The BLOCK HEAD Dose it really run too hot or is it just a MYTH ?

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#1
1) Milling the fins
2) Shaving the head 40th - 60th or 160th
Note* If worried about the valves hitting the head - just measure the valve lift height

Howzit,
Lets yalk about the Block Head.
When the Block Head first came out I was reading some bad reports. Some said it was too thick and ran too hot. I bought a Block Head to check it out. I could see it needed some work. First thing, plug the extra hole in the head. I took the head to my friends shop. Had the head milled for high fins all the way down to the spark plug hole height. I Took the head back home and shaved off the bottom 160th. I make all my combustion chambers 300th deep. Need to have room for future resurfacing.
By milling and shaving the head I uncovered some voids in the casting. Both on the bottom and the top. I was praying that the voids didn't go all the way through. I used the head for about a week. I could see compression gasses coming out the voids on the top. This head with the milled fins is now JUNK a paper weight. It would be OK if I had just SHAVED the bottom 160th off.
The combustion chamber on the stock Block Head is 460th deep 460th - 160th = 300th
I ordered another Block Head and shaved it down 160th. Installed it on my bike to see how it's gonna behave. Its not bad at all I got top power and its not too hot. I ran it in the summer in heat up to 100* I run the NE Westman Cast Iron Cyl. You would think that combo would have melted down. But NOPE
Everything is A-OK and now the same Block Head has over 5,000 miles on it.
Just make sure you don't have a head gasket leak. Then you'll over heat. Any bike would.
But the Block Head is a little modern looking. Not as RETRO as the NE High Fin Repops.
I've tested 6 different styles of NE Heads. From 3 different people. I wont tell you the names of the 3 NE heads that CRACKED ( Only after 2,000 - 3,000 miles and all 3 CRACKED right by the spark plug hole ) I will tell you the name of the 3 NE heads that didn't crack WHIZZER USA
To weld cast aluminum it weakens the aluminum strength by the weld and will crack again right by the weld. I had 2 of those repops welded and guess what they both cracked again right by the weld. Only after around 1,000 more miles. So it's not worth it to try to weld it a 2nd time Now I have 2 nice paper weights that cost over $150 each and paper weight that cost $260 Live and Learn
The Block Head I installed on the NE Cast Iron Westman Cyl all head bolt holes are for 8mm bolts The Block Head has two 10mm bolt holes. I just went to Ace and bought two shoulder bolts 10mmx shoulders 14mmLx8.125 threads. The shoulder14mmL is perfect for the Block Head shaved 160th If ya only shave the head 40th - 60th get the shoulder 16mm long.
I noticed there is a weak spot on the Block Head. The LEFT REAR BOLT HOLE. The countersink for the head bolt and the inside of the combustion chamber is kinda thin in that spot. UNDER 2mm. If its gonna CRACK it's gonna CRACK right there. Right above the exhaust port. I'll keep my eye on it.
Dose the Block Head really run too hot? Is that a MYTH?
It's a MYTH. Yea the Block Head runs a little hotter but not too hot. and SHAVED 160th. No CRACKS in the head yet. Unlike some VERY expensive NE repops I mean paper weights.
If you have a Block Head I suggest not to mill the top for fins. I suggest to get some POWER and SHAVE the bottom 160th off.
I hope this info can help someone
ALOHA
Wrench

Note*
When using a head with a combustion chamber 300th deep. It is recomended to burn high octaine fuel 91 + Or you might hear a knock an ping

Note* Knock and Ping
Combustion ( ignition ) before spark @ TDC Common in high compression engines That should burn high octaine fuel 91 +

Note*
Some think that advancing the timing by moving the trigger plate 23* before TDC is a good idea? I question that The stock trigger plate is @ 14 before TDC.
Advancing the timing @ 23* before TDC might be OK if you have a Race Whizzer that revs between 7,000 and 8,000 RPMs
But you will still lose 1 to 2 MPH on the low end while gaining 1 to 2 mph on the top end. Is it worth it?

Wrench in the Tool Box

EDITIDED 11/24/2018 NOTE* @23* before TDC is not necessary for an almost stock New Gen Whizzer
 

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Street Ryderz

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#2
Howzit,
Like i said I Question the Theory of advancing the timing @ 27* before TDC ?
The way I see it. If you make the timing @ 27* before TDC. Ignition will occur where pre ignition was taking place. You should be using high octane fuel 91+ if you have a high compression head. so ya don't get pre ignition. ( Knock and Ping )
The piston has not reached high enough in the cyl boar @ 27* before TDC @ 17* before TDc the piston is just ready to go back down THUS the best spot for ignition. With the timing @27* before TDC Of course you wont hear a Knock and Ping even using reg fuel 87. Because ignition is too early Not enough compression has been made THUS your LOOSING POWER.
How do you figure 27*is better ? Do you really think the piston is gonna beat that spark to the top?
I hear advice given to people all the time. That's it's a good idea to advance the trigger plate to 27* before TDC
Just because it sounds COOL. Dose not mean its a good idea.
Would someone PLEASE tell me WHY the 27* Theory is a good idea?
Wrench
While I'm not sure exactly what the advance curve looks like for the whizzer engines,the Chinese engines we use had their base timming at 25 btdc and with the curve would advance beyond 30 degrees,Now you have to remember that even just at 4k (rpm) the piston is traveling up/down 66.6 times a second and there is a delay for the coils to saturate and discharge that has to be taken into account,then as rpm climb the curve should drop the advance down below the base figure to match up to the pistons speed.Advance is needed down low to aid acceleration and when the base timming is too low it shows strugling to bring the rpm up.
 

Street Ryderz

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#3
Like you said your not exactly sure. Thanks for your input
I'm not exactly sure as to what the curve looks like for the wizzer because I've never tested it.But the reason for the advance is the same, as it is with all engines the only varible being the amount of degrees.
 
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#5
While I'm not sure exactly what the advance curve looks like for the whizzer engines,the Chinese engines we use had their base timming at 25 btdc and with the curve would advance beyond 30 degrees,Now you have to remember that even just at 4k (rpm) the piston is traveling up/down 66.6 times a second and there is a delay for the coils to saturate and discharge that has to be taken into account,then as rpm climb the curve should drop the advance down below the base figure to match up to the pistons speed.Advance is needed down low to aid acceleration and when the base timming is too low it shows strugling to bring the rpm up.[/QU
Street Ryderz
Thank you for your explanation. That was a very good.
ALOHA Wrench
 
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#6
Howzit,

I moved the Stock Trigger Plate forward 3/8" - 7/16" 8 years ago. I swear I saw no difference
Now 8 years later I'm going to TEST the 2 Trigger Plate settings agian.
And yes I do understand the reason for advancing the timing. I was just comparing the Advanced Timing to Pre Ignition to give one an idea the relationship to piston height in the cylinder.
For my TESTS I'm going to set up a course.
4 road markers on flat level ground. Record the distances and MPHs as I pass each road marker and top MPH past the last road marker.
Starting at marker #1 with a 5 MPH rolling start.
I will do 3 TESTS for each Trigger Plate setting STOCK and ADVANCED 3/8' - 7/8"
To get the FACTS.
I've always heard people suggesting that moving the Trigger Plate is a good idea. In the Dec. Whizzer News Letter it was said that by advancing the timing one would gain mid range power.
My motor has always been very strong in the mid range power band.
I need to do TESTING to find out if this is a good performance mod.
I have never seen anyone post the FACTS. Only how to move the Trigger Plate Timing and suggested results.
I will post my TEST RESULTS as soon as TESTING is over in the near future.
I know it's cold out for most of you. But soon as it warms up. Will other NE-5 Whizzer owners do some of their own TESTING.
So we all can have some FACTS to compare.
Set up a course with 4 road markers on flat level ground. Do 3 TESTS for each Trigger Plate setting STOCK and ADVANCED.
Record MPHs as you pass each road marker and top MPHs past last road marker to check top MPH
List any speed mods.
See if you can tell the differences.
Then POST RESULTS
ALOHA
Wrench
NOTE* Use telephone poles or street lights as road markers. If there not too far apart.
 
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#7
Howzit

The TEST RESULTS are in.
I tested a NE-5 with a high compression head.
Trigger Plate STOCK or ADVANCED. There was no difference.
If you think your missing out on a good performance mod. Don;t worry about it.
It might make you feel better having the Trigger Plate moved forward 3/8" - 7/16".
Because as the Advanced Timing Theory goes. It's so ya don't loose power at high RPM's
Just because it sounds COOL dose that mean ya should do it?
Sure why not?
It might make ya feel better.

ALOHA wrench

NOTE*
No other TEST RESULTS are needed.
See if YOU can tell the difference.
 
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