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

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

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.

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.

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

thanks!

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.

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.

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....

:confused::confused::confused::confused::confused: :confused:

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.

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?

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.

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

You're wrong... On both counts. You can only use #6 on the GTE for timing as it runs a wasted spark setup, not so on the GE; You MUST have the engine at normal operating temperatures, no critical diagnostic codes present, and you must jumper TE1 and E1 so the ECU does not adjust the ignition timing and sticks to the programmed map explicitly.

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.

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.

CRE, where do you get the info that you use a dead plug to check timing? How in the hell would you check the timing on a car that is not going to run right or idle with a non-running cylinder, building pressure and not detonating? I do see the thing about jumping the diagnostic though, sorry bout that.
chupacabra, you should have marked your distributor (sorry I said cam position sensor before, scold me) before you pulled all the stuff apart so you knew how it goes together. Like I was saying, and CRE said, you need to check you mark on the distributor before you install to make sure it is lined up. http://www.cygnusx1.net/Supra/Librar...aspx?S=IG&P=19 If it still runs like shit, set it back at TDC, pull out the distributor and try another tooth. Make sure you did not accidentally hook up spark plug wires in the incorrect order first, it could happen if your were not careful.... You said at first (my cams don't line up perfect) neither do mine even before I took the motor apart. The one on the exhaust side was a little to the inside. Here is the pic, if yours is like this there should be no problem. It is hard to see if your not looking at it in person but hope it helps.... I still think its your distributor but I dunno, this is why I don't help people with there stuff. :boring:

http://www.toyota-supra.info/forums/...6/DSCF0018.jpghttp://[IMG]http://i1183.photobucket...6/DSCF0018.jpghttp://i1183.photobucket.com/albums/...6/DSCF0018.jpg

My88isGREAT, it looks like you need to slip your timing belt off and correct your intake cam. It's obviously off by a tooth

As usual, no idea what on Earth you are talking about... RTFM. On a N/A, which is what this person has, you can only use wire #1 to check timing. On a GTE you may use either #1 or #6 as they always fire at the same time; It's called a wasted spark setup. Now go away.

Then stick with it. No need for you to go making exceptions just for us. ;)

It may be the angle of the picture and it may be as close as it's going to get. With older belts (and cheap modern production on new ones) you'll get extra slack on the belt and thus inaccurate tooth spacing.

OK Mr. Smart guy, then how come I have TWO motors and they are EXACTLY the same, the angle on the exhaust is slightly inside, IF I moved it one tooth in either direction it would be totally screwed. As for old belt, it was EXACTLY the same when I put the motor back together with the new one, must be a conspiracy and Gates Racing is in on it too. All I can say is bring your bag of bolts & nuts and put some money on it!!! Its like when I try to help my buddy with his bone stock 77 Camaro 305, runs beautiful, does not even smoke. He ask me "what can I do to get some more power out of it" so I give him some suggestions, but when someone else is there "a hater" they say "Put a 350 in it..." Then he wants to make it look better, so I tell him to put some fatter tires on the back like 10" wides, and clean up the factory rims, they are in beautiful shape. Once again yes "a hater" says "Put some 20"s on it..." So I wont help out any more guys don't worry. Don't want to help out to tell them where the timing should be set if they did not even read the book for themselves to know...:x:

Wow.... piece of work.

He was just going by the pic and due to the angle it DOES look like it could be off a tooth.

As for the belt, yes, some are dead perfect and some a hair off.... That's not a big deal because it's only ever 1? or 2?.

You didn't even know how to set the ignition advance so perhaps you ought to pipe down a little Junior.

I won't cry... I'm sick of posting corrections and missing data after every one of your posts.

ouch.... LOL

anyways...:rofl:

I dont ever remember saying "my cams dont line up"....because they do. perfectly. I triple checked my valve timing, AND my ignition timing.

I really dont appreciate "my88isgreat" implying that I didnt "read the book".
so....:gtfo: not to mention that he said "gates racing is in on it too" does that mean they built your engine for you? cuz i built mine all by myself.

Thanks CRE for the useful information. I swapped out the fuel pump relay and resistor with another one and it didnt change anything. I also put a jumper wire on the TPS connector and checked my fuel cut. according to the TSRM (that i actually read ;-) my fuel cut should be at 1800 then return at 1200. My actual fuel cut is at about 2400 and returns at about 1900. This is actually the only thing i can find "wrong" with the car.

advice?

oh and how do you bypass the relay? by connecting a jumper between +B and PR on the fuel pump relay connector? thanks!!

:dance:Yes they did! thanks for asking! :gotnos:

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.

Here are some photos of a uncut and a cut head. The more you cut a head the flatter that rounded part under the thermostat standpipe connection gets. It's something to look for when buying a head. I had my head and block resurfaced and ended up using an old school metal shim gasket under the Toyota factory gasket. I sprayed the bottom of the shim gasket That contacts the block with Prematex copper spray. After 7 years and 35K miles, I haven't had any issues. Alternatively, you could use a thicker stacked metal head gasket alone but you really need to prepare the surfaces first. Here is a link to a company that can supply most any thickness of shim gasket you want. I wouldn't go of more than 0.040" though. It's been discussed in other forums that a 0.020" cut is a small fraction of a degree out of timing. The Toyota manual allows 0.010 but doesn't say anything more than that.

Innovative machine & supply: https://innomach.com/cylinder-head-shims

WOW! Resurrected after over 11 YEARS!?! :eek2: