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.

cre · 03-26-2011, 01:14 AM

A non-interference engine is only such as long as the distance between the piston crown and the valves isn't reduced beyond a given point. I don't remember how much room you've got on the 7M before that safety margin is gone.... But, that has absolutely nothing to do with timing.

No, even with slack being pulled up by the idler the timing is still skewed.... You're not removing the slack evenly, just on one side.

BT's right though, the difference is negligible and in most cases not a concern.

El_supracabra · 03-29-2011, 05:37 AM

Thanks a lot guys! that is a bit of a relief about my timing. Ill still keep it in mind though...

so far i have Ohm tested the TPS (tested good but needs adjusted), the ISC valve, the MAF, the primary coil, igniter, all 3 pickup coils, the fuel pump relay (for S&G's) and voltage tested all of my VSV's. Im thinking that i may need to replace my fuel injectors or replace my ECU....

El_supracabra · 03-30-2011, 08:15 PM

well i swapped out my ECU to no effect. I set the TPS using the feeler gauge/Ohm meter method. And double checked my ignition timing. Everything seems to be fine. Ive noticed some improvement, it doesnt stumble until 4500 rpms now, and runs REALLY strong up to that point. Scary strong actually. LOL

I think there is a serious DEMON under the hood just dying to be released......If i could just figure out this stinking problem!!!!!

anymore suggestions are VERY welcome.....

I think my next step is to replace all of my injectors, my fuel pressure regulator and my coil.

My88isGREAT · 03-30-2011, 09:26 PM

I had .020" taken off my head and had absolutely no problem. Did you check the timing? You know it idles at the 10 degree mark and not the 0 degree mark right?

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.

03-26-2011, 01:14 AM	#7
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	A non-interference engine is only such as long as the distance between the piston crown and the valves isn't reduced beyond a given point. I don't remember how much room you've got on the 7M before that safety margin is gone.... But, that has absolutely nothing to do with timing. No, even with slack being pulled up by the idler the timing is still skewed.... You're not removing the slack evenly, just on one side. BT's right though, the difference is negligible and in most cases not a concern. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

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.

03-29-2011, 05:37 AM	#8
El_supracabra Intake Join Date: Feb 2011 Location: South of Columbus, Ohio Posts: 45	Thanks a lot guys! that is a bit of a relief about my timing. Ill still keep it in mind though... so far i have Ohm tested the TPS (tested good but needs adjusted), the ISC valve, the MAF, the primary coil, igniter, all 3 pickup coils, the fuel pump relay (for S&G's) and voltage tested all of my VSV's. Im thinking that i may need to replace my fuel injectors or replace my ECU.... __________________ 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.

03-30-2011, 08:15 PM	#9
El_supracabra Intake Join Date: Feb 2011 Location: South of Columbus, Ohio Posts: 45	well i swapped out my ECU to no effect. I set the TPS using the feeler gauge/Ohm meter method. And double checked my ignition timing. Everything seems to be fine. Ive noticed some improvement, it doesnt stumble until 4500 rpms now, and runs REALLY strong up to that point. Scary strong actually. LOL I think there is a serious DEMON under the hood just dying to be released......If i could just figure out this stinking problem!!!!! anymore suggestions are VERY welcome..... I think my next step is to replace all of my injectors, my fuel pressure regulator and my coil. __________________ 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.

03-30-2011, 09:26 PM	#10
My88isGREAT Stock Join Date: Mar 2011 Location: somewhere Posts: 15	I had .020" taken off my head and had absolutely no problem. Did you check the timing? You know it idles at the 10 degree mark and not the 0 degree mark right?

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