Thunderbolt VI or V?

[mike456]

i have a 1992 5.7L mercrusier S/n OD709044 with Thuderbolt ignition. Do I have Thunderbold IV or V? I have timing instruction that Don posted for Thunderbolt V a few weeks back. If i have Thunderbold IV do I use a different procedure?
THansk

 

[Bondo]

Re: Thunderbolt VI or V?

I Think you've got the T-Bolt IV,.......

All you have to do is Hook it Up,+ Time it.......
No Base mode like the T-Bolt V........

 

[Don S]

Re: Thunderbolt VI or V?

Your engine could have either, but they are easy to identify. If it's a Thunderbolt V ignition your distributor will have the knock module and ignition module mounted on the distributor like the one pictured below. Then you need to put it in base timing.

If your distributor has only an ignition module only on the distributor or the module is on the exhaust riser plate, then it's an Thunderbolt IV and does not require being in base timing mode.

 

[mike456]

Re: Thunderbolt VI or V?

Started a tune up and the rotor is stuck (Thunberbolt IV) . when I pull up it does not want to come off. Am i correct that there is nothing holding it on and that it just needs a little help? i'm thinking i'll put a vice-grip on and tap it up with that.
Just thought I would check so I don't brake something.
Thanks

 

[Don S]

Re: Thunderbolt VI or V?

Yep, it's just stuck, nothing holding it on.
I use a couple of screwdrivers under the rotor to pry it up. Be careful and don't damage the sensor. The screw drivers need to go in under the plastic part, that metal piece will just bend.

 

[Bonus]

Re: Thunderbolt VI or V-now roto

Re: Thunderbolt VI or V-now roto

I had to chip mine off in peices (same ignition). It had not been off in many year as you cannot get the cap off without pulling the motor. (makes tune ups a hassle) Be careful not to damage anything, bent shaft, etc.

Bob

 

[mike456]

Re: Thunderbolt VI or V?

Its really stuck!! I have now managed to brake off most of the top part of the rotor. I tried putting a vis-grip on it and bracing a piece of wood under the vis-grip (being sure it cleared to metal part on the rotor) then tapping down on the end of the vis and it still does not want to budge (but did brake some of the pastic).
When you say that the screw driver needs to go under the plastic part do you mean I should tap it in at the point where the plastic meets the metal? I would then brace the wood under it to push up.

Any other ideas would be appreciated. Whould heating it (with air not fire!) help in any way?
Thanks, you are the best!

 

[Don S]

Re: Thunderbolt VI or V?

No, don't go tapping screwdrivers under the rotor. What probably happened is the last person to install a rotor followed the manual and used locktite on it. (why they recommend that is beyond me, but they do) you will need to use heat to remove it. then clean the shaft and dry install the new one. It will still be tight, and you do not need Locktite.

 

[Bondo]

Re: Thunderbolt VI or V?

What probably happened is the last person to install a rotor followed the manual and used locktite on it. (why they recommend that is beyond me, but they do) you will need to use heat to remove it.

Ayuh,.............. I could never understand That Either..........

With the slight downward pressure from the Button,+ Gravity,.......

I have never been able to justify using it.........

 

[f_inscreenname]

Re: Thunderbolt VI or V?

I ended up cutting mine off with a dremmel with a cutting wheel. Split down both sides and pry open with a screwdriver.

 

[mike456]

Re: Thunderbolt VI or V?

Ran out of time to work on it yesterday but i'm back at today. Its absoultly amazing that Merc would recommend putting locktite on a pastic piece! what does the manual stay about how to remove one thats on that way? I'm not optomistic about heating it as I don't have a heat gun and will try a hair dryer. It seems the pastic is way too thick to heat to any significant temp that would casue the locktite to let go. i fear I'll be braking it away in pieces as a few others posts have noted.
Why is boating such fun but simple things like this become such a hassel!!

 

[Don S]

Re: Thunderbolt VI or V?

Use a propane torch to heat the rotor, just be careful. The hair dryer probably won't get hot enough

What you need is a special tool for your tool box to help you with all these problems.
It's PN is 90-816463, and It's called Mercruiser Service manual #15

 

[I/O WALDO]

Re: Thunderbolt VI or V?

I wack-um with a hammer (lightly) and remove the pieces.

 

[mike456]

Re: Stuck rotor on Thunderbolt VI

Re: Stuck rotor on Thunderbolt VI

heat did not work so I hack sawed the top of the plastic till I hit the post. Then I was able to get a chissel in the cut and brake off each side. I looks like rust (not loc-tite) was the problem. I had to use some sand paper to clean off the post. Then I put a coat to oil to hopefully prevent future issues. Closed up everything and she started right up.
Thanks again to all who chimmed in especially Don S.