TBucket Engine Project (Dart SHP)

[Indycars]

Even $1100 Brodix IK200 heads need lots of love and grinding ! Now this is one of the worst intake ports,
but they all had something similar just not as deep of a ridge where the cutter stopped. A 1/32" ridge may
not sound like much, but when you run your finder across it, it feels pretty big. The CNC cutters left a washboard
effect the entire length of the cut, I also smoothed this out. Being careful NOT to remove anymore than necessary.
Luckily this is very easy to remove with a Tapered Cartridge Roll.

Before Any Modifications


After Modifications

 

[grumpyvette]

you might or might not have increased flow effectively with that port clean-up, work,
the washboard surface is somewhat beneficial on the lower 1/2 of the runner as the boundary turbulence, the rough surface tends to cause tends to keep some of the fuel in suspension that a glass smooth surface might allow to sheet or fall out of suspension on the smooth surface.
probably 70% or more of the port flow is in the upper port
this may help

http://v-eight.com/tech_forum/viewtopic.php?f=39&p=6582

 

[Indycars]

So if this was your heads, would you have blended the ridge, but left the washboard ???

I was aware you don't polish the intake ports, but using a medium grit cartridge roll would leave enough surface
roughness to keep the fuel in suspensions. Is that a wrong assumption ???

 

[grumpyvette]

ID have and usually do, blended the ridge,if its present in the lower runner walls but left the washboard in the lower 1/2 of the port and blend and smooth the upper port walls and roof.
Id really doubt you've hurt anything doing what you did , and you might have helped , but generally its the upper half of the port walls and roof that benefit from a bit of time slightly smoothing the surface with a flap wheel

be aware that head bolts enter the block coolant passages,
so if you failed to dip the bolt threads in sealant when they were assembled,
through the heads coolant can seep up along the head bolts,
into the area under the valve cover
btw read this

both of these work great at sealing head bolt threads,

 

[DorianL]

Washboard effect is something I learned from the book you guys sent me - has something to do with slip vacuum slowing flow and micro-vortices acting like roller bearings and sliding efficiently the flow.

AFR does it all the way down...

 

[Indycars]

Washboard effect is something I learned from the book you guys sent me - has something to do with slip vacuum slowing flow and micro-vortices acting like roller bearings and sliding efficiently the flow.

AFR does it all the way down...

I'm amazed that they can get a cutter all the way thru the port like that. I can't tell for sure, but it looks like the
valve guide even has a similar texture.

I knew it's better to have Turbulent flow and NOT Laminar flow along the port walls to keep the fuel in suspension, I
didn't think it needed to be like a washboard. Probably some other things going on I'm not aware of also.

Thanks for the comments !

 

[DorianL]

yes... even the valve guide. I was so impressed, i had to take a pic!

 

[jteu2002]

my 220 afrs look like thise (they got a competition finish from AFR )

 

[Indycars]

Well......guess I will do things differently next time. I'm hoping this is a minor detail.

Thanks for the feedback !

 

[Indycars]

I took the crank to Crankshaft Service Company to have them check out the crank and see if them could
get it any closer on the run-out. Previously I measured 0.0012" on main #4. They said they measured
more like 0.0018" on #4, but they straightened it to 0.0005. Any further and the adjacent main #3 would
be more than 0.0005".

Today I setup with the front and rear main bearings in place, now I get 0.0010" on main #2. Surely they
would have checked all the mains before calling it good. As you can see from the chart, #4 is much closer,
but according to my measurements they just moved the problem to main #2. Now without a doubt I have
to question my measurements, this is not something I do very often. But I didn't just take one measurement.
I checked fore and aft of the oil passage, remove the dial indicator and setup again doing this five or six
times and I always get similar readings.

One difference worth noting is when they setup to take measurements they use the front and rear seal
surfaces, this has to make some differences in our measurements. I'm using the front and rear main
bearing surfaces.

I'm frustrated at this point. I didn't buy high a dollar crankshaft, but I would have thought a Scat crank
would be within 0.0005" or less everywhere. Where do I go from here, can I increase the clearance on
main #2 to 0.003" ???. Or maybe I need to have someone else check the crank for run-out, maybe it's just my
measurements are wrong.

 

[grumpyvette]

while its not IDEAL, from a pragmatic view point if you set all the main bearing clearances to spec. on the loose end of factory specs
Main bearings 0.002 - 0.003" for most engines,on small blocks, in that .025-.027 range I doubt youll have any issues at all, now obviously you could call the guys you had polish the crank journal and get their input, but having seen how much clearances vary and still having seen engines run long healthy lives built with those tolerances in the bearing clearances you are just not that far off.
but if it was my build ID break out the plasti-gauge and check it out, your dial indicator may be the problem not the clearances and having a second check method is almost mandatory, remember YOUR the BUILDER and its YOUR CALL, if its going to make you have sleepless nights, until it measures dead on, then by all means have in polished again, but like I said Ive seen many engines live long health lives having been built with FAR LESS CAR and EFFORT than your putting into this.
obviously the first step is verifying measurements, ID start with green plasti-gauge

btw

do you have snap gauges and mics?

 

[Indycars]

while its not IDEAL, from a pragmatic view point if you set all the main bearing clearances to spec.
on the loose end of factory specs Main bearings 0.002 - 0.003" for most engines,on small blocks, in that .025-.027 range
The machine shop said I have 0.002" to 0.0022".

I doubt youll have any issues at all, now obviously you could call the guys you had polish the crank journal and get their input,
but having seen how much clearances vary and still having seen engines run long healthy lives built with those tolerances in
the bearing clearances you are just not that far off. but if it was my build ID break out the plasti-gauge and check it out,
Going to do that today.

your dial indicator may be the problem not the clearances and having a second check method is almost mandatory, remember
YOUR the BUILDER and its YOUR CALL, if its going to make you have sleepless nights, until it measures dead on, then by all
means have it polished again,
Are you thinking that the clearances are the problem ???
Most all my comments refer to the RUN-OUT of the crankshaft. One comment I made was to open up the oil clearances on
main #2, so that the run-out would have more room inside the bearing.

but like I said Ive seen many engines live long health lives having been built with FAR LESS CARE
and EFFORT than your putting into this. obviously the first step is verifying measurements, ID start with green plasti-gauge

btw
do you have snap gauges and mics?
Yes, I have a cheap set of snap gauges. The micrometers I have are nice ones.

 

[Indycars]

While preparing to plasti-gauge the mains bearing clearances, I noticed the burr from Line Boring
the mains ??? Maybe they were already there, since I don't see any signs of grinding marks on the
main cap surface. Every main cap had a burr, although most were smaller.

Bottom line I made sure they were gone.



I took this picture thru a eye loupe with 8X magnification.

 

[grumpyvette]

a few careful strokes with a jewelers file will clean that up nicely, its both common and nothing to lose sleep over, but its a good thing you found that, its also common for guys installing bearing shells to get those burr chips into the machined clamping area, surface between the main cap and block and that can be a problem as it prevents the main caps and bearings from seating correctly

http://www.harborfreight.com/12-piece-p ... -4614.html

 

[Indycars]

If I really had a problem with run-out, then the clearances on Main #2 should change as I check the
clearances at every 90 degree of crank rotation. I checked all the mains with Plasti-Gauge, but also
check #2 every 90 degrees to see if there was any change in the oil clearance.

All four times it stayed the same at 0.002".

 

[grumpyvette]

"All four times it stayed the same at 0.002".

looks like your going to be ok!


any more progress on the engine?

 

[Indycars]

What do you think about the radius on the exhaust valve margin. ??? Does it need more ???

 

[grumpyvette]

radiasing the exhaust valve edge is usually done to reduce the tendency for the exhaust valve sharp edge angle from burning or holding enough residual heat that might be causing detonation issues as obviously exhaust valves run a good deal hotter than intakes and bleed off heat mostly when briefly seated or thru the valve guides,its always a good idea with the higher heat nitrous produces, its common practice but Ive rarely seen power gains, back cutting intake valves does tend to show flow gains

read these links
http://www.chevyhiperformance.com/techa ... index.html

viewtopic.php?f=52&t=2787&p=7220&hilit=+back+cutting+valves#p7220

http://www.diyporting.com/valve_seat_issues.html

http://www.team-integra.net/forum/blogs ... ality.html

http://www.diyporting.com/gtpex.html

http://www.nitrouskits.co.uk/Technical/head-mods.htm

 

[Indycars]

Ok....it's obvious that I like shinny objects. I'm stopping with the exhaust valves, just not worth the effort
to polish the intakes. I dare any carbon to stick to these babies !!!

But you got to admit they sure look good !

 

[grumpyvette]

that is impressive polishing work, and having that super smooth surface should help slightly in reducing ash and residual burned oil residue accumulation