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 Posted: Aug 9, 2017 10:39AM
Total posts: 89
Last post: Aug 9, 2017
Member since:Sep 20, 2012
I do. I used it to adjust the timing last week.

 Posted: Aug 8, 2017 12:47PM
Total posts: 8467
Last post: Aug 19, 2017
Member since:Jun 5, 2000
US
Asking for a Dwell/Tach probably did get you a lot of stares.  Regardless, you probably got a better price through Amazon.

So the next question has to be... do you have a timing light?  If not, that should be your next piece of diagnostic equipment.  When you are ready to invest, use Amazon again and look for Actron CP7529 or Actron CP7528

 

Doug L.
 Posted: Aug 8, 2017 11:43AM
Total posts: 89
Last post: Aug 9, 2017
Member since:Sep 20, 2012
I looked all over for a dwell-tach and nobody had one. Most folks had no idea what it was but the man at a locally owned parts store looked at me with big eyes and said "Holy crap!! I haven't sold one of those in years!" One guy at one of the chain stores tried to lend me a compression tester (it's the same thing, right? haha). 

So I had to order one off amazon. Should be here in a few days...hopefully.

 Posted: Aug 3, 2017 01:32PM
Total posts: 7214
Last post: Aug 20, 2017
Member since:Aug 14, 2002
CA
Quote:
Originally Posted by dklawson
Dwell/tachs are not hard to use.  Once you use them a few times you will not even have to think about how to hook them up or what they are showing.  When searching for them you may also find them listed as engine analyzers.

The local parts store (like Advance) should have products from Actron.  These will be modern, digital versions of the analog gauges many of us bought in our youth.  Many modern dwell/tachs are built into a multimeter platform so you'll have a lot of other diagnostic tools.  It will prove to be a useful tool both around the house and for the car.
Doug: thanks for the outline of what's currently available. My dwell-tach dates from the previous century!

.

"Hang on a minute lads....I've got a great idea."

 Posted: Aug 3, 2017 10:43AM
Total posts: 8467
Last post: Aug 19, 2017
Member since:Jun 5, 2000
US
Dwell/tachs are not hard to use.  Once you use them a few times you will not even have to think about how to hook them up or what they are showing.  When searching for them you may also find them listed as engine analyzers.

The local parts store (like Advance) should have products from Actron.  These will be modern, digital versions of the analog gauges many of us bought in our youth.  Many modern dwell/tachs are built into a multimeter platform so you'll have a lot of other diagnostic tools.  It will prove to be a useful tool both around the house and for the car.

Doug L.
 Posted: Aug 3, 2017 10:17AM
Total posts: 89
Last post: Aug 9, 2017
Member since:Sep 20, 2012
Quote:
Originally Posted by Dan Moffet
What you need (we always need another tool, right) is an instrument called a "dwell-tachometer".
I had a feeling I was going to need another tool! Hopefully they have one at a parts store nearby. Are they easy to use? It doesn't sound too hard.

 Posted: Aug 3, 2017 09:29AM
Total posts: 7214
Last post: Aug 20, 2017
Member since:Aug 14, 2002
CA
What you need (we always need another tool, right) is an instrument called a "dwell-tachometer". It looks a bit like a voltmeter but does specific jobs. Connected to the ignition system and set to rpm (and the appropriate number of cylinders - 4,6, 8 etc.) it will tell you exactly the speed of your engine. Set to 'dwell', it tells you exactly in degrees how long your ignition points are open to fire the coil. It is a much better way to set points than feeler gauges.
Price should be around $30 for a decent basic unit.

.

"Hang on a minute lads....I've got a great idea."

 Posted: Aug 3, 2017 08:45AM
 Edited:  Aug 3, 2017 08:56AM
Total posts: 89
Last post: Aug 9, 2017
Member since:Sep 20, 2012
Ok.

So I adjusted it yesterday but I don't think it's quite right. It's better, less bogging at WOT but not perfect. I removed the vacuum and plugged the hole with my finger. I did notice it changes when I took my finger off.

Thank you for that explanation. That helps a lot.

One question, how do I set the idle to 1500 if I don't have a tach? I just revved it by hand but that clearly wasn't precise enough.

 Posted: Aug 3, 2017 05:15AM
Total posts: 7214
Last post: Aug 20, 2017
Member since:Aug 14, 2002
CA
No.
Disconnect and cap the vacuum advance at the carb (to avoid an air "leak").
Warm up the engine and set the idle speed to 1500rpm.
Set the timing advance using a timing light to 8 degrees before top-dead-centre.
The "+0" means you cannot vary the setting more than 8 degrees.
The "-2" means you may retard the timing (say for altitude or other driving conditions) down as far as 6 degrees BTDC, no less.

So, start with 8 degrees and if you hear knocking/pinking/pre-igntion (different names for the same thing) retard the timing a bit.
Reconnect the vacuum advance and test drive.

.

"Hang on a minute lads....I've got a great idea."

 Posted: Aug 2, 2017 12:18PM
Total posts: 89
Last post: Aug 9, 2017
Member since:Sep 20, 2012
Quote:
Originally Posted by Dan Moffet
Actual idle speed timing advance would depend on the size and build of the motor, but Haynes has a whole 2 pages, depending on the distributor installed as well.
Note timing has to be set with the vacuum advance disconnected, with the tube capped at the carb end and idle at a specific rpm to ensure the centrifugal weights don't come into play.
If you set the timing with the vacuum advance connected and you open the throttle, the vacuum goes away and so does the advance. Timing would be retarded. The engine would run horribly until the rpms managed to get up to the point the centrifugal advance comes into effect. Round about 2000 rpm, you might be seeing the spark finally getting into "advance" territory and finally getting a bit of power.
That's exactly what's happening. The distributor is a 59D4E . I was under the impression that it was better suited to a big bore engine because that's what I bought it for, but the 7ent site doesn't say anything about it being designed for use in a small vs large bore engine.

I'm looking at the specs. It says 8* +0* -2* BTDC at 1500rpm. Does that mean 8* at idle and -2* at 1500?

 Posted: Aug 2, 2017 11:10AM
Total posts: 1824
Last post: Aug 6, 2017
Member since:Aug 29, 2001
bogging?

always start with the easy stuff- carb oil

http://www.minimania.com/SU_CARBS___Dashpot_oil_

 Posted: Aug 2, 2017 10:58AM
Total posts: 7214
Last post: Aug 20, 2017
Member since:Aug 14, 2002
CA
Actual idle speed timing advance would depend on the size and build of the motor, but Haynes has a whole 2 pages, depending on the distributor installed as well.
Note timing has to be set with the vacuum advance disconnected, with the tube capped at the carb end and idle at a specific rpm to ensure the centrifugal weights don't come into play.
If you set the timing with the vacuum advance connected and you open the throttle, the vacuum goes away and so does the advance. Timing would be retarded. The engine would run horribly until the rpms managed to get up to the point the centrifugal advance comes into effect. Round about 2000 rpm, you might be seeing the spark finally getting into "advance" territory and finally getting a bit of power.

.

"Hang on a minute lads....I've got a great idea."

 Posted: Aug 2, 2017 07:41AM
Total posts: 89
Last post: Aug 9, 2017
Member since:Sep 20, 2012
Sorry I went missing for a while. I had had enough and brought it to a mechanic. With the summer always being so busy, I haven't had a chance to get back to it until today.

Anyways, he got it running. I guess the distributor had gone bad. Luckily I had a spare. It runs now but there are still some issues. First, the bypass hose sprung a leak so I had to take it home to replace that. Second, when I was drove it around the parking lot, the motor would bog at the upshifts and then slowly reach about 2k rpm before it would rev as normal. He felt it was the ignition timing but since the bypass hose was spewing water, we couldn't run it to troubleshoot further. Would this issue be caused by bad ignition timing? Also, what should it be set at for a small bore A+?

 Posted: Jun 20, 2017 10:12AM
Total posts: 7214
Last post: Aug 20, 2017
Member since:Aug 14, 2002
CA
When it runs for "5 seconds", how does the engine die? Does it stop firing abruptly, or does it gradually slow down in rpm until it stops? Slowing down and stopping suggests too much or too little fuel. An abrupt stopping of firing (like when you switch off an engine) suggests loss of ignition. Figure out which it is.

When it dies, remove a couple of spark plugs quickly and sniff them for gas (as in unburnt fuel). If they are dry it suggests an absence of fuel. If they are wet or smell like fuel, it suggests loss of spark and/or too much fuel = flooding.

You mentioned the bowl is more than 3/4 full with the top and float removed. That suggests a bad float or one that is set too high., or is sticking. The fuel level in the bowl corresponds (generally speaking) to the level of fuel in the main jet, where the carb sips gas. If it is too low, the carb has to work too hard to get fuel and the engine starves. If it is too high, the main jet can actually overflow, trickling raw fuel down into the intake system, and the engine floods. Once it floods, it won't fire until the cylinders and spark plugs are dry enough. That may take hours, unless you remove and dry all the plugs and crank the engine with the plugs out to expel the over-rich mixture and then put the plugs back to try again.
Another possible flooding situation is that the inlet jet needle, controlled by the float, is not sealing properly, allowing the fuel pump to push gas right through the bowl and main jet on into the intake manifold.

If the bowl is full but the tube connecting it to the bottom of the main jet is damaged, worn or dirty, you may get a slow trickle of fuel into the jet, enough to start the engine but not enough to keep it running... for a few seconds. Sound plausible?

.

"Hang on a minute lads....I've got a great idea."

 Posted: Jun 20, 2017 09:53AM
Total posts: 7214
Last post: Aug 20, 2017
Member since:Aug 14, 2002
CA
Image Gallery
DrewM: your photo is kind of distorted, possibly because you held the camera (phone?) too close. Try taking a picture farther back, like I did - attached are two photos of my old HS4.

.

"Hang on a minute lads....I've got a great idea."

 Posted: Jun 20, 2017 08:29AM
 Edited:  Jun 20, 2017 08:33AM
Total posts: 89
Last post: Aug 9, 2017
Member since:Sep 20, 2012
Does this picture help? I hope it isn't too big. This angle suggests that the narrow part of the dashpot cover is a lot taller than it actually is.


 Posted: Jun 20, 2017 08:19AM
 Edited:  Jun 20, 2017 08:26AM
Total posts: 89
Last post: Aug 9, 2017
Member since:Sep 20, 2012
Quote:
Originally Posted by dklawson
I will try to post a picture below.  Unfortunately it is hosted on the MG Experience website.  Sometimes direct links to their pictures do not work.  The picture shows an HS2 next to an HS4.  You'll observe they look very similar but the vacuum chamber on the HS2 is much smaller in diameter.


How well did the engine run before you removed the head?  Really the carb and ignition settings should not have been disturbed when you replaced the head gasket.  I'm not sure we're looking at the right spot to find the problem.

As a quick test, the next time the car refuses to start, tip a thimble of gasoline down the carb throat and try to restart the engine.  If it bursts into life, runs briefly, then dies, you have a fuel delivery problem.  If the engine refuses to start, you either have a flooding condition or an ignition problem to sort.



It actually ran pretty well. I think I may have hit something while removing the intake? I remember that being a struggle.

Ok, I can try that.

 Posted: Jun 20, 2017 08:11AM
 Edited:  Jun 20, 2017 08:15AM
Total posts: 89
Last post: Aug 9, 2017
Member since:Sep 20, 2012
Quote:
Originally Posted by h_lankford


there are some inconsistencies in this thread that concern me . Sorry if this sounds conspiratorial, but......

compression went from low to normal: 

(1) by removing the adjuster nuts that felt "so tight they started to strip." How does one reassemble that? Stripped= not hold. 

(2) performed without asking for advice on cam lobe location and adjustment sequence, yet other questions suggested lots of help needed on simpler procedures.

(3) can someone explain to me how a head that was running fine (except for coolant leak) and had presumably normal valve adjustment, say .014", have that head removed, then replaced, and the valve lash on all four cylinders be not just a few thou but all way far off, thus lifting the valves off their seats and losing compression? A way too thick new head gasket, yes. Anything else? (I am excluding a warped head or heaped up around the studs since the compression figures are now reported normal and there is no coolant leak.) Someone may answer "it happens" but I'd like to hear more.









That's ok. My race car was an FI rotary. I'm almost completely self taught. I've picked up things here and there from friends and manuals, etc. Piston engines are rather new for me. I understand the basics but some of the details, ie which size needle to use in which carb, are things I still have yet to learn. There's no better engine to learn on than these cheap little small bore engines.

(no idea why that first part is quoted)
1 The outside of the nuts were becoming rounded. The threads were all fine. Heating them expanded the size and allowed me to loosen and correctly adjust them with little effort. I didn't think a heat gun would heat them enough because the one I had for cleaning loose rubber off the slicks didn't get very hot. I was pleasantly surprised to see that sears now carries a better heat gun that gets hot enough to melt your ice cream from across the room.

2 A friend did once show me how to do this on my previous mini. I also have the manual which lists the which valves to adjust and in which order. It's pretty simple, in my opinion.

3 I wish I knew. Only thing I can guess is that the new copper gasket was thinner than the old copper gasket I took off. Maybe a different manufacturer.

 Posted: Jun 20, 2017 08:06AM
Total posts: 8467
Last post: Aug 19, 2017
Member since:Jun 5, 2000
US
I will try to post a picture below.  Unfortunately it is hosted on the MG Experience website.  Sometimes direct links to their pictures do not work.  The picture shows an HS2 next to an HS4.  You'll observe they look very similar but the vacuum chamber on the HS2 is much smaller in diameter.


How well did the engine run before you removed the head?  Really the carb and ignition settings should not have been disturbed when you replaced the head gasket.  I'm not sure we're looking at the right spot to find the problem.

As a quick test, the next time the car refuses to start, tip a thimble of gasoline down the carb throat and try to restart the engine.  If it bursts into life, runs briefly, then dies, you have a fuel delivery problem.  If the engine refuses to start, you either have a flooding condition or an ignition problem to sort.

Doug L.
 Posted: Jun 20, 2017 07:45AM
Total posts: 89
Last post: Aug 9, 2017
Member since:Sep 20, 2012
Quote:
Originally Posted by dklawson

When you say it ran for 5 seconds and died, was it running when you released the key or only when you held the key in the start position?

You put a new coil on.  Which coil did you install?  What are the colors of the wires on each coil terminal?  Look carefully at the colors.  If one on the coil (+) terminal appears white, make sure it is not "off white" or "pink".  Let us know the coil wire colors.

Refresh my memory.  Which carb(s) do you have, HS series or HIF?  If HS carbs, do you have a single or dual carbs?

When you say the bowl is full, how full is it?  With HS carbs the bowl is to the side of the main carb body and you can inspect the fuel level by removing the 3 screws and taking the lid off.  The bowl should not be full, it should be about 1/2 to 2/3 full when there is no float taking up space.



It was running on its own, not off the starter. It'll crank and crank on the starter but it did fire and run this time. It was a quick flash of excitement!

I don't recall which coil it is. It's a new spare I had from another project that didn't come to fruition. I'd have to dig through receipts to find out for sure.

I believe the carb is an HS4. Though I will be honest I don't know how to tell the difference between the HS2 and HS4. I thankfully only have 1 carb to worry about.

The bowl is quite full. It was over 1/2 full though I didn't look to see exactly how full. I was just looking to see if there was any fuel in there.

I can take pictures if that makes it easier.

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