Engine stripped ready for tuning - help needed

[db971]

Cheers Jss, this is my first time at this so taking the softly softly approach ;-)

[briggsy]

Hi db971, great thread! what are you using to remove the material ?

[db971]

Briggsy, I was using 431 & 438 sanding drums. Plan to use some other bits. See the following thread for more info vespasmallframeforum.proboards.com/thread/18036/dremel-bits-porting?page=1&scrollTo=151854

[db971]

Ok, new dremel bits in hand and it was off to the hut.

I'm sure the intake sides are ok and have enough material removed. Appreciate any comments.

Need help on this one - Also worked on the casing and managed to burst through both side (feck, was enjoying myself so much I forgot to bloody stop). Will I have to have the casings welded at the blows hole below or would quick steel metal putty be ok? Again appreciate any comments

Intake web side




Intake manifold side




Casings modified





Casing side 1 - do I need to remove anymore material as per the comments on this image?




Casing side 2 - do I need to remove anymore material as per the comments on this image?

[jonnysnatchsniffer]

i doubt it would make any difference if you did, tho you didnt need such a steep angle for the transfers
ive been told that there is not much of a power gain in this area and that its the inlet and exhaust where the power is

[db971]

Cheers JSS. So much for the softly softly approach :-). Don't know whether quick steel metal putty will be ok or whether I need to weld the holes?

[amazombi]

The problem with welding is that there is a good chance you'll need the gasket surface machined again once you're done. I'd use JB weld or something like that.

[db971]

Thanks Amazombi.

I assume once I clean off this surface on the casings that there is nothing else to change or remove/modify?

I am now looking to modify the polini evo cylinder barrel.

Can you confirm that the images & details below are correct before I remove any material.

Cylinder exhaust port. Measured 29.9mm, to adjust port up to 27.5mm (remove 2.4mm of material).






Cylinder exhaust port. Remove the humps to open up the internal more . Have marked with black marker.





Cylinder exhaust gasket area. Open up diameter to 32mm to suit the Franz pipe.
(Is there a gasket for the cylinder to exhaust that should be fitted ( have the one with the kit but is smaller than 32mm)?




Thanks for any comments and help I appreciate there are a lot of questions I'm asking :-)

[jonnysnatchsniffer]

yes that what you need to do, use the piston to scribe a line across the barrel to get a flatter port and radius the sides a little, also make sure when you have removed the material that the walls of the port are straight, no trumpety shapes if you know what i mean, ie the edge of the port in the barrel face meets a straight line to the edge of the port at the manifold end, u can use the sticky out bit of vernier calipers to make sure
no gasket with the franz, just use some high temp silicone, which you can also use on the head

[db971]

cheers jss

[db971]

Appreciate any comments on the pics below re porting. I have roughed out the material and want to check if I should remove more material before I polish off the surfaces?

Polini cylinder porting - looking down the barrel at the exhaust port after removing material and adjusting position up to 27.5mm






Polini cylinder porting - Pic of the barrel at the exhaust port after removed material and adjusted position up to 27.5mm. I used a red marker in the cylinder barrel to mark along the top of the piston at 27.5mm. I also used the template rub to give shape. I have still to polish off/fine sand.





Polini cylinder porting with piston slightly lower





View from the exhaust port with material removed (top and bottom of the port) and the diameter opened up to 32mm. Do I need to remove any more material?



Another pic of the exhaust port



Thanks in advance

[amazombi]

Did you make the port wider too? Looks a bit like it. I'm asking because it is fairly wide out of the box already.

You could go for a straighter top edge with radii in the corner and maybe a slightly raised middle (1mm or so) to help the rings. You should also have a look at that top edge again as it is now. Not sure whether it makes a huge difference, but I'd try to make the top edge smoth and symetrical, your's looks a bit "outlaw". The pictures of the the exhaust channel are not very good (or my eyes are letting me down), so difficult to comment on that.

[db971]

Hi Amazombi, No I haven't made the port wider.

When you say straighten the top edge would this be ok or should I go a bit higher at the left and right sides (have marked in yellow a line that I would look to come up to. The top edge I had planned to smooth out




This is a close up of the exhaust port






Thanks for your comments and help.

[db971]

Should I follow the profile and remove material to the yellow mark on pic above? Appreciate any help.

[jonnysnatchsniffer]

here you go, sorry for the shit picture but you get the drift

[db971]

Thanks JSS. Sorry for the delay in responding (had a baby last year and sometimes difficult to get into the frigging shed to work on this :-) ). Anyway completed the changes and will tidy up with fine wet & dry. Appreciate any comms. Now to start on the gear box and a dry build to determine packers etc

[db971]

Are there any other bits on the engine I need to remove/port prior to starting the clean up and assembly of the engine?

[briggsy]

Apr 14, 2014 19:32:10 GMT db971 said:

Are there any other bits on the engine I need to remove/port prior to starting the clean up and assembly of the engine?

Hi.......you may need to cut some of the fly side case to allow the cylinder to fit in place. Put the cases together any try and place the cylinder on.

[db971]

thanks briggsy. I have ordered cylinder base spacers and will trim casing accordingly. I was wondering if there were any additional work to the cylinder, casings or crank?

Also what gear box oil (ST90 or SAE30 etc ) should I consider using for drt selector, 4 gear box and drt xmas tree?

[db971]

Apr 15, 2014 16:27:12 GMT db971 said:

I was wondering if there were any additional work to the cylinder, casings or crank?

Also what gear box oil (ST90 or SAE30 etc ) should I consider using for drt selector, 4 gear box and drt xmas tree?

Is there anymore work to the casings crank or cylinder prior to assembling?

Regarding the gear box oil - any thoughts on the Rock Oil GRO (gearbox racing oil) SAE EP 75w90?

Thanks