Cameron Rector
New member
Hello,
I have a 262 Vortec V6 that isn't making much power after the original heads were rebuilt. This is not the original engine for the boat and I am not even sure if it is a marine engine or a car engine or wether it even matters. BTW it has a Berkley Jet on it.
So here's what I know. The engine runs smooth however takes awhile to get on plane. It feels like it's only getting part throttle. I checked the throttle and the primarys are opening all of the way. I checked the vaccuum secondaries and they only open about half way on accelleration. You can force them open with your finger but you don't get any additional power. This pointed me to ignition timing.
On the lake without a timing light I gave the distributor about 1/8" turn in the advance direction and the engine came alive. It sounded crisper and really accellerated well. I only did a couple of hole shots and put the boat back on the trailer.
Now that I am home with a timing light here is what I find.
My initial timing is sitting at 20 BTDC and with the Thunderbolt IV advance it adds 14 deg. making a total of 34 deg advance. The engine runs pretty dang good here, although steep for initial timing.
The Thunderbolt IV timing for a 262 shows is should have the initial set at 8 deg and the Thunderbolt IV will add 14 deg for a total of 22 deg.
I am not an expert boat mechanic (that the reason for my post) but, on most stock Chevy V8's they like 32 to 34 deg total timing. Why would a boat engine differ so much from a car engine for total timing?
I verified the TDC mark on the ballancer is correct using the positive stop method. I have also verified that 8 deg initial + Thunderbolt IV gives me another 14 deg as per the book. The problem is this leaves a bunch of power on the table.
So, could I have a car engine that has a magical difference from a marine engine?
Should I a after market distributor and curve it my self?
I see that the Thunderbolt V has a Acceleration Advance Envelope that pushes up to 34 deg total timing. Should I change to a Thunderbolt V distributor?
I have spent a bit of time working on magnitos and disturbutor in my life so I don't understand why you wouldn't want more than 22 deg total timing. But before I go burning up an engine out of ignorance to the marine industry; I am asking for some expert opinion and advice.
Thank you all in advance,
Cameron
I have a 262 Vortec V6 that isn't making much power after the original heads were rebuilt. This is not the original engine for the boat and I am not even sure if it is a marine engine or a car engine or wether it even matters. BTW it has a Berkley Jet on it.
So here's what I know. The engine runs smooth however takes awhile to get on plane. It feels like it's only getting part throttle. I checked the throttle and the primarys are opening all of the way. I checked the vaccuum secondaries and they only open about half way on accelleration. You can force them open with your finger but you don't get any additional power. This pointed me to ignition timing.
On the lake without a timing light I gave the distributor about 1/8" turn in the advance direction and the engine came alive. It sounded crisper and really accellerated well. I only did a couple of hole shots and put the boat back on the trailer.
Now that I am home with a timing light here is what I find.
My initial timing is sitting at 20 BTDC and with the Thunderbolt IV advance it adds 14 deg. making a total of 34 deg advance. The engine runs pretty dang good here, although steep for initial timing.
The Thunderbolt IV timing for a 262 shows is should have the initial set at 8 deg and the Thunderbolt IV will add 14 deg for a total of 22 deg.
I am not an expert boat mechanic (that the reason for my post) but, on most stock Chevy V8's they like 32 to 34 deg total timing. Why would a boat engine differ so much from a car engine for total timing?
I verified the TDC mark on the ballancer is correct using the positive stop method. I have also verified that 8 deg initial + Thunderbolt IV gives me another 14 deg as per the book. The problem is this leaves a bunch of power on the table.
So, could I have a car engine that has a magical difference from a marine engine?
Should I a after market distributor and curve it my self?
I see that the Thunderbolt V has a Acceleration Advance Envelope that pushes up to 34 deg total timing. Should I change to a Thunderbolt V distributor?
I have spent a bit of time working on magnitos and disturbutor in my life so I don't understand why you wouldn't want more than 22 deg total timing. But before I go burning up an engine out of ignorance to the marine industry; I am asking for some expert opinion and advice.
Thank you all in advance,
Cameron