LT1Cruiser

Hi Guys
I bought a 350 LT1 that Im dropping in a custom offroader. The dude I bought it off said it was a '94 engine. OK, AFTER I bought the motor I started reading about the LT1s and everywhere I read said 'LT1s, great engines except for the useless goddam optispark pre '95'. Goddam I thought to myself, cant even hose down your engine and I wanna take mine swimming. Anyway, found a tech article on the net on how to drill holes in your old opti and convert to vented style. Bought the harness off ebay and pulled the waterpump off/ balancer, got at the optispark then what the hell! I have a '95 engine! there are vents off the bottom of the optispark and I didnt notice because the harness had been removed for transport. I now realise it wouldve been easy to figure out but just took the guys word for it it was '94. At long last here is my question!! Now that I have the damn thing out, should I pull it to bits and clean it up or is it better to let sleeping dogs lie and just reinstall it. I may have spilled antifreeze on it when I removed it but if it is sealed to start with it should be OK huh? Any suggestions would be greatly appreciated. I am getting close to having the beast running now so am pretty excited to hear this legendary LT1 roar that I hear you guys talk about so much. Thanks in advance.

TobyZ28

Hmmm tough one What I would do is look at the seal very carefully and see if it looks still "ok".
- If the opti looks sealed perfectly still, I would leave it alone.
- If I had a lot of milage on it, or the seal looks pretty ugly and dont mind waiting for a new one to arrive, i would get a new one on. Obviously the best and most costly thing to do...
Personally in either case I really wouldnt want to take it apart and put it back together and hope it all seals perfectly... :/ But thats just be, I'm still waiting to get an inverse torx set to open my old one up so I still dont know what they look like inside


Also, guage how hard an opti install is for you, if you put it back in and it craps out a few 1000mi down the road would it really be "that" big of a deal getting a new one? If it is a huge deal, then maybe its best to just put a brand new one in anyways. If not, chance it and maybe itll be good another 50000mi anyhow.

lt4 fd

I think your going to have a lot of trouble taking it "swimming" some people have their optispark die because they ran over too big of a puddle and water splashed on it. Vented doesnt mean water doesnt effect it anymore if anything its a way for it to get in if your going offroading seriously. Good luck anyways though and hope it works out in the end

LT1Cruiser

Surely though if the opti is completely sealed, vent connections completely sealed and all other opti electrics are water proofed (standard procedure for 4wd engine bay) then the opti should be submergible....

bunker

You prolly got a car off someone like many of us who did a 95 opti conversion and wondered what would the other bugger thing LOL, or do LS1 brake upgrade not saying anything and watch the next poor bugger to buy LT1 brake pads and never figure out why the heck they don't fit LOL

GreenDemon

People think optis are somehow special in that water only affects them? Any ignition component in any vehicle does not like water. The opti just gets a bad rep because of it's unusual (and unfortunate) location and because of it's unique design.

I was changing plugs on a new jeep at school and this thing still has a friggin conventional distributor cap. Interesting to know my archaic LT1 has more technology than a straight six from a new jeep.

Just make sure your seals are good and you should be fine.

LT1Cruiser

Maybe it is a '94 but with the full conversion. How would I tell if thats the case? I have a OBD1 computer p/n 16188051. On shoebox's site the vacuum feed for the opti sits further down (?) towards the back of the intake manifold relative to the EGR vacuum source, whereas I think my opti vacumm was plumbed in front of the EGR feed (Im not sure but the vacuum harness was removed and there is a nipple there that has been blocked off with insulation tape prior to shipping). Interestingly when I went through my box of crazy wires and **** I haven't needed to use yet I found the old opti harness. Strangely though it has a dual connector on the end where it plugs into the vacuum source, whereas my new harness does not... Hmmm, this is all very interesting anyone make light of all this?

Tom Piper

The LT1 engines with iron heads had the vented Opti-Spark in '94. The LT1 engines with aluminum heads got the vented Opti-Spark in '95.

Tom Piper

LT1Cruiser

alloy heads, def from an F-body

shoebox

...then look at the VIN derivative stamping on the side of the block. That will tell you the year.

1stz28

The screws on the top of the throttle body are the correct size for the opti screws. Remove one and use two nuts locked together or just a pair locking needlenose pliers and you can get the opti apart like that. Worked fine for me.

91RSLT1

If I were you and I had the engine sitting there I would go ahead and put a new opti on. It is far easier to change an opti while the motor is outside of the car/truck, than when it is in the vehicle. You already have the other one off, so go ahead and bite the bullet, slap it on and forget about it. A new opti is a nice thing it offers a piece of mind.

Eff

What???? My 94 has aluminum heads...

anyway. if you already got that far, replace the drive seal and the waterpump seal, I've heard of some other peeople siliconing the hell out of it to protect it too. don't know how much luck they had with it

Cmr0z28

Your point?

turbo_Z

Maybe the guy didnt know what year his car was. Just open the drivers door and on the inside where it lists recommened tire pressures and other bs it should also have a date or build date.