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shaving the head
Topic Started: Jul 28 2014, 07:28 PM (1,626 Views)
Beer4Blood
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So time has come to rebuild my g10 that got fried by an oil pump failure. I've already shaved .040" off my head. Curious if I can go another .040" with out trouble?? And what would my final compression be relatively with a total .080" missing??? If it's a bad idea what would you recommend??? Thanks
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econoboxer
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I am the one on the left.

not likely.

part of what determines if you can, is if your pistons sit below or above the block.
The head gasket is abt 0.032, give or take- if you are in the hole on your pistons, you m-i-g-h-t be able to. If you have a zero deck or positive piston to bore clearance- you will more than likely smack a valve with your piston- and will not likely be able to run pump gas, also- your timing belt tensioner may not be able to take out the slack- and you'll need a bigger pulley. Measure your combustion chambers to see where you are- but- I don't think its a good idea- personally

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freegeo
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I know I have read were you can safely take off .050" from stock height. Anything after that you better check things out really well for interference.

You usually only need to take off as much as needed to true and clean up the head or block to get it flat.
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Beer4Blood
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Well I seem to recall the wizard of g10s telling me you can shave up to ,100" but you start to get into engine studs. I'll have to check but it's my understanding the g10 is a non interference engine....
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freegeo
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In stock size it is a non interference engine.

This is a statement from the Johnny Mullet's head repair guide.

First thing before going any further is to get a straight-edge and make sure the head is not warped. If so, then get it milled at a machine shop. You can safely take off up to .050 or more.

Your right it can be more than .050", but how much more. You should really do some calculations on the engine before just have more taken off.

I believe I asked a question about my head and a pit in it. If you take off too much your timing belt won't tighten up properly. You would have to look into getting a oversized tension pulley.
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Car Nut
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When I first saw your topic heading, a picture of a bald guy appeared in my minds eye. :lol
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Beer4Blood
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So where does one acquire an oversized tensioner
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David95237


off of a 1.3.
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clarkdw


Assemble the cam in the head. Put valves on maximum lift and measure them to the head surface. Assemble the bottom end. Measure deck height. Add head gasket compressed thickness, mine is about 0.040".

Add and/or subtract the numbers to give you the clearance or interference. This will tell you whether it will be an interference or non-interference assembly and allow you to calculate the maximum resurfacing before it becomes interference. If it is interference you need to assemble the complete unit and check with the cam timing set where you want it. My vert has 0.050" off and is not even close.

I am using the stock tensioner at maximum adjustment. My belt is as loose as you would want to run it. It can be taken off and put on without touching the tensioner. The 4cyl G13 tensioner is larger. I am not sure if it is too large. I never got around to trying one on my engine. The loose belt has never given trouble or timing variations so I just left well enough alone.
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Justahoby
Unqualified informant

Beer4Blood
Jul 28 2014, 07:28 PM
So time has come to rebuild my g10 that got fried by an oil pump failure. I've already shaved .040" off my head. Curious if I can go another .040" with out trouble?? And what would my final compression be relatively with a total .080" missing??? If it's a bad idea what would you recommend??? Thanks
Im doing it on a stock G10 (about .080")and a thinner fel pro gasket... no worries here
Edited by Justahoby, Jul 29 2014, 12:00 PM.
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econoboxer
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I am the one on the left.

clarkdw
Jul 29 2014, 11:51 AM
Assemble the cam in the head. Put valves on maximum lift and measure them to the head surface. Assemble the bottom end. Measure deck height. Add head gasket compressed thickness, mine is about 0.040".

Add and/or subtract the numbers to give you the clearance or interference. This will tell you whether it will be an interference or non-interference assembly and allow you to calculate the maximum resurfacing before it becomes interference. If it is interference you need to assemble the complete unit and check with the cam timing set where you want it. My vert has 0.050" off and is not even close.

I am using the stock tensioner at maximum adjustment. My belt is as loose as you would want to run it. It can be taken off and put on without touching the tensioner. The 4cyl G13 tensioner is larger. I am not sure if it is too large. I never got around to trying one on my engine. The loose belt has never given trouble or timing variations so I just left well enough alone.
:gp

clark said it best.

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econoboxer
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I am the one on the left.

clarkdw
Jul 29 2014, 11:51 AM
Assemble the cam in the head. Put valves on maximum lift and measure them to the head surface. Assemble the bottom end. Measure deck height. Add head gasket compressed thickness, mine is about 0.040".

Add and/or subtract the numbers to give you the clearance or interference. This will tell you whether it will be an interference or non-interference assembly and allow you to calculate the maximum resurfacing before it becomes interference. If it is interference you need to assemble the complete unit and check with the cam timing set where you want it. My vert has 0.050" off and is not even close.

I am using the stock tensioner at maximum adjustment. My belt is as loose as you would want to run it. It can be taken off and put on without touching the tensioner. The 4cyl G13 tensioner is larger. I am not sure if it is too large. I never got around to trying one on my engine. The loose belt has never given trouble or timing variations so I just left well enough alone.
:gp

clark said it best.

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perfesser
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Elite Member - Former Metro owner

When you move the head down that much, you are also changing the cam timing, so you'll need clark to get you a cam sprocket with the right holes added.

He milled my head 0.040" when he was rebuilding it. It moved the cam timing 8-10 degrees and bumped the CR by about half a point. It runs like a dream!
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clarkdw


perfesser
Jul 29 2014, 01:06 PM
When you move the head down that much, you are also changing the cam timing, so you'll need clark to get you a cam sprocket with the right holes added.

He milled my head 0.040" when he was rebuilding it. It moved the cam timing 8-10 degrees and bumped the CR by about half a point. It runs like a dream!
Actually it is Mike Cove who takes care of all the cam and sprocket end of 3Tech and until recently, all of 3Tech's products. I am the late comer and merely "follow the leader".
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Beer4Blood
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Justahoby
Jul 29 2014, 11:58 AM
Beer4Blood
Jul 28 2014, 07:28 PM
So time has come to rebuild my g10 that got fried by an oil pump failure. I've already shaved .040" off my head. Curious if I can go another .040" with out trouble?? And what would my final compression be relatively with a total .080" missing??? If it's a bad idea what would you recommend??? Thanks
Im doing it on a stock G10 (about .080")and a thinner fel pro gasket... no worries here
done it before or first time out?? and what about this dreaded belt slack??
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