quicky eyeball cam timing check. once you have verified TDC on the balancer, take off either valve cover. turn the engine past tdc. #1 or #6 rockers. if no movement turn engine 1 full turn to tdc again. rock engine back and forth thru tdc and you should see both rockers rocking back and forth right at the tdc mark. that shows exhaust is just closing and intake opening right at tdc, like it is supposed to. if chain jumped, both valves will be moving 10 or 20 or so degrees late. i think the 2 common timing gears are 34 and 44 teeth. so about 7 or 10 degrees a tooth. pretty unlikely. very few of these cars have orig 40-plus year old timing chain and gears. but possible.

 

Silver brings up some good points about AFRs. I have read about this issue before. What he is saying is, that AFR made the ports so big for additional flow that there is no meat for the rocker stud threaded hole. So, its drilled clean through, into the runner instead of stopping short. So you can imagine that any vacuum on those studs from underneath will draw oil out of the valvecover area.

Should you be concerned? IDK. Maybe not all AFRs are like that. But before I would start removing 16 rockers and studs, I would buy a dental mirror and take a peak inside the runners of one head anyway. If you see any rockerarm stud threads in the runner, then you know what you need to do.

You would think that AFR was aware of this issue and already sealed the rocker stud threads. Who knows?

 

At this point I would pull the heads....clean everything up (valves) and get a bridge with indicator.....verify the timing mark is off (which it probably is).....
Time and gaskets are all you lose here....
Trust but verify....40 posts speculating what the issue may or may not be is not doing anything.

Jebby

 

thats my plan. I will get it done when I have time.

 

 

Ahh the voice of reason. Thanks Jebby. From where you are it will take about an hour to pull a head (barring unforeseen difficulties ie exhaust bolts) . One thing I do is keep each valve train separate by putting the components for each valve in a baggie and labelling that baggie. I even try to mark the push rod end so it goes back in its proper orientation. When assembling, use never seize of the exhaust bolts.

For the record, I don't think you are set at 45 degrees BTC. If I get my stock 350 at much more than15 BTC it tries to rip the teeth off the flex plate when I try to start it. I don't think you cam timing is off either, Back in the day the 350 came with nylon tooth cam gears which wore quickly. I jumped one tooth and could barely get it home. If you are at 45 degrees BTC, the piston is about 1" down in the cylinder and I don't think any of the TDC tools will hit the top of the piston. As for the timing damper outer ring moving, it would have to move 2" circumferentially to be off 35 degrees. I never had one of these fail, but I would suspect if it did move this much, it would keep moving as I tried to time it and the timing would at best be inconsistent, the damper would likely wobble or worse you would find 2 pieces; one connected to the crank and the other on the road.

I think you either have a problem with your timing light or you have the wrong damper or indicator on the timing chain cover is off. .

Good luck

 

I truly believe it is probably the old late/early timing tab mismatch....this is easy to screw up....see it all of the time....
It is why everything I work on gets a billet tab with pointer and corresponding balancer...
In over 25 years I have seen people chase their tail and spend thousands tracking down problems that don’t exist due to timing.
The OP’s engine may run fine but the fact is that it is probably no where near optimal timing for the engine because it is impossible to tell.
Once you know....you know....before that, everything else is speculation.
And you gain tremendous piece of mind knowing.....

Jebby

 

it certainly could be the timing light, so I need to find or buy another one. As for the damper or indicator, I already checked this but could be wrong. I will try to verify......again. Once I can get a TDC determined I will methodically go from there as there has to be something simple wrong.

Apparently the common piston TDC tool that screws in to the plug hole does not work on AFR heads due to angle. I am pulling the head and doing it that way.

 

Great ideas for possible causes. Probably one simple thing when you find it.
If you are going to pull the head, you should do the compression test first, so you know if you have a problem there that may be related to your oil issue.

 

yep.....that’s the plan.

 

OK, I did a compression test today. First I did a cranking compression test with my old Lisle compression tester, and all cylinders indicated 200-205 PSI on a cold engine after about nine pulses. All of them came up immediately on the first crank above 100 psi or more. I then checked the accuracy of my Lisle tester against another known good gauge, and my Lisle is indicating about 5 psi high, SO, I would say the actual cranking pressure is 195 - 200 on all cylinders.

I then did a differential check on cylinder #1 and it indicated a 4% loss at 100 psi. I did not check any other cylinders given they were all consistent with the cranking check. I would expect all cylinders would leakdown close to the 4%. This was down with my new Longacre leakdown tester.

So, interested in your input. Seems to me, my cylinder compression is as good as it gets.

 

4% is excellent......195 psi is also excellent and on the edge of pump gas with a fast burn chamber. No issues here.
To recap....you need to look at exposed rocker studs in the intake port, wiped out valve seals, and intake face sealing....these three things are the only way to get oil in the ports. I believe the oil in the intake is simply reversion.

Jebby

 

Found out some interesting things this afternoon on my engine that I think explains some of the problems. I pulled the left cylinder head and established TDC with Comp Piston Stop, by swinging the crank both ways, marking those locations with blue tape, splitting the difference and marking TDC on the timing wheel. So the harmonic balancer TDC mark is correct as indicating true TDC, based on this check and the coat hangar pointer. Look at the pictures, the blue tape shows both the two piston stop points, and the mid point identifying TDC, which perfectly matches the 0 mark on the balancer.The harmonic balancer is not the problem, and has not slipped. With the engine at TDC, the dots on the cam and crank are perfectly lined up.

I pulled the balancer and attached the timing wheel to crank with the barrel attach nut in the kit. I measured lift off the intake lifter. I checked the cam timing, using both with the intake centerline method that Comp recommends, and the traditional way checking at 0.006 lift and at 0.050, and comparing to the cam card numbers. I also posted picture of my card.

Here is what I found, checked it three times to make sure no mistakes. The intake centerline, according to the card should be at 106 degrees. Its actually at 110 degrees, four degrees retarded. And the dots are perfectly lined up. When checking the intake opening point at 0.006 lift, the cam card says it should be 29 degree BTDC. Its at 25 degrees BTDC, which I believe confirms the cam is installed FOUR degrees retarded. I also calculated what the lift should be at 0.050 lift, and it also confirms the four degree difference. Please back me up on my numbers, but I believe I am correct. The total lobe lift is only showing about 0.327, when the cam card says it should be .330. So, it looks like the cam was not ground per specification, if I am correct.

So for four years, I have driven this car, thinking it was a big disappointment from what it should have been, and now maybe we know why. I thought I degreed the cam when I installed it, but I may have just stuck it in and lined up the dots. I really do not remember.

As for the ignition timing running at 40 degrees advanced at 800 RPM, with vacuum disconnected, the TDC check today confirms the balancer has not slipped, but since the timing pointer was ten degrees off, it was really running at 30 degrees advanced, which is still way too much. So either I have a timing light issue, OR this four degree cam timing difference is somehow affecting it the engine in a way that requires more advance to run?? Is that possible?.

So, if I get this cam timing corrected, which is going to require an adjustable timing gear setup..….will my engine substantially different, and how much? I don't know if Comp Cams will do anything about this being so far off, after four plus years.

Honestly, my mind is frazzled with all this, so if I am interpreting any of this wrong, please let me know.

 

Hard to tell in the picture, but does the crank sprocket have three slot choices / options?
They usually are:
Zero, 4* retarded, 4* advanced via symbols.

My last Cloyes set of instructions must have been dropped in a mud puddle. The drawing and symbols were a blurry mess. Triangle, square, circle, but I figured it out.
And years ago they had offset keys just to mess people up. And make sure the cam sprocket does not have an old offset dowel bushing. E-gads. The things people used to do.

 

This....
If you find that the bottom gear is in fact in the correct position....buy a Cloyes Hex-a-Just and degree it out....4 degrees is not going to cause distributor timing to be way off to run....

Jebby

 

I am still "out-to-lunch" about the four degrees retarded issue. H-m-m-m-m-m-?

At 16,000 miles, I would say some slight timing chain stretch would be worth maybe one degree retarded from specs. As for the cam lift missing three thousandths, I suppose some oil w/o zinc could be its demise or normal wear. But that's really close. I bet a tear-down of any engine with 16K would show 0.02 - 0.03 wear on lifters or lobes. Miniscule.

Most performance cams from the factory come with 4* advance built in. It gives the brand new cam owner a satisfactory low-end grunt.
Your cam is reporting 4* retarded. You would have very little grunt off idle. But scream above 5,000. That's kind of what you said from the begining.

I think you should run your test two more times looking for exact matches as before. Then shine a good light on the crank sprocket. See if you can make out a symbol or number near the keyway and look for additional keyways.

 

Its a factory GM single roller chain, there is no second or third keyways in the lower sprocket. So if I am fixing it, I am buying new set. I have checked it all enough times.....its four degrees retarded from where it should be. Intake centerline is supposed to be 106,.....its ay 110. This car has always disappointed me with "very little grunt off idle.....but it does scream at 5000" So, it seems I have a problem that could make this 350 more my liking, but frankly, it will still not be a 406. I think the 350 ship has sailed. I cannot imagine that fixing this four degrees off is going to take it from a high RPM screamer to a big block low end torque engine. I am ready to pull it and sell it. What do you think?

 

Because you have the timing cover, harmonic balancer, W.P. etc off, by all means purchase a good timing chain set with the three key ways. You can get sets from $20 to $100. Get something in the middle. Maybe Cloyes True Roller double.
Then set it "straight-up", zero mark. Run your test again. Not satisfied with specs matching cam card? Set it up at 4* advanced. Run your test again.

Once the cam is phased where it belongs, I think it will feel like you added 100 horse. Advancing the cam that many degrees will move the power band to around 2,000-5500. This is more streetable and torquey. Keep this engine.

 

Buy the little bag of offset cam degree bushings and bring the cam back into time. Cheap and effective. You drill out the cam gear and pop the bushing in. The cam gear bolt lock plate will retain the bushing. Re-check the cam timing and run it.

 

Sounds like you are well on your way to solving your problems. Basically timing issues. A 4 degree retarded cam will make it run weak down low. Fixing that will help a lot. I also don't know if you ever got the initial and total engine timing set properly. That could easily make this engine fell 50-100 hp weaker, down low and upstairs.

1. Get your cam degreed in correctly. You are almost done with that. 4 degrees retarded is a lot.
2. Fix the pointer to read TDC when the piston and balancer is at TDC. You can't correctly set timing without it. You don't know how retarded your total timing might be, and even 4 degrees off is a lot and will only add to its already weak output.
3. Set your inital timing to somewhere around 12-15 (with no vacuum advance) and then set the total advance to exactly 36 degrees. This should occur around 3500 rpm depending on you distributor set-up. You must make sure it does not advance any more than that at higher rpm.
4. Looks like you have a degreed balancer. If not add a timing tape or just a mark at 36 degrees. I would set your timing without using the dial back feature on the timing light. They are known to fail.

Once you get the timing set correctly you will find this 350 a lot stronger and maybe a lot more to your liking. This cam should pull strong from 1600 up.
There is always the option of going one step smaller on the cam, that one should pull strong from 1200.
But get the timing correct first.