3 cyl Thunderbolt ignition

[bfitz]

I've a 3 cyl Thunderbolt ignition, battery CD, seperate switch box ['74-'76 roughly] on a 3 cyl modified for APBA hydroplane. I'm running into a wall at 6800rpm. Anybody know if these switch boxes have rev limiters? If so, how can I defeat it, or is there a switch box without a rev limiter?<br />Thanks

 

[remmer38]

Re: 3 cyl Thunderbolt ignition

I might be wrong but 6800 rpm sounds pretty high. Is it piped or something similiar? What size motor? Your post got me curious.

 

[Clams Canino]

Re: 3 cyl Thunderbolt ignition

The CD ignition inline sixes seem to max out in the low 7's. Mine pulls OK into the mid-sixes but it's not ported for top-end. I don't think it's an ignition thing as the ADI ones tend to run out of steam there also. 6800 might be all you can get out of that three without XS type porting.<br /><br />-W

 

[bfitz]

Re: 3 cyl Thunderbolt ignition

Thanks for the replies.<br />The engine is modified with expansion chambers, raised porting, ligtened pistons, etc....Bought it from a friend that wouldn't lie to me. He used to get 7800 and I have no reason to doubt him. Only difference is the switchbox, but I'm not sure if it's a rev limiter or the coil is breaking down. Engine runs up to 6800 then lays down and "shudders" a little....fuel system checks out, not going lean or outrunning it's fuel pump....other than that, ignition system works fine..

 

[Clams Canino]

Re: 3 cyl Thunderbolt ignition

OK - try a different switchbox then. <shrug><br /><br />-W