Cant get timing right on my 78 with MSD 8365 Distributor
 

So here is my second technical post of the night...And the second time I wrote it thanks to my internet crashing!!! GRRRR!

So I purchased a new GM HEI MSD 8365 Distributor for my 78. I had the stock distributor in it, bought a new intake and decided, I'll throw a new $370 distributor in it too. Luckily since I'm an idiot, I sold the original one on ebay for $30! So, I have nothing to fall back on now. The problem is this...I cant get this thing timed right to save my life. I'm beginning to wonder if I have a defective distributor or whether I just dont have it set up properly. I've talked with some of the local high performance shops in the area, and they have all stated they've gotten defective MSD Distributors new out of the box...so it makes me wonder...? Now I used a timing light and I used the old traditional TDC method with putting my finger over the #1 cylinder until it blew it off while turning the engine over...

Here's the problem...I'll have the car running, idle sounds great and no vibration. I'll take the car down the road and higher RPM's create backfiring and the car runs like a$$. So I bring it back and advance the timing. Now the idle runs like a$$ but under higher RPM's, she runs better. I bring it back and try to find a happy median and it just doesnt happen. It either runs good at low RPMs or good at high RPMs, but not both. And these adjustments I'm talking about are miniscule. Like, no more than an inch in rotation. So when I get the timing set at a driveable rate, I tighten the distributor down and park the car. I'll take the car out a week later and it runs like a$$ again? I retard the timing and it begins running "decent"(and I use that term loosely) again. Then, a week later, I'll go to drive it again, and it runs like crap. So this time I advance the timing and it'll run decent again. Everytime I drive it, timing has to be adjusted??? Its like it drives fine one day and then the next, it'll only run on 7 cylinders and the 8th will come in sometimes.

Now the distributor is not moving, all plugs and wires are new and have been checked(no arching or meltdowns). I have the AFR 180cc Eliminator heads. As far as the springs in the distributor, I have the factory supplied bright silver springs in it now. I removed the factory installed heavy silver stiff springs and put the loosest ones they provided in it. I have not changed out any of the bearings but dont know if that matters? Has anyone had any trouble out of these or any input as to how to get this PITA to run right? If you can, you'd be my hero! Any ideas/suggestions/etc? I hate to just buy another distributor after spending so much on this one...

Your initial timing, total timing and total with vacumn need to be correct. This requires the correct vacumn can. springs and limit bushings. No distributor has the correct curve out of the box. Check the timing sticky by BarryK and Lars timing and vacumn can links here.
http://forums.corvetteforum.com/c3-t...long-post.html

PS: are you sure you don't have a vacumn or intake gasket leak since the intake change?

Awesome material there...Yea, I'm leak free fortunately. Hopefully, I can sit down and do some much needed reading. Looks like some great material and thanks for the referral!

You should put a non-dial-back timing light on it with a timing tape on the harmonic damper and record what the timing does at 750 rpm, 1000 rpm, 1250 rpm, and so on up to ~3500 rpm. (Ensure that the vacuum advance is disconnected during this effort.) The timing should advance smoothly from about 12 degrees up to about 35 degrees and then hold steady.

If you find that the advance curve did something odd, post what you recorded. There may be an easy solution for this problem, but you'll need to post the test results first.

Those advance curves they put in there arent exactly accurate.
If you can find someone with a dist machine who can put a nice curve on it for you. Mine was WAY off according to the bushing spec.

Are you using a timing light? An inch of dist movement is a HUGE difference in timing. Your AFR heads shouldnt need a ton of total advance btw.

If you know of noone Google Bob Jennings Dyno shop ,
He will get the curve right the first time.

I agree with the timing tape suggestion. Measure and plot your curve so you know what's going on. It doesn't have to be perfect to run right, just close. Then adjust from there. Heck, you might call the buyer of your original HEI and offer him $45... Good luck, you will get there.

That is correct. Use a non-dial-back timing light. The issue is that the MSD distributor makes a multi-spark and not every dial-back timing light can handle this.

Günther (don´t ask why I know this :toetap:)

two things cause your issue, loose timing chain, defective control module, if it ran fine with the old dizzy, your chain is fine, call MSD's tech line and have them send you a good one. if it ran fine before the dizzy change and runs like cr$p now, its the dizzy.

Ughh, sorry for the late reply to the thread that I started. Man with the races coming into town, its been a total nightmare with work and will be chaotic for the next few weeks. Yea, theres no doubt 1 inch made a huge difference...between driveable and non-driveable. You've got my interest peaked here. Never actually heard of a distributor machine. I do have a wireless timing light but to be honest, I havent touched this thing since about 3 weeks ago. Its sitting in my buddies shop right now collecting dust. Can you give me some more insight on Bob Jennings and how this curve is accomplished?

Oh and on a side note...wanted to let you know Jim got me hooked up on my AFR heads for my 96...matter of fact, they came in yesterday morning! Now just gotta scrounge up the $$$ for all the goodies to go with them!

Will definitely record and post my findings. Purchased another distributor...just a plain jane HEI Street Fire distrib which is made by MSD. I honestly didnt wanna go with another MSD, but was a little hesitant on these other "China made" distrib's. I saw some Proform distrib's, but got to digging and read A LOT of negative reviews on them. BUT, I didnt wanna spend another $350 on a different brand nicer distrib either considering I have $379 in this paperweight...Street Fire seemed to be best bang for the buck...

Well, and I strongly considered calling MSD about a return and replacement. But the last time I called them about a 6A box that had a rattle in it new out of the box...they played "100 questions". Now to me, I didnt know that these boxes came with the option of the "rattle" inside model lol. I called them and they started asking me if I hooked it up and tried it to see if it worked anyways. I'm like, well considering its rattling, no. Obviously if something is rattling inside, something is probably broken and I'm sure that part was probably connected to another peice to serve a purpose at one point in time. I told them I didnt want to connect it and then it not work and then have to tear that one out and go through it all again. I'm sure the guys at MSD dont just throw extra unnecessary parts inside just for the heck of it. Then they asked if I had tried this and if I had tried that. I'm like..."Is all this really necessary???" Im just afraid they're gonna make me jump through the same hoops again. They did finally send me a new box but GEEZ...you'd of thought I was pulling teeth. The other problem arises is that this distributor was bought last March-ish but not installed until June or so. So I know its outta warranty b/c its been over a year. So I think I'm honestly just screwed...:(

Send it to Bob.
Getting another one may not help I pulled my hair out with mine
These bushings/stops they supply are not accurate unfortunately went through the same thing as you wouldnt time right thought I needed a special light etc.
Timing would jump around on the balancer...perfect now

My car runs NIGHT and day differently super happy.
Youll be glad you did. Hes an old timer who has been doing these for over 40 yrs. If the names Bob Lambeck, Dick Landy Reher Morrison etc ring a bell he was racing right along side them back in the day. Knows his stuff.

http://maps.google.com/maps/place?oe...12051697150475

Ok...that definitely sounds like a plan to me. Now, what all information does he need as far as sending the distributor to him. Obviously he's not gonna have the car but not sure if he does something standard to all distributors to get them where they can be fine tuned easier?

MSD lists the advance curves and stop bushings in the instruction sheet. with a dial back timing light and some time it's not that tough to setup.
A timing tape is kind of cool, but not necessary- with a dial back light and some white paint/nail polish at the "0" mark on the balancer and a dot on the timing tab it's easy to see.

I think all of you are probably right, it just gripes me to buy something new, and have to 'fix' it, they should work ,out of the box. he could have spent the money he's going to spend fixing that pos on a better product.