Thundrebolt IV ignition module
 

Where do I get one? Do they still make them? Mine has stamped on it 8C31A V8 HP its for 509CI w/ 250 blower

Re: Thundrebolt IV ignition module
 

ttt

Re: Thundrebolt IV ignition module
 

That number doesn't show up on this document

Re: Thundrebolt IV ignition module
 

Heard that one(V8 HP) is no longer available :(

Re: Thundrebolt IV ignition module
 

Yep, listed as no longer available. Its the module used on HP500's with a TB IV ignition.
Best options would be to find a used one or switch to a V6 module or get a Crane box and use one of there preset timing curves.

Re: Thundrebolt IV ignition module
 

i have a v8-hp and a v8-20, anyone know what the difference is in the timing curve, i think they are both 20* advance but one comes in slower and i think the HP is all in by 3000rpm or something like that.
im running the v6 module for a blower application. only 14* advance.
kevin

Re: Thundrebolt IV ignition module
 

The HP modules are discontinued. I always ran the V6 module on my SC engines.
EYEBURN, you are correcty. The V8-20 only has about 15 degrees at 3000 rpm. Full advance is over 4000 rpm.
Gary

Re: Thundrebolt IV ignition module
 

Dose any now the item number for the one that replaces it or a different one that will work the same.

Re: Thundrebolt IV ignition module
 

I graphed the Tbolt IV advance curves based on the information given in Dennis Moores BBC book.

Dave

Re: Thundrebolt IV ignition module
 

No replacement listed.

http://www.mercruiserparts.com/Show_...CAL+COMPONENTS