgrade to a digital 6 version but need to understand the problem more before dropping another 400+ into it.

Lots of things going on. The carb is out of tune, there is a lot of rear gear (4.88's), the cooling is a bit of an issue, the chassis needs to be set up, the list goes on. I did get a new set of rear wheels and tires, and one seated last night. The other one is a direct descendant from the devil and will be dealt with at a later date. When you stand on the throttle, she'll spin through 1st, 1/2 way through 2nd, and chirp the tires in 3rd. So the drag slicks should fix that. The end game will be to throw another 200-300hp shot of nitrous on the car, so the additional traction will be put to good use.

[LarryHoward]

Hmm. I’ll gve it a shot. Chance that the radiator is plugged a bit or maybe a bit small. Seems the car was built to run hard for 1o seconds at a time and the system may just be under spec a bit. Also possible that the water pump is compromised a bit. Tough one to troubleshoot.

Double pumper is tough to tune. That and the significant advance could make it finicky at idle. You might try a lower initial advance and see if the idle performance improves any. Will cost you some top end but the attempt will help you isolate the idle issue. I’t doesn't lope at a fast idle but what does it do if/when the idle speed comes down to 6-800?

Battery. Couple of tenths sounds like a resistance issue. Check wire gauge, connections for corrosion, etc. verify voltage drop by using a good MM to check voltages at both ends. Don’t trust the gauge to be accurate.

[Audrey]

Thanks Larry, I was hoping to get your feedback.

Radiator did have some muck in it (but is aftermarket and much larger than stock). Brownish color, muddy texture. Slowly getting all that out, but I do wonder about the pump and am thinking of putting an electric on for a more consistent flow. At idle, I can disconnect one fan, and it'll keep the engine cool while idling in the garage at precisely the stat temp. Or within 5*. As rpms increase it keeps up to around 3k rpms, then it starts creeping. I don't let it get higher than 210*. However with a 3500 stall converter, the engine doesn't cruise at 1500-2000, more like 2600-3500 and only 3 gears and no OD, would be nice to keep cool at 3500 if possible but I may be asking too much. I THINK the pump impeller could be cavitating at 3000+ and limiting flow. It's an older cast iron unit.

I'm a little concerned about the carb size. Similar builds are coming in with 750cfm but then bump to 830-850 cfm if the redline is over 6300. I'll have to look into that as well. https://www.holley.com/retailer/carbselector/

Wire gauge is 4ga, length of run is 20-25' max. Had some lose connections and corrected, MM showing same drop over the run. Not too worried about it as it's at least charging now.

[Orestes Munn]

So, is this intended for the street, the strip, or something entirely other? It would be a hell of an eye catcher with HYR graphics on it.

[TheOffice]

If you had time and money to burn you could have bought a boat!

I don't miss points, plugs and carbs. The tolerances on needle valves in carbs are close to zero. Any wear and it will not run right. I see a rebuild in your future!

Joel

[Ajax]

Eh, the Atomic 4 in my Pearson 30 was pretty tolerant. It had all of those and ran reliably.

[Audrey]

So, is this intended for the street, the strip, or something entirely other? It would be a hell of an eye catcher with HYR graphics on it.

This is murica, why not both?
No stickers for now.

Other slick was mounted on the rim and inflated last night, they're 3"2 as opposed to 31" tall but did come in at 18 lbs less PER TIRE. So 32 lbs off the spinning drivetrain. Rear 1/4 is pretty close to the tire but I think it'll work.

Double checked the fuel levels in the bowls, they're good, checked the setting on the idle mixture screws. They are 3/4 turn out from being bottomed out. Holley recommends starting at 1.5 turns out from bottomed. Once I get it to idle on it's own, I'll start there and re-adjust the timing to something more normal. This weekend might be the time to do it since they're calling for rain.

I had a boat, it cost me money sitting at the dock.

[Soñadora]

that's a sweet hot rod you got there. 67,68,69,70, 70 1/2 are my fave Camaro.

Sounds like you know what you're dealing with. I have this vision of 'retiring' and spending winters rebuilding old VW and/or Porsche motors. It's good therapy.

[Ajax]

that's a sweet hot rod you got there. 67,68,69,70, 70 1/2 are my fave Camaro.

Sounds like you know what you're dealing with. I have this vision of 'retiring' and spending winters rebuilding old VW and/or Porsche motors. It's good therapy.

You could do this: https://www.cnn.com/videos/style/2018/0 ... n-orig.cnn

[Soñadora]

that's a sweet hot rod you got there. 67,68,69,70, 70 1/2 are my fave Camaro.

Sounds like you know what you're dealing with. I have this vision of 'retiring' and spending winters rebuilding old VW and/or Porsche motors. It's good therapy.

You could do this: https://www.cnn.com/videos/style/2018/0 ... n-orig.cnn

Sacrilege!

99% of the appeal of a Slowmaro is the gritty, smelly, physical presence of that internal combustion engine.

Don’t get me wrong. Love the idea of a Tesla-powered car. Maybe in something like a Miata or BMW. You know, something boring like that.

[SemiSalt]

If it doesn't drip a little oil, it's not a real XKE.

[Ish]

If it doesn't drip a little oil, it's not a real XKE.

I suspect the pros have a hidden oil drip pump just for the hell of it. They could throw in some molybdenum and Wurtzite Boron Nitride for yucks just to throw the punters off.

[Soñadora]

If you're going to be working on English cars, make sure you have the right parts...

[Audrey]

Ok, tried to get the carb dialed in a bit more. Dern thing won't idle lower than 1200 rpm when warmed up. As in, it runs fine, but even removing the idle screw out all the way won't drop it down lower. I'll check for vacuum leaks. Mean time I set the idle mixture screws to 1.5 turns from bottomed out like holley suggests. Haven't driven it yet, but it sounds good. Still a little surging at idle and almost got it to lope, but once it warmed up over 180* it just idled at 1200. To be fair, I don't expect it to idle less than 1000, but that'll make a big difference in the jerking when putting it into gear.

Timing. Checked it warmed up. No vacuum advance (none on the distributor). Initial timing is set to 24* BTDC. Full advance is 38* BTDC. Kinda surprised no pings at WOT on 93 octane given the static and dynamic compression. I have had a dieseling run-on issue before but not consistent. I'd like to limit the timing to 38* at full advance, and lower the initial timing down to something like 16* at idle. Hard starting would suggest that's a good idea, I think the dual battery set up is overpowering/hiding any hard starting issues w/ CCA.

Thoughts? I'm used to changing timing issues via set the dizzy where you want it at idle, then go into the ECU and change the spark maps. Obviously I'll need to do this a different way w/ the dinosaur.

[Jamie]

Yeah, the whole analogue carb thing is putting my head in. I'm used to just logging the parameters and changing the ECU settings. Also timing on a an NA engine....much bigger number from what I'm used to.

[BeauV]

24° BTDC at idle is NUTS! That alone could be what forces the fast idle. It may not run at all at 24° when it's only going 500 RPM because there isn't enough velocity through carb and intake to deal with the spark going off that early. I'd need to dig in a bit, but unless you have crazy cams, I'd think that 8-10° BTDC would be fine at idle.

The old school distributors have what is effectively a cam inside them. it controls the advance curve as the the either vacuum or mechanical advance mechanism kicks in. The shape of that cam (which is usually just the side of a metal plate that rotates within the distributor) is how you control the spark advance curve. As a result, you'll get good at making new plates and should have a different plate (or entire distributor) for each activity. On the Morgan I have three distributors with radically different advance curves for street gas, auto cross, and road race. Each makes assumptions about the octane of the fuel and the desires of the driver for how the motor behaves.

I can't lay my hands on a diagram right now, but you should be able to find the advance plate in a diagram of your distributor.

You also may have enough air moving through the carb to require running fast just to keep the car running. I have Weber DCOE-40s on the Morgan. For street use I use chokes in the carb that take the 40mm throats down to 32mm so that I can drive the damn thing without having to keep it revved up to 1,500 RPM just to keep it running. On the 32mm chokes I can idle at 750 RPM, with the 40mm chokes I have to keep it above 1,500 or it dies. I have a LOT of cam overlap so there's no way to get down to 500 RPM.

Hope that helps.

(I've never had to work with an automatic trans. That would drive me NUTS.)

[LarryHoward]

I agree with Beau. On my 4 cylinder Porsche 912 with a few (well, more than a few) engine mods, I had summer and winter distributors. Winter had a very aggressive advance curve suited for a cool (air cooled) engine. In Florida summer conditions, the car wouldn't accelerate with that advance curve without severe knock. For autocrossing, I reset the timing and dwell for 60 seconds of cool engine terror. At the end of the event, I put the standard summer distributor back in before driving home. On summer settings, it would idle comfortably at about 350-400 rpm. For radical autocross? Idled at about 1200.

[BeauV]

Larry, some day we're going to discover we were both at the same event and didn't know it.

[Audrey]

Beau, I agree, I think the timing is a big issue. On my old car (355ci, 10:1 c/r 6spd car, 230/244 dur @ 0.050) I ran 12-14 initial timing. I think 36 total, then used a box to retard it for the N2O. 24* initial kinda blew me away.

W/ the 355 the cam 230/244 would lope around like a proper muscle car. 112 LSA. The New car has more cubes (which usually hides the lumpy idle with more cubes) but the cam is a lot bigger, compression higher, borderline on 93 octane actually. So I figured it would sound quite aggressive, but actually does not. Cam spec's below, dynamic compression is probably 9:1 or higher (don't know the dome volume on pistons). I may do a compression test just to get some numbers.

Cam specs below.
https://www.summitracing.com/parts/crn-118531/requiredparts/brand/redirect?obanner=HP50IYouTube

Larry, thanks. The PO never did anything with it but tool around town a bit. Never had it at the track or dyno so I don't think he cared much about how it actually ran. It's just looked cool. I, on the other hand, don't believe in buying a race horse and never stretching their legs. The answer may very well be travel w/ a timing light, dial back initial to 14-16 for around town and back up to 24 for track days.

[BeauV]

Wow 294° at over 1/2" is a REALLY tough cam to get running right. I'm not at all surprised that it idles fast or not at all. The worst I ever got 255°. This is really interesting. I'll chat up a few hot roders here in Santa Cruz to see what they think. I may find them this weekend.

[Audrey]

New elec. water pump arrived. Will be going on this week. Once I get that done, I'll back the timing off and see what happens w/ the idle. I'm tempted to pull the timing chain cover and see if the cam is installed straight up or adv/ret. We'll see how motivated I am right before the Annapolis boat show this coming weekend...

Thanks for the replies everyone.

[BeauV]

New elec. water pump arrived. Will be going on this week. Once I get that done, I'll back the timing off and see what happens w/ the idle. I'm tempted to pull the timing chain cover and see if the cam is installed straight up or adv/ret. We'll see how motivated I am right before the Annapolis boat show this coming weekend...

Thanks for the replies everyone.

Ah, I'd forgotten about that trick/mistake. Yes, someone could have put the motor together for Full Race All The Time and decided to use a cheaper distributor by simply moving the cams. Does that motor have a chain? I thought the old big blocks had timing gears, but I'm WAY out of date on those sorts of motors.

BTW, my distributor for street driving on normal fuel has a thumb screw on the side so you can advance/retard about 6° without using any tools. Clever these old Brits.

This picture is from a TR-6, but my 4 cylinder engine works the same way.

[Audrey]

My old motor I put a double roller chain on it. Stock is a single chain, cam and crank sprockets, look just like a bicycle's.

This motor has an upgrade from the standard upgrade. Which is a gear to gear set. Stronger and more accurate, but makes more noise driving around. Solid lifters are loud and the exhaust is loud, but I still haven't experienced any detonation that I can feel/hear.

That thumbscrew set up is pretty cool. If I only had a laptop and ECU again.... couple key strokes and it would be done.

[BeauV]

laptop - pssfffttt! Where's the fun in that

[Jamie]

laptop - pssfffttt! Where's the fun in that

That's totally fun - going out late-night for some 4th gear pulls and logging. People at the gas stations look at you funny with a laptop seat-belted in the passenger seat.

[BeauV]

laptop - pssfffttt! Where's the fun in that

That's totally fun - going out late-night for some 4th gear pulls and logging. People at the gas stations look at you funny with a laptop seat-belted in the passenger seat.

You should have seen them stare when the first Google street view photo cars would show up with the twirling mirror and extra generator running in the trunk to provide power because the car's engine wasn't putting out enough to run the electronics and also move the car

[Audrey]

Got the new waterpump plugged in, wired up and tested. Pulled the thermostat to circulate coolant w/o the car running at temp. Went to reinstall thermo and the bolt stripped out. I think this was a long time coming after inspecting the threads. Drilled and tapped, then heli-coil. Going to grab a longer bolt as well. Need to test drive tomorrow night, slap the slicks on it, and hopefully get to the track this thursday for a couple test n' tune runs before the tracks close. Might get it weighed tomorrow if there's time. We'll see if the temps stay low at cruising speeds.

[Audrey]

Didn't make it to the track but did get a short drive in yesterday afternoon. Temps were well behaved with the new waterpump, didn't have time to put the sticky tires on. I made a few pulls but they were kind of a joke pedalling it the whole way. Got back to the garage just in time to have the radiator crack and dump coolant all over the garage floor. So I'm in the market for a new one. I think the car sat so long w/ old coolant that its corroded from the inside out, a shame really, the radiator was a nice unit.

[Tim Ford]

Got back to the garage just in time to have the radiator crack and dump coolant all over the garage floor. So I'm in the market for a new one. I think the car sat so long w/ old coolant that its corroded from the inside out, a shame really, the radiator was a nice unit.

Get your local dog-owners to bring their pooches by and lap that shit up. They love it!

(JK, dog lovers!)