PORT TIMING, AND COMPRESSION QUESTIONS!

[renortp]

hi, sorry for my bad english , i´ll do my best.

last weekend was working on my blaster, i opened my engine, i was checking degrees, and i have:
190 exhaust duration (open at 85 )
120 transfers duration
squish clearance = 1.4mm (aprox) i will take accurate measurement on this week.
rechamberes head 18.5cc
compression 125 psi
stock head gasket.
alevation 1,500 meter of sea level. (aprox 5,138 Ft)
stock cylinder 66.5, with wiseco piston.

the questions are:
what do you think about my engine mods?
how i can improve my engine? (using stock cylinder and crankshaft)
I know if i rise the exhaust degrees i will lose compresion, ----
how can i rise the compression to 160psi (i will run with 93 pump gas) whit my ports timing (190 exhaust degrees)??
my style ride are between trial/ and ocasional and informal drag racings.
any ideas or suggestions??
all the work will be done on my garage. (homemade)jja

thaks

 

[renortp]

someone who wants to give me any opinion? any suggestions??

 

[joeak47]

First off, don't get stuck on numbers...

PORTING is your answer! Get that cylinder ported while your getting a NEW piston fitted to that cylinder as well. Get a quality after market pipe too.

 

[renortp]

Joeak47, first for all, thanks for your videos on your youtube channel, and all your post about "rechambered head" .
Next, about my question, i have a FMF pipe, is not the best pipe, but is better than stock, the piston is new, only have 2 tanks of use. (Sorry for my bad english)
You said, porting is my answer, if i continue porring, i will be loosing compression rigth?

 

[joeak47]

First off...your english is fine.
That FMF pipe you have is a great pipe!
So you just had your cylinder fitted with a new piston? Does this mean that the cylinder was measured for taper, roundness, and a new piston was fitted properly? Or...does this mean that you just put another piston in it?
To me, 125 psi of compression seems low for a fresh top end at sea level with a 18.5cc chambered head. I say ... Hmmm?

 

[renortp]

First off...your english is fine.
That FMF pipe you have is a great pipe!
So you just had your cylinder fitted with a new piston? Does this mean that the cylinder was measured for taper, roundness, and a new piston was fitted properly? Or...does this mean that you just put another piston in it?
To me, 125 psi of compression seems low for a fresh top end at sea level with a 18.5cc chambered head. I say ... Hmmm?

the history :
I re-sleeve my cylinder, because it was on 68mm, now return it to 66.50 with a new piston wiseco, (engine only have 2-3 tanks of use), i think the cylinder was measured fine before instal a new piston,
my elevation ,1,500 meter of sea level. (aprox 5,138 Ft),
i bought a new compression tester kit, and i checked the compression on a cold engine, (i don´t know if a cold engine affect)
i´m thinking today replace the base gasket for a new one more thinner, waiting reduce the "squish clearance " to 1mm.

is a good idea? what do you think?

 

[jus_me]

If you lower the cyl than you will change the port timing. Not by much but it will. Might want to look into a thinner head gasket instead of a thinner base gasket. Have you re chambered the head or just shaved it down?

 

[renortp]

If you lower the cyl than you will change the port timing. Not by much but it will. Might want to look into a thinner head gasket instead of a thinner base gasket. Have you re chambered the head or just shaved it down?

I have rechambered head , following the joeak47 videos , cc finals 18.5 - 19 cc

 

[joeak47]

I would get that cylinder ported! You sound pretty handy with tools. Why not try the porting templates that Ken sells? You won't regret it! The porting, re-chambered head you did (looks great), and proper jetting will get you 30+ HP on pump gas!
Go here for the templates \/ \/ \/

http://www.kenoconnorracing.com/portingtemplates.html

 

[renortp]

This is my cylinder,

 

[renortp]

And this is the cheap way that i measured my ports timing, i rised 13 degrees the exhaust port, now have 190, , and 5 degrees my transfers,