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

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?

cre · 03-31-2011, 12:56 AM

If it's bogging under ~4KRPM then check all the vacuum plumbing under the intake plenum. A problem with the ACIS system will cause sluggishness at lower RPM.

Yes, 10?BTDC with the diagnostic jumper in place.

My88isGREAT · 03-31-2011, 01:49 AM

supracabra, did you set the cam position sensor back to where it needs to be when the motor is TDC before you installed it? Sounds like something simple that your missing. You don't need to jumper anything to check timing, just hook up timing light to #6 plug and see if it is running at 10 before TDC

El_supracabra · 04-01-2011, 03:30 PM

LOL @ my88isgreat When i FIRST posted that i had set it on 0* i didnt know that. But a couple days later, i was reading on cygnusx1 and discovered that interesting little tidbit. I set it correctly, but its still not running perfect. I think i am going to start throwing parts at it.

cre · 04-01-2011, 07:58 PM

I wouldn't do that...

First I would try bypassing the fuel pump relay and resistor (passenger fender) as it switches around 4K.... if that doesn't do anything either I'd take it from the top:

Remove the timing belt cover, loosen the tensioner and slide the timing belt off. Make sure that the dowel for each cam and gear is in the center hole on both cam and gear. Remove the #1 spark plug and place a 12" dowel in the hole, rotate the crank until the dowel stops moving upward and check to see if the 0? mark on the harmonic balancer is correct. After you verified that all the indicators are accurately pointing to 0? pull the CPS and reset it (again :P ); See the FAQ for a thread on setting timing it has a picture showing where the CPS internals should be pointing once the CPS is installed so you can make sure it didn't skip a tooth on you.

Go back over the wiring. Disconnect and inspect every plug/socket; Unbolt every ground and clean them all very thoroughly with sandpaper... The same for the face of the head/block/chassis that they bolt to and even the flange of the nut. A couple common mistakes here are people not bolting down all of the grounds on the back of the intake plenum or forgetting one of the wires on the back of the head on the exhaust side (especially the black wire with yellow stripe that bolts to the fire wall).

Inspect the vacuum lines and routing. Make sure the lines for the fuel pressure VSV are all correct.

03-26-2011, 01:14 AM	#2
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 --->

03-29-2011, 05:37 AM	#3
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	#4
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.

04-01-2011, 03:30 PM	#8
El_supracabra Intake Join Date: Feb 2011 Location: South of Columbus, Ohio Posts: 45	LOL @ my88isgreat When i FIRST posted that i had set it on 0* i didnt know that. But a couple days later, i was reading on cygnusx1 and discovered that interesting little tidbit. I set it correctly, but its still not running perfect. I think i am going to start throwing parts at it. __________________ 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.

04-01-2011, 07:58 PM	#9
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	I wouldn't do that... First I would try bypassing the fuel pump relay and resistor (passenger fender) as it switches around 4K.... if that doesn't do anything either I'd take it from the top: Remove the timing belt cover, loosen the tensioner and slide the timing belt off. Make sure that the dowel for each cam and gear is in the center hole on both cam and gear. Remove the #1 spark plug and place a 12" dowel in the hole, rotate the crank until the dowel stops moving upward and check to see if the 0? mark on the harmonic balancer is correct. After you verified that all the indicators are accurately pointing to 0? pull the CPS and reset it (again :P ); See the FAQ for a thread on setting timing it has a picture showing where the CPS internals should be pointing once the CPS is installed so you can make sure it didn't skip a tooth on you. Go back over the wiring. Disconnect and inspect every plug/socket; Unbolt every ground and clean them all very thoroughly with sandpaper... The same for the face of the head/block/chassis that they bolt to and even the flange of the nut. A couple common mistakes here are people not bolting down all of the grounds on the back of the intake plenum or forgetting one of the wires on the back of the head on the exhaust side (especially the black wire with yellow stripe that bolts to the fire wall). Inspect the vacuum lines and routing. Make sure the lines for the fuel pressure VSV are all correct. __________________ 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, 09:52 PM	#1
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.

03-30-2011, 09:26 PM	#5
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?

03-31-2011, 12:56 AM	#6
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	If it's bogging under ~4KRPM then check all the vacuum plumbing under the intake plenum. A problem with the ACIS system will cause sluggishness at lower RPM. Yes, 10?BTDC with the diagnostic jumper in place. __________________ 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 --->

03-31-2011, 01:49 AM	#7
My88isGREAT Stock Join Date: Mar 2011 Location: somewhere Posts: 15	supracabra, did you set the cam position sensor back to where it needs to be when the motor is TDC before you installed it? Sounds like something simple that your missing. You don't need to jumper anything to check timing, just hook up timing light to #6 plug and see if it is running at 10 before TDC

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