I am in need of a wise Mechanics help.....

[d510addict]

So after fiddling and tinkering with my truck forever I still have the same problem and its making me want to tear the engine apart and start from scratch.

 

What I have.....

-L20b block bored 20 thou over with the deep dished pistons

-W53 peanut head with full rebuild and 280z valves

-stock cam???

-EI Dizzy

-32/36 Webber with manual choke

 

The problem is it has never run real well....idle problems....lack of tunability of carb......cant advance the ignition timing past 5 (the marking plate on the block may or may not be the correct one) or so w/o major pinging. I have run down and fixed some vacuum leaks and that helped things, but it still isn't that good and I cannot find anymore leaks. I have replaced the dizzy once thinking that was the problem and though going from a very worn, to a less worn dizzy did help it still has issues. I have only ever run Premium and non ethanol premium (92 octane) on this motor and as requested by the engine builder used Royal Purple oil.

 

The cam timing seems to be spot on....the line on the cam thruster plate is just to the left of the notch    _    on the cam gear exactly as shown there while using hole #2 on the cam gear. I did a compression test on all cylinders and came up with 185ish on all cylinders (very little to no variance in pressures).

                                                                                                                                                                       V

 

I have few things to do still.......add a bit of high octane fuel or some sort of booster to my tank to see if that changes anything and retard the cam timing by 4 deg to hole #1 (though is it possible to have the markers line up correctly if the cam is off a tooth??). After that I am out of ideas on the things that I do understand.

 

What the opinions of others on this board? Is there anyone in the Milwaukie/Portland area willing to take a look at it? I have no money as I am on disability while recovering from a operation......but I have barter......521 glass and random parts, lower A arms.....various heads etc.

 

I know its a lot to ask but I am in serious need of help, I need this thing working properly so I can get to work reliably once I get off disability.

 

Thank you very much, Derick

 

                                                                                                                                                                 

[banzai510(hainz)]

YOu been on here before awhile ago.

The cam sounds lined up correctly. Wheres you engine builder? He should know. Royal purple on a L motor?

Dont adajust to number #1 where you get that from. L20s coem from factory in #2.

 

Hopefuuly you seen my video and Know how to install a distributor.

If you cant get past this 5 or what ever you mean?  each sawtooth is 5 deg right? so it would be 2 sawtooths. then on back side of the dizzy is a 8mm bolt and readjust the timming plate from underneath to get the say 10deg advanve you need.

 

 

so you have 185 across all cylinders and that sounds good. so the valves are good .

 

I say adjust the timming till you get the spec of a L20. I dont know what it is but Ill say 10dbtdc right now and then drive it and adjust,

then try a new carb

 

 

this is simple fix. less than hr fix with the right part. proplem is you have no money to try all this out. or spare parts

[Doctor510]

I'd check the mechanical advance in the distributor.  Try this.  Warm up the motor, idle speed at about 1,000 RPM, Using an advancing timing light, the one with the dial,  set the TOTAL timing to 34-36*BTDC at 2,800 RPM, lock the dist and check you idle timing.  If it idles and runs well, you're good to go.  If not the dist should be re-curved.

[d510addict]

Sorry Hainz I mean I cant set the timing past 5 degress before top dead center, it is undrivable at 10-12.

[d510addict]

What do you mean by Die Timing?

[d510addict]

Hainz I want to retard the cam timimg to #1 just to see if I could be off a tooth. Though it sounds as if it is set correctly.

[Doctor510]

Hainz I want to retard the cam timimg to #1 just to see if I could be off a tooth. Though it sounds as if it is set correctly.

Cam timing is probably NOT your problem, the location of the dist/oil pump shaft is more likely.  Do some research and reset it, I like the reference 11:25, FAT back.  Check it out here, lots of good pictures for you to look at.

[racerx]

Not sure about your dizzy but on my L16 distributor there's a adjustment 10 mm bolt that can Retard and Advance the timing and underneath the adjustment plate there's an 8mm bolt that can also help with adjustment of timing.  Also once you set your total advance, you can plugged the vacuum coming out of the 32/36 carb to the Distributor, courtesy of Doctor510.

 

Have you checked the engine's vacuum with vacuum gauge? Should be about around 17-24 at idle. When you did the compression check did you use a plug in type or screw in type because what I found with the plug in type vs. the screw in type was that it was reading higher than the screw in type.  If you are reading 180 or so that's dam good.  Did you mess with any of the jets on the carb or have you cleaned them out? I think it's something minor.

[d510addict]

Doctor510 I will check dizzy position and set timing today....quick question, do I leave vacuum unplugged while doing so?

 

Racerx I used the screw in type. I have messed with jetting......I believe I increased the size of the jets.

[d510addict]

@Hainz I have spare carb and parts! The carb is an old holley originally a stock option on a Ford Falcon, it was what originally came on the L16 when I bought the truck. But I was literally keeping the thing together with JB weld and chewing gum.....It needs a serious overhaul and needs to be dowb jetted for the much smaller L series engine. I ended up scouring for the weber as it was the much cheaper and easier option. The weber was new in box though I have no idea what it was jetted for originally.

 

Anyone have a good idea where to start with jet numbers?

[Doctor510]

Doctor510 I will check dizzy position and set timing today....quick question, do I leave vacuum unplugged while doing so?

 

Racerx I used the screw in type. I have messed with jetting......I believe I increased the size of the jets.

Plug the carb vacuum fitting, leave the dist vacuum adv unit alone.

[LenRobertson]

Here is the link to the DQ carb articles:

https://docs.google....zRjMmE0MGY3NTA1

The issues are Vol.1, Issue 3 and Vol.2, Issue 1.

 

Info on both Hitachi and Weber. I think there was a table of jet sizes for the 32/36 in the second article.

 

Len

[datzenmike]

If you are sure you are at TDC and turned the cam only clockwise to set it then the cam timing is fine.

 

You say idle problems. What problems? Can't turn the idle down without it quitting?

 

Setting the timing... What RPM is it idling at??? If above 900 the mechanical advance may be adding 6 extra hidden degrees so it will only read 5 degrees before pinging begins. Timing should be set at around 700-800 RPMs. If you don't have this idle, setting the timing is almost a waste as it will need resetting later. 

 

If everything working properly you should have zero vacuum advance at idle. Unfortunately this is not usual so unplug the vacuum advance hose when setting timing. The vacuum advance port is just above the throttle plate when set at proper idle. If the idle is turned up, the throttle plate may be up at or above the port and intake vacuum may be present and altering the advance. You don't have to seal the hose end, it's not causing an intake vacuum leak.

[Doctor510]

What do you mean by Die Timing?

IDLE sorry

[d510addict]

The engine RPM surges alot at idle, like its loading up. It will idle more steadily at higher RPM but very up and down if I back out the idle speed adjustment. I will put a guage on it to set the idle RPM to 800 and redo timing.

 

DatzenMike.....I was doing it wrong!! I was turning counter clockwise. Tomorrow I will turn it clockwise to line everything up and let you know the results.

 

Just curious 'what if' my cam gear as advanced 1 tooth? Would the affect be drastic?

[Ranman72]

Doctor510 I will check dizzy position and set timing today....quick question, do I leave vacuum unplugged while doing so?

 

Racerx I used the screw in type. I have messed with jetting......I believe I increased the size of the jets.

you say it seems like its loading up 

did you up size the jets for any particular reason  reason 

[d510addict]

I went 1 size up to see if it made any difference on how the engine ran. Wasnt based on logic really. Just knew the engine wasnt right and it seemed like a lean run issue and this engine is far from stock. But it made little to no difference.

[DanielC]

Almost every thing you can adjust affects something else, and not what you intend it to.  If the idle speed is too fast, mechanical (centrifugal) advance starts coming in, you cannot accurately set the timing.  Throttle plate open too far, vacuum advance comes in, you cannot set the timing at idle.

check compression , if good and nice and even, in all four, that is a start.  Are you sure you have no vacuum leaks?  really sure?

you need a dwell tach, and a vacuum gauge.  Adjust the valves, or check them.  Have the idle speed below 800, remove the vacuum hose from the distributor, plug the hose.  Now set ignition timing.

With the ignition timing set, hook up the distributor vacuum.  Ignition timing should not change, at idle.  Hook up a vacuum gauge, turn the idle mixture screw for highest vacuum.  If idle speed goes above 750, turn it down with the idle speed screw.  Adjust the idle mixture screw for highest vacuum, at 750 rpm, and when you are there, turn the idle mixture screw in to drop idle speed to about 700.

[datzenmike]

The engine RPM surges alot at idle, like its loading up. It will idle more steadily at higher RPM but very up and down if I back out the idle speed adjustment. I will put a guage on it to set the idle RPM to 800 and redo timing.

 

DatzenMike.....I was doing it wrong!! I was turning counter clockwise. Tomorrow I will turn it clockwise to line everything up and let you know the results.

 

Just curious 'what if' my cam gear as advanced 1 tooth? Would the affect be drastic?

 

Advanced or retarded it will still run fine. It's very subtle but advanced cam timing favors low speed power and retarded favors high speed. Hardly noticeable but there. It will also (as Daniel pointed out) affect everything else, like idle intake vacuum.

 

To check the cam timing turn up to TDC ONLY clockwise. If you overshoot back up about 1/4 turn and try as many times as needed to get it right. This clockwise direction keeps the chain tight on the tension side and places all the looseness on the slack side. This is how the cam and chain would be positioned if it was running. 

[banzai510(hainz)]

cam is 95% percent fine I think.

 

You should be able to get  0 deg to 25 deg with adjusting the dist dist advance and retard. If NOT I think your off a tooth.  there are enough timmed  L motor dist spindal photos at TDC.  yes the 11/28 position. intsll the dist and should be close to get #1 plug wire on there and middle of the timming plate adjustment. fine tunning is moving the plate with the 8mmm on underside of the distributor.

 

Now if this is good. dist could be worn out then the carb.

 

carbs wear out also. but I find distributor are usually worn out more often or the weights springs fall apart or the adavanve locks up.

My last cuttin out proplem on my 521 was at High rpm it would cut out. I swapped out the dist and was fixed/ Then noticed late the adavance plate was stuck!!!!!!!!!!

 

 

also tell us the carb setting. Dont want to find out you have the carb speed screw cranked all the way in there. thats why the idle jumpeing around as your trying to run the main jet as a idle .

 

Dont trey to out think us on moving the chain to the #1 position. Its not the proplem. if anything put on TDC and take photos. we will tell you... I ran a tooth off before. They still run fine enought to get to twork

[d510addict]

[banzai510(hainz)]

I call it good.

I gareentee that is NOT you proplem

 

unless you not at Zero on the bottom.

 

L20 sawtooth timming marks only have 1 notch on the crank. Unless you got that wrong I say its good

[d510addict]

I set everything but thr carb as the vacuum isnt budging my guage.

[banzai510(hainz)]

 dont know what thats means ?budging my gauge?

[d510addict]

There isnt enough vacuum at the carb to register on my vacuum guage at 750 rpm.