meowmix123

Lurker finally posting out of desperation. If I had any hair, I wouldn't by now. Truck still will not start after checking compression, ensuring I had spark by pulling the plug and cranking with it near a body ground, and ensuring I had fuel going into the carb by pumping the throttle and seeing, hearing, and smelling fuel going into it. The engine will crank continuously, firing every once in a while or shooting smoke/flame out of the carb, but never more than one cylinder at a time it seems like. I'm worried I might have destroyed the piston rings by now cranking it so much, and I need some guidance in where to go from here.

Background:
Bought my truck for a decent price out in the sticks with a blown headgasket, ultra worn-out front springs, and garbage tires. Been cleaning it up and repairing as I go, had the head surfaced when I got it off, new valves, springs, machined the rockers and camshaft, etc. As I reassembled, I carefully followed step-by step guides, as this is my first major engine work.I used Fel-Pro gaskets. Installed LCE emissions block-off plates as I went. Intake was surfaced, new ebay "weber" carb. LCE oil pump, new water pump, radiator, oil pan pickup, new battery, new battery cables, ignition module, coil, wires, plugs, timing chain, and new Hedman header.

I adjusted the valve clearance per my Chilton guide. I used assembly grease where indicated by the Chilton or by LCE's or my machinist's instructions. I torqued everything to spec with my Tekton wrenches. I made sure I was at TDC on #1 cylinder as I installed new parts, and made sure the distributor was aligned properly as it went it.

What am I missing? How do I begin figuring out what I'm missing? I'm a clueless newb that felt like I had a handle on it until recently. I've been trying to keep it step by step and diagnose the problem methodically, but now I'm at a loss. I would hella appreciate any help you guys could give me.

Charchee

What are we working on here? Year model and engine. Regardless, It sounds like your valve timing is off.

meowmix123

1980 4x4 pickup 20r 4spd

I will check the valve timing tomorrow first thing. So that I can learn, what makes you say that's the likely cause?

uncleblues

If your other information is correct, this is the most likely culprit.

Set your motor at TDC and check your #1 valves. They should be closed. If they are not, your timing is off 180 degrees.

gsp4life

I recently finished my first, a 22re. I was sure that I had it tdc so I stabbed the dizzy and fired it up.

Or tried to. It did the same thing you're describing. I only cranked it 10 seconds, cause I knew it should've fired right up as everything was primed.

Pulled the valve cover and at "tdc" #1 valves were tight!

Pulled the dizzy, spun the rotor 180° and it fired up on the second crank!

It happens. Let us know if that's the problem

gsp4life

Edit: by 'valves' I meant the #1 rocker arms were tight.

Charchee

Because you had the chain off while replacing the head, backfire and the randomness of the cylinders firing as you described. I was just trying to tie the symptoms together. That may not be your issue and it could be in the ignition timing. The smoke/fire out of the carb makes me think that your intake valve is either not closing on time or is opening too early for whatever reason, allowing combustion gasses back into the carb. I have never owned a 20R so you may want to get some additional feedback before you tear it down to the chain. I was just thinking you may have the timing off just a little after reinstalling everything. It not uncommon. Even for the pros which I am not.

meowmix123

Well it looks like I was too disorganized during assembly. I set motor at tdc, rocker arms on cylinder #1 are loose, distributor was off 180°. It also appears that the single bright link on my timing chain is one link advanced(?), Clockwise on the cam gear. Before I drain everything out of the engine to pull the timing cover...that's the next step, correct? Could I have damaged the valves or cam with that small of a misalignment? Or by trying to start it too many times?

Charchee

Your oil pump was turning while you were cranking on it so I doubt you did any major damage. It's probably good that you had the timing wrong if you had things loose under there. If it had run, you might really have done some damage.

gsp4life

Hey before you go tear it apart, be aware that although the cam gear has 36 teeth and the crank gear has half at 18, the chain has 98 links (I think, a 22r has 96 with a shorter block). What that means is that mathematically, the chain won't have the bright link in the same spot at tdc for many, many revolutions cause the numbers don't divide evenly like that.

Please don't make me do the math, it's not my strong suit, lol.

I can't tell you for a fact that the chain is set right, but after that initial install, you can't count on the bright link anymore once it's been cranked.

gsp4life

Just thought of a decent way to tell if it's right. Rotate the engine with a breaker bar to tdc, making sure the crank pulley mark is exactly at 0°. Don't go counter-clockwise to readjust, chain has to stay perfectly tight. Now check the timing dot on the cam sprocket. On a 22r the keyway points right up to 12 o'clock, but the timing dot would be to the left at 11:45 or so. Don't know about the 20r, but hopefully it's in the manual or you already know where it should be on a correctly timed engine.

It should be obvious enough if it's a whole tooth off that you'd be able to tell. Maybe check some photos online for reference.

Good luck.

meowmix123

I thought of that right after my last post, and visually checked tdc and verified the valves were timed correctly with the piston. So my distributor was off 180, which I fixed, and I just tried to start it again with no luck. Still seems like it's trying to fire. Should I do another compression test?

meowmix123

Might add that it sounds to my ignorant ears like the spark is firing on a cylinder but not igniting, and it's still backfiring out of the carb. Could my carburetor be to blame? Improper set up, too much or insufficient fuel pressure, etc? Or my valve clearance is off?


Thanks a ton for y'all's help by the way

Charchee

I hardly ever suggest doing this but will it run on starting fluid? Have you double checked to make sure your plug wires are on the correct cylinders.

Charchee

Your carb could be an issue if it's giving you too lean of a mix. A really lean condition can cause a backfire through the carb but I really feel like it's an ignition timing issue. The reason I suggested starting fluid is to try and pin the blame on the carb and shorten you list of suspects down to one. If it does the same kind of thing, have someone crank on it while you hold a timing light on it. That's going to be the easiest way to troubleshoot that end of it. One more thing I just thought of that can cause a lean condition and backfiring is a leaking intake manifold gasket which will allow more air into the system than the carb can match with fuel. You did have it all apart. Did the new gasket give you any kind of trouble when you installed it?

Here is one more scenario just to think about. Say you had every one of your plug wires on the wrong plugs. What would happen? I would imagine nothing would happen because the spark is coming at the wrong time on all cylinders but you know what they say about a broken clock. It's right twice a day. Eventually you would have one of the cylinders spark close enough to the right time and give you some kind of combustion. Since it wouldn't be timed correctly, it would almost certainly backfire when it hit. Don't read too much into that. Just spit-balling, trying to explain the intermittent hit on only one cylinder at a time.

gsp4life

Well, glad to hear the timing's right but something else is going on.

To help diagnose a potential air leak you might have to to smoke-test the crankcase and see if your getting a big enough leak to prevent start-up.

Hard to find and air leak any other way on a non-running engine.

I don't know enough about carbs to be of any help there, sorry.

meowmix123

After correcting the distributor, I sat around for a bit trying to keep myself from "fixing" random things until I broke them. Figured I would go through step by step the reassembly and think about any points I was uncertain about. Settled on the valve clearances. I've never used a feeler gauge for anything before, and I'm a total novice at engine stuff. I remember being uncertain about the "slight resistance" you're supposed to feel when the valve lash is adjusted properly, and being very conservative ie leaving too much clearance. Rechecked and readjusted all the intake and exhaust valves, some of which I can't believe I felt were correct before, and the engine started on the first crank and ran for 30 minutes while I tuned the carburetor and worked the throttle to break in the cam.

Long story short, I was timid. Woops. Battery is now dead so truck won't start again, but my nightmare is over. Thanks dudes. Learning is fun.

gsp4life

Nice!!! Good work getting it running so soon

I also used to set mine too loose, common mistake.As far as I can tell, slight resistance means the next size up feeler gauge won't fit.

Charchee

You done good my friend. Hard to believe a valve adjustment would be the difference between a dead engine and one ready for the highway. A no start issue is the best form of education you can get on your engine. Especially when you finally solve it. Good work!

meowmix123

Thanks guys, it feels good to finally have it running, I've been stressing over this on weekends for about a month and a half. I've been doing all the work on my own, so it helps a ton to have knowledgeable folks to bounce ideas off of. I'm sure I'll have many more newbie questions for y'all. Cheers!