Hot Rods Trying to set lash the proper way on a SBC 350!

Well, like I was saying , you don't need much pre-load. You would want the lifter to function like a solid lifter.
In fact a solid has to be used to check valve lift. It needs to be the exact same height as the lifter used. Otherwise your lift figures will be off, and may not pass tech.

 

Where's jeff dunham and the woozle

Know the thread pitch and 1 flat or 1/6 turn or 60 deg rotation is dial indicator accuracy is it not?

 

Just stating the obvious here, but in this thread we didn't have either a $60,000 sprint car motor or a professional engine builder, we had a novice hobbyist who was struggling with a basic valve adjustment on a basic SBC. When he finally got the valves adjusted by doing it dynamically he was lead to believe that what he did was wrong, increasing his doubt about it. If you read the entire thread, and there may be another 1, the poor guy was getting conflicting advice from many different people, who were all trying to help, but some of it was just not helpful, especially when 1 person would tell him to do one thing, and somebody else would come in and tell him to do something else, and after he did that he'd get some other advice to do something else. He finally made it through, but it was a tough row to hoe.

IMO what the guy needs to know now is the method he used is fine, the adjustment is done, don't worry about it. It's OK now to move on to other issues and put this behind him.

 

Whoops. Hit the post button.
I totally agree with everything you said. Except the last part. If he ever wants to do it again he needs to know there is another way. The engine he is working on is no stock SBC with AFR heads and HR cam, so I'd bet he's going to be in there again in the future.
I waited to post this until he got it running, just because of the "too many cooks in the kitchen" deal.
I followed this whole thread because valve train geometry is one of my favorite subjects.

 

Not addressing any one person here but I seem to remember our friend had mysteriously ground the ball completely off of one of his pushrods. I suspected , as he said, he couldn't tell where zero lash was. I believe at that point, I tried to explain how to find zero lash and then pre-load it from there, using a static method. He must have done something close to that when he got his new parts in.
Others chimed in with their favorite method, which you've got to expect, on a forum this large.
In the end, it looks like he used a little of this...a little of that, and it all worked out.
Whew!

 

Whew! I just got caught up in reading all the posts after asking if the Vacuum lines were ok as shown in my latest pic, or would it be better to route vacuum lines as instructed by Edelbrock...and I was wondering ...Should i create a new thread on EdelbROCK 800 CFM Carb and SBC 350 settings! only because this thread is still discussing valve lash setting, for a good reason as there are many ways to do this as stated. I do feel confident that the valves are set good, my only doubt right now is if I should of did a 1/4 turn, instead of a 1/2 turn. I wanted reliability, so I opted for a 1/2 turn after zero lash. Other than that, I do understand the high level of this valve lash adjustment in a running engine or in static settings on a non running motor. It's the low level stuff that starts sounding like Chinese, but I am comprehending the jargon. Here is a carb pic, I called edelbrock for the correct rebuild kit for this carburetor, it was rebuilt a few months back. He said it was a 800 cfm carb (#1813S 0189) which I suspect is too big for a SBC, but the previous owner did say he had carb issues...he may have thought bigger was better? Thanks again guys...you all are very intimating...the discussions in here are way over my head...for now!

 

BuLLeTCoLeKToR, well done on getting the SBC running.

Lash settings are as different as buttholes, everyone has one and everyone wipes it a different way.
Sometimes the HAMB goes a bit ham on a subject.
If you know the cam/lifter maker, go by their procedure.
Lash is definitely one of those things you have to do a few times and find where it is right for you(and your engine).

From your description on how the carb was misting, it makes sense.
What was happening was simply the engine rotating backwards a bit after a no start. Pretty common. Engine cranks over, the A/F mixture is being pulled into the intake plenum, runners and combustion chambers. With no starts, the engine will be cranked, then with no starting the engine may rotate backwards a bit due to compression in several cylinders, an intake valve will be open and the piston pushes the A/F mixture back up out the intake past the carb. If the timing is off enough a spark may occur while the intake valve is open, and that's when you would get a proper backfire through the carb.

It's good practice to have a damp rag handy or to just leave the air cleaner on, something to suppress a potential open flame. With an engine bay/garage there is always the potential to ignite something else, gas fumes/spills, hydrogen gas from the battery.

Do you have a tachometer hooked up to the engine?
I haven't seen you mention any rpms, the higher the rpm the more timing is going to be shown. Advancing timing will increase idle rpm.
Usually to set the base timing, disconnect vac adv can, plug the hose(no vacuum leaks) set the base timing at ~500-700rpm, reconnect vac adv, and then reset idle speed via the carb again.

Now you get to play around with idle screws and vacuum gauge to get the idle mixture proper. With an automatic you will get a better result with the parking brake on(wheels chocked) and in Drive. This will give better throttle response in gear.

Then you would want to verify that your charging system is working properly. Battery should hold a full charge when the truck is off. 12.4-12.6 Volts(wait a few minutes after turning the vehicle off as capacitance in the system may show 13V or more for a while).
Running, the voltage would ideally be above 13 volts but not higher than 14.4. Again check this with the truck in drive and all the lights and HVAC and accesories on. If the voltage drops below 13Volts running you may have a dirty/corroded/loose connections.

A common issue I see with faulty/low charge/micro drains are lead-acid(liquid) batteries that are filthy and covered in electrolyte from the battery. Make sure the battery and battery tray are clean and dry. Any of the green cleaners(409, Simple Green,etc) are great at removing this, spray on, let soak, hose off.

AVS is 800cfm but it has air doors on the secondaries that will only open on actual air demand. If the AVS is similar to Quadrajets and Thermoquads, the air doors control the metering rods for the secondaries. Properly tuned the carb will only allow the demanded CFM at the correct rate. Air doors are usually spring controlled to prevent the doors from snapping open causing a bog. They work independently of throttle control, so even if the secondaries are at WOT, air doors are only going to open enough for air demand be it 450CFM, 650CFM, or 750CFM.

 

Ok, so here is where we are at. First we disconnected the vacuum advance from the dizzy and plug it with a golf tee, we then plug the port on the passenger side of the edelbrock carb. We then started at 6-8* advanced on the timing lite...we reconnect vacuum lines and put air filter back on. The TDC line that was at 8* advance is now at about 5-6 degrees ahead of the previous 8* mark, idle seemed high, so I idled down to have a nice idle in park. We know that this is not a stock cam, we were told it was a mild cam, but it may be a 1/2 or 3/4 cam...the previous owner doesn't know. We then took it for a spin and it would bog when demand (load) is called upon, such as climbing a hill or hitting the throttle. We then brought the truck back to our garage, advanced to about 10-12, same thing...but it got better, we went all the way up to 15* advanced and it started to bog but would clear up when letting off the gas...it would actually clear up when letting off the pedal, but that is not the way you drive a hot rod! So I do have a Tachometer, and a timing light with timing Mark's up to 60*. I feel we are close...but what should we do from here, do we keep advancing the distributor to run at a higher rpm...say 18*? and then idle down? I am close guys..
Oh and at idle/park...it idles nice at about 1000 rpms, but when we engage drive...the tach goes down to 400 to 500 rpms...and idle gets rough, I installed a fuel regulator and dialed down fuel pressure from 7 psi to 4.5. Thanks again guys!

 

Good this is a solid start.
Timing is going to be with the crank. Hand in hand. Just make sure the total timing is all in by ~3000rpm. You will be in the mid 30° range. so 33-36.
I would suggest leaving it at the original 6-8° mechanical locked down, hook everything back up, start the engine, annoy your neighbors by holding it at 3000rpm, and using your timing light adjust the light til you find out what the total advance now is. If it's in the mid 30° range then you are good for now. Leave it be.
If you get past 38° total you may start getting into detonation, not good for parts. Keep the total timing in a safe range, stick with 36° max for now. You can always recurve the distributor.

Gross tunining is what you are doing now. First get it to run, two get it to operate, three tune it.

Timing would not cause a bog. Timing would make the engine a bit sluggish but not bog. Unless you are losing voltage dramatically and its killing power to the coil. But I believe your current issue is carb tuning, or lack thereof.

I wonder if the secondary air door is opening too soon/fast. I would take note of where the screw is, unlock it, and then tighten the spring up to slow down opening. And see if that improves pickup. If it does then you're on the right track.
Pickup your tuning guide for your carb, I'm going to guess if the PO didn't have the cam card he probably doesn't have that either.

EDL Carb Tuning Guide

Start there and follow the steps. Download it for faster viewing. And pull your plugs after doing a change. You don't want to see white plugs nor fouled out black plugs.

 

Has anyone seen this diagram????.....

 

My suggestion would be given where you have now got to it's time to take it to a tuning shop. Unless of course you're relishing the did it myself challenge, but you should be able to short circuit things somewhat by investing some time on Youtube for your Edelbrock tuning.

Chris

 

If your mechanical advance is working properly it should have about 22* movement ( by 3000-3500 rpm )

So with vacuum advance plugged set the timing 36* @ 3000 rpm. To do this have a buddy wing the rpms up for short periods (about 5 sec) at a time. (Stay clear of the Fan )

If the distributor is working right the advance at idle will fall at about 14* 36 - 22 = 14
If you don't have that much movement the advance springs are to heavy (full advance won't come untill higher rpms) Or the weights are binding and not allowing movement.
Mr. Gasket sells a kit with lighter springs 928G for about $12.00, I like have my advance all in by 2000 rpms.
(especially with a stock converter)

Take it for a ride with the vacuum advance both plugged and connected, see what runs better.
Performance cams like lots of timing, so the bog may be partially in the vacuum advance
When you tip in the throttle, vacuum goes down, causing the vacuum advance to go away resulting in not enough timing to keep the engine happy.
Then you back off the gas and vacuum goes up to advance it again.

 

This sounds promising, thanks for the Carb tuning guide, I will read it today...and try some of these suggestions, the bog is weird...engine has some power...OMG, this thing is "Strong, pulls nice after the bog, just part of hot rodding I guess, lots of tweaking on adjustments. What did you mean by "where the screw is, unlock it"? Thanks again...

 

Does this mean...after we set the initial timing at 8* (with vacuum advance golf tee'd and carb port plugged up) and locked down, reconnect all vacuum lines back to normal and do I mess with the idle screw to bring the truck to a nice idle or do I leave it as is, once I lock down dizzy, connect vacuum lines and put air filter back on? The idle It goes up a bit...so just wanna do it right. And the 22* movement, does that mean that I should see the TDC line climb and be right at the 22* mark on the timing light as I approach 3000 - 3500 rpms? Thanks again

 

22* movement is just the mechanical advance limit only, so if you set it at 8* you will only have 30* total @ 3000 rpm
8 + 22 = 30

So if you set timing at 14* idle (with vacuum advance plugged) timing should be 36* at 3000 rpm.
14* + 22* = 36*
So as you approach 3000 - 3500 rpms the timing light should read 36*

Again try running driving it with out vacuum advance hooked up. See how it runs Does it ping under load?
If yes try backing off timing a few degrees until detonation stops.

Then try the vacuum advance and see if you end up with the bog.

 

Ok...I will try this later today

 

BINGO! I plugged the vacuum advance on my 355 and the car was a lot better and I did have a bog too. All my timing is in by 2500 (have old stock car guy helping me...), total is around 36. The stock cars we ran around 38. I'm running a small-body el-cheapo eBay special HEI with an external coil.

Also 800 CFM is sort on the fat side for a mild-not-wild SBC. Mine is around 400 HP and Lunati suggested a 700 CFM carb. Mine is a Holley.

 

Yeah, my engine might run better wit

Yeah, a 700 cfm Edelbrock would be better I feel, but this was on the engine when I bought the truck...so, it's what I need to try to set first, dont wanna dump money into another carb if I dont need to.

 

Rule of thumb
Smaller CFM carb will increase low and mid range rpm drivability while cutting some top end rpm power. Larger carb will increase top end rpm power levels while cutting low and mid range rpm drivability.
That's very general remember.

You can calculate the carb requirements with a volumetric effiecency equation with realistic rpm goals. It would be nice to know the cam numbers then someone can determine the required converter stall speed. The cam and torque work together and should be matched to do so.

 

Carbs aren't like shoes, meaning if the shoes are too big you can put on 4 pairs of socks and get by. No socks for carbs.

I'd be guessing that you do need to

 

One thing at a time. I'm also not partial to Edelbrocks, been playing with Holleys for many years. Some guys love them.

 

With valves set properly & dist dropped @#1 on TDC comp. it should fire. Are the new lifers pumped up? You can do it once they’re installed by priming the oil pump & slowly rotating engine over until all pushrods get oil to the top.


Sent from my iPhone using The H.A.M.B. mobile app

 

Uh oh... Have you adjusted the secondary flapper to try to get the bog out of it?

 

No, I have not adjusted the secondary flapper in anyway...I will after I read the guide on how to do this. Right now, I have the mechanical advanced to 15*, locked down and idling nicely, the bog is still there, the only way to get past the bog is to rev the engine up a bit, if I gradually apply load...it will bog, a higher rev will bypass the bog... if that makes sense, but I am way more than willing to tweak out on the carb guys.

 

Not quite ready to jump into the carb, although that's probably where your current problem is.
As mentioned, get a MR G HEI curve kit. The counterweights aren't the greatest design, but go ahead and put them in, and also a pair of just about the lightest springs. Set your light at 34-36 degrees. Rev the engine to about 3 grand or till the timing stops advancing. Turn the distributor until your timing mark comes back to zero at full advance. Plug in your vacuum advance. Re-adjust your idle as low as you can so it doesn't stall in drive.
Now, forget the timing issue for a while.
Now you can work on the carb. Read up on AVS's .
You can probably go to 5 psi for now. Report back

 

I could write you a book here, but there are hundreds of them out there already. Briefly - think of RMPs as air flow and airflow is measured in CFM. The carb work and delivers fuel based on pressure differential between atmospheric pressure and the low pressure in the carb throat venturies With large venturi the differential is not as precise or profound at low Cfm or RPM. When you raise the RPM you are increasing the CFM and the pressure differential getting those variables into a range where the large 800 CFM carb can do its job. Decreasing the size of the venturi gets the constant in range to do its job with the variables presented in driving.

For some homework,
What's the CFM demand of a 283, a 327, a 350, a 383, and a 454 engine running at 1000 rpm and 5500 rpm.
Solving those will help you towards understand a bunch .

 

I'd guess that 80% of the bogs I've seen are lean bogs. Meaning there is not enough fuel delivered to match the air flow requested.

The quadrajet carb is infinitely adjustable, to the point of confusion for some folks. The edelbrock is extremely simple and adjustable enough to deliver satisfactory drivability but will leave some compromises to deal with. If you don't know better or different you won't mind.

They are kind of funky looking but the street demon 625 is a great carb IMO. It has Small primary Venturis and a large goggle valve secondary. It's a hybrid of quadrajet, thermalquad, carter and other design features.

 

Is the accelerator pump working?

 

Yes, accelerator pump is working fine...push down on it, fuel is expelled through the squirters.