Author Topic: any tips for seperating the head from the block  (Read 1779 times)

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Offline the technological J

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any tips for seperating the head from the block
« on: August 17, 2012, 09:56:17 AM »
ive done everything... i even broke a few fins trying to pry it... the block pulled off the  pistons but i cant get this this thing apart.... there are only 6 bolts(4 under the pucks and two by the cam chains) holding it together right?

 the pistons look terrible and theres a gouge in one of the cylinders


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Offline lucky

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Re: any tips for seperating the head from the block
« Reply #1 on: August 17, 2012, 10:05:59 AM »
Broke a FEW fins!!! wow.

Usually a large rubber mallet to keep from damaging the cylinder head.

Clymer's manual Page 87. Illustration #42 Shows 22 nuts and bolts.
2 bolts and 20 nuts.

But wait....You did not even tell us which engine!
« Last Edit: August 17, 2012, 10:07:45 AM by lucky »

Offline tlbranth

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Re: any tips for seperating the head from the block
« Reply #2 on: August 17, 2012, 10:07:04 AM »
It's been years since I had the engine apart but it seems there were a couple of fairly well hidden nuts or bolts that held the head on. Look up from the bottom. If you're sure you have all the fasteners off, try hammering a hard wooden wedge in there. Someone here will know for sure what the bolt pattern is.
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Offline Tugboat

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Re: any tips for seperating the head from the block
« Reply #3 on: August 17, 2012, 10:57:02 AM »
Heat gun + rubber mallet + patience.
If it's worth doing, it's worth doing twice.

Offline madmtnmotors

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Re: any tips for seperating the head from the block
« Reply #4 on: August 17, 2012, 07:21:25 PM »
Find the remaining bolts. There are some bolts that are NOT studs and do not extend all the way to the crankcase, they only extend through the head into the cylinder block.
« Last Edit: August 17, 2012, 07:23:22 PM by madmtnmotors »
TAMTF...


Wilbur



Projects:
"Evolution": http://forums.sohc4.net/index.php?topic=100352.0
"P.O. Debacle": http://forums.sohc4.net/index.php/topic,126692.msg1441661.html#msg1441661
F2/F3 O-rings: http://forums.sohc4.net/index.php?topic=113672.msg1300721#msg1300721
Cam Tower Studs: https://www.mcmaster.com/#93210a017/=t19sgp
Clean up that nasty harness: http://forums.sohc4.net/index.php?topic=137351.msg1549191#msg1549191
http://forums.sohc4.net/index.php/topic,148188.msg1688494.html#msg1688494
http://forums.sohc4.net/index.php/topic,139544.msg1579364.html#msg1579364
                                          
Charging system diagnosis: http://forums.sohc4.net/index.php?topic=1012.msg8345#msg8345
Get the manuals: http://manuals.sohc4.net/cb750k/
The Dragon: http://forums.sohc4.net/index.php?topic=45183.msg1571675#msg1571675
Headlight Switch: http://forums.sohc4.net/index.php?topic=113986.msg1283236#msg1283236
Branden's leak free top end thread: http://forums.sohc4.net/index.php?topic=107040.0
Engine Lifting Made Easy: http://forums.sohc4.net/index.php/topic,58210.msg1684742.html#msg1684742
                                      http://forums.sohc4.net/index.php/topic,100352.msg1675840.html#msg1675840
Static and Dynamic Timing: http://www.hondachopper.com/garage/carb_info/timing/timing1.html
Airbox Gasket Replacement: http://forums.sohc4.net/index.php/topic,114485.msg1290000.html#msg1290000
"Café" : http://forums.sohc4.net/index.php/topic,84697.msg953814.html#msg953814
PD Carb Choke Linkage: http://forums.sohc4.net/index.php/topic,100352.msg1669248.html#msg1669248
                                    http://forums.sohc4.net/index.php/topic,110931.msg1248354.html#msg1248354
                                    http://forums.sohc4.net/index.php/topic,48858.msg515204.html#msg515204
Follow up on your damn posts: http://forums.sohc4.net/index.php/topic,144305.msg1791605.html#msg1791605
Taiwanese Cam Chain Tensioners:  http://forums.sohc4.net/index.php/topic,155043.msg1774841.html#msg1774841
Gumtwo Seat Cover: http://forums.sohc4.net/index.php/topic,164440.msg1897366.html#msg1897366
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Tank Latch: http://forums.sohc4.net/index.php/topic,165975.msg1919495.html#msg1919495
Shorten your forks: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-shorten-forks-td4042465.html DO NOT CUT THE SPRINGS!
Clutch How To: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-change-and-adjust-a-clutch-SOHC-td4040391.html
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Offline the technological J

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Re: any tips for seperating the head from the block
« Reply #5 on: August 17, 2012, 10:07:01 PM »
am i missing something?
 the yellow are the stud nuts i removed
the light blue and orange are the bolts under the puck anf the darker blue are also the bolts
manual Page 87. Illustration #42 Shows 22 nuts and bolts.
2 bolts and 20 nuts.

 so if im not mistaken 16 yellow, 4 light blue and orange, and 2 darker blue makes 22
70 KO...sold to fund the ST http://forums.sohc4.net/index.php?topic=88800.0(Alpha)
74 Kaw 250 Enduro http://forums.sohc4.net/index.php?topic=124278.0
K4 added to collection! http://forums.sohc4.net/index.php?topic=104784.0
78 750K... http://forums.sohc4.net/index.php?topic=60257.0 (Omega)sold to fund the K4
94 ST1100..Gone
72 750 K2 Stay tuned!

Offline madmtnmotors

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Re: any tips for seperating the head from the block
« Reply #6 on: August 18, 2012, 05:01:37 AM »
tj,
   Good schematic, I believe you have found all of the bolts. Just wanted to make sure before you continued exerting force trying to seperate the two. Sorry I don't have any tried and true method for seperating such well mated parts, other than patience. Keep us posted.
TAMTF...


Wilbur



Projects:
"Evolution": http://forums.sohc4.net/index.php?topic=100352.0
"P.O. Debacle": http://forums.sohc4.net/index.php/topic,126692.msg1441661.html#msg1441661
F2/F3 O-rings: http://forums.sohc4.net/index.php?topic=113672.msg1300721#msg1300721
Cam Tower Studs: https://www.mcmaster.com/#93210a017/=t19sgp
Clean up that nasty harness: http://forums.sohc4.net/index.php?topic=137351.msg1549191#msg1549191
http://forums.sohc4.net/index.php/topic,148188.msg1688494.html#msg1688494
http://forums.sohc4.net/index.php/topic,139544.msg1579364.html#msg1579364
                                          
Charging system diagnosis: http://forums.sohc4.net/index.php?topic=1012.msg8345#msg8345
Get the manuals: http://manuals.sohc4.net/cb750k/
The Dragon: http://forums.sohc4.net/index.php?topic=45183.msg1571675#msg1571675
Headlight Switch: http://forums.sohc4.net/index.php?topic=113986.msg1283236#msg1283236
Branden's leak free top end thread: http://forums.sohc4.net/index.php?topic=107040.0
Engine Lifting Made Easy: http://forums.sohc4.net/index.php/topic,58210.msg1684742.html#msg1684742
                                      http://forums.sohc4.net/index.php/topic,100352.msg1675840.html#msg1675840
Static and Dynamic Timing: http://www.hondachopper.com/garage/carb_info/timing/timing1.html
Airbox Gasket Replacement: http://forums.sohc4.net/index.php/topic,114485.msg1290000.html#msg1290000
"Café" : http://forums.sohc4.net/index.php/topic,84697.msg953814.html#msg953814
PD Carb Choke Linkage: http://forums.sohc4.net/index.php/topic,100352.msg1669248.html#msg1669248
                                    http://forums.sohc4.net/index.php/topic,110931.msg1248354.html#msg1248354
                                    http://forums.sohc4.net/index.php/topic,48858.msg515204.html#msg515204
Follow up on your damn posts: http://forums.sohc4.net/index.php/topic,144305.msg1791605.html#msg1791605
Taiwanese Cam Chain Tensioners:  http://forums.sohc4.net/index.php/topic,155043.msg1774841.html#msg1774841
Gumtwo Seat Cover: http://forums.sohc4.net/index.php/topic,164440.msg1897366.html#msg1897366
Primary Drive: http://forums.sohc4.net/index.php/topic,166063.msg1919278.html#msg1919278
Tank Latch: http://forums.sohc4.net/index.php/topic,165975.msg1919495.html#msg1919495
Shorten your forks: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-shorten-forks-td4042465.html DO NOT CUT THE SPRINGS!
Clutch How To: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-change-and-adjust-a-clutch-SOHC-td4040391.html
Late model K7/K8/F2/F3 front sprocket cover removal: http://forums.sohc4.net/index.php/topic,178428.msg2072279.html#msg2072279
630 to 530 conversion: http://forums.sohc4.net/index.php/topic,180710.msg2094423.html#msg2094423

Sent from my Tandy TRS-80!

Offline MCRider

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Re: any tips for seperating the head from the block
« Reply #7 on: August 18, 2012, 05:30:33 AM »
IMO you have all the bolts out. I would not hit the fins with anything yet (too late). I use a teeny tiny chisel, 1/8 or 3/16",  placed right into the head gasket. Probably in the rear first. Tap it with a solid hammer till you hear the tone change meaning the gasket has let go. Then work around.

Do not go deep with the chisel, just enough for a tone change, 1/4' or less. Last resort to do this, can't be helped.

Usually it just pulls apart.
« Last Edit: August 18, 2012, 05:32:05 AM by MCRider »
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Offline lucky

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Re: any tips for seperating the head from the block
« Reply #8 on: August 18, 2012, 07:42:16 AM »
am i missing something?
 the yellow are the stud nuts i removed
the light blue and orange are the bolts under the puck anf the darker blue are also the bolts
manual Page 87. Illustration #42 Shows 22 nuts and bolts.
2 bolts and 20 nuts.

 so if im not mistaken 16 yellow, 4 light blue and orange, and 2 darker blue makes 22

Looks like you got it right.
When you hit the cylinder block tap it on the sides too because although it has locating dowels there is some movement, and when you tap it from different sides
It will help break the bond. Big wide rubber mallet.

When you hit the fins p or down is when they break.
Just hit the sides.

Offline camelman

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Re: any tips for seperating the head from the block
« Reply #9 on: August 18, 2012, 08:34:59 AM »
I usually tap a thin knife blade between the mating parts in situations like this. Put the edge of the blade in the middle of the gasket and gently tap it. If the parts don't come apart, then you still have a tight bolt in there.

I haven't hurt any mating surfaces by doing this yet and I've used this technique for years.
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