Forum » General Engine Building Discussion » Time Attack 2JZ-GTE VVT-i build questions

Time Attack 2JZ-GTE VVT-i build questions

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i am building up a 2jz for use in time attack and I had a few questions now that i have things taken apart (photos included). I do not have access to a machinist right now due to the great lock down of 2020. I am hoping that people could help me with a little bit of experience here. Piston 1 and 5 have metal flakes on the top of the pistons, but the engine turns just fine and did "run" before i pulled it out of the car, albeit with quite a bit of blow by.

I was hoping that you could give me a little help picking out pistons and rods, especially when it comes to piston size due to how much work you think might need to be done for the cylinder walls.

A little bit about goals, I am going to attempt to reach right around 1000 horsepower, preferably on pump as i can find it anywhere, but I do have access to e85 locally to me if need be. I will be using the OEM crank and probably cams.

other things that i would love some help on, helping with valves, springs, retainers etc...

I do have a decent budget, not super crazy, but also not traveling this year for racing has allowed me to divert budget to rebuilding my backup/level up engine.

Thanks in advance for your help.

p.s. sorry for such large images. Came right off phone. Also including them in a file attachment to the post.

piston 5 with some cylinder wall

[img="blob:" alt=""]

piston 5 close to top[img="blob:" alt=""]

piston 1 close to top[img="blob:" alt=""]

piston 1 with exposed cylinder wall[img="blob:" alt=""]

I believe you will need to upload those images to a hosting service, then post a link to them - they don't work using the method you used.

A flaking appearance is usually a sign of detonation, there may also be corresponding marks on the head.

I would strongly recommend you using bigger camshafts for your power goal as stock camshaft will take you nowhere but breaking things up (especially on pump gas) because of very high dynamic CR.

Thank you for the responses. I have uploaded the images to imgur so you can view them

Cylinder 1 at top

Cylinder 1 with wall exposed

Cylinder 5 at top

Cylinder 5 with wall exposed

@georg1970 I could be wrong, but i have been told the factory cam would make, but I am open to getting a new one. Can you (or anyone) make some suggestions? I do have a few requirements that I would like to keep in mind.

1. I want the engine to stay a non-interference engine so there is a limit on lift, I am just not sure what that is (id love to know if you do)

2. I know changing the lift and duration changes the requirements for springs and retainers etc. I would like to know what I should be looking for there.

Thanks again for your help

Factory cam would make it but with a great chance of stressing out head components or even breaking them. I would go for hks272 cams- there are 4 builds around here successfuly using these cams with 1000+ hp and they get the job done perfectly. Especially in time attack where you rev your engine high most of the time - the stock cam would not give you the wild top end power band you need.

Goodness, I don't think I've seen such damage with the engine still running.

Basically detonation, and possibly a slightly lean mixture, has caused the piston to overheat and throw of tiny particles of molten aluminium, that is adhering to the cylinder walls - what condition is the head in, as usually there is corresponding damage there.

@Gord the head looks just fine. No issues there. None of the.metal flake like on the pistons. The top of the walls and pistons is all I have found so far. My next plan is pulling the pistons and looking at ring lands and rings.

@georg1970 thanks for the recommendation on the cam. Can you also recommend some valves and springs or at least what I should be looking for there?

Thank yoy

Ferrea, Brian Crower would be just fine...