Having recently inherited an old A-body from a family member (still alive - all good), I've gotten hooked on the old-school muscle cars. Like most guys in the same situation, I've also gotten hooked on endlessly tinkering with the thing since my "old" EFI cars wouldn't let me do squat. But I've come across a perculiarity which I can't quite figure out, so I was hoping someone might have an idea or two.

A little background info: I've got a relatively stock 225. "Relatively" in that it's head has had hardened seats fitted, which included having a few thou shaved off, along with a set of old (vintage unknown) extractors, a 2½" pipe and a Holley 2300 (375cfm from an old Ford V8, mounted on the Super Six manifold using an adaptor plate - the BBD which came with the manifold is cactus). I've also fitted an after-market electronic ignition setup I bought cheap on eBay - not a true HEI, but solid state (appears to be a replica or remanufacture of the Bosch unit found on WB Kingswoods). It's this last part which is the main source of my conundrum.

Basically, I set the timing according to the manual - 5ºBTDC. The engine was strong, but lacked punch so I wound it out to 10º. Still not a great deal of improvement and a vacuum guage was used to set what it "wanted" instead. I wasn't exactly sure how much advance I'd given it since the marks only show up to 10º but I really didn't want to keep pushing it since I'd already moved the distributor on its bracket to keep going higher.

A few weeks later I got the chance to test with a lamp which allowed me to dial in the advance and finally see where I was running. 26ºBTDC at idle w/o vacuum. Yet it still didn't ping, and probably could have taken more. I even double-checked to make sure the mark on the harmonic balancer was in the right place. Best I can figure, both the mechanical and vacuum advance on the unit are working (at least, they don't have any obvious reason to not work) which leads me to my question...

Is that much advance without problems normal, or should I be looking at the distributor to see if there's a problem with the curves?

Cheers.

I would also be curious for tips on how to get it feeling a bit punchier. It could probably drag itself up a wall if it had traction, and will spin the wheels on take-off at 2/3 throttle, but it just seems to lack that sense of urgency when it comes to raising engine speed - despite being the lightest, most powerful vehicle I've ever owned. The economy is also pretty bland at around 20mpg imperial (~16mpg US), but I figure the two things may be related.

What year is the engine?
How long did it sit?
The year would help to determine what governor might be in the distributor, 7R, 9R, 15R etc. and will determine the length of the slots for the weights to move for the mechanical advance.
Sounds like the advance plate might be sticking or the pins that the weights mount on are rusty.......You may have to take it apart, clean it and re-lube it to get the mechanical advance working better.......

Take a look at the distributor recurve section under the Engine FAQ and use Joe's spread sheet to map your current curve. Then you can see what is happening and when. I disconnect the vacuum advance and log those numbers, then hook it back up and log the totals. If you log in 500 rpm increments you can get a baseline pretty quick.

My old stock 79 engine feels pretty punchy. I am running about 52 degrees total. (with vacuum advance added)

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

You'll want to check how accurate your TDC mark on the crank pulley is. It's not uncommon for the outer ring to slip & give you incorrect timing readings (ie your actual timing is retarded compared to what the timing light shows.)

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63 Valiant Wagon
225 - 4 bbl

52 total????that just doesnt read right to me.I probably am wrong butt that seems way high.Would like a explination why I think this is so wrong.Guzzi Mark

Lemme see if I can answer the questions so far...

It's a '68 (VE) Valiant Regal. It came into my posession about 6 years back, having been a daily drive since new until that point. Finances, unfortunately, meant it sat for 5 years before I got it back onto the road as I couldn't afford to do the few repairs it needed plus maintain my vehicle at the time. In the year since I got it back on-road, it's been my daily drive and clocked up just under 5,000mi.

However, the distributor is not the factory unit. As I mentioned, I picked it up off eBay: this one here. It's paired with the recommended Bosch MEC 718 coil and the ballist resistor is no longer in the circuit. Perhaps worth mentioning is that it never really had a lot of punch with the original setup either; but I didn't do as much work on the timing when it was fitted.

Dad also brought up the possibility of the harmonic balancer having shifted, so I did check that yesterday. While my testing was hardly scientific (I didn't remove the alternator, so getting at #1 was a pain - #6 wasn't an option due to the master cylinder) I can say with a fair degree of confidance that it's within 5º of where it should be.


I'll get out there either today or tomorrow and check the current curves. Perhaps that's where I should have started?

Yeah, I reckoned it might be one of those when I saw your initial post. About a year ago I sent that seller a question asking where the distributor was made. He replied "Piss off, I'm not going to answer dumb questions for a $74 item." Translation: China! Perusing various car forums I find not much good being said about these. People seem to have driveability and reliability troubles with them. You might be able to get it to work satisfactorily, but it seems to me you may wind up either reinstalling the original dizzy (perhaps with a Pertronix kit) or doing something more akin to the HEI upgrade with a real Chrysler distributor, either a US-made item as linked in the HEI article or, as described here, a later Hemi-6 item.

How many miles are on this engine? Weird timing to get it to run acceptably and lack of vim, vigour and moxie suggest a slack timing chain to me. Have you checked? See here.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Madmax/6,

Go to the engine FAQ section and the recurve thread and look at my old spread sheet. That was what I used on my 9.5 to 1 compression motor running 12 degrees initial.

On the current stock 1979 barn find I am running the curve is much quicker and I am running 52 degrees total.

My new spread sheet I am running 6 degrees initial, up to 19 mechanical @ 3000 rpm and quite a bit of vacuum advance. This curve feels much punchier on an old stock engine and around town, local driving I am getting
22.5 plus mpg.

I am limiting the mechanical to about 20 twenty degrees on both motors with and adding a lot of vacuum advance with a VC-208 can that is slotted for extra throw. That way if I am heavy footed it is still punchy and if I drive nice the vacuum can kicks in like an overdrive. It feels very responsive at any rpm, never flat or lifeless.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Mark and Ted,

There is often miscommunication about "total" timing. Ted means with vacuum advance AND mechanical advance (full on, above 2500 or 3000 RPM). Many racers say "total" is just the (full) mechanical advance number with no vac hooked up. Typically, you'll want around 25-30 deg max mech advance and then add 15-25 deg more vacuum at part throttle cruise for best hwy mileage. Vac advance goes away (comes off) when you floor it.

I run my cars around 26-28 deg total mech, and add about 20 deg of vac for a total in the high 40s at part throttle cruise.

Lou

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Home of Slant6-powered fun machines since 1988

Best I can figure, the engine has a total of around 158,820mi on it (original engine, but the odometer only shows 6 digits - including one decimal place). Unfortuantely I have no real idea of what the maintenance history of it is like as the uncle I got it from is not what I'd call mechanically minded. He looked after it fairly well but specifics aren't available.

I was afraid you'd mention that about the distributor. I did try to research it before I bought it with no luck at all - the only information I could find was a guy trying to put one on an XP Falcon without knowing what he was doing. Fortunately, I still have the old setup in full just in case and I believe there's a local parts place with a Pertronix Ignitor in stock that I might take another look at. It's just a shame I can't afford to do something a little more tried and tested, and none of the parts places I know of seem to carry an electronic dizzy on its own to do my own HEI mod.

Unless, of course, the HEI mod would work on this cheap distributor. Wonder if that would solve some of its problems...? also wonder where I could get an HEI module, since I'm not sure what Aussie engines would have used such a beast.


Unfortunately, I didn't get a chance to more thoroughly check out the timing curves due to a lack of the proper tools (no tacho). At least that won't stop me from checking for timing chain slop.

*ed: After doing some reading... perhaps it would be a good idea to wire in a relay for the ignition? I've spotted a lot of guides that recommend this for the HEI conversion - perhaps this replica dizzy is more sensitive.

well maybe it's how you ask...I asked and here is their reply
china?

yes

- dizzy-su

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slant six's RULE!
http://www.usajon.com

Thanks Lou,Thats what I was missing.Mark

Quick update from today's efforts....

Checked the timing chain for slop. There's the tiniest amount of delay between moving the crank and the rotor following suit. So I figure that's a dead end there.

Also checked for voltage drop leading to the coil and distributor to test the viability of ftting a relay. Not even 0.1v with the engine running which I guess leads me to another dead end.

Out of sheer, morbid curiosity, I've backed the timing back down to 10ºBTDC and tried re-tuning the caruburettor to match. Idle mix is down about a quarter turn on both, but the weird part is that it seemed content to let me drop the float level by a lot. I'm not exactly sure how much is "a lot" because I was trying to tune by ear - for medical reasons I have to concentrate harder on that, so I forgot to count the turns while I was at it. Best guess is I lowered it by a good quarter inch, if not more, without any ill-sounding effects. If only I had some level ground to check the sight plug...

Will be taking a test drive tomorrow with a screwdriver and shifting spanner; just in case. Starting to wonder if it could take all that extra timing because I was flooding it - and it would certainly explain the mileage.

Hi Thalyn, you may want to do some reading before "adjusting" your carburetor, take a look in the engine section's FAQ for links to service manuals covering most Mopar carburetors, and follow the instructions to get it right.

BTW, a relay to feed the ignition is never wrong.

If you follow this link, there is a link in the text to our australian member BUCKET 656's installation, and he also includes a down-under shopping list with part numbers. Good luck.

Olaf.

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Aspenized

I've got it booked in to have someone tend to the carbi properly in just over a week's time. For now, I'm just getting it "close enough", since I don't have access to O2 sensors and what have you. Assuming, of course, the verdict doesn't come back that the thing isn't worth saving (it's a 45-year old carburettor, so it wouldn't surprise me).

I'll likely go ahead with the relay when I pick it up this afternoon from having a wheel alignment done. Doesn't matter how good the engine is running if it doesn't go where I want it to, after all!

The relay is in and, after getting it wrong the first time, working perfectly. For now it's just hanging off the B+ pole hanging out the back of the alternator, though I may move it later just to make things neater.

For those in need of a good laugh, the "got it wrong" part mentioned earlier was from my first attempt to neatly wire the thing into the existing harnesses, etc. Dragged power straight from the battery and took the signal input from the wires going to the ballast resistor. For those who can't already see what was wrong, I wound up only having power to the coil with the key in the "on" position - made it incredibly difficult to start the car, since the power to the coil was cut in the "start" position.

Oh well, it's in there now and it's working exceptionally well.

Which brings me to a question I've touched on briefly before, but would like to ask more clearly now. How exactly is the GM HEI module of any kind of benefit? I can understand how the Pertronix kit works by simply replacing the points, I understand how an MSD kit can do some funky stuff by being the point of control for the entire ignition system, but having the GM module between the coil and the distributor? That just doesn't make sense.

Is it making a more-clean break of the circuit? Does it have pre-determined "gaps" set to better control the duration of the spark? Given it's location in the circuit, it seems as though the actual presence of an HEI coil is pretty much independant of the HEI module itself. Have I missed the mark entirely, or is there some kind of car-voodoo going on here that I've not taken into account?