3VZ-FE Head Skimming & Compression Ratios

[wood_patrick]

Not done the syringe test yet but just been down a local machining shop.

A 1mm skim they have quoted me £96 inc for both heads, a bit steep but got another couple of places to try yet.

Heavily leaning towards the 1mm slice, but only thing I'm concerned about now is by how much it will throw the cams out of sync from the original position and also each other... It will only be marginal but wondering if its worth getting the pulleys re-machined to compensate or just slap them on and see how I get on? :-/ Probably the latter as pointless spending too much for a test build I suppose.

[wood_patrick]

Found another local shop that wants £40. Much better! :-)

[cdwood2010]

Even the head looked surpised.....

[wood_patrick]

Hahaha. :-)

[snowtigger]

Don't forget to deck the block as well?

[wood_patrick]

Nope. Not doing block. Maybe on the next rebuild but I'm using the heads to remove metal cos if it goes bang I can just weigh a set of heads in and swap them over. Got a spare set (or two) here so worth a gamble for the cause. :-)

If it works then next time might be worthwhile, but I would then take .5 from the head and block to ensure 2 good surfaces.

[cdwood2010]

Reserve your judgement until you've inspected the block face.

Unless it's perfect (like your build) then it's worth getting it decked. The last 3VZ I rebuilt (CamryVan) the block looked like someone had engraved patterns in the block, right where they didn't want to be.

[wood_patrick]

Well if it has to be done then so be it, but hoping I can get away without doing now. :-)

[adamh]

pat i just penciled some stuff, for every 0.1mm you skim, a head will move 0.05mm closer to centre line. as luck would have it, and believe it or not ripley... if you skim 1mm, your heads move 1mm closer together (2 of), of course because 30 deg = 2:1 in trigy 1:1 = 45 etc , i penciled a cam pitch design based on a hypotenuse of 395.6 which is pitch between crank axis and camshaft axis and it changes the relation of the cams to eachother by 1 degree!.

its fair to say if you skim 0.1mm of each head, your heads move together 0.1mm, and your cams index away from eachother by 0.1 deg!.
at some point the 0.1 deg index will start reducing because of arc etc, but for the small skims its pretty linear figure.

The 395.6 i took by scaling a drawing off a toyota manual (superbodge and am proud) , if you could check its roughly 396mm then the inclusive indexing of both cams = 1 degree at 1mm skim. if theres error in my measurement for every 4mm i was wrong it changes the final figure 1%.

the cams are 120.8 PCD i allready took that measurement long time ago. 1 deg that isnt to bad, but some of your bolts on the gaurd might not line up perfectly because the horizontal pitch is changing 1mm, something to consider.

[aussiemr2]

Will the inlet manifold still sit properly in the V with that big a skim?