- Joined
- Dec 10, 2002
- Messages
- 3,327
Friends I just got done measuring the timing numbers on the production motors...these number run really good!
- bore .816
- stroke .867
- ave exhaust timing 186 (main exhaust port 189 and exhaust boosters 183)
- boost 132
- transfer 135
- crank open 211 ATDC
- crank close 69 ATDC
- total intake duration 217
After I tested each of the protype motors I sent them to Martin Truex to run...Some lessons we have learned during testing:
- Tank needs to have 5/32 tubing. I simply could not get my boat to run more than a few laps with the 1/8" tubing in my tank. It would run strong and then just quit.
- These motors need a nice long break-in. I tried to "go fast" before it was completely broken in and it just acted weird...after about 20 oz of fuel through it on the bench it settled down and acted PERFECT.
- I don't recommend very low oil fuels and I DO recommend some castor in the fuel.
- The motors do not need much water cooling (both Martin and I ran them most of the time without even hooking up the waterline). They really need to get up to temp to get the P/S fit right and burn the fuel.
- We found as Martin was running the first two motors (I gave Martin the green light to modifiy these first prototypes any way he wanted) he actually stuck the pistons. We determing this to be caused by 1) low oil in the fuel (12%), 2) No castor in the fuel, 3) running the motor hard before they were fully broken in (he was trying to get ready for the Huntsville record trial and didn't have much time), 4) running the motor too cool.
On his runs with the last prototype (completely stock...this one is just like the production motors) with a little castor added to the fuel, no water cooling, and after I had finished the break-in, his decription to me on the phone was simply "AWESOME".
Aaron, Martin and I have found these to be the most powerful of all the 45 motors we have run. Great torque and will turn a ton of RPM. (Aaron or Martin, if I have misspoken, please step in and give your accurate findings).
Yes I agree the rear exhaust with the 180 degree header is not as "swoopy" and may not fit as nice in some boats as the front exhaust motors, but I think the performance will make-up for it.
Glenn
- bore .816
- stroke .867
- ave exhaust timing 186 (main exhaust port 189 and exhaust boosters 183)
- boost 132
- transfer 135
- crank open 211 ATDC
- crank close 69 ATDC
- total intake duration 217
After I tested each of the protype motors I sent them to Martin Truex to run...Some lessons we have learned during testing:
- Tank needs to have 5/32 tubing. I simply could not get my boat to run more than a few laps with the 1/8" tubing in my tank. It would run strong and then just quit.
- These motors need a nice long break-in. I tried to "go fast" before it was completely broken in and it just acted weird...after about 20 oz of fuel through it on the bench it settled down and acted PERFECT.
- I don't recommend very low oil fuels and I DO recommend some castor in the fuel.
- The motors do not need much water cooling (both Martin and I ran them most of the time without even hooking up the waterline). They really need to get up to temp to get the P/S fit right and burn the fuel.
- We found as Martin was running the first two motors (I gave Martin the green light to modifiy these first prototypes any way he wanted) he actually stuck the pistons. We determing this to be caused by 1) low oil in the fuel (12%), 2) No castor in the fuel, 3) running the motor hard before they were fully broken in (he was trying to get ready for the Huntsville record trial and didn't have much time), 4) running the motor too cool.
On his runs with the last prototype (completely stock...this one is just like the production motors) with a little castor added to the fuel, no water cooling, and after I had finished the break-in, his decription to me on the phone was simply "AWESOME".
Aaron, Martin and I have found these to be the most powerful of all the 45 motors we have run. Great torque and will turn a ton of RPM. (Aaron or Martin, if I have misspoken, please step in and give your accurate findings).
Yes I agree the rear exhaust with the 180 degree header is not as "swoopy" and may not fit as nice in some boats as the front exhaust motors, but I think the performance will make-up for it.
Glenn
