Toyota 4a block, 16v small port head questions.

[bzrspeed]

Which 1sz-Fe Inner Shim should I use as an upgrade? They come in 5.12 to around 5.67 as I want to get high RPM but dont want to pay for a TODA/TRD kit. As this is a bufget rebuild.

Would Blacktop 20v pistons work? I have been offered a NOS pistons from Toyota for $45.00+gst.

Would thyey cause vlave slap as the cut outs are not correct?

[Dell'Orto]

They shouldnt contact unless the belt breaks, or you machine the head lots. Shim size would be entirely dependant on cam choice wouldnt it?

[bzrspeed]

I slipped up sorry. I am using Blue Top 16v 4a cams

II have never tuned a toyota engine before so new for me, I have worked on the engines a few times and lots of other toyotas but This will be my first japanese rally car. Had raced european fiats and lancias before.

[QikStarlie]

no point going undershim/ one peice on standard cams. only need to change if your going to cams with aggressive ramp rates. if so you need to measure up valve clearances and order to suit. or get the valve tops machined to suit

dont use the 20v pistons. stick with the small port pistons or aftermarket higher compression if serious build.


what are your plans for the engine? just a rebuild or going for more power, big cams etc??

[bzrspeed]

The engine will be going into a ford escort MK2 as a RS1800 replica. You heard about ford escort? Its a Rear Wheel drive car from Germany.

I am thinking maybe a set of 7m-gte valves as they are larger. I know you loose power if below about 220hp but they would be a good upgrade on a 160hp engine? yes?

Dont want a lot of power, just want it to be a good duel purpose engine. I know the triangle of performance tuning, you can choose 2 of the 3 things, wether performance, cost or relaibility..

[Truenotch]

If you look at Dave Vizard's work his theory says that a bigger valve will always equate to more horsepower.


I used to have a 4AGE head that was built to near atlantic specs with 7m valves and under bucket shims - there was a fair amount of work in making it right because I think the valves are shorter (might stand corrected here) so you need to make a custom shim to go under your bucket. Have also heard that 1ZZFE buckets will work in a 16v head, but have never tried it myself. If you're going to that much effort though, you should look at fitting big cams too.

Also agree with the man above - stick with the small port pistons and run a thin gasket or do a skim to get the compression up.

And yes, we know escorts in NZ - they are the most popular classic race/rally cars here.

[bzrspeed]

Honda in thier 1600cc dohc engines use much largter valves and make much more power then the toyota engines which use very small valves. I do not know why toyota did this, it makes no sense as most other perofrmance 1600cc engines use larger valves. Even fiat uses much larger valves then toyota.

I know there are a few escorts in NZ, i think they look nice, the mk2 ones do the mk1 ones are a little funny. I was going to put in an old fiat but could not.

Maybe stay normal valves then, but blacktop rods are much lighter then small port, i think 14mm vs 8mm and pistons lighter too so means more power as less wastage. I dont have the money for TRD/TODA parts and i think they rip off anyway.

[Bling]

One thing I know is you don't want to be using blacktop rods. Lighter yes, more likely to break, also yes.

[iOnic]

lulz don't replace smallport rods for blacktop rods

You're a bit vague about your goals/expectations out of the engine. You don't want a lot of power but what is a lot? How much power do you actually want? How high will you rev it? What will the engine be used for? You want a good dual purpose engine but haven't mentioned what either of the two purposes will be? What's your budget? What ECU will run it? What fuel do you plan on running? Is forced induction an option? Increased displacement?

As cool as it is to know what car the engine is going in, it really doesn't give anyone an idea of what you want out of the engine and that will affect the advice you get.

[bzrspeed]

oops.
Its for a rally/street engine, power i would like 170hp but thats a push i know so anything over 150hp would be great. I need it to rev to 8,000 revolutions per minute so when change gear still within powerband. I would like powerband 4,000 to 7,300 which would match gearbox good.

Fueling will be by carburation as escort is carburated and i have a set of webber 45dcoe's which i am planning to use with a adaptor. Fuel injection is easier but as it doesnt have a return setup and it will be a lot of work i would like to stay with carburation please.

I would run it on 95/98 octane when racing, normally daily driving maybe 95 still. I doubt engine would work on 91.

I do not like turbochargers or superchargers as its easier to break and costs go upwards. I like to keep engine as a naturally asperaited induction. Maybe bigger displacement but toyota didnt make a bigger enginr with g wide angle head except in the celica.

I want it to rev and rev quickly like the fiat twincam.

[QikStarlie]

for those revs, dont need to do anything fancy to bottom end.

id use silvertop rods, the are a bit lighter than smallport ones but still plenty strong for what you want. balance it and arp rod bolts for peace of mind. rest factory spec.
ive been running same setup as above with toda pistons, has been revd to 8500-9000rpm for the last 10,000k, no issues

piston choice should come down to cam choice. if running big valves and cams, you will want higher compression pistons with bigger valve cutouts.

if your on a budget. i'd use smallport pistons, trd head gasket and a head skim. get compression up to 12-13:1 some fairly large cams & springs to suit, but sticking with stock shim setup. factory valves.
you can machine the seats out while still using factory valves. then port to suit. if you keen.. we went around 1.5mm bigger on the inlet and 1mm on exhaust while keeping good shape and seal on my latest engine.

i'd be looking at something like 193-c
http://www.camshaftshop.co.nz/index.php ... ducts.html

take your time to dial the cams in, and play around with inlet runner and extractor lengths. also make sure you have go penty of exhaust flow. after extractors as can cause revison and big loss in low-midrange power


if you want more, will start to get pretty expensive..


Edit: flywheel. can use blacktop if sticking with budget theme (5.9kg) or go aftermarket

[RedMist]

Your plan seems at odds with your other thread (of limiting hp and RPM to match the BDA).
You also seem to have a misunderstanding in regards to the necessity for shim under bucket. Shim under is simply used for very high lift, high ramp rate cams where they can pickup the shim (from on top of the bucket) and throw it through the side of the rocker cover.
If you're chasing cheap HP then I think you are heading in the wrong direction. The 20 valves have considerably more valve area than the 16 valve and develop more power natively.
Then again you could plug almost anything up to that shell. You need to define your goals, find a class you want to enter, build to the maximum limits of that class.
By the way, valve area is critical to swirl, squish and flow. The reason the 4age valves are small are simply to ensure the engine develops efficient power at a lower/wider power range.

[Vertigo]

By the way, valve area is critical to swirl, squish and flow. The reason the 4age valves are small are simply to ensure the engine develops efficient power at a lower/wider power range.

This inherently disappears as valve size increases?

[Mr Revhead]

Design comprises to ensure you can drive it to the shops when cold!