LT1 issue
 

During testing last night, The clamp on the upper radiator hose came loose resulting in the hose coming off during the launch of a test pass. The car left hard and the motor began to flutter bad at the top of first gear. It felt like a fuel issue.
Aborted the run and returned to the pits where I found the hose off at the intake, near the throttle body opening. I believe the hose came off and the throttle body got a healthy dose of water. FYI, the water has water wetter (Red Line) and likely a very small bit of antifreeze left from the winter.
I re-filled the radiator and proceeded to make another pass. This pass resulted in the car acting like it had a fuel issue, and was down on power. In third gear (4 speed car),it laid over ,climbed to 6500, dropped to 6000, then slowly climbed up to 7000.
I clicked it off at that point.
So far, I have only examined the plugs, and they all appear OK.
I was wondering if perhaps there was some residual radiator solution in the intake that showed up during this pass.....or if I have other, more significant issues.
I will go thru the valves and check spring pressure,lash,rockers etc. later today.

BTW, When I drained the overflow in the garage last week, the puddle did not dry up for a few days....Likely the effect of water wetter and residual antifreeze. That's why I'm thinking there may have been some residue left in the intake.
Thanks for any help/advice.

Re: LT1 issue
 

If it got a big enough gulp of water down the intake it could have hydraulic damage in the lower end. I would do some serious checking before running it again. Bent rod or damaged piston would be possible. Engines do not like water in the combustion chamber. Hope its minor. Leak check and compression check would be first. Look for differential between cylinders.

Re: LT1 issue
 

Mike, That is my concern. I'm going to run a compression check today. I did one last month so I have good baseline data.

Re: LT1 issue
 

Compression check results:
1,3,7,2,4,8 all same at 200psi.
5,6 both at 180psi.

Interestingly on same journal.

When tested last month, all 8 were same at 200psi.
Looking at valve train next and will run leak down tonight . Need to borrow the tools.

Re: LT1 issue
 

IF it got that big of a dose of water. It might also have gotten some in the optispark. They are famous for problems when the water pump starts going bad and weeps antifreeze. I imagine a large dose all at once would cause similar opti problems.

Re: LT1 issue
 

Rob, Interesting comment.
As I was looking at the area where the water could go, it became apparent that the one connector receptacle, located around 11:00o'clock facing the engine is wide open and not utilized as this set-up is configured. Looking down into the receptacle with a flashlight exposes the 3 terminal prongs. I'm certain that this area was the recipient of a good bath during this process.
As indicated in the previous posts, I'll continue down the path Mike suggested and complete the leakdown test .
Hopefully I get good results.
If I chase the optispark unit, does it need to come apart to "DRY OUT" or will time cure the problem???

Thanks
John

Re: LT1 issue
 

Have a lot of experience with Opti's.
Water got in mine it created a small almost undetectable carbon track.
PMed it with a new Cap and Rotor worked fine.

Had a few Opti's fail.
Tried 3 Summit versions because of price.
All three failed in 6 months. It was the Trigger.

Twice my GM brand new units failed after 6 months.
Discovered carbon tracking the other a cracked rotor with carbon tracking.

Always keep a rebuilt Unit and a Rebuild Kit.

Never know when the water pump will spring a leak.

D

Re: LT1 issue
 

This car has a crank trigger....I believe that is why there is no harness connected to the receptacle for the optic sensor module.
However, The opening where the harness would connect is a direct path to allow water into the dist.cap/rotor area. I looked in ther with a flashlight and thwere was definitely moisture on the sensor terminals. Put a Q-tip in there and definitely came out wet.
If leak down does not show anything, tomorrow I remove cap/rotor.

Re: LT1 issue
 

If you got water inside of the Optispark plan on replacing the cap and rotor. In the future fill that plug for the optical sensor with silicone.

Re: LT1 issue
 

Got a spare cap and rotor. Will replace tomorrow.

Re: LT1 issue
 

^^^^^^^^^ There ya go.

Re: LT1 issue
 

As they say in the NFL....After further review"....
The valve train all checked out OK
The motor leaked between 5-7% with one outlier at 9.5% (cold)
There was evidence of moisture in the Optispark connector receptacle.

Tomorrow will replace cap/rotor AND plug the connector hole as suggested.
Thanks for a lot of great help.

John

Re: LT1 issue
 

Looks like the ATI balancer needs to come off to get one of the fasteners to the cap. Am I missing something?

Re: LT1 issue
 

Yes you have to pull the balancer off to get the cap or the whole opti off.

Re: LT1 issue
 

Got it off. What a pain in the *** to change a dist, cap!!!!
I guess the Engineers never considered the service aspect of their design.

Re: LT1 issue
 

IF you think its bad on a race car. You should try it sometime on a street car with all the emmissions and other crap bolted to the front of the engine. Its a real sweatheart of a deal then. LOL.

How did it look was there water in it?

Re: LT1 issue
 

Rob,A minor waterfall came out after the dist cap fasteners were loosened. The area where the rotor and cap appeared OK. The water was behind the white plastic shield. The metal shield was rusty.
Incidentally, The unit still contained the cam timing disc and module. Is this still necessary with the crank trigger or can I take them out?
Also, I could not find a socket to remove the bottom two (recessed) fasteners on the cap.I had to modify a small pair of channel locks to remove them. What size star or metric is that??

Also, filled the Connector receptacle with silicone as discussed earlier.

Thanks,
John

Re: LT1 issue
 

OK....The Optispark cap bolts are E4 Torx. Not a socket found in regular tool or auto parts stores. Apparently Snap On and Matco carry them.
However, on another forum A guy posted that the throttle body cover screws are the correct size torx. As I had a spare throttle body, I removed one of the screws, chucked it up in a vice grips and got a tool (however crude) that works.

Re: LT1 issue
 

That is basically what MSD sends you with a new cap and rotor or complete Optispark. Its just a screw with a thick nut on it. As far as taking the stuff out of the inside (wheel and sensor). I have always left mine in with no problems. Glad you found the problem and are back on track.

Re: LT1 issue
 

Thanks Rob.