Quick update on this ongoing project. Still haven't made any meaningful progress on the four barrel conversion, but getting closer. I am getting ready to re-baseline my numbers with stock power on both props (19P 3 blade Vengeance and 22P 4 blade B1) as soon as I get the drive back on and the weather cooperates. Going to use a shop tach and better GPS this time.
I did get some maintenance done over the winter:
- All new exhaust / driveshaft / shift bellows. The ones that came off appeared to be the originals from 1998.
- New lower shift cable. Old one was shot and it was getting tough to shift.
- New gimbal bearing. Had the dealer throw one in when I bought the boat and they did a poor job. Really banged up the bearing installing it. Found a new mechanic that seems to be great.
- Aligned bearing & coupler.
- Pair of new Interstate 1000 CCA marine batteries.
- New sacrificial anodes.
- Built a rolling drive stand so I don't give myself a hernia on the drive installation.
Also picked up a Thunderbolt V ignition module from a HP500 to lose the stock rev limiter. It has 20deg of advance built in by 3k, so I'm going to shoot for 10-12 initial and 30-32 all-in. The Vortec heads are apparently picky about too much timing. I know about grounding the purple/yellow wire to get the TB V in base timing mode.
Going to install a remote oil filter mount and a 2qt filter to add some capacity, hopefully lower temps a little, and make oil changes easier. Haven't decided on an oil cooler yet, but I will probably mount a temp gauge to the filter mount to help monitor it and see if it is necessary. Last summer oil pan temps were in the 240-250 range after a hard run, tested via IR temp gun. This is about the max I am comfortable with, but I'm afraid a cooler might not allow the oil to heat up enough to burn off condensation. Water temp never gets above 175 and normally hovers around 165 (with a 160 tstat).
To add some intrigue on the prop testing, I noticed that I have a shallow-v pad about 12" wide on the keel of the boat from the step all the way to the transom. So it is a 21deg, single stepped hull with a pad. Pretty complex for a bowrider... I think some of the ZXs (26/27/28) were running twin steps and a pad. I will hang some pictures on here at some point.
More to follow, just trying to keep all of this updated on one place.
"Speed's fine, but accuracy is final."
- Bill Jordan
1998 Donzi 21LXR
1971 Boston Whaler 13