User Tag List
Results 736 to 740 of 740
Thread: Looper exhaust porting
-
06-07-2019, 10:15 AM #7365000 RPM
- Join Date
- Oct 2017
- Location
- Hugo, MN
- Posts
- 326
- Thanks (Given)
- 36
- Thanks (Received)
- 18
- Likes (Given)
- 62
- Likes (Received)
- 81
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
Great looking motor!
-
Captain75 thanked for this post
-
06-07-2019, 03:08 PM #737
-
Captaincj liked this post
-
07-04-2019, 02:40 AM #738
Hello!
Break-in should be over soon, I think...
So far the motor has consumed appx 200ltrs of fuel, first 40 at 4% mineral oil, last 60 at 3%.
Many short rides with plenty of warmup before pushing the throttle. It feels very strong, midrange punch is awsome which has been noticed by my sons when tubing.
I haven’t let it rev past 5000 yet, so I don’t have any wot numbers, but things look good.
The mods made last winter was extensive (or at least time consuming...) behind-the-liner work iot remove rough spots and increase velocity through port openings. Some of the transfers were aimed a bit more towards the back wall iot prevent short-circuiting.
The big second mod was the intake: Last year I had problems with burned reeds and melted stuffers, a vicious circle that made things worse as time went by. The burned stuffers affected the reeds that eventually had a hard time sealing.
This year my stuffers are replaced with CCMS stuffers, modded to fit my milled early type mainfolds. Although the mainfold already has some serious stuffing, I can guarantee the CCMS stuffers does their job!!
The difference in off-idle throttle response is huge! Like someone wrote in another thread on another topic; Its like stepping on a fire cracker instead of a rotten grapefruit
I can really recommend this product!!
During break-in I have used the stock steel reeds because my CCMS reeds was destroyed together with the burned stuffers described earlier. So, next up after finishing break-in would be adding a new set of CCMS reeds, maybe race instead of sport this time iot take full advantage of all other mods.
Last but not least, some cooling mods has been made which seems to work fine, apart from water leaking from the rubber coating on my recifier!?
To be continued...
-
SS Minnow thanked for this post
-
07-17-2019, 04:42 AM #739
Hello again!
Since I’m currently being on family vacation in beautiful Sicily/Italy, I’ve had the opportunity to reflect upon my latest build, described in the later parts of this thread. To me the funniest part is always the build, way more than the actual driving. Therefore, while having some inactive time on a sunbed, I’m trying to recap all the mods iot see if there is anything left that could be done, this while searching the market for an Etec 300 at a resonable price (btw, hard to find over here due to limited market).
Below I’ve tried to conclude all the mods iot make it easier for readers to have an opinion- or sharing their ideas w/o having to read the whole thread.
Basic part facts:
P/H is an Evinrude -98 closed deck, mounted on an -87 adapter and mid. The crank and rods comes from an -87 aswell, although refreshened to the best of my knowledge and ability.
-98 Mid bore carbs with adjustable idle screws are being used.
-87 cooling- and electrics are being used.
-Early style intakes, w/o the ”teacup wall”
All new bearings and seals.
List of mods:
- Exhaust ports raised and widened to 250 specs.
- Exh idle reliefs closed (set screws and jb weld)
- All casting imperfections removed from all ports, intake mainfolds, and rodslots.
- Sleeves and casting matched on all intake ports while stock exit angles and durations has been maintained (hopefully).
- This last winter a huge amount of extra work was added to ensure a smooth transitation from the cyl floors into lower port entrances and port cavities iot increase speed and reduce turbulence.
- All bores has been honed straight and round, wiseco’s added.
- Piston F/p holes has been enlarged and matched to each sleeve openings.
- The reedcages has been lapped and entrances matched with intakes, CCMS stuffers and stock gaskets.
- Intake mainfold angles towards the reeds has been adjusted to better ensure a ”straight shot” towards reeds. Finally, after all grinding, the mainfolds were sandblasted internally, iot create a surface that promotes proper fuel/air atomization.
- CCMS stuffers has been mounted between cages and mainfolds. All the empty cavities around the reedcages has been filled.
- Block counter bores has been filled with wooden dowels.
- The exh adapter has been cleaned from casting flaws and the transitation between p/h and adapter has been improved.
- Stock 2.7 heads are being used, together with added cooling dams between the chambers.
- The stock flywheel has been lightened on a lathe.
- The upper idle reliefs situated high on the back of the mid has been enlargened (~20mm) and drilled straight through into the can, iot promote a better off idle response aswell as a sweet sound.
- Lower has got 2 holes drilled(14mm) on each side, just above cav plate.
- The VRO has been removed and replaced with an Holley blue, set at 6psi. The VRO cavity has been filled with epoxy.
Apart from adding new reeds, what have I missed?
What more could be done to enhance performance?
I have no intention to rev higher than 6600-6700.
I have a pair of tighter 2.7 heads, but I doubt that I dare to raise compression more due to the weight of the boat and the fuel being used (Swedish 95 equals appx US 90-91 oct.) Current comp is appx 135-140psi, timing is set at 16deg.
The only mod I can think of is to cut the reedcages to create fewer- but larger windows? Is that a beneficial mod considering my rather moderate revs?
Looking forward to hear your ideas!
Best regards
AndersLast edited by Captain75; 07-17-2019 at 04:47 AM.
-
07-17-2019, 05:26 AM #740Banned
- Join Date
- Jan 2015
- Location
- Wisconsin
- Posts
- 2,331
- Thanks (Given)
- 458
- Thanks (Received)
- 343
- Likes (Given)
- 6429
- Likes (Received)
- 5147
- Mentioned
- 4 Post(s)
- Tagged
- 0 Thread(s)
Man, I have nothing to add except that it is cool seeing your work, ideas etc. Would love to see how your motor compares to the stock one you started with on a dyno.
Thanks for sharing.