I don't think so. I wonder if the only time they have no slop at all is when the engine is new or rebuilt. I think they all will stretch during normal engine operation. Someone will correct me if I am wrong.:grin::grin:
I do know when I assembled my engine with TA's billet roller chain some years ago, it was tight, mains were line bored, so chain/gears were something over size (don't remember how much), then years later I had to go into the engine again, the chain was much looser, I thought, "hmmmmmm" and moved on. I remember seeing a video, and Smokey Yunick commenting how timing chains whip around like a slithering snake when in operation, that's just what they do:shock:
By any chance did you pull the reman dizzy out to check the gear to be sure the roll pin dint snap off and let the gear move? I saw this once with a Ford and i chased that problem for days before i figured it out. Every time i checked it the timing was off, i would reset it, it would run fine for a day or so and move again.
Yep! Things happen in ways that people do not realize, more often than not. The timing chain 'stretch' is based on the ductility of the steel used in the links and rollers; also in the wear that occurs over time/miles inside the links and around the rollers (and on the teeth of the gears). It's common for a timing chain to lose 1-2 degrees after break-in, and up to 4-5 degrees with lots of miles on it. When it 'stretches' it retards the timing, so set your cam install point accordingly to match your dynamic compression and grade of fuel you wish to use. In other words, advance your install more so you can get away with the next grade up of pump gas until it breaks in, but plan on the overall combination to be centered around ~2* retard from where you'd put it if no chain stretch were considered. This means DCR should be accommodated in about .2-.3 :1 range within the ideal spectrum. I.E., For 'plus' (89 octane) fuel, set DCR to 6.75-7.00 (closer to 7:1) based on 'no' stretch, so when it does 'stretch', your DCR will be closer to 6.75, where 89 octane should run it fine. While it's close to, at, or slightly above 7:1, put in a few gallons of premium (91-93 octane) along with the plus to give it a safety barrier while breaking in. You'll need to do this anyway when breaking your rings in. Edit: also for a 'did you know?'--timing chains 'stretch' more at higher RPMs than at lower RPMs, based on centrifugal forces and increased strain against the timing gears...which means your timing is even more retarded at higher RPMs vs lower RPMs based on the unmeasurable variable of timing chain ductility flex (stretch). Gary
So mine being 8. Is there any other type of checks I should do thru the fpump hole, maybe back it up so the slack is on the drivers side and push or pull thw chain and measure or anything? Also does it mean the timing I set with my light is not what it actually says?
Yes. But can one compensate for the other to affect the end result, seeing as valves opening and closing and firing of sparkplug is what matters. ( Along with the piston being in the right spot)
You can play with ignition timing to see what your engine wants. The best way is on a chassis dyno or at the track. Maximum HP or trap speed will tell you what it wants. Just because one engine wants 33* doesn't mean that some engines might want 35 or 36 total.
Without a dyno or racing, I guess I mean in general since the cam delay is now known, isnt there an alteration that can be made to the ignition timing to counter it? Or maybe not since the piston position is more important to the spark plug fire timing?
No, you want me to tell you some easy thing to do, and I can't. You have to use your butt dyno and your ears to figure out what YOUR engine needs.:grin:
FIXED - UPDATE: So I wanted to get back with everyone. I finally focused on getting the project completed. * - I did tear down the front of the engine, timing cover removed, (Note: the chain had NOT jumped a tooth, but was very loose), I did change the timing chain and gears with a Cloyes stock set. New chain eliminated the potential slop in setting my timing. * - I also found out that my fuel pump eccentric on the cam was worn, not horrible but a noticeable groove, so I replaced that also. That could have reduced my overall fuel pressure (another possible performance problem). * - Tore down the oil pump to check for ware, all was good, gears and clearances all within specs. Packed with Vaseline and reassembled. Filled new oil filter with oil and reinstalled. * - Installed a new crankshaft seal in the timing cover. Installed a new cover gasket set and the timing cover was reinstalled. * - Primed the oil pump with a ground down large screwdriver and drill through distributor hole onto the oil shaft. Oil pressure came right up and I ran the drill for about 5 mins to circulate the oil throughout the engine. * - Installed the harmonic balancer, pulleys and belts to the accessories. I did leave the fan and shroud off to make it easier to set my dwell and timing. Installed the hoses and filled the radiator with water only. I did this in case I had any coolant leaks and needed to drain the radiator again. * - I also changed the thermostat and housing gasket because it was leaking a little bit, glad I did because the old thermostat was really cheap and probably not going to last much longer. * - Installed new points/condenser into the distributor and set the points gap to .017. (Engine kept on TDC compression stroke, timing mark zeroed out throughout the process). Lined up the #1 spark plug distributor post with the rotor and reinstalled the distributor. Verified spark plug wire placement one more time. * - At this point I stopped. I wanted to read up on the vacuum connections on the QJet I don't know why but I'm glad I did. Through my reading I learned much more about ported versus manifold vacuum. I went and looked at the current connections on the carb and sure enough i had my vacuum advance hose to the distributor on a manifold vac instead of the ported vac. I must have done that years ago thinking it was going to help my performance. I moved the hose back to the ported vacuum on the carb. Remember that my primary problem was I couldn't get the engine to idle correctly. Now I got a little more excited about starting the engine and dialing it in. * - Triple checked everything one last time and then had my wife crank it over. I took a few cranks to get the fuel up the the carb, then it kicked over and came to life. It sat on high idle for about 2 minutes, then I asked her to tap the accelerator to get it off the high idle and choke. It dropped down to the lower idle, a little rough but it stayed idling. This was a good sign because before it would just die. * - I had the tach/dwell meter and timing light connected, vacuum advance hose disconnected and plugged. First I set the dwell to 30 degrees, then the idle to 850 rpm's. I then set the initial timing to 10 degrees BTDC and the engine really smoothed out, reset the RPM's back to 850. I did not hear any stumbling or valve knock. So far so good. * - Now came the big test, putting the car in gear, this is when the engine would usually drop to a really low RPM and stumble, start hearing valve knock then stall. I got in the car and put the brake on and slid it into drive. The idle dropped about 150 rpm's and kept idling while in gear. No stumble, no valve knock, just a smooth idle. I let it idle in gear for about 5 minutes, Oil pressure good, temp good, put it back in park and shut off the engine. Waited about a minute and started it up again, it fired back up and idled perfectly both in and out of gear. * - The next step was to reconnect the vacuum advance to the distributor and see if the engine ran the same. I unplugged the hose connected to the ported vacuum from the carb and connected it to the distributor. The engine idles the same, very smooth in and out of gear. * - I think my major problem with my idle was having the distributor vacuum advance connected to the wrong carburetor vacuum port. My engine needed the ported vacuum instead of the manifold vacuum on the carb. I was getting too much advance at idle using the manifold vacuum versus the low vacuum at idle from the ported connection. I know many of you are shaking your head saying "You dummy, that's obvious" In my defense, everyone of us had to learn about this at some time, and i realize some use the manifold port. The stock set up on my engine runs best on the ported vacuum. * - I spent the next hour dialing in the mechanical advance and initial timing to reach 32 degrees total timing at 2500 rpm's. Took the car for a drive and it drove like it was brand new. I'm so happy I got her running well just in time to put her away for the winter.. yuck yuck. * - Final set up is 750 rpm at idle, 650 in gear, 12 degrees of initial timing, 20 degrees of mechanical advance, 32 total advance at 2500 rpm's. * - All the work that I did and new parts I installed to fix this problem may not have been needed. It is a process of elimination and learning how things work. I am very glad I rebuilt the front end of the engine, I know the parts are good now. The engine is running very good, and I can go out for a drive with confidence. Thanks for all the great advice and "How Too's". Maybe someone else can read this and fix their issues without all of the additional work. Digging in and fixing stuff is why I own the car and love the hobby.
That's EXCELLENT news:TU: Glad to read you figured it out and it all worked out for you, feels good to get it running like it should, even if it is time to put it to sleep for the winter huh? Nice engine compartment too:bglasses:
Now that is the kind of story I like to read, well done! I bet with the new timing set and advance plumbing it is really peppy.
I had forgotten how fun this car is to drive. How the whole body lifts when I give it some gas. I feel the torque and yes its pretty peppy, my shift kit give me a distinct tire chirp shifting from 1st to 2nd. I'm hoping there may be a few late fall car shows I can take it to. I really missed driving this car. :TU::Brow:
In case someone hasn't chimed in yet, how about a points conversion kit in there?non fram filter? vacuum test results, and whether you did any carb tuning yet. Glad to see you got it all set up, great write up and follow through. This is a good project for anyone to do if they are unsure about the reliablity of the components you changed.
