How many members are local to Oklahoma City?

[trentonm]

I ask because I'm curious if any of you all know of someone (or maybe one of you) who has more knowledge than my grandfather and I do about the U20 who is also local to us. We've gotten close to getting our roadster road worthy, but we just can't quite get there. It feels like no matter what we do our car just doesn't want to run the way it should. Now I'm a total newbie at 21 years old so I can guess as to what needs adjusted but I don't really know. And my grandpa does have a fair bit of knowledge from owning roadsters in the past but it isn't super in depth. It seems that there are so many variables at play and my attempts to do research and learn often leave me overwhelmed or more stumped than I was before. So, for anyone local to OKC/Moore area, is there anyone around that we could contact to lend a helping hand?

[theunz]

Do a search here for screen name “guyatou”. He lives in OKC and has been fixing and flipping roadsters for a few years. He might be able to help.
Can you describe your issues? Most often it comes down to carburetors or ignition issues. You just need to tackle it one item at a time. Lots of good trouble shooting advice available here.

[trentonm]

Do a search here for screen name “guyatou”. He lives in OKC and has been fixing and flipping roadsters for a few years. He might be able to help.
Can you describe your issues? Most often it comes down to carburetors or ignition issues. You just need to tackle it one item at a time. Lots of good trouble shooting advice available here.

thanks! we've more or less had issues getting the car idle consistently and reliably. we've got some z theraps SU's and an east coast roadster distributor. so i'm sure our issues come down to some combination of timing and tuning carbs. my grandfather also had our cam "modified" by a local guy who works on cams. but i could not tell you how it was modified so im sure that is affecting any timing issues we may have. we finally got the car on the road last night, ran mostly fine aside from not wanting to idle, which is odd because in the many days before driving it it did an alright job idling. maybe its our cam but it seems most comfortable idling around 900rpm, which is what it was doing before getting it on the road, with the occasional slight dip or rise in rpm. then we buttoned everything up, but air filter back on, and then it doesnt want to idle, just wants to die. really im thinking someone with more experience could get our issues ironed out or at least identify them much easier than we could.

[Gregs672000]

As Mike said, we may be able to help remotely. Idling at 900rpm is just fine, 1000 seems a bit fast for me, but anything under 1000 is fine. Ya, we do need to get some idea what was done to the cam. Changing the lift or duration of the cam will change many things, but that requires pulling the cam and sending it to a shop that specializes in that... was that done? The other change is cam timing, but that too requires either purchasing an adjustable cam gear or modifying one by drilling out the bolt holes to allow movement and removing the set pin... again, he will know if that was done and it is easy to see. The only other thing would be purposely moving the cam one tooth either left or right... bad idea as it throws the cam timing way off and can result in bent valves etc. We can check that too but it requires more description.

We can help you check some things. Your spark plugs are an insight to your engine. Start by examining them, noting their color (the insulator should be tan, not dark black or white) and equal in color regardless... if 1 & 2 and 3 & 4 are different, then that tells you there is a carb/intake tract issue that feeds that pair. If only one is different or are not grouped as I said (1&2 or 3&4) then it says there's an issue in THAT cylinder (valve adjustment, compression issue, spark plug/wire). Investigate and report back.

You must have the proper tools, including a unisyn or other airflow meter (snail, google it) to check and adjust equal airflow through the carbs... hoses, listening etc just don't cut it. Review how the carb linkage works so you fully understand what does what, and realize that it all snaps together and the dog bones can be out of adjustment themselves and can throw off any screw-based changes... just spend time looking at how it works (as well as how the choke system works too so you know it's not hanging up etc). Review diagrams etc. Fuel to air ratio is adjusted by the dial on the bottom of the carb mainly for idle, with the taper of the fuel needle controlling it elsewhere, but changes to the dial will change ratio throughout I believe.

Valves must be adjusted to spec (I like 6 intake and 8 exhaust COLD, but anything close but not tighter than that is fine).

Do a compression test to make sure they are all within 10lbs of each other and at least 150lbs (tested with all plugs out, clutch pressed in, throttle wide open, good battery and 10 cranks each), and if not report back (borrow or buy a gauge, check Harbor Freight or similar).

Ignition timing is also critical and needs to be checked with a timing light (harbor freight has a cheap one that will work fine). Should be 17 degrees at idle and advance past the final mark (the timing light I mentioned can be used to tell you total advance... it's called a "dial back" timing light) to 35 degrees or so (you can guess based on what the marks show on the crank pully... each one is 5 degrees, with the far left being 0 and the far right being 20). The vacuum advance should work if the dizzy is new. (Note: timing numbers are for a non-smog engine/distributor; if smog, then 0 for initial timing, with it still advancing to 35 degrees total above 3500rpm)

You can check for intake leaks with carb cleaner by spraying around gaskets for the intake and carbs, noting if the idle changes significantly.

So, let's check the basics with the right tools, then if all checks out we can discuss the cam, but unless we have clear info what has changed there we will proceed with these first. You can do this and you will learn a lot!

[theunz]

Greg gave some very good advice and you should use it. Carbs, valves, distributor, cam,…are all one system and need to play well together. The fact that you said it was running pretty good until you put the filter back on makes me think your carbs may be set to rich and when you put the filter on it just chokes it out. Is the filter clean? There is a very good write up by Keith Williams on carb set up in the tech wiki. Carb balancing is VERY important for a smooth idle and is one of the first things I would suggest. I highly recommend the snail type over the uni-syn as it doesn’t starve the carb for air while using.
As for compression numbers, I would be more concerned with variances between cylinders than high numbers. Anything over 10% could indicate a problem in that cylinder.
Air leaks at the carbs or intake manifold can cause poor idling as well. You can check by spraying some carb cleaner around the carbs and manifold and listen to see if the idle speed increases. Be careful around the exhaust so you don’t start a fire. I have heard that WD 40 will work as well.
Good luck and keep at it and you will get there!

[trentonm]

As Mike said, we may be able to help remotely. Idling at 900rpm is just fine, 1000 seems a bit fast for me, but anything under 1000 is fine. Ya, we do need to get some idea what was done to the cam. Changing the lift or duration of the cam will change many things, but that requires pulling the cam and sending it to a shop that specializes in that... was that done? The other change is cam timing, but that too requires either purchasing an adjustable cam gear or modifying one by drilling out the bolt holes to allow movement and removing the set pin... again, he will know if that was done and it is easy to see. The only other thing would be purposely moving the cam one tooth either left or right... bad idea as it throws the cam timing way off and can result in bent valves etc. We can check that too but it requires more description.

We can help you check some things. Your spark plugs are an insight to your engine. Start by examining them, noting their color (the insulator should be tan, not dark black or white) and equal in color regardless... if 1 & 2 and 3 & 4 are different, then that tells you there is a carb/intake tract issue that feeds that pair. If only one is different or are not grouped as I said (1&2 or 3&4) then it says there's an issue in THAT cylinder (valve adjustment, compression issue, spark plug/wire). Investigate and report back.

You must have the proper tools, including a unisyn or other airflow meter (snail, google it) to check and adjust equal airflow through the carbs... hoses, listening etc just don't cut it. Review how the carb linkage works so you fully understand what does what, and realize that it all snaps together and the dog bones can be out of adjustment themselves and can throw off any screw-based changes... just spend time looking at how it works (as well as how the choke system works too so you know it's not hanging up etc). Review diagrams etc. Fuel to air ratio is adjusted by the dial on the bottom of the carb mainly for idle, with the taper of the fuel needle controlling it elsewhere, but changes to the dial will change ratio throughout I believe.

Valves must be adjusted to spec (I like 6 intake and 8 exhaust COLD, but anything close but not tighter than that is fine).

Do a compression test to make sure they are all within 10lbs of each other and at least 150lbs (tested with all plugs out, clutch pressed in, throttle wide open, good battery and 10 cranks each), and if not report back (borrow or buy a gauge, check Harbor Freight or similar).

Ignition timing is also critical and needs to be checked with a timing light (harbor freight has a cheap one that will work fine). Should be 17 degrees at idle and advance past the final mark (the timing light I mentioned can be used to tell you total advance... it's called a "dial back" timing light) to 35 degrees or so (you can guess based on what the marks show on the crank pully... each one is 5 degrees, with the far left being 0 and the far right being 20). The vacuum advance should work if the dizzy is new. (Note: timing numbers are for a non-smog engine/distributor; if smog, then 0 for initial timing, with it still advancing to 35 degrees total above 3500rpm)

You can check for intake leaks with carb cleaner by spraying around gaskets for the intake and carbs, noting if the idle changes significantly.

So, let's check the basics with the right tools, then if all checks out we can discuss the cam, but unless we have clear info what has changed there we will proceed with these first. You can do this and you will learn a lot!

incredible response. thank you!
i think getting our cam checked out will be a top priority, without knowing what was done to it i feel there’s no way to get things right. i’ve sort of glanced at spark plugs without thinking too much about them but i’ll take a closer examination of those.
i’ve learned the basics of su’s but i’m constantly learning more from folks like yourself. we did pick up a unisyn tool, although i was only ever to get the “ball” to go about a quarter ways up the tube. and that was with the unisyn tightened all the way. is this normal? what does this tell us about what the carb is doing?
i believe we got the timing pretty close to 17 degrees when installing the distributor. although our timing light just decided to crap out on us, so we’ll be getting a new one soon to check it.
your response was incredibly detailed and i appreciate your time. every bit helps, and you’re helping me learn!

[trentonm]

Greg gave some very good advice and you should use it. Carbs, valves, distributor, cam,…are all one system and need to play well together. The fact that you said it was running pretty good until you put the filter back on makes me think your carbs may be set to rich and when you put the filter on it just chokes it out. Is the filter clean? There is a very good write up by Keith Williams on carb set up in the tech wiki. Carb balancing is VERY important for a smooth idle and is one of the first things I would suggest. I highly recommend the snail type over the uni-syn as it doesn’t starve the carb for air while using.
As for compression numbers, I would be more concerned with variances between cylinders than high numbers. Anything over 10% could indicate a problem in that cylinder.
Air leaks at the carbs or intake manifold can cause poor idling as well. You can check by spraying some carb cleaner around the carbs and manifold and listen to see if the idle speed increases. Be careful around the exhaust so you don’t start a fire. I have heard that WD 40 will work as well.
Good luck and keep at it and you will get there!

i think you’re right about the carbs running rich. last time we checked and replaced spark plugs they were a bit dark…so that makes sense. thank you! every response is helpful.

[josemariagervacio]

Hey! Were down the street from your grandpa!

I walked up your drive a few months ago to talk about the blue roadster lol

I have a low windshield r16 my husband and i just started restoring, not sure I can help much (only owned it since October) but we are local and you if you need extra hands you can message us!

[Gregs672000]

Hey! Were down the street from your grandpa!

I walked up your drive a few months ago to talk about the blue roadster lol

I have a low windshield r16 my husband and i just started restoring, not sure I can help much (only owned it since October) but we are local and you if you need extra hands you can message us!

This is what I love about the Roadster... it's not just a car, it's a family! New friends to be made!

Trentonm, we're happy to try and help, you're very welcome! I get smiles out of this too, so it's always a win/win for me, and you can see by the other folks who chime in, we care about your success and enjoy sharing in It!

I agree about the filter and overly rich idle mix. Regarding the unisyn, I sold mine but as I recall I could turn the center dial in tighter making the opening smaller and could really choke down the engine if held flat over the throat, enough to kill it no problem. ALL the air must come to the engine via the carb throat... anything else is an intake leak. Regarding the cam... can you post a pic of it and the Gear? Can you post a video of the engine running? A "typical" change to the cam, unless it was an extreme change or poorly done shouldn't wipe out the idle completely, but it can make it necessary to play with ignition timing and fuel ratio a bit more. The more info we can get on the cam the better, but I also don't want you to get too distracted by it yet... more data (like plug color/burn differences, valve adjustment, filter condition etc) is needed. You mentioned it ran pretty good otherwise... does it have decent power? Will it generally rev well to 6000 rpm (assuming it's not unsafe or making loud noises) on the street (premium fuel is required by a U20). This info may help us too. When I first built my U20 (first of everything, including my first engine rebuild) I ran it for several miles with the wrong spark plug firing order and I was excited that it just ran and would do 80mph... I had no idea what it was really supposed to run like, and was even more excited when I got things sorted out!

Keep digging, you're making progress!

[Gregs672000]

Not sure what to make of the unisyn issue/experience, and I don't have mine anymore. CAREFULLY and SLOWLY place your palm over the carb throat... it should suck your hand in strongly if you cover it (can surprise you the first time). If the engine doesn't seem very upset with you covering it with your fingers then it's getting air somewhere else. But I kinda doubt you have a big intake leak or it wouldn't die when you install the filter.

[trentonm]

Hey! Were down the street from your grandpa!

I walked up your drive a few months ago to talk about the blue roadster lol

I have a low windshield r16 my husband and i just started restoring, not sure I can help much (only owned it since October) but we are local and you if you need extra hands you can message us!

hey! i do remember you! such a small world. how’s your car going?
we just took ours out on the road tonight, down eastern to 7/11 and around the neighborhood. seemed to do pretty well. idle is still a little off but was otherwise good. needs some more tweaking. we’d love to check out your car sometime!

[trentonm]

Hey! Were down the street from your grandpa!

I walked up your drive a few months ago to talk about the blue roadster lol

I have a low windshield r16 my husband and i just started restoring, not sure I can help much (only owned it since October) but we are local and you if you need extra hands you can message us!

This is what I love about the Roadster... it's not just a car, it's a family! New friends to be made!

Trentonm, we're happy to try and help, you're very welcome! I get smiles out of this too, so it's always a win/win for me, and you can see by the other folks who chime in, we care about your success and enjoy sharing in It!

I agree about the filter and overly rich idle mix. Regarding the unisyn, I sold mine but as I recall I could turn the center dial in tighter making the opening smaller and could really choke down the engine if held flat over the throat, enough to kill it no problem. ALL the air must come to the engine via the carb throat... anything else is an intake leak. Regarding the cam... can you post a pic of it and the Gear? Can you post a video of the engine running? A "typical" change to the cam, unless it was an extreme change or poorly done shouldn't wipe out the idle completely, but it can make it necessary to play with ignition timing and fuel ratio a bit more. The more info we can get on the cam the better, but I also don't want you to get too distracted by it yet... more data (like plug color/burn differences, valve adjustment, filter condition etc) is needed. You mentioned it ran pretty good otherwise... does it have decent power? Will it generally rev well to 6000 rpm (assuming it's not unsafe or making loud noises) on the street (premium fuel is required by a U20). This info may help us too. When I first built my U20 (first of everything, including my first engine rebuild) I ran it for several miles with the wrong spark plug firing order and I was excited that it just ran and would do 80mph... I had no idea what it was really supposed to run like, and was even more excited when I got things sorted out!

Keep digging, you're making progress!

we are making progress! the other night we advanced our timing to around 20 degrees and that seemed to help out a fair bit. our thinking was, if our cam is “upgraded”, maybe we could set our timing according what a solex car should be set to, being 20 degrees according to our service manual.
so we tried it, adjusting our carbs a little bit, and we had what i thought was a pretty solid idle right around 850 rpm.
but we took it out on the road tonight (no air cleaner) and it wasn’t idling the same as it was the day before in the garage. it almost seems like every time we start the car up it does something different. but it did seem to do well otherwise when we drove. revved up well from what i could tell.
we’re starting to wonder now if we have starter issues too. pulled into the driveway after the drive, shut er off, and went inside for a bit. then going back out to pull the car in the garage it simply wouldn’t turn over. battery at 12.43 volts. so we’re going to be checking that out next.
again i thank you for the response as every little bit of info helps!

[josemariagervacio]

Going good so far! @pre.z.1600 on Instagram!
You can hmu there, currently it's stored in Midwest city. Hopefully we can get it moved here soon, but yeah would be nice to have someone local to share information with!

[Gregs672000]

It's a process eh? The 20 degree solex version advance was primarily due to the Solex carbs not being set up to run vacuum advance on the distributor (no vacuum port) but ignition timing is somewhat based on what any particular engine wants. However, be careful as too much advance means that the spark event occurs earlier in the upward stroke of the piston on the compression stroke. Because fuel needs time to burn, you advance the spark event earlier into that stroke, which is what the distributor does internally as rpms increase to give that time. But that also means the explosion is pushing back against a mechanically driven piston, and if that happens too early the engine starts fighting itself. You'll hear it as a knocking or pinging sound when the engine is under load/being pushed hard. Ping and (worse) knock can also occur even when the timing is "correct" if the fuel is too low an octane rating because the fuel is igniting by itself (due to compressing it) or burning in a less than even manner. Octane rating is the ability of the fuel to resist exploding before you want it to or that helps it burn more evenly. Premium fuel is not "better" fuel, it's simply more resistant to exploding.

What you're describing (changes in idle etc) could suggest some worn parts or changes that occur due to heat... things expand and move. For example, the throttle cable will tighten up with heat, increasing idle rpm. If you get the idle set, then drive it and notice differences, spray some carb cleaner around the gaskets and see if it changes, or check linkage. And remember, your spark plugs are your insight to the engine. Over time they will tell you how it's running in general and if there's a problem with a carb or an individual cylinder. Working with clean plugs makes this easier so you can see what your adjustments are doing... get a couple sets, you'll use them eventually anyway!

Regarding the cam, one thing that is typically done is to increase the "duration" of the cam, meaning how long it keeps the valves open. I can't go into great detail here, but there is a mechanical "overlap" in the mechanical timing of things (intake vs exhaust values) that moves the "sweet spot" or where it all works "best" within the rpm range (idle to 7000+ rpms). Usually the change done moves the sweet spot up higher in the range, creating more power but also higher up, with some loss or changes at lower rpm. This can cause problems with idle, and also partly why a solex version needs a bit more idle timing advance and also why a "big cam" engine is more dirty at idle... it's usually not as efficient down in lower rpms so it pushes unburned fuel out the exhaust, increasing emissions. Without knowing what cam we have, we'll just have to keep messing until it's as good as it gets.

[trentonm]

It's a process eh? The 20 degree solex version advance was primarily due to the Solex carbs not being set up to run vacuum advance on the distributor (no vacuum port) but ignition timing is somewhat based on what any particular engine wants. However, be careful as too much advance means that the spark event occurs earlier in the upward stroke of the piston on the compression stroke. Because fuel needs time to burn, you advance the spark event earlier into that stroke, which is what the distributor does internally as rpms increase to give that time. But that also means the explosion is pushing back against a mechanically driven piston, and if that happens too early the engine starts fighting itself. You'll hear it as a knocking or pinging sound when the engine is under load/being pushed hard. Ping and (worse) knock can also occur even when the timing is "correct" if the fuel is too low an octane rating because the fuel is igniting by itself (due to compressing it) or burning in a less than even manner. Octane rating is the ability of the fuel to resist exploding before you want it to or that helps it burn more evenly. Premium fuel is not "better" fuel, it's simply more resistant to exploding.

What you're describing (changes in idle etc) could suggest some worn parts or changes that occur due to heat... things expand and move. For example, the throttle cable will tighten up with heat, increasing idle rpm. If you get the idle set, then drive it and notice differences, spray some carb cleaner around the gaskets and see if it changes, or check linkage. And remember, your spark plugs are your insight to the engine. Over time they will tell you how it's running in general and if there's a problem with a carb or an individual cylinder. Working with clean plugs makes this easier so you can see what your adjustments are doing... get a couple sets, you'll use them eventually anyway!

Regarding the cam, one thing that is typically done is to increase the "duration" of the cam, meaning how long it keeps the valves open. I can't go into great detail here, but there is a mechanical "overlap" in the mechanical timing of things (intake vs exhaust values) that moves the "sweet spot" or where it all works "best" within the rpm range (idle to 7000+ rpms). Usually the change done moves the sweet spot up higher in the range, creating more power but also higher up, with some loss or changes at lower rpm. This can cause problems with idle, and also partly why a solex version needs a bit more idle timing advance and also why a "big cam" engine is more dirty at idle... it's usually not as efficient down in lower rpms so it pushes unburned fuel out the exhaust, increasing emissions. Without knowing what cam we have, we'll just have to keep messing until it's as good as it gets.

it amazes me the amount of knowledge you have. but i love learning! its funny, everything i've learned from what you've said so far makes total sense but its something i would never think of on my own. like advancing the timing too much causing a knock or ping, for example.
i'll try to get some photos of the cam today and videos of the car running as well.
i haven't had a chance to check our spark plugs after driving yesterday so i need to take a look at those also.
if we're looking at a "big cam" situation, what would that mean for valve clearance? less clearance? more?