Captainofiron

iTrader: (1)

Well I recently purchased a MSD Pro Billet Optispark. A few people had asked me to take some pictures and to make a comparison on the GM Opti and the MSD Opti.

So here is a write up and a comparison to the OEM GM unit.
MSD Pros and Cons
Pros: Adjustable timing, better one piece housing design, less likely to leak, no connectors to leak from. beefier opti sensor, beefier opti disk. extra cap bolt. MSD Cap is thicker and seems stronger. Rotor is beefier and indexed. Brass contacts all around.

Cons: Cost, O-ring gasket is a PAIN! to install.

Write Up:
The MSD unit is made from one piece of aluminum, therefore allowing for less possible leak points opposed to the two piece GM Cap. Also since the harness is sealed from the inside and has no connector hole it again allows for less possible leak points. The MSD unit has adjustable timing, but MSD techs told me that you needed to fab up a timing reference like on the older SBC before you attempt to adjust the timing. The MSD Cap is alot thicker and does not have the recesses that the GM unit has, therefore it would be stronger and resist cracking more. The MSD cap has all brass contacts which means better conduction than that of the GM mystery steel contacts.

Here are the comparison pics:

Mighty Whitey

never really got to see an MSD unit apart. looks like a much high quality piece than the OE unit..

any word on the reliability of these over stockers?

my opti junked out the High-res circuit on thursday (makes the 5th one in a year) I'll give the parts-store brand one more chance, then I'm going with an MSD, I can't take this crap any more!

METAL MANIAC

I have a question for you as beens you have taken one apart. Does the distributor have an oring installed when you get it? In my situation this is going to be a new motor that I am going to put it on so there would be no need to take the cap off for me as long as it has a oring already...Thanks MM

96capricemgr

iTrader: (1)

Should be noted the cap and rotor fit a stock opti base so using those as plusses for buying the whole thing is not really the whole story.

One MAJOR con that should be noted is this should not be used unless you fabricate a timing pointer and switch to a keyed hub and marked damper so you can confirm adjustment of the optical pickup. Otherwise you are just hoping timing is right.

Captainofiron

iTrader: (1)

No the Oring comes in a little plastic bag, I talked to an MSD rep and he said you can order a preformed gasket opposed to the oring,

Its a good idea to take off the cap during installation though, just so you can make sure you got it pointing the right way. Also I couldnt get mine on with the cap on.

As far as reliability, I took it earlier to the car wash, and guess what I did, I washed the engine compartment and blasted it, and not even a hickup. It ran perfect. If I would have done that with the old one, I would have been stuck until it dried and then some.

Oh and 96capricemgr they come from MSD set to the OEM opti timing, which is two turns out on the adjuster screw. And I addressed the need for a external timing reference in my original post.

z_speedfreak

iTrader: (3)

im wondering how the msd's adj timming feature works in conjunction with the pcm which should have the last say in what timming your actually running right? what does the computer think when you mess w/ the timming?

hazyredeyes

iTrader: (1)

MSD said it was set to factory timing specs. about 2 turns out. When i installed mine it was set from the factory at almost 5 turns out
All i did was turned the adjuster back in untill is STARTED to seat, and then went 2 turns back out. Waalaa!!

I really wished MSD included a timing chain cover seal for the opti. I installed my opti, and it had a small oil leak coming from the rear seal. i took it back off and changed the seal. I did take the opti apart to see if any oil got in it and it was fairly clean. But i did notice that the rotor inside was rubbing the seperator plate. It had a red circle around it. But i deemed it ok, and put it back on.
I wouldve taken pictures but the digi cam was outa commission.

Honestly though i couldnt tell a difference with engine performance from 2 turns out to 5 turns out. But then again, my fuel pump is all F*ed up.

All in all though, it is a really nice piece that youll never really see!!

Time will tell how good these really are.

-PEPE-

iTrader: (10)

great write-up, so like I've seen a thread or two stating the billet gets too hot causing problems? Just curious if you've ran it yet or not.

chree

I read where someone else was able to get it on with the cap installed... I hope it is possible. I have the 8381 and I've already installed the o-ring and put locktite on the screws. It was hard installing the o-ring on my workbench, I can't imagine doing it in the engine bay.

That is the ultimate test. Cool.

My adjuster appears glued in place. I guess I need to get a timing tab to check my timing before I make the swap. Are there timing tabs that are known to work?

I will try to take photos when I do the swap... sometimes it's hard to stop when you're making progress. The 8381 has a hose assembly for adding the vent feature.

BlackScreaminMachine

iTrader: (17)

Nice write up. I am out of the LT1 game but my stocker GM units never had issue, had the front off over 10 times, I sold optis to other customers, never an issue.

This should resist blowing out.

Captainofiron

iTrader: (1)

Yea it runs really nice. I took it to WOT and up to 5500rpm. ran real nice.

hey chree if you have the non vented Opti it might not hit on the balancer hub, the only thing that was making contact on the hub was my venting tube.

The only thing I have noticed about it was that it idles a little different when cold, but after that its great.

i420tom

iTrader: (11)

i guess i got lucky with mine as i did not check the timing. I literaly just slapped it on and all is great!!

On the note of adjustable timing: wouldnt timing adjustment via the optical sensor also adjust injector timing as well as ignition timing? Also note that i do not have a crank sensor as i am a 94.

what the heck does the crank sensor do anyway? enable codes for opti res issues?

before msd i had major opti issues and no codes. was not even using cap and rotor. THANKS DELTEQ

Captainofiron

iTrader: (1)

the crank sensor gives the engine an even better idea of where the pistons are, and as a sort of back up to the opti disk.

You just slapped it on? did you make sure the oring was installed??

seawolf06

iTrader: (8)

Don't install the o-ring! Make sure to get the gasket from MSD.

The timing adjustment is only meant, AFAIK, to correct timing when you advance or retard a cam. It is NOT meant to advance or retard ignition timing or "injector timing". Those are always controlled by the pcm and must be programmed.

A-man930

iTrader: (2)

Ok, so I have a dumb question in refrence to adjusting ignition timing. I know the old fasioned way to advance/retard timing was via engine vacuum or a mechanical device (centrifugal?) So how is the timing retarded/advanced on the LT1? I can see how a distributer-less system such as the gen III motors works, individual coilpacks all electronically controlled by the ecm... But in an LT1, there is still a mechanical device distributing spark from one coil to each individual plug, yet you can change spark tables through a tune alone? Does the computer have direct controll over the physical position of the rotor within the opti? Are the opti disk and rotor on a common shaft? Or are they independent? And what are all these ignition boxes for? I see what they're advertised to do, but where do they fit in the picture? Like I said, dumb question, but I had to ask sometime...

Captainofiron

iTrader: (1)

No the rotor is affixed to the camshaft via a driven gear, it cannot be adjusted externally. The way the computer controls it is with the use of the optical disk and sensor, but I still dont understand how it can do that, since the rotor tip is so wide, I would assume that it simply makes the coil fire later or sooner, therefore that is why there is a limited range of adjustment on the MSD ( I think its +or- 7 degrees) but thats a good question

A-man930

iTrader: (2)

So I guess the contacts between the rotor and individual points are big enough to allow those +/- 7 degrees of adjustment, even at speed. The computer accomplishes the timing change by firing the coil sooner or later, like you said... I think that makes sense.
*edited for coherence* lol

A-man930

iTrader: (2)

Another thought... Would this limitation of timing adjustments make it impossible to run an anti-lag system on a turbo application? Since anti-lag is designed to ignite the intake charge very late in the combustion cycle (as much as 40 degrees, to keep exhaust flowing high/hot enough), it would require a distributorless system, correct? Sorry about the hijack, but these pictures sparked my curiosity (pun intended, )

Captainofiron

iTrader: (1)

that was a good pun, I have no idea when it comes to forced induction maybe someone can chime in here