Question on milled heads - Toyota Nation Forum : Toyota Car and Truck Forums

lexusmech · 02-03-2005, 08:04 PM

I have a 2vz motor that I'm semi building up. I had the heads milled .010 to up the compression from 9.0 to 9.4/5 range. I was later informed that this might affect my cam timing.

Has anyone had experience with this? I haven't found aftermarket cam gears for this motor so I might be stuck with what I have. Any insight or info would be appreciated.

If you're already thinking about the valves hitting, then if you saw the pistons you'd know they're not going to hit. They're dished pretty good and the pistion still has a 1/8 till it tops out to the block surface. Specs from the factory say something about .020 max removed anyhow so I think I'm ok.

CrawlingEye · 02-03-2005, 09:49 PM

I'm interested in hearing the final word on head milling. I was debating milling my head to gain some CR without having to worry about the added weight of higher-CR pistons (and cost).

alltrac165 · 02-05-2005, 09:16 PM

On the 22R, if you remove a total of .020, it retards the cam timing by 2 degrees, or 4 degrees of crank rotation. So assuming that all remains roughly the same on your engine(overhead cam with a cam gear of about the same diameter), you would have lost about 2 degrees crank rotation. Retarding the cam effectively reduces your compression at low rpm which hurts low end power so it's not a great scenario. 2 degrees isn't a WHOLE lot but still, might want to look into adjustable cam gears. Or, if you can degree the cam and find out how much it has moved, you could possibly have your crank gear re-machined with a new keyway to bring it back to correct timing.

Toysrme · 02-05-2005, 09:28 PM

Ummmm I hate to tell you, but all of the VZ family has a CR between 9.4 and 9.6-1
If memory serves me correct (and a2vz-fe owner) a 2vz-fe's start out with a 9.4 CR.

It's not going to do anything with the timing. It will ADD a tiny bit of slack in the belt, which is going to be immediately taken back out via the hydrolic tensionor. Thus-Hence-Forth the timing will remain identical!

We's so smaaaaat!

Forget decking/milling. Spend the $100 on a metal gasket that never blows, and have the guys port and polish the thing.

You'll be the first that's done it on a 2vz-fe that I know of, which pretty much means world-wide. You'll probably get 20-25hp out of it. That'll bring you into the first gen 3vz-fe and 1mz-fe hp figures. (torque no, hp yes)

lexusmech · 02-06-2005, 01:15 AM

Well to start, I know for sure the 2vz has 9.0 CR. I work at Lexus and have access to factory manuals. The 3vz went to 9.6 CR.

I discussed this with several mechanics at work and they helped enlighten me.

As for the metal gasket, since there are very few options for this motor, I bet finding a metal gasket would be very tough unless the 3vz metal gasket would work (they have the same bore, and if they have a metal gasket for that motor) To late anyhow, I already milled the heads. I did some port matching already. Polishing to me is not worth the money unless you're racing.

And yes the tenstioner does take up the extra slack, but the distance from centerline to centerline of the cam and the crank has changed. Since the tension will stay the same, the rotation of the cam/crank will take up the difference in length.....we's almost so smaaaat. Imagine the block and tackle setup on a hoise. To change the distance between the two pullyes, one of the pulleys must rotate.

The 22R is a 4 banger, so the .020 in travel is directly pointed to the crank. In the V6, the .010 is pointed inward, so for discussion, only .005 might only be the difference from crank to cam centerline. On that assumtion, the difference would be .5 degrees of cam timing.

As for HP, the 3vz is .5 L larger, runs 9.6 CR and is 30 HP more. I'm hoping for 15 hp more. I bought a balanced motor and an aluminum flywheel so hopefully that will free up a few more.

I looked for adjustable cam gears for my motor and didn't find any. I know the dia. and tooth count is the same as a 1mz, but the offset of the gear is different. Mostly I would want the cam gears to tune the motor. Then have Jetspeed rewrite the ECU. Man that would be sweet. In the future maybe.

CRAWLING EYE- find if you're engine is an interference engine. If it is, you might be SOL. To calculate the change in CR, calculate the combustion chamber volume. This is cylinder volume divided by stock CR. Then divide the cylinder volume by desired CR. Subtract desired comp. chamber volume from stock camber volume to get difference. Divide the difference by cylinder bore. That will yield amount to mill.

alltrac165 · 02-12-2005, 05:02 PM

Quote:

Originally Posted by lexusmech

(snip)

And yes the tenstioner does take up the extra slack, but the distance from centerline to centerline of the cam and the crank has changed. Since the tension will stay the same, the rotation of the cam/crank will take up the difference in length.....we's almost so smaaaat. Imagine the block and tackle setup on a hoise. To change the distance between the two pullyes, one of the pulleys must rotate.

The 22R is a 4 banger, so the .020 in travel is directly pointed to the crank. In the V6, the .010 is pointed inward, so for discussion, only .005 might only be the difference from crank to cam centerline. On that assumtion, the difference would be .5 degrees of cam timing.

(snip).

Ditto what you say on timing retard. Since the tensioner only takes up slack on one side of belt/chain, it MUST rotate a gear to absorb slack on the other side.

On the head bit, each bank of the V6 should be inline with the crank. Each head gasket surface, or deck, should be square with the crank as well. As a result, if you mill the head .010, then that should move the cam gear .010 closer to the crank. Assuming the cam gear is driven from the crank like every other engine I know of, then you would see the same retard as an inline would, assuming the gears are similarly sized.

lexusmech · 02-12-2005, 08:59 PM

The mating surface of the head points inward, not directly at the crank. i.e. the shortest distance between two points is a straight line. Well the .010 removed wasn't as straight line to the crank which is why the whole .010 wasn't applied to the total of retarding the camshaft.

If the heads were 45 degrees to crank centerline, then thats halfway between horizontal and parallel, which would half the .010. I want to say they're actually 60 degrees from the crank centerline so that would be around .060.

Nevertheless...I don't think it will be problem. I do want adjustable cam gears though just to tune the motor more. What sux is you can't adjust the exhaust because its tied to the intake cam internally.

alltrac165 · 02-13-2005, 04:47 PM

^well you can't adjust the exhaust independantly of the intake anyway, but it will advance and retard WITH the intake.

So you're saying that the deck is not perpendicular to the piston bores? The only engine I know of that is like that is the VW VR6 which is a weird little animal in itself. The pistons must travel directly away from and towards the crank centerline in a single plane and the deck is almost always totally perpendicular to that. In a V configuration, the crank is at the bottom of the V and the heads at the top. On a 60 degree V6, that angle of the V is 60 degrees. So yeah, each head is at an angle like 30 degrees from straight up and down, but so is the deck of the block and the bores so the deck is still square with the crank. The crank is not directly vertically under the head, it's off to the side between both heads. I'm not sure I understand your engine if it's different from that. Now, granted, the cam gear is probably not dead center of the head if its DOHC so it wont travel DIRECTLY towards the crank, but that difference is so small it's not worth trying to figure out.

Here's a bare V6 block
http://images.google.com/imgres?imgu...D%26ie%3DUTF-8

here's a diagram of a toyota 1MZ
http://images.google.com/imgres?imgu...UTF-8%26sa%3DN

Forgive me if you have something different, but I've never heard of such a thing by Toyota.

lexusmech · 02-14-2005, 10:52 AM

Yeah after looking at it closer, Yep, I'm wrong. Not sure what I was thinking. So on that note:

I guess my cam timing will be retarded 1 degree? Damn, my engine is retarded! Well I'd still like to work on getting adjustable cam gears. I think the outter gear dia. and width is the same for the t-belt so If I could get the centers made or something (I have a friend thats a machinist), and use the outters from a 2JZ or something, that would be cool.

Toysrme · 02-14-2005, 02:37 PM

Well... You could just take the valve covers off and slip the exhaust cams a tooth. If 2vz cams use the same gearing as 3vzfe cams, be aware that is a +/- 18* change!

You could get that to work if you could find adjustable gears with 25* of play however...
You're right on the 2vz's having a 9:1 CR too. My bad.

Why, exactly, do you want adjustable cam gears? There is so much dyno tuning to find so little power.

Pineapple · 02-14-2005, 02:43 PM

Quote:

Originally Posted by lexusmech

Yeah after looking at it closer, Yep, I'm wrong. Not sure what I was thinking. So on that note:

I guess my cam timing will be retarded 1 degree? Damn, my engine is retarded! Well I'd still like to work on getting adjustable cam gears. I think the outter gear dia. and width is the same for the t-belt so If I could get the centers made or something (I have a friend thats a machinist), and use the outters from a 2JZ or something, that would be cool.

Cut out center of stock T-belt pulley. Leave enough from the spokes for bolts. Get your friend to machine an Alum center hub with radial slots. You got yourself a light weight adjustable pulley

SmokingTires · 02-14-2005, 10:12 PM

Quote:

Originally Posted by Toysrme

Ummmm I hate to tell you, but all of the VZ family has a CR between 9.4 and 9.6-1
If memory serves me correct (and a2vz-fe owner) a 2vz-fe's start out with a 9.4 CR.

9.2:1 here!

lexusmech · 02-14-2005, 11:03 PM

Pineapple- whats funny is before I read your post i was thinking about that. I might use the original hub too. I've got it all worked out in my head how I think it will work.

The main thing is actually putting it on a dyno to tune the cam and ignition. Jetspeed said they can reprogram the computer, but if you change cam timing, how can you just "plug" in ign. timing....? I'd like to see if I can unlock some HP in the engine, but how much will I get for all that $$ and trouble?

CrawlingEye · 02-14-2005, 11:38 PM

jetspeed's crap. if you want ignition timing, use an msd ignition and their digital ignition computer or go with EMS.

either way, to conclude everything, I'll be running 10-1 CR in the summer, or if I have the funds to drop the new head in sooner, then maybe spring. trying to do as much as I can in as little time as I can. we'll see what happens, hopefully my plans will work out as I hope.

Toysrme · 02-14-2005, 11:46 PM

I also have still never heard of anyone being able to reprogram non-common perofrmance Toyota ECU's. So I'm with smoking saying it's bullshit.

lexusmech it's easy... You program more advance into the signal to off-set it. That, however, doesn't fix the fact that the cam timing is off. You'll get very little. There is a review of cam gears on a 3.0L Maxima. It gained at best 3hp...

Find my 3vz-fe SMT-6 install thread if you want to play with things.