Squish measurement
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Banned
Joined: May 2018
Posts: 4,576
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From: Viet Vet, crossroads
I have it dwn to about .030 again .
Now on to valves, I have them cut @50 deg rather then the usual 45deg
dental plastic cut into strips
I ported the heads with boat bows around the guide bosses, and always have had great success.
I end up pulling this apart about every 20K, so I am not too concerned if they burn or not with the very narrow seats.
The seats are placed way to the top.
My last set went 20 K and were just starting to show some seat damage around the valve face.
The BIG reason it is apart- The cam drive gear came loose and the pistons kissed the valves.
After much homework I am convinced the EVO does not like a larger cam on the straight cut pinion.
The HIPO springs are trying to work it back and forth.
I measured the Total TIR and is less than three .
Next- to do the mock-up and check vale clearances again.
CC the chambers again.
Last edited by ChickinOnaChain; Jul 28, 2018 at 12:47 AM. Reason: Multiple posts
Thread Starter
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Banned
Joined: May 2018
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From: Viet Vet, crossroads
Thanx!
The only reason I don't use solder, it is is not led anymore.
I don't want to hurt anything on rollover.
The dental stuff is real soft yet holds the shape for measurement.
Got her all back to the ,030 plus or minus a fudge.
It varies a little around the circumference.
This is one of the MOST important measurements anyone can do in the engine to get it to run right..and its boring to everyone?
Back to the favorite kind of wax, I guess. LOL
Harley comes dwn the line with .050 more squish and more .!
Harley has everyone brainwashed into their stage 1, 2, 3 BS cause they left it on the table to sell ya latter.
They know..its no secret they want to sell you SE heads,
If you look...these are EVO heads wit completely different chambers.
I think Harley offers something like this?
Next look at how the valves how they are unshrouded.
Pay attention!
The only reason I don't use solder, it is is not led anymore.
I don't want to hurt anything on rollover.
The dental stuff is real soft yet holds the shape for measurement.
Got her all back to the ,030 plus or minus a fudge.
It varies a little around the circumference.
This is one of the MOST important measurements anyone can do in the engine to get it to run right..and its boring to everyone?
Back to the favorite kind of wax, I guess. LOL
Harley comes dwn the line with .050 more squish and more .!
Harley has everyone brainwashed into their stage 1, 2, 3 BS cause they left it on the table to sell ya latter.
They know..its no secret they want to sell you SE heads,
If you look...these are EVO heads wit completely different chambers.
I think Harley offers something like this?
Next look at how the valves how they are unshrouded.
Pay attention!
Last edited by ChickinOnaChain; Jul 28, 2018 at 12:47 AM. Reason: Multiple posts
Grand HDF Member
Joined: Nov 2009
Posts: 4,315
Likes: 1,663
From: Tampa
I'm actually not a fan of squish anymore. I've gone through a number of bikes, both OEM and Harley modified, and all the ones with any kind of squish bands always gave me detonation or pinging at some point in operation. Take my new 106" for instance. I've go the timing at 28 degrees and when I roll on the throttle with the highest octane I can buy at the pump I get the ping knocks and rattles until the VOES kicks in and takes about 15 degrees out of the ignition. My 88" Sportster had it too but being a lighter bike they didn't last too long. And my previous 14 Vstrom 1000 did it at heavy throttle in 6th.
Long story short, I'm doing my 106" cylinders again but this time I'm using flat tops. I'll be at 9.5:1 with a much more reasonable 185psi cranking. Right now I'm over 215 psi. Yes she pulls great but I don't like putting my engine thru that. I want a great street motor, not a stoplight runner that's not fun on the long haul and I'm willing to give up a few HP to have it.
Then I'll build a turbo for it.
Long story short, I'm doing my 106" cylinders again but this time I'm using flat tops. I'll be at 9.5:1 with a much more reasonable 185psi cranking. Right now I'm over 215 psi. Yes she pulls great but I don't like putting my engine thru that. I want a great street motor, not a stoplight runner that's not fun on the long haul and I'm willing to give up a few HP to have it.
Then I'll build a turbo for it.
Thread Starter
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Banned
Joined: May 2018
Posts: 4,576
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From: Viet Vet, crossroads
Interesting-
Most anything one can study will tell ya to pull it dwn tight to avoid the ping, and gain the power for the expansion rate.
I have been running 10,5 to 1.
Also, cam and LSA will have a lot to do with ping ping at the lower RPM scale.
I must admit..once in a while i do get a rattle on hotter days.
But on inspection here all is still ok inside.
I am using a DM 530.cam, smooothed everything so no hot spots develop.
Double plug
Most anything one can study will tell ya to pull it dwn tight to avoid the ping, and gain the power for the expansion rate.
I have been running 10,5 to 1.
Also, cam and LSA will have a lot to do with ping ping at the lower RPM scale.
I must admit..once in a while i do get a rattle on hotter days.
But on inspection here all is still ok inside.
I am using a DM 530.cam, smooothed everything so no hot spots develop.
Double plug
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,899
Likes: 8,006
From: poway
I'm actually not a fan of squish anymore. I've gone through a number of bikes, both OEM and Harley modified, and all the ones with any kind of squish bands always gave me detonation or pinging at some point in operation. Take my new 106" for instance. I've go the timing at 28 degrees and when I roll on the throttle with the highest octane I can buy at the pump I get the ping knocks and rattles until the VOES kicks in and takes about 15 degrees out of the ignition. My 88" Sportster had it too but being a lighter bike they didn't last too long. And my previous 14 Vstrom 1000 did it at heavy throttle in 6th.
Long story short, I'm doing my 106" cylinders again but this time I'm using flat tops. I'll be at 9.5:1 with a much more reasonable 185psi cranking. Right now I'm over 215 psi. Yes she pulls great but I don't like putting my engine thru that. I want a great street motor, not a stoplight runner that's not fun on the long haul and I'm willing to give up a few HP to have it.
Then I'll build a turbo for it.
Long story short, I'm doing my 106" cylinders again but this time I'm using flat tops. I'll be at 9.5:1 with a much more reasonable 185psi cranking. Right now I'm over 215 psi. Yes she pulls great but I don't like putting my engine thru that. I want a great street motor, not a stoplight runner that's not fun on the long haul and I'm willing to give up a few HP to have it.
Then I'll build a turbo for it.
I would say pull more timing in the area of the ping and make sure the AFR is right..A lot of guys like to bump the timing so it hits full advace at say 2500. Many time that doesn't work. I own a number of bikes that crank over 200 psi (couple were 220) running the same socal gas. One of them is a Dyna running 11.3 to 1 cr. When you get to 220 timing does become more critical. I do think that trying to hit 0.030 on the nose is a waste of time. Anything between 0.030 and 0.040 is OK as long as the squish area is sufficient.
Thread Starter
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Banned
Joined: May 2018
Posts: 4,576
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From: Viet Vet, crossroads
Thanx
I can use the info.
The Daytona TT is very accommodating and I do end up in race modes on a low number on the dial.
I still get 32 to 35 loaded heavy, two up! ( 80 MPH and more)
The AFRs do run fat to help and I am OK with that.
My drive pinion slipped last fall ( I think from the high spring pressures).
I was gonna take it apart, -that just guaranteed I did. Thank god it was after I got back from Sturgis...!
The exhaust kissed the valves..slightly -You know the dril herel.
I have always wanted to try raised ports, so I am giving this mod a try this time.
The pistons are angle dome from Axtel and have a big sqish area.
I still have some work to redo on the ports and back side of valves.
I should maybe have it together in two weeks or so.....
A couple more mockups to go.
All advice is appreciated.
I share liberally with others too.
I do follow mauldones , Unicks, Porsche ideas and design .
I have had truly great results from unshrouding, back side work,
Some scoff at the piston polishing, but what I have found is carbon does ot stick to
the very smooth surfaces.
Working on it, finally got is dwn to 83 cc and 83.5 cc
I will pull a little off the piston as i am out of places to take more from the head.
Next is some more valve work, -top cuts radius , back cuts etc etc.
I really concentrate on getting all the ruff edges smooothed over so not to have hot spots.
I can use the info.
The Daytona TT is very accommodating and I do end up in race modes on a low number on the dial.
I still get 32 to 35 loaded heavy, two up! ( 80 MPH and more)
The AFRs do run fat to help and I am OK with that.
My drive pinion slipped last fall ( I think from the high spring pressures).
I was gonna take it apart, -that just guaranteed I did. Thank god it was after I got back from Sturgis...!
The exhaust kissed the valves..slightly -You know the dril herel.
I have always wanted to try raised ports, so I am giving this mod a try this time.
The pistons are angle dome from Axtel and have a big sqish area.
I still have some work to redo on the ports and back side of valves.
I should maybe have it together in two weeks or so.....
A couple more mockups to go.
All advice is appreciated.
I share liberally with others too.
I do follow mauldones , Unicks, Porsche ideas and design .
I have had truly great results from unshrouding, back side work,
Some scoff at the piston polishing, but what I have found is carbon does ot stick to
the very smooth surfaces.
Working on it, finally got is dwn to 83 cc and 83.5 cc
I will pull a little off the piston as i am out of places to take more from the head.
Next is some more valve work, -top cuts radius , back cuts etc etc.
I really concentrate on getting all the ruff edges smooothed over so not to have hot spots.
Last edited by ChickinOnaChain; Jul 28, 2018 at 12:48 AM. Reason: Multiple posts
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Seasoned HDF Member
Joined: Jan 2015
Posts: 15,998
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From: Sandy Eggo's North County
Based on GM's use of pistons lately that have "POFT" (path of flame travel) designs, performance is greatly enhanced. Take a look at the crowns of the "LT4" engine used in current Corvettes. They have sharp edges on them. I would have thought the same regarding "hot spots" on edges, but they seems to have figured out the cooling.
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Thread Starter
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Banned
Joined: May 2018
Posts: 4,576
Likes: 978
From: Viet Vet, crossroads
Next is the valve detail
I am not smart enough to be able to see into the combustion chamber(s) to know where the hot spots are.
I know there is now equipped to do so, however, it is not within my financial grasp.
So ... I will message my angle tops to where I think they need to be.
I know everyone wrestles with ways to get the carbon off stuff.
In the end, for the pistons, I fired up the Dremel using small fluffy scotch brites .
It ripped the carbon off in less than a minute!
Being my pistons are dome angle tops I still had some in the very tight valve pockets
.Looking through my arsenal of Dremel tools I found a very small stiff wire wheel.
Purrfect!
It got right dwn into the valve recess and done!
I wish I had thought of this years ago!
Last edited by ChickinOnaChain; Jul 28, 2018 at 12:48 AM. Reason: Multiple posts
