newb timing question/issue

New here, but my issue is more pressing than greetings. I've got a crate 350 referred to as 'rocket block' it has a flat tappet cam(only thing I think you need to know as far as my issue is concerned) so the ultimate issue is my timing. I was driving around and the truck began running different. It was running higher rpm and pinging when id hit the throttle a litl bit. Too far advanced as far as I understand. I shut it down and hook up the timing light. Check it and it was at about 15 degrees above. My paperwork says it should be at ten. So I set it. Pull out of the driveway. Sounded normal, hit the throttle as I normally would. Pinging like mad. Back in the driveway, back to 15. I repeated the process. Didn't work. Is there anything that could be doing this aside from the fork that holds the dist in place? Or perhaps that bolt stretched out? I've had to readjust my timing every 5 or so months to keep it where it should be. Any suggestions? I'm having an off day and it could be as simple as anything. All advice is appreciated.

How about some real info??? Like year, make, model??? Is it computer controlled? A lot of them are nowadays.. Need some data to offer an opinion.

Bet ya the hold down bracket is junk or a chinese 1.
Get a stocker and your problem is solved.

I agree with you on his one.Computer controlled dizzies can be a factor.

Quote:

---

Originally Posted by 34_40

How about some real info??? Like year, make, model??? Is it computer controlled? A lot of them are nowadays.. Need some data to offer an opinion.

---

Sorry,I'm not too knowledgeable on the engine. It is in an 84 gmc fullsize and it has a box under the dash with only one wire going to the hei dist. It did have more wires, but all of the emissions were removed and they were cut. Not sure what else to share. Its just a cast iron block with 1.94 heads. Flat tappet cam, alum. Pistons, 4 bolt main, edelbrock perf carb n intake. If you need to know more ill dig out the paperwork on the engine. Thanks for the help so far. I'm going to buy a hold down and bolt for it today and see what happens.

Well when you tighten down the bolt/clamp-can you move the dizzy??.

No I cannot. Not by hand.

OK, you said GMC. Does it have Electronic Spark Control (ESC)? It will have a badge usually on the back of the truck. Anyway, you can tell if it has ESC by the fact it has TWO connectors coming out of the metal distributor housing (not the cap). The ESC is intended to alter the timing under load but sometimes it gets a mind of its own. You can easily remove the ESC from the function.

First thing to do is unhook the spark control computer lead from the pink wire and hook the pink wire directly to the dist. cap. Make sure you plug it into the cap at the BAT terminal. The second thing is to locate the 4 wire connector that feeds into the ignition module. There's a brown (D), green (C), white (B), and black (A) wire there. The letters in () are on the black clip that the wires come out of. You jumper the green (C) and black (A) wires together by adding a short wire stuffed temporarily into the back side of the connector.....just use a short piece of wire and strip each end and stick it into the connector. IF you have a problem, pull the jumper out and you are back to normal setup. IF this jumper works (after testing for a few days), you can permanently make a jumper by cutting the wires and soldering them. You could also replace the 7 pin module with a 4 pin module to elimnate the ESC feature.

So I just tried everything again. Got the engine warm. Set timing to ten degrees. Rev the engine once, check timing right after revving it. Its up to 13. I can't explain it. I cannot turn the dist even right after checking it again and it being higher. The dist didn't move, but my timing advanced 3 degrees. I don't understand it. I didn't buy a new clamp or bolt since I couldn't move the dist so figured that won't change it. Could it be anything in the dist itself?

If it is slipping as you describe, it is either the balancer is broken OR the timing chain is jumping. Either is a mystery since a jumping timing chain will quickly get you a cam that is seriously out. A slipping balancer will get you a problem because, if you line up the timing to the correct amount, the timing will be off (because the mark slipped).

Check list: vacuum advance disconnected...right?
Does the timing ever "slip" the other way? It seems like you have described it slipping at least several times.....Do you notice if it is ALWAYS advanced too far?

Sorry, I missed your post robot. No esc on this rig. It has one 3 wire plug coming from the dist body to the c- grd b+ on the cap. The only remaining wire from the box under the dash is pink and goes straight to bat+ on the cap along with a larger pink wire(ignition source) that's all. The box has a brown wire going to ground, but I don't think that's an issue.

The vac advance is disconnected and plugged. The timing has retarded itself aswell. Once down to 4 once to 6. But it tends to advance more often than not. The rig sounds pretty good when I have it set to ten and just let it idle, but as soon as I rev it even a litl it starts to advance. And when I rev it a few times it can jump as much as a degree at a time. Not hard revs mind you but more than a quick blip.

The advance mech in the dist is seizing onto the lower dist shaft--

you might be able to work some lube into the shaft but easiest way to fix, remove dist, remove drive gear, then with shaft out of dist housing, separate the top advance meckism and lube the inside till it moves freely and then reinstall every thing--this was common back in late 70s early 80s--

Thanks to jerry and robot. Ill try lubing the dist shaft first and see what happens. I'm almost.positive the installer of the engine (dealership) used the original dist(84) when they did the work. So that would be commonplace to what jerry stated. Thanks again. Any other advice will be heard. Thanks again fellas.

first off what fuel are ya running in it? 87-90-92-or 94 octane.....the lower the octane, the lower the advance. Lower octane= shorter burn. On 87 octane......advance 4-6.....on mid grade 6-9 and 92 octane 10-13, on 94 octane advance 13 to 15......this is based on stock or close to stock horse power.

Running 87. Its pushing approx 300 horses and 380tq. According to the paperwork.

I am using 87 octane. I suppose based upon your list and the paperwork calling for ten degrees I ought to be running premium.

unfastened the dist. Lifted it a litl, squirted some turbine oil(from a zoom spout bottle) down the hole and let her set for about half hour. Set the timing and tried it again. It retarded itself. Down to 8. Hit the gas again. 6 degrees. I havnt a clue what to do with it.

on this mystery ill go with Mr jerry. I have no info to add to your problen. other than a slipped distrybueter gear or like mine a bad modulel

here's what happens and sounds like your problem--The advance portion of the gm type dist are up in the top of the dist just under the rotor--they don't get enough libe and start sticking/hanging up on the shaft---they may advance and stick advanced, so you reset the timing lower---then they may not advance so you set it up---issue is that the advance won't return to bottom and then won't advance so you are constantly chasing it----the dist needs to come apart to fix it properly , however you might be able to work some pentrating oil into it from under the rotor--

That sounds likely. I've talked to a couple friends that have said the weights stick and could need to be lubed. Ill check it out. Thanks again for the advice. I truly appreciate it.

Well -I'll chime in with my 2 cents worth. I concur with Jerry - the insides of the distributor are probably gummed up. I would also suggest that you take the distributor out, take it completely apart and clean it really well with solvent or carb cleaner. If you use spray cleaner, please remember to use wraparound safety glasses that cover your eyes completely as that stuff is very nasty in the eyes!

The illustration below shows an exploded HEI - they're all pretty much the same (this one is from 1982) and the components are generally like the picture. When you reassemble, use a dielectric silicone grease on the weights and around the main shaft. Make sure to get the bottom seal back in the correct place or you will have more lubrication than you can imagine from the engine's oiling system!

Good Luck,
Glenn
Attachment 50364

So pulled the dist and found a few things just under the cap. There were shreds of spring material(carbon brush, spring), washer that said spring attached to, and some rock hard carbon bb's. All bouning around as they please. And to top it all off, the rotor was sitting crooked due to a cross threaded screw. Oops. That was holding up the spring loaded weights. It had a good amount of rubbing between the weights and rotor. That could have been hanging the weights up and causing them to stick in the extended or relaxed position. That could be the issue. But I changed that cap n rotor about a month ago, no issues til now. Oh well. Since the dist is out and in some pieces, ill be rebuilding tomorrow(or over a couple days) when I have time at the shop I work at. Ill post my success or failure when I m finished with it. Thanks to all who helped.

Not sure it where me I would rebuild one or try to find a good deal on a better used one.I am thinking you could find a deal on a better dizzy.

Well I'm gonna give it a go as I work in an electrical parts shop(we don't do dist) but my boss has done a couple himself. So ill try it out and if it doesn't work I'm only out 2 bucks for the di-electric grease. There's an accell unit at a local store for 120. Is this a good price?

the part surrounded by the red outline in Glenn's post (main shaft) is actually an "assembly" and is what needs to move freely on the longer shaft---

your findings under the cap==cocked rotor, springs wts etc will probably fix your deal but i still would recommend that you lube that inner shaft and make sure that it moves freely

Yup - what Jerry said.. And go ahead and try a cleanup and new cap/rotor. Like you said, you'll be out a few dollars for the grease and the cost of a cap and rotor but you'll learn something in the process. As to $120 for an Accel unit - that's about right for a new unit.

Well it certainly is a good lesson. Something I havnt messed with before. I'm not quite finished with it. I stopped at a local speed shop and the fella told me that I needed to do a couple things differently. I shouldn't have used white lithium grease on the shaft. High heat wheel bearing grease instead, oops. And that same stuff on where the weights guide. And that I installed my gear upside down. Hahah. I was rushing to get her done. Then was told to pull it down again. He also informed me about the harmonic balancer. Make a note of this(if it matters to you) on small chevs from 55 to 68 the timing marks were spot welded to the block, and that the harmonic balancer monting bolt by the timing mark was in line with that mark. In 69. And up the mark was moved ten degrees away from being inline with that bolt. So this is how I am to check if the balancer has slipped.

So, dist all backk together again. Clean and in good order. No start. I positioned the mark on the harm.balancer to zero. Tdc. Then rotated the dist til the rotor pointed the no.1 position on the cap. And I checked my plug wires a few times. They're all in order. And at tdc with rotor in the correct position I'm not getting the rig to start. It'll crank and backfire occasionally, but it usually just cranks and makes obnoxious noise. What could it be?

Did you verify TDC compression stroke, or just TDC? Sounds like your distributor may be 180 out of phase. If not I'll defer to Jerry & Glenn.

You're 180* out and stay away from anything that says Accell

When you put the dizzy back,before hand did you line up the oil pump drive slot with a flashlight and a long screwdriver so the slot was facing front to back??.You said you had some doubts about the H/B and it's timing marks.Now might be a good time to check that.Pull the valve cover for number one cylinder.Watch the exhaust rocker open and close,the intake valve open and close,and then the piston on number one at TDC.The piston at TDC should be showing 0 on the H/B.

No luck. First tried turning the dist 180. Nothin. Then Cranked the engine by hand to tdc. Pulled no.1 plug to make sure(stuck a pen inside and felt the piston) turned the oil drive key so that when I set the dist in the rotor pointed at no.1 on the cap, where it should be. Again, nothing. I am replacing my plug wires correctly. I've checked over and over to be sure. I havnt a clue as what to do next. As for the oil key, why should it be positioned with the groove front to back? I tried it and when I set my dist in it it wouldn't point to no.1 on the cap. I don't see how the oiler key position would change things. I know that's what keep it from dropping in a setting correctly, but does position matter as long as I'm getting the rotor to point where I want it to? I'm baffled.

That is the way we set them at the Chevy engine plant when during testing them we found them to be off.You can get the dizzy to drop,but it would be one or two teeth off.Is the H/B on 0 when 1 is at TDC??.It has to be there to get the teeth on the cam to line up with the dizzy and line up with the oil pump drive.You need the proper timing position to advance or retard the dizzy correctly.

With the dist where its at, no.1 at tdc, and zero on the mark, the rotor is pointing at no.1 on the cap. So, mechanically, is this all correct? How it should be? Perhaps its electronic failure now. How often do these factory modules wear out? It said singapore on the backside, so I was skeptical putting it back in, but before I pulled the dist, the truck ran. All I did with the module when I pulled it down was wipe it off with a rag and plug it back in. I put the dielectric grease on the backside. I did put the dist back together correctly. No missing parts. All in the same order and position it came apart. So I know that the moving parts are good.

I mean the dist parts are correct. Please tell me if the tdc and rotor are all set how they should be.

So can anyone tell me if I'm setting it up correctly from a mechanical standpoint. No.1 at tdc, compression stroke. Dist rotor turned to face no.1 on the dist cap. Is this all correct? I havnt been under the hood for a couple days, been busy, but I do need confirmation. Thanks again.

You can't put di electric grease under a module

Put the crank pulley at about 20* btc and turn the dist til the rib on the rotor (reluctor)lines up exactly in the middle of the center of the module windings(where the metal sticks thru
you should be able to check for spark just by turning the ignition on and off causing a spark

Quote:

---

Originally Posted by stavi

So can anyone tell me if I'm setting it up correctly from a mechanical standpoint. No.1 at tdc, compression stroke. Dist rotor turned to face no.1 on the dist cap. Is this all correct? I havnt been under the hood for a couple days, been busy, but I do need confirmation. Thanks again.

---

Aaaaa-did you read what I suggested????.That sir is not a guess.:rolleyes:

Sorry,listen closely.That is the door on here slamming behind me as I leave this thread.My work here is done.:mad:

Hmm – don’t know why you used dielectric grease under the module. Dielectric grease is high content silicone and works well to keep moisture out without being electrically connective. As mentioned above, use it on the rotating-weight assembly. Not a good for the underside of your module where it meets the heat sink. Should use a heat sink paste there.

Okay - let's fix this thing once and for all. Go back and read this entire post - pay special attention to Gary and Jerry then there are two things YOU MUST DO. 1) Enlist a friend (to be used a little bit later, I’ll tell you when) and 2) Purchase a six pack of your favorite beverage (again – I’ll tell you when you need this!!


As to your timing issue, you need to be absolutely certain that #1 is at top dead center (TDC). There is, or should be, a TDC or zero mark on your balancer. You’ve indicated that there may be a problem with your balancer so this might be a good time to procure a new, known good harmonic balancer. There will be other degree marks however; the TDC mark will usually be the last mark to come to the pointer on a stock balancer when the engine is rotated. It is almost always the predominate mark in term of length and will have a “0” (zero) next to it

This mark on the balancer indicates TDC of the piston in the #1 cylinder. This may or may not be on the firing stroke as the cam rotates at half crank speed, it is possible for the ignition to be 180 degrees out of phase with the crank. As such, the cam is aligned on the firing stroke of the crank only every other revolution.

There are several ways to positively guarantee the crank-to-cam phasing. If you can easily get to the #1 sparkplug, remove it and cover the hole with your finger and enlist the services of a friend to rotate the engine. As the engine approaches TDC, both valves close and compression will blow your finger away from the hole. As this happens, check the balancer. You should be close enough to TDC to see the mark. This might take several tries to get the feel for the compression but believe me, you’ll know. Once you’ve felt the compression. Rotate the engine back to the zero mark.

Now the No. 1 piston is at TDC with the cam aligned to be on the firing stroke. If the distributor were to be installed here, the spark would be retarded. Rotate the engine about 15 degrees in the direction it runs (clockwise looking at front). Rule of thumb - on a small-block Chevy, approximately 1/16 inch on the surface of the balancer (any size) is real close to 1 degree. This is not exact, but it will be close enough to start the engine. Timing tapes are available from your local parts store (or Summit) that allows you to fully degree a stock balancer.

Drop in the distributor when the crank is positioned at about 15 degrees. Remember to turn the oil pump drive so the distributor tang engages it as the distributor gear meshes with the cam gear. If done right, the rotor will point to the No. 1 terminal on the cap. This may take some time, and a bit more effort than you thought, but now the distributor will be correct and ignition timing close enough to start and adjust. When the engine fires up, adjust your timing and go for a test drive. Okay – now sit down (with the friend you’ve enlisted) and have cold one or two – depending on the thirst level. I sometimes need three – but only if I’m not going to drive anywhere for several hours!

Trust me – I’ve worked on a lot of SBC and I still need to think this through each time I remove and replace a distributor. Take your time, don’t get frustrated as we’ve all been here – you will get this!

Good Luck,
Glenn