Non interference engine proof

[weeJohn]

It has been asked and stated a few times so I decided to do some measuring while I had everything apart.

With the intake valves fully open and stock 4efte (7.2mm lift) cams in, the valve protrude past the face of the head 4.9mm (once skimmed head).

With the intake cams fully open and 5efhe (8.0mm lift) cams in, the valve protrudes past the face of the head 5.7mm (once skimmed head).

With the pistons at top dead center, the bottom of the valve pockets are 5.0mm below the face of the block (once skimmed face)

So when you add in the 1.2mm standard head gasket, the pistons can never come into contact with the valves (even with 5efhe cams and both the head and the block skimmed).

Doing the math, using a TRD 0.6mm head gasket COULD remove the clearance built in by Toyota, so the engine stops becoming non interference, but as I dont know how much has actually been skimmed off my head and block, I cant say for sure. The same goes for using high lift (8.2mm +) cams.

I hope this helps rather than worries people, but its been asked a lot so I thought some info was better than none.

 

[Ted]

rotating mine round with belt off (0.6mm gasket) piston hits valves. guess its something to think about when choosing a 0.6mm gasket. good work there fat boy.

 

[AdamB]

Lads what pistons you using?
Surely it makes a difference as I thought forged pistons have larger valve cuts?

 

[weeJohn]

Lads what pistons you using?
Surely it makes a difference as I thought forged pistons have larger valve cuts?

Forged Wossner pistons, listed as lowering compression to 8.0:1, Bulimia boy above there has Weisco 10cc dished ones in his.

The cut outs for the valves were the same depth on my forged pistons as they were on a stock set.

 

[gorganl2000]

excellent info weejohn
i'll be saving that for future reference

what interesting names you guys call each other...lololol

 

[Skalabala]

Buddy can you please clay the valve reliefs when engine is timed and turned? Pretty please?

 

[weeJohn]

Buddy can you please clay the valve reliefs when engine is timed and turned? Pretty please?

Sorry you have lost me.

 

[AdamB]

Think he wants to know whats the highest valve lift possible without having contact?

 

[Skalabala]

yes or the most lift and head skimmed combo

 

[Skalabala]

or just standard cams, with how much can the head be skimmed?

 

[Skalabala]

Please?

 

[weeJohn]

I cant say for sure because my block has been skimmed and I dont know how much was took off the head.

It was really to prove that in stock form its non interference.

 

[thefalls]

I did the same thing but valves didnt touch the pistons. Block hasnt been skimmed though. Head was skimmed once.
Pistons are wisecos -10cc,dished.

 

[weeJohn]

I did the same thing but valves didnt touch the pistons. Block hasnt been skimmed though. Head was skimmed once.
Pistons are wisecos -10cc,dished.

What head gasket did you have fitted?

 

[thefalls]

0.60mm TRD.

 

[weeJohn]

Same set up as Ted, pretty sure his block was skimmed but.

 

[Skalabala]

John buddy what does the word "but" mean on the end of you sentences?
Was wondering as some people use the supra 75mm piston and have to shave it 3mm!!! And then there is almost no valve reliefs left?