how does milling the cylinder head affect the valve timing??

El_supracabra · 03-25-2011, 02:22 AM

I milled .020" off of my cylinder head, is this going to throw off my valve timing? do i need adjustable cam gears? please advise.

86.5 mk3 7mge non turbo

907mge · 03-25-2011, 03:04 AM

The 7mge is a non interferance motor to begin with, so no. The only thing it will do is raise the compression a bit.

btwilson86 · 03-25-2011, 07:24 AM

The teeth on the timing belt most likely would not perfectly align due to the shorter gap between cams and crank, so to get timing set perfectly you should use adjustable cam gears. I'm assuming at most they will be a degree or two off, so it may not be very noticeable if you ran without the adjustable cam gears.

El_supracabra · 03-25-2011, 09:41 AM

I see what you are saying....hmm...well, wouldnt you be able to "take up" the extra slack with the idler adjustment?

when i put it in time, i rolled it over 360* and it seemed to line back up perfectly. Would that cause it to completely fall on its face at 4000rpm and spit and stumble? It will BARELY make it to 6000. and only if i HOLD it to the floor.

El_supracabra · 03-25-2011, 09:43 AM

see the thread "the unfixable mystery problem". lol EXACT SAME problem

thanks!

907mge · 03-25-2011, 09:52 PM

I would think that that little amount would not throw off the belt that much. After all it is only 2/100ths of an inch. I would think you probably have another problem.

pishta · 06-04-2022, 05:49 PM

Quote:

Originally Posted by 907mge

The 7mge is a non interferance motor to begin with, so no. The only thing it will do is raise the compression a bit.

Wrong...the cam timing will be retarded because the cam cog will be closer to the crank cog and will roll CCW a smidge. You can only mill an OHC about .02mm before you need to cut and use a "head saver" shim. these are usually .020" an allow a .020 cut on the head or block to preserve factory valve timing.

03-25-2011, 02:22 AM	#1
El_supracabra Intake Join Date: Feb 2011 Location: South of Columbus, Ohio Posts: 45	how does milling the cylinder head affect the valve timing?? I milled .020" off of my cylinder head, is this going to throw off my valve timing? do i need adjustable cam gears? please advise. 86.5 mk3 7mge non turbo __________________ 86.5 Supra NA: milled head .020, decked block .007, .5mm+ pistons, port & polished intake manifold and cyl head,OBX header, 3-angle, cold air intake, Cometic MLS HG. ALL NATURAL! CHEVROLET- Cracked Heads, Every Valve Rattles, Oil Leaks Every Time FORD- Flipped Over, Rebuilt Dodge DODGE- Dirty Old Dust Gathering Engine I'd rather drive a Toyota, than push a ford.

03-25-2011, 07:24 AM	#3
btwilson86 Super Moderator Join Date: May 2007 Location: Billings, Montana Posts: 1,034	The teeth on the timing belt most likely would not perfectly align due to the shorter gap between cams and crank, so to get timing set perfectly you should use adjustable cam gears. I'm assuming at most they will be a degree or two off, so it may not be very noticeable if you ran without the adjustable cam gears. __________________ 1989 7MGTE R154 Targa Top White Package w/Blue Interior Driftmotion 57trim CT26, Upgraded Intercooler, 2.25" Hard Pipes, 3" Turbo Back Exhaust with Test Pipe, HKS VPC w/GM 3 bar MAP sensor, APEXi S-AFC, Walbro 255lph fuel pump, ProSport EVO Series Boost / Fuel Pressure / AFR gauges, Lotek a Pillar Gauge Pod, HKS Type 0 Turbo Timer, Eibach Lowering Springs, Tokico Illumina II TEMS struts, custom powder coated Motegi Racing TrakLite wheels

03-25-2011, 09:41 AM	#4
El_supracabra Intake Join Date: Feb 2011 Location: South of Columbus, Ohio Posts: 45	I see what you are saying....hmm...well, wouldnt you be able to "take up" the extra slack with the idler adjustment? when i put it in time, i rolled it over 360* and it seemed to line back up perfectly. Would that cause it to completely fall on its face at 4000rpm and spit and stumble? It will BARELY make it to 6000. and only if i HOLD it to the floor. __________________ 86.5 Supra NA: milled head .020, decked block .007, .5mm+ pistons, port & polished intake manifold and cyl head,OBX header, 3-angle, cold air intake, Cometic MLS HG. ALL NATURAL! CHEVROLET- Cracked Heads, Every Valve Rattles, Oil Leaks Every Time FORD- Flipped Over, Rebuilt Dodge DODGE- Dirty Old Dust Gathering Engine I'd rather drive a Toyota, than push a ford.

03-25-2011, 09:43 AM	#5
El_supracabra Intake Join Date: Feb 2011 Location: South of Columbus, Ohio Posts: 45	see the thread "the unfixable mystery problem". lol EXACT SAME problem thanks! __________________ 86.5 Supra NA: milled head .020, decked block .007, .5mm+ pistons, port & polished intake manifold and cyl head,OBX header, 3-angle, cold air intake, Cometic MLS HG. ALL NATURAL! CHEVROLET- Cracked Heads, Every Valve Rattles, Oil Leaks Every Time FORD- Flipped Over, Rebuilt Dodge DODGE- Dirty Old Dust Gathering Engine I'd rather drive a Toyota, than push a ford.

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03-25-2011, 03:04 AM	#2
907mge 20psi boost Join Date: Dec 2009 Location: Harrisburg Posts: 759	The 7mge is a non interferance motor to begin with, so no. The only thing it will do is raise the compression a bit.

03-25-2011, 09:52 PM	#6
907mge 20psi boost Join Date: Dec 2009 Location: Harrisburg Posts: 759	I would think that that little amount would not throw off the belt that much. After all it is only 2/100ths of an inch. I would think you probably have another problem.