Building a 4AGE - Seeking some advice.

[Killswitch]

Hey all, realise this is a far from new topic. Searched a bit and found some info, but just after some reassurance I'm heading in the right direction!

I have a JDM Bigport 4AGE that will be going into my KE70, there are just a few things I'm not sure about that I'd like some feed back on. Hoping for a reliable, revvy fun engine with a bit more power over stock.

Will be going 0.5 or 1mm oversize cast pistons due to rusty bores, would prefer a higher compression ratio - would be great if someone could recommend a brand/part number. Don't wanna stuff around with rebushing smallport pistons. Assuming I run better fuel, will the stock ECU (JDM if that makes any difference?) be happy running higher compression, if so... how high?

I realise I need new head bolts due to stretching, but what about rod bolts and other fasteners?

I should be right on cleaning up the head to help flow, but unsure whether or not to bother with new valve springs, and if so, to go heavy duty or not. Currently won't be running aftermarket cams, but might later on. Have no idea about the previous life of this engine though. Have decided to spend cam money on an aftermarket light flywheel instead due to the ECU's limitations!


Last but not least, I would love to have the bottom end balanced but up here in Darwin theres not a lot of options. I understand this is fairly important for reliability at high rpm and the like, but if I choose not to do this how great an effect will this have on character i.e. how it revs and also the reliability of the engine?



Sorry for the random questions, I believe I have the rest of everything sorted and just wanted some confirmations before I order parts soon.


Thanks

Danno

[TooF]

all new bolts (mains, rods, head, fly)

the small port pistons are faily decent pistons and not obnoxiously expensive. 10.3 ?(iirc)

pull the head off and have a look at the condition of it. if its got lots of miles a regrind and reshim is in order. balancing is defiantnyl worth doing but i cant say who up there can help you out.. go talk to your local machineshop or enigne builder and they will be able to help you out.

id suspect there will be someone that can do it.. even if it is at what seems like an odd joint. goto who ever locally rebuilds diesel/truck/heavy equip motors. i imagine there will be someone in darwin supporting the local minerals industry doing that sort of work.

[Ben Wilson]

TooF - The smallport pistons use a larger small end than the early rods.

You can use the standard pistons and shave the head to bring the compression up.

[TooF]

ah sorry i didnt read that wel.. if you have JDM 18mm/40mm engine then im not 100% sure what piston options are around. have you considered moving to a 20/42mm crank and rods ?

[feral4mr2]

has the engine already been pulled down to see if it in fact the smaller internal 4age?

10.5:1 c/r smallport pistons work great in the vermins bigport.



o/t... i should get up to darwin again sometime... is the birth place of my ownership of the feral.

[30psi 4agte]

What sort of budget do we have to play with ?

[Killswitch]

Engine hasn't been pulled down yet, currently sitting without the head off. thats aboot it, will be attacked later this week once the parts car is stripped and taken to the crusher. If once stripped it will take the small port pistons then my piston problem is solved, not keen on forking out for another crank and rods.

Otherwise, will shaving the head to bump compression up to say, 10:1 to 10.5:1 have any adverse effects?

I don't have a massive budget, the less the better but will be attempting to do it once and do it right so will spend the money where needed. Would really prefer to stay under $1500, but as said I have more money and will spend it if required! I believe I have access to cheap machining(but quality), which will help a fuckton but this will be confirmed later this week.

Thanks so far

[30psi 4agte]

Ok
Well id go with new head bolts and possibly rod bolts if there is money left after gaskets, rings, machining etc etc.

Cleaning up the ports/ port matching is an old school trick but one that is a must
Leave the cams and valve springs std. They wont give any dramas. You can still put cams in later if you decide too and keep the std springs providing you keep the lift to under 8.35mm. There are HKS cams around that give good results and keep within this margin. So you can save some $ there.

As for geting it to perform ...... what sort of external hardwear do you have.
Exhaust / extractors ?
Air intake ?
These things can found relativley cheap and can provide good gains in response and power.

I dont know if i would even bother to go with a aftermarket flywheel. I dont think the advantages are worth the cost unless chasing every last hp and cost isnt an option...... Even then i dont know if its worth it ----- but thats just me

Mabe this money could be spent on rod bolts or the pistons ?

[The Real Roadrunner]

if your not looking to make over 200hp i would just buy a G/C smallport and re-ring it, shave the head at the same time and fit a trd H/G .8mm metal. they make more power stock so this will only increase and they are a shitload stronger bottom end wise.
cheers
linden

[Killswitch]

Ok
Well id go with new head bolts and possibly rod bolts if there is money left after gaskets, rings, machining etc etc.

Cleaning up the ports/ port matching is an old school trick but one that is a must
Leave the cams and valve springs std. They wont give any dramas. You can still put cams in later if you decide too and keep the std springs providing you keep the lift to under 8.35mm. There are HKS cams around that give good results and keep within this margin. So you can save some $ there.

As for geting it to perform ...... what sort of external hardwear do you have.
Exhaust / extractors ?
Air intake ?
These things can found relativley cheap and can provide good gains in response and power.

I dont know if i would even bother to go with a aftermarket flywheel. I dont think the advantages are worth the cost unless chasing every last hp and cost isnt an option...... Even then i dont know if its worth it ----- but thats just me

Mabe this money could be spent on rod bolts or the pistons ?

Well, I'd prefer to buy new valve springs so depending on the cost difference between stock springs vs heavy duty I'll let that decide. Definitely going to do the porting as you said.

I have some nice 4-2-1 extractors with a full 2.5" exhaust (already on the car, it's a bit big but eh), will need to buy a new filter set up as the current one is fubar but I don't really know what just yet.

I'm not entirely sure on the flywheel myself, but after reading that thread on here that discussed lightened flywheels it seemed like a worthwhile investment compared to say, buying cams or the like. For an N/A engine anyway, seems a bit more convoluted with a boosted engine as the flywheel helps to build boost or some such. I'll see how it goes as it progresses, will be one of the final things I order, if I even do.

if your not looking to make over 200hp i would just buy a G/C smallport and re-ring it, shave the head at the same time and fit a trd H/G .8mm metal. they make more power stock so this will only increase and they are a shitload stronger bottom end wise.
cheers
linden

Not really a viable option, well it is but I don't really want to go down that route. I've already got a RWD engine, all it needs is some new life and I would prefer to build up a whole engine myself.

But thanks


and to anyone:
Assuming I can't fit smallport pistons, its not possible to get higher compression cast pistons? What brand would people recommend for cast pistons?


Muchos Gracias!

[oldeskewltoy]

Hmmm you can go with the Singapore/EUG 10 to 1 pistons(I've already posted the info in another thread....http://www.toymods.net/forums/showth...950#post482950 ) you can use those on a small rod with no other issues.

New rod bolts a MUST...also flywheels /clutch bolts. Headbolts are NOT stretch bolts(they ARE TTY but NOT stretch... they can be reused as long as there is no damage!) Same for main bolts. Now that doesn't mean you can't buy new if you want too.... but if you are saving dollars all around, mains and head bolts can be reused (cleaned and lightly oiled) if undamaged.

Cams can do wonders! In my opinion they should be considerd the first internal mod. I like Webs 294(grind#, NOT duration) they are a VERY good all around cam... see my dyno sheet in the dyno section.

Be VERY careful porting the large port head... as Bill points out in his web pages it is much easier to screw up the head then to improve it...

One nice thing about the mild compression bump and the mild cam bump is they can run on the stock ECU. What many people forget is the ECUs back then are rather primitive and have a working range... keep mods within that range and the ECU has no issues

[oldcorollas]

tprque to yield bolts ARE bolts that stretch. in some cases they can be reused, but each time you retighten them, you are reducing the cross-sectional area of part of them. they will fail eventually, but the number of re-uses is not constant.
headbolts are cheap, and new bolts are cheap insurance

only change cams if you want to change the rpm range of your engine.
choose the rpm range first and design everything else around that.

[oldeskewltoy]

tprque to yield bolts ARE bolts that stretch. in some cases they can be reused, but each time you retighten them, you are reducing the cross-sectional area of part of them. they will fail eventually, but the number of re-uses is not constant.
headbolts are cheap, and new bolts are cheap insurance

.

Hmmm, let me rephrase..... the Toyota head bolts NEVER changed part numbers. In the early 4AGE engines the torque rating was 44#. The same bolt is used with the newer 22#, 90 degrees, 90 degrees. In either case they factory manual does NOT say replacement is required....

With that said... you are quite right... headbolts are pretty cheap, worth the invenstment... I was just offering a low cost potential option....

only change cams if you want to change the rpm range of your engine.
choose the rpm range first and design everything else around that.

Thats the beautiy of Webs 294... they are only 10 degrees more duration. Stock cams run out of breath at about 6600, Webs boost the peak hp by only 2-300 rpm, well within the stock ECUs capability.

[Killswitch]

Ok, all new head, rod, flywheel and clutch bolts. sorted!

Still undecided on cams, and the flywheel for that matter I guess. Might just hold off on both for now.
The power you made oldskewltoy is around what I'd be pretty damn happy with but really its not that far from stock (which is a given I guess due to stuff all change in duration). How much for the pair of lumpy sticks from Web? I think at this stage I'd prefer to go a larger duration at a later date when I can afford an ECU to accommodate the cams, if I even decide to go down that route! Although I guess this goes against oldcorollas advice, don't know what rpm I want just yet!

I guess thats most of my queries sorted. Once I pull down the motor and check out what size the rods are I'll know what to do about pistons (hopefully!) and will update here.

Thanks so far everyone for all your help, and if anyone has anything else to add re: pistons, lightened flywheel or anything then don't hesitate!

Danno

[oldcorollas]

what i meant was.. the rpm range you choose will dictate things like..
cam size, valve springs, extractor and intake lengths and everything else related to them...

seems pointless to only go up 10 deg duration for the cost of 2 cams... second hand HKS jobbies are not that exxy (200-250 or so each at a guess?)

flywheel will allow the engine to rev faster and the car will have a lower effective weight (less to pull) in lower gears....
flywheel - expensive, but if it effectively reduces your cars weight by 10 or 20%.. not that exxy really