I wasn't sure so I did a quick Google search and read about 4-5 highlights that said you double the 8 cylinder reading for a 4 cylinder
CK5
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Dad's 'Mad, The no longer hibernating 1957 Nomad.
- Thread starter ZooMad75
- Start date
Well it’s good to get the refresher on the old tech. It’s been since high school since I checked dwell. Thanks guys.
Doing a little research it looks like dwell should be in the 28-32 range. Going off of specs that I remember my dad telling me that this has the 30/30 grind cam from the 365hp 327 (I’m guessing a match to the carb) the exact spec is 30 degrees dwell with 10 degrees advance.
I’m finding the 30/30 cam is different from the 097 Duntov. Both are rowdy. I’m not messing with valve lash at this point as the clatter went away once the engine had some heat in it.
But I’m totally going to check timing and dwell and adjust as needed.
dwell for a v8 should be between 28-32°, Dam my memory said that but i had to double check. I actually ran a point distributor in my Chevelle till @2001. Had to wait till after y2k ya know lol.
Very cool The Mad is alive. I had black gooey crap in a pick up tube on my kid's 67 F250. I it drove from the sellers, and it was only a year till next attempt to run.
Very cool The Mad is alive. I had black gooey crap in a pick up tube on my kid's 67 F250. I it drove from the sellers, and it was only a year till next attempt to run.
It’s not really a “show” car in that sense, as nobody in their right mind would award it a trophy. Especially if I take it to a Nomad convention. It will be in a “display only” category and not judged.
But I may take it to a show or two, if anything just to be able to park inside the show than out in a parking lot full of normal cars. Easy to check other cars out and bring in some chairs and a cooler full of cold drinks.
Driving is totally in the plans. I plan on getting to a Nomad convention with it in the next couple of years. Power Tour would be a bucket list item but I’d need it to be a bit closer for the time off side of things.
There’s some cool cruise nights that go on during the summer around Denver that I plan on hitting up. Golden has the Supercruise the first Saturday of the month, Englewood has one in June or July. I’m more for the hanging out type events vs an organized judges show with specific classes.
Main thing is to just use it. Not as a daily but get it out and enjoy it.
Back when I was a kid it was the family car. The five of us fit better in it than our 1969 Toyota Corona. We’d take it to my grandparents house in Cherry Creek for Sunday dinner from time to time. I can remember hearing old school country (which wasn’t old then) like Willie, Waylon and such over the am radio on the way home in it.
Might be why I had Willie Nelson radio on pandora booming through my garage all weekend.
Yes, the 2818-1, I believe was 600 vac secondary. And an oem GM carb too. Pretty cool stuff!
the 30/30 cam was rowdy and mid to upper rpm. With 346* of duration/effectively @ .050 more like 254*, and a net lift of .455, it was meant to run. Note that this cam was only used in big valve heads (2.02/1.60) and high compression engines.
the 097 cam was much milder and originally used in the hi perf 283 and up to the 63 327-340&360hp engines. Those engines had 1.94/1.50 valves.
Rob, any idea what pistons are in the engine ?
the 30/30 cam was rowdy and mid to upper rpm. With 346* of duration/effectively @ .050 more like 254*, and a net lift of .455, it was meant to run. Note that this cam was only used in big valve heads (2.02/1.60) and high compression engines.
the 097 cam was much milder and originally used in the hi perf 283 and up to the 63 327-340&360hp engines. Those engines had 1.94/1.50 valves.
Rob, any idea what pistons are in the engine ?
I don’t know exactly what pistons are in the 327 but I do know the compression is on the higher side. 10:1 wouldn’t be a stretch because I don’t remember it being happy on 91 octane juice.
So this was the engine in the car when Dad bought it. But the guy he bought it from worked at Craig Chevrolet in Arvada, specifically in the parts dept. So adding up what I can validate, 30/30 cam, over the counter replacement 327 block, double hump fuelie heads, high compression, carb from a 365hp 327, the only non-gm part is Wieand intake. I think he was smart enough in the gm parts books to put together a pretty stout package. Is it totally set to the 365hp engine specs? I don’t know. But it’s not hard to have an idea what he put together.
It’s pretty cool to me that it’s all GM stuff short of the intake. Besides, I’ve got an intake in the stash to make it all GM. Dad picked up a ligit 1970 LT-1 high rise 4bbl intake 30 odd years ago. That would top off the package for sure.
How is the pcv plumed on that block. I saw the oil fill in the front of intake on 1 video, but not well enough to see a pcv valve. Most if not all SBC up 66 would have had the road draft tube boss cast into the block at the rear of the intake. For PCV this would have been the fresh air vent with a tube to the factory air cleaner.
Only some 67? model year SBC came with q jet mounting and a front oil fill. Before this the common carb was Rochester 4 Jet square bore. Might be why an after market was chosen.
edit: re-watched some of the videos. Looks like it still uses the road draft tube. The oil fill is the fresh air inlet filer. Not sure if the 70 lt1 intake has the oil fill tube or not.
Only some 67? model year SBC came with q jet mounting and a front oil fill. Before this the common carb was Rochester 4 Jet square bore. Might be why an after market was chosen.
edit: re-watched some of the videos. Looks like it still uses the road draft tube. The oil fill is the fresh air inlet filer. Not sure if the 70 lt1 intake has the oil fill tube or not.
The 365hp intake (3844461) has more squared off runners compared to the LT-1 and aftermarket intakes. Flow through the runners was like hitting a wall at every turn. I took mine off and put an rpm airgap on and gained almost 3 tenths.
The Corvette edition of the PCV system (no valve) was from the oil fill tube to side of carb and the rear block opening went to the air cleaner base to draw filtered air into the lifter valley and the filler tube would provide a vacuum on the valley. The fitting on the side of the carb had an orifice in it.
The Corvette edition of the PCV system (no valve) was from the oil fill tube to side of carb and the rear block opening went to the air cleaner base to draw filtered air into the lifter valley and the filler tube would provide a vacuum on the valley. The fitting on the side of the carb had an orifice in it.
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Near as I can tell the pcv looks consistent with what it should be for a ‘57. Oil filler cap is vented and it has a road draft tube.
I think the LT-1 had already been drilled for the oil filler tube. Though I’m not looking to swap it currently as it’s running good as is. It’s not like I have a local drag strip to run it down anyway.
Tonight I wanted to see if I could make the vintage Sun tach to function.
These are interesting items as they use a separate transmitter under the hood.
The wild thing about these tachs is the transmitter uses two 1.35v mercury based batteries. The mercury batteries have been out of production for a very very long time.
Here’s the look inside.
The batteries are close in size to a standard AA battery. I remember my Dad talking about the batteries and that he couldn’t just stuff a pair of AA’s in there. I could not remember why.
Kicking the google-fu into high gear to research it I found why. The mercury based batteries maintained the rated voltage of 1.35v over the life of the battery vs how an alkaline battery sees the voltage drop more over time.
However, the electronics within the transmitter are based on the 1.35v batteries. So running modern AA’s at 1.5v would cause the tach to read inconsistent and inaccurate. Some of the older farts on the HAMB indicated guys have discharged AA’s with a flashlight to bring the voltage down to not overload it.
So I found a couple of slightly discharged batteries in my led shop light that measured in at 1.25v. I pulled the transmitter off the inner fender and swapped them in. I put the unit back on and hooked it up.
I haven’t run the car since Sunday but a couple pumps on the throttle and a turn of the key and it lit right off. However the needle on the tach didn’t twitch at all.
I may put a pair of fresh batteries in just to see if it would work at all even if it’s not accurate. Many indicated the they would work with AA’s, so it is worth a shot.
Worst case I sent off the transmitter to get reworked with modern electronics and drive the old tach. I’m not sure if anybody here have any experience with the old tach but I’m open for suggestions. Dad had the same tach in the white car so if I can get this one working I’ll take care of it too.
I think the LT-1 had already been drilled for the oil filler tube. Though I’m not looking to swap it currently as it’s running good as is. It’s not like I have a local drag strip to run it down anyway.
Tonight I wanted to see if I could make the vintage Sun tach to function.
These are interesting items as they use a separate transmitter under the hood.
The wild thing about these tachs is the transmitter uses two 1.35v mercury based batteries. The mercury batteries have been out of production for a very very long time.
Here’s the look inside.
The batteries are close in size to a standard AA battery. I remember my Dad talking about the batteries and that he couldn’t just stuff a pair of AA’s in there. I could not remember why.
Kicking the google-fu into high gear to research it I found why. The mercury based batteries maintained the rated voltage of 1.35v over the life of the battery vs how an alkaline battery sees the voltage drop more over time.
However, the electronics within the transmitter are based on the 1.35v batteries. So running modern AA’s at 1.5v would cause the tach to read inconsistent and inaccurate. Some of the older farts on the HAMB indicated guys have discharged AA’s with a flashlight to bring the voltage down to not overload it.
So I found a couple of slightly discharged batteries in my led shop light that measured in at 1.25v. I pulled the transmitter off the inner fender and swapped them in. I put the unit back on and hooked it up.
I haven’t run the car since Sunday but a couple pumps on the throttle and a turn of the key and it lit right off. However the needle on the tach didn’t twitch at all.
I may put a pair of fresh batteries in just to see if it would work at all even if it’s not accurate. Many indicated the they would work with AA’s, so it is worth a shot.
Worst case I sent off the transmitter to get reworked with modern electronics and drive the old tach. I’m not sure if anybody here have any experience with the old tach but I’m open for suggestions. Dad had the same tach in the white car so if I can get this one working I’ll take care of it too.
Very cool stuff. I have an old Sun tach, but not that old lol late 70's
Wow, I never knew tach transmitters were a thing. It's basically a repeater, so whenever the distributor fires, the relay creates a parallel pulse. The advantage, of course, is that you isolate the tach from the nasty voltage spikes coming from the ignition coil. This would be so easy to accomplish with solid state electronics now I'll be surprised if nobody offers it. You might try NiMh batteries, as their discharge curve is pretty flat, although more like 1.25V. I would probably set an LM317 to 2.7V and power it from switched ignition (unless the goal is to keep it original, of course). This could be done with a potentiometer and the tach could be easily calibrated.
With a unit that old, there's a good chance one or both capacitors is bad. Do you have a DMM that can check them? Even with no batteries, the relay should chatter along with the distributor and you could set the clearance/dwell.
How I *think* it works, is that every time the points close and the ignition coil is charging, that capacitor charges to 2.7V. When the points open and the spark occurs, the energy stored in the capacitor is delivered to the tach. So the more often spark events happen, the higher the average voltage delivered. That means calibration of the tach depends on the capacitor value and the battery voltage.
With a unit that old, there's a good chance one or both capacitors is bad. Do you have a DMM that can check them? Even with no batteries, the relay should chatter along with the distributor and you could set the clearance/dwell.
How I *think* it works, is that every time the points close and the ignition coil is charging, that capacitor charges to 2.7V. When the points open and the spark occurs, the energy stored in the capacitor is delivered to the tach. So the more often spark events happen, the higher the average voltage delivered. That means calibration of the tach depends on the capacitor value and the battery voltage.
I think my meter can check the capacitors. I’ll look at it tonight.
The one option I’ve found is a device that would replace the guts of the transmitter with solid state parts. It would hide inside the box and with moving the wires around a little it will still have the vintage look. Here’s a link to the instructions:
It’s not an expensive part and well within my ability to install.
Looks like a super cool way to update and still have the vintage style
You could also build a very simple circuit like this for a few $:
It steals power from the ignition coil and triggers off the points through a little filtering so you get 1 event per spark. I'd like to see an optoisolator in there, but hey, it's cheap.
I bet you could also steal the guts out of any regular tach and with a little tweaking it would work the old tach head.
An LM2907 circuit like this is probably about $5.
That technoversion box is nice, but you don't need most of the features (you already have a V8 tach in V8 car). I get it, though, a non-electronics person is going to just buy the box.
It steals power from the ignition coil and triggers off the points through a little filtering so you get 1 event per spark. I'd like to see an optoisolator in there, but hey, it's cheap.
I bet you could also steal the guts out of any regular tach and with a little tweaking it would work the old tach head.
An LM2907 circuit like this is probably about $5.
That technoversion box is nice, but you don't need most of the features (you already have a V8 tach in V8 car). I get it, though, a non-electronics person is going to just buy the box.
I’m not against building something as I have the ability and understand the schematic. But it’s one of a few dozen things I need to get done on the car plus a pile of work on the K5. I’m looking at it more from the convenience factor. I can add in the tach converter pretty quickly and just change the position of the wires to the terminals on the box. Outside of the most astute vintage tach nerd noticing the red wire on the wrong terminal nobody will know it’s been altered at all.
My goal is to get it working and still look like it always has. The 60’s era parts carry a vibe that I want to keep. I’d have more time in sourcing all the components and assembly than I would just stuffing this little box in there. It will cost me more, but it will save me time and bandwidth on my brain which I’ve been short of both lately. So it probably ends up being a wash.
But I do appreciate the suggestion and want to look at the schematics on my laptop tonight. Who knows my cheapskate side might win out and I end up doing it anyway.
So I pulled the box off the fender tonight to see if I can test the capacitors with my meter. Turns out my meter can only test the capacitance with the part removed completely and each leg stuffed into two slots on the meter. I’m not taking them out, yet. I did check resistance on the two on the top. Both showed a rising value to infinity. Last I checked that’s normal.
Since I already had it apart I tossed in the fresh AA batteries I had out. With them in place I double checked that I was seeing voltage on the tabs that the batteries contact because the smaller batteries can be pushed in too far the negative side will not contact the tab.
With it put back together I remounted it on the inner fender. With the wires reattached I went ahead and gave it a try. The engine barked to life again and the tach was working! Hell yeah!
I broke out the tach/dwell meter to check the accuracy. Amazingly the meter works better when you attach the lead to the negative side of the coil. (It’s was the the first time in 30 odd years I hooked one up last weekend)
The tach showed more on the mark than last time and showed about 200 rpm less than the reading on the Sun. Though the dwell reading is dead nuts at 30 degrees.
I’m ok with the 200 rpm difference. That tach setup is 60 years old the fact it works at all is a bonus. I’ll get some NIMH rechargeable batteries so I can take care of the other ‘57 too. The lower voltage might bring it closer but I’m not going to sweat it if it’s not perfect.
But it’s a hell of a little victory. I will say this the needle action is so smooth. The needle doesn’t flicker or wiggle but just smooth motion as the rpm’s go up or come back down. I don’t remember any of my auto meter tachs working like that. Old tech is so cool.
Speaking of which while I had the engine running I tried out the AM radio. It works too! It takes a couple minutes for the tubes to warm up it started to pull in signals. I went up and down the dial and worked good. Too bad all that’s on the AM dial around here is religious, Hispanic, sports or hard core conservative. No oldies. I think I’m going to explore having one of the Wonder Bar radios converted to modern guts with FM and Bluetooth. At that point I’ll probably add some 6x9’s in boxes under the rear seat to go along with a dual voice coil speaker in the stock location. I’m not looking to go full audiophile on it, but I need a little background music to go along with the pipes.
Since I already had it apart I tossed in the fresh AA batteries I had out. With them in place I double checked that I was seeing voltage on the tabs that the batteries contact because the smaller batteries can be pushed in too far the negative side will not contact the tab.
With it put back together I remounted it on the inner fender. With the wires reattached I went ahead and gave it a try. The engine barked to life again and the tach was working! Hell yeah!
I broke out the tach/dwell meter to check the accuracy. Amazingly the meter works better when you attach the lead to the negative side of the coil. (It’s was the the first time in 30 odd years I hooked one up last weekend)
The tach showed more on the mark than last time and showed about 200 rpm less than the reading on the Sun. Though the dwell reading is dead nuts at 30 degrees.
I’m ok with the 200 rpm difference. That tach setup is 60 years old the fact it works at all is a bonus. I’ll get some NIMH rechargeable batteries so I can take care of the other ‘57 too. The lower voltage might bring it closer but I’m not going to sweat it if it’s not perfect.
But it’s a hell of a little victory. I will say this the needle action is so smooth. The needle doesn’t flicker or wiggle but just smooth motion as the rpm’s go up or come back down. I don’t remember any of my auto meter tachs working like that. Old tech is so cool.
Speaking of which while I had the engine running I tried out the AM radio. It works too! It takes a couple minutes for the tubes to warm up it started to pull in signals. I went up and down the dial and worked good. Too bad all that’s on the AM dial around here is religious, Hispanic, sports or hard core conservative. No oldies. I think I’m going to explore having one of the Wonder Bar radios converted to modern guts with FM and Bluetooth. At that point I’ll probably add some 6x9’s in boxes under the rear seat to go along with a dual voice coil speaker in the stock location. I’m not looking to go full audiophile on it, but I need a little background music to go along with the pipes.
The glow of that tach takes me waaaaay back. So cool.
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Nice work Zoo, yep the tach video puts thoughts of several cars from my youth back in my head.
As much as I like stuffing led bulbs in everything I have, it would be wrong to do it to this car. The warm glow of the dash lights (which all work btw) is very nostalgic. I can remember looking over my dad’s shoulder in the middle of the night on our way to Omaha for a convention run to see the dash lit up. Dad was popping cinnamon fire jolly rancher candies and swigging Pepsi to keep alert. We left at one or two in the morning to get into town mid day and get a large chunk of the drive out of the way in the cool of the night vs heat of the day. I loved that the high beam indicator lit the bow tie in the cluster in red.
Totally brought me back too. Can’t wait to fix the other one now too.
