Newbie question - engine build options

[m1tch]

Hi all,

My mechanical skill is fairly average but I am looking to learn a bit on my project car - as its not a daily drive, I have moved from being unsure how to change spark plugs to now where I am confident enough to change suspension, do all service tasks, remove rocker covers, intake pipework, exhausts, cylinder head rebuilds etc basically things that can be unbolted and bolted together again. As mentioned I wanted to learn a bit more using this project car, mainly around engine tuning and building, as its not a daily drive I can take my time and not rush with measuring tolerances etc.

Anyway, I was initially going to go with a 2zz swap but am now looking to simply boost the stock 1zz engine instead as when I chose a project car I didn't really want to go an engine swap (but the fact the 2zz is a bolt in is handy!), I know that leethesparky's car is running on stock internals with good power at low boost so at least I can initially go down that route.

I do however know that the stock rods aren't exactly the best when sat next to stock 2zz rods so I am looking to swap them out, for me the good news is that I can swap out rods and pistons with the engine in - to be honest I am a bit scared about such a massive job as to drop an engine and box so I like the idea of keeping the engine in and simply unbolting the head and sump.

I know that the stock pistons are highish compression so not ideal for higher boost due to detonation, so ideally I would want to swap out both pistons and rods, my issue is that the engine is fairly high mileage and the aftermarket pistons start from 79.5mm eg 0.5mm oversized.

I am just wondering if I would be able to run the slightly larger pistons in the slightly worn bore and simply rehone the bore without needing a complete rebore (as it would need the engine to be removed) - I would of course check the specs on the bores anyway to see what sort of wear the engine current has but was just wondering if its even an option.

I guess for me there are a few options:

Boost the stock engine as is on low boost
Change out the stock rods for uprated rods but stock pistons
Change out the stock rods for uprated rods with lower compression pistons but rehone only (if this would even work)

The other option I guess would be to boost the stock engine on low boost and then build up another 1zz engine in the garage and bite the bullet and drop the engine so I can then change flywheel, clutch and maybe upgrade the gearbox with better 3rd and 4th gears.

I guess I am just looking to see how far I can go without needing to drop the engine, I think it might just be a bit scarier than I think due to the fact that the stock engine bay is kinda crammed with pipes.

I am aware its a very newbie question but just wanted to ask everyones opinion, I am aware that I am trying to cut corners slightly without taking the engine out, just building up my confidence to try something a bit more serious as I don't want to get stuck half way and then not be able to get to the car on the road etc. Tempted to go down the spare 1zz engine route and upgrade the box so everything is together to slot back into the car straight away.

[ChrisGB]

Until you can measure the bores, you won't know how to proceed. Oversize pistons means a rebore, but until you measure the bores, you won't know if it needs a rebore.

[jonbill]

I think 'engine in' is ok for replacing bearings and piston rings, anything else I think needs to be done properly.
I think getting a spare and building that sounds like a good option.

[Carolyn]

Just a couple of points on a subject that many on here know loads more than I.

If you're going to do any serious engine work, take it out of the car.  Just getting the head off in the car is something you will only do once, I promise.

There are plenty of well boosted 1ZZs out there that don't have special rods or pistons.

I agree with both Chis and Jon.

[m1tch]

Just a couple of points on a subject that many on here know loads more than I.

If you're going to do any serious engine work, take it out of the car.  Just getting the head off in the car is something you will only do once, I promise.

There are plenty of well boosted 1ZZs out there that don't have special rods or pistons.

I agree with both Chis and Jon.

Thanks for the help on this, wasn't sure how fragile the OEM pistons and rods were and good to know that removing the head isn't the easiest with it in the car. I think I might look to boost the stock engine (oil drain in the easy to remove sump) and see how it goes. I will then look to build up a better engine in the garage and take my time over it, will also look to uprate the box at the same time so that when I do swap over the engines its reliable at the higher power levels - which would be the end game for the project car as I am planning on keeping it long term.