Hey I was looking into getting a c4 but I live in a part of oregon that is really wet and rains often which already isn't a good combo with a car like this but I wanted to know if the rain would ruin my optispark or if there was a way to protect it like a cover or something?

 

Rain won't get to it. Coolant leaks can, however. And you should never get near it with a garden hose.

Live well,

SJW

 

I live just north of Seattle and have been driving my 95 year round for many years. No impact on any electronics as a result of 50K driving in the rain.

 

Do not worry about the opti here in the northwest. As Mr. Peabody states there are a lot of C4s being driven daily on the wet side of the Cascades. Pick yourself up a clean low mileage 95 or 96 and you will have a great car to drive whenever you want to regardless of the weather.

 

95' and later have a vent incorporated to draw moisture out of the opti - it's hooked to engine vacuum.

 

I've driven my '95 in torrential rain, and my '94 in normal rain. It's not a problem. The problem is when you try to take a pressure washer to the engine bay, or your water pump craps out and dumps coolant all over it from above. The 95+ style optisparks are even better about it, and you can get aftermarket versions of the 92-94 that have the same fixes.

 

The early Optispark ignition systems were all prone to failure-That is why GM discontinued them soon after--They all get water intrusion into the cap from either rain or coolant leaks-Your best bet is to install an aftermarket MSD ignition system that is far better sealed--and not that pricey No problems ever again

 

The real fix is an opti from Petris or OptiDoc--not just an MSD cap, but properly built and sealed and vented. Definitely pricey, but it's one of those "do it once, do it right" sorts of things that nets you another 100k miles or more before you worry about it again. Highly recommended.

 

After having three other brands fail through the years, including MSD, I finally settled on trying Petris. The company does a great job and now I am totally satisfied. Actually, it would appear the Petris really woke the car up. Never has run as well. Seriously.

 

Petris built my C4...extensive stuff...and he did a nice job. He even changed my LT1 to a reluctor based system w/coil on plug and a Holley ECU.

Build thread is here: https://www.corvetteforum.com/forums...ld-thread.html

 

JB, fantastic information. I never saw that thread until your post today. Your sharing of such extensive modifications is the kind of stuff that makes this forum great. You no doubt have answered many questions so many here have wondered about C4 possibilities. I wish you many years of satisfaction with such a project.

 

It's a beast that's for sure. A raw, visceral experience. I wanted a Detroit Speed built muscle car of some sort (3rd gen Camaro) but figured a built C4 would be much cheaper plus I always liked the looks of the C4 over every generation save the C2.

My other toy car is a Fiat X1/9 with a Honda K20 swap. 200whp and 1885lbs wet.

 

No it's not. Plenty on here have bought the MSD and found it DOA...others, shortly thereafter. MSD is a$$urance of nothing.


.

 

My experience also. I bought the super duper billet adjustable timing (4+/4-) MSD and it never ran really satisfactorily until finally giving up completely after only a few thousand miles. It was very disappointing. It was a premium price so I thought it might be the best way to go. I was wrong. From now on it will be only Petris for all things C4 for me.

 

The Optispark II as some call is use in the 95-96 Corvette. I can be retrofitted on the 92-94 models.It was also used on all iron head LT1 L99 engines. The Opti II has internal changes simplifying sensor replacement. Sensor was never available separately, however a trip to the salvage yards can.net good sensors off of wrecked full sized cars. The 92 LT1 was rushed into.production, because GM was screwing over the guy who refined reverse cooling for the SBC. Optispark was not reliable but GM didn't want to pay the man. So the cars were built and later recalled and revised Optispark distributors installed.

 

The second-generation opti is a major improvement over the first-gen units. However, they are not interchangeable, and I'd like to see a recall notice that promised the removal of a first-gen unit, and replacement with a second-gen unit. I'm also doubtful about any correlation between the development of that distributor and the reverse-flow cooling system on the LT1 engine. What had one to do with the other?

Live well,

SJW

 

Let's clarify a few things that seem to keep popping up here and elsewhere.

The first-gen opti had a variety of design shortcomings. It was vented, but only passively by way of weep holes in the lowest part of the housing. Despite its shortcomings, many of them went 100K miles without failure. Probably far more did not. The accumulation of condensation, and corrosive ozone from the arc between the rotor tip and contacts in the cap, contributed greatly to early failures.

The second-gen units were actively vented. A small amount of clean fresh air was drawn through a hose from the intake bellows, downstream of the MAF sensor, to the distributor housing, then through a second hose and check valve to the intake manifold. This pretty much eliminated the accumulation of moisture and ozone within the distributor. These distributors also had improved bearings, and a revised coupling to the camshaft. These revisions prevent simply swapping a second-gen unit in place of a first-gen unit. It can't be done without also swapping the camshaft and timing cover. Active-venting can be added to first-gen units, and many of the aftermarket replacement units include this feature, but swapping the entire second-gen unit into a 1992 - 1994 Corvette LT1 engine is not a simple, bolt-on proposition.

I've never heard of an opti failure that was a result of driving in rain, and I can't imagine how rain would get to the unit short of actually submerging it in standing water. Coolant leaks, or water from garden hoses or pressure washers from well-meaning, but poorly-informed owners, however, are common problems.

The GM opti units used an optical sensor that was supplied by Mitsubishi. These sensors have a good history of reliability. Sadly, they are no longer available new from Mitsubishi, and the off-brand replacement sensors that are available seem to have been prone to infant mortality.

I was fortunate to need a replacement opti for my '94 back in 2004, when the original Dynaspark units were still available from DynoTech Engineering. It has pefrormed flawlessly for 17 years now. DTE sold that product off to a buyer who appears to have been unable to sustain it, so that is no longer an available option for those who need replacement units. Best bet these days seems to be a rebuild that installs new bearings, a Mitsubishi sensor if needed, an actively-vented cap, Loctite on the rotor screws, and good attention to sealing of the housing. Installation of an actively-vented unit in a 1992 - 1994 Corvette involves making the necessary vacuum hose connections to the intake bellows and the intake manifold by way of a check valve, with attention paid to ensure these hoses are not routed such that they might be pinched shut or cut or abraded by sharp or moving parts.

When the opti is functioning as designed, it does a superior job. The trouble comes in when they fail. They are a nuisance to replace because of their placement under the water pump, and many of the replacement units have proven to be unreliable.

Live well,

SJW

 

i never stated directly interchangeable. Opti II requires the correct timing cover and drive components. Wiring and connector are the same..it wasn't an.uncommon upgrade 20 years ago.
The Recall stated only applied to the 92s came out in 92, years before the opti II was made. Y and f bodies used GEN 1 opti in 94 while b and d bodys got GEN 2.

 

Connector is different. The Opti II uses a long weatherproof connector, which I assume was done to further try to reduce moisture intrusion into the connector and make it a little more rugged.

 

There is a reason for that. The one I got after the company changed hands was the worst I ever installed. Didn't last 5K miles IIRC. Guy on the phone blamed it on "oil "contamination which was an outright lie. The guy finally offered me a replacement after I showed him the pictures. Oh yeah, let me just spend another afternoon of labor to replace your defective unit with another one of your defective units. I got my refund.