260hp I/o expectations

[reelapeelin]

Originally Posted by 1224bret

Well from the few that have this set up sounds like I'm pretty close to where I should be. I think the engine that was swapped in was quite possibly a automotive engine. The reason I'm thinking of chain stretch is that I can't seem to get the timing right. It won't run right without the timing light showing around 29* advance at idle I still have to check and make sure the pointer and balancer match up at top dead center, probably my first weekend project. I tried to set it at 8* but it doesn't want to start with tht timing and at 8* initial I can only get 27mph top speed and forever to get on plane. I don't seem to have any detonation where it is now and I think I'm actually still somewhat retarded as far as what it sounds like now. I will do some more checking and try to get some fresh fuel in it this weekend. I just rebuilt the carb but I need a new secondary metering rod hanger since mine looks slightly bent. This thing has been a can of worms since I got it. Thanks for all the help and if anyone has more performance numbers with this set up I'd appreciate it seems like not many 260hp I/o's are out there. Thanks agian!

Spare...do they make the electronic (Petronix?) ignition for this motor...that might help him out some here...

[step up here]

It should the thunderbolt IV system which is very good!

[spareparts]

Originally Posted by step up here

It should the thunderbolt IV system which is very good!

what he said. If you look on the box, the last two numbers tell you haw many degrees of advance it has in it, check that against your light. I have seen them act up and keep all the advance locked in, but otherwise a pretty good set up


btw, check your tach!!!!!

[garagenc]

Originally Posted by reelapeelin

Spare...do they make the electronic (Petronix?) ignition for this motor...that might help him out some here...

Reel yes they do I converted mine over this year to the pertronics distributor and haven't had a problem since.
My old one fried and when I checked into it there was only 52 of the electronic ignition systems left in the world so that is why I converted mine over.

[1224bret]

Well I think I have it dialed in better now. I found that part of the old pointer was broken so I was using the wrong notch as a reference it looked to be a aftermarket deal. I used some msd timing tape and centered it to tdc. Runs like a champ now still getting right at 40mph which is fine. Thanks everything guys its much appreciated. What is this patronix conversion? I know about their points conversion thing but these already are breakerless ign correct? Are you doing away with the thunderbolt module all together? Is there any issues with the thunderbolt IV? Anything else I should look at doing as far as reliability is concerned?

[garagenc]

Originally Posted by 1224bret

Well I think I have it dialed in better now. I found that part of the old pointer was broken so I was using the wrong notch as a reference it looked to be a aftermarket deal. I used some msd timing tape and centered it to tdc. Runs like a champ now still getting right at 40mph which is fine. Thanks everything guys its much appreciated. What is this patronix conversion? I know about their points conversion thing but these already are breakerless ign correct? Are you doing away with the thunderbolt module all together? Is there any issues with the thunderbolt IV? Anything else I should look at doing as far as reliability is concerned?

Mine was very simple; pull the old distributor and drop in the new one and connect the wires.

[1224bret]

So you keep the thunderbolt module with the new dizzy? Is the patronix unit a marine unit? Or is it just a self contained 1 wire distributor style?

[spareparts]

Pertronix isn't going to be any better than the Thunderbolt, a pertronix is great if you are replacing points, but its not needed for the Thunderbolt . If something goes wrong with teh Thunderbolt, a pertronix distributor may be a cheaper alternative, but I prefer the Thunderbolt as it has an electronic curve, rather than mechanical. Keep the set up you have, check your total timing to make sure its coming all teh way in. The V6 boxes are the hot tip on v8s as the timing comes in faster, but I doubt you would be able to tell a differnce

[garagenc]

Originally Posted by 1224bret

So you keep the thunderbolt module with the new dizzy? Is the patronix unit a marine unit? Or is it just a self contained 1 wire distributor style?

It's a marine set up

[1224bret]

Ok one last question regarding the performance of my v. I just ran the numbers on my prop and it is a Michigan wheel aluminium 17p. I'm getting 40mph at 43-4400 rpm doe that sound right? I know when I first made this post a few of you guys said it should be turning a 19-21 pitch. If I want to go stainless I know they normally recommend dropping a few inches off the pitch which would put me at a 15? Sounds awful short on prop for a 260hp inboard to me but I'm not used to the weight of these boats. What are you guys with the v8's running as far as pitch?