4AGZE Engine rebuild in pictures (56K no way)

[Icsunonove]

one of your pistons seems to have put on alot of weight since removal

i dont think any rebore is gonna fit that one in ! lol

Lol, it's actually a piston out of one of these devices:

how much did the hone cost?

Don't know, but not much. You can do it yourself if you want. It's just that I have an excellent engine rebuild place less than 1/2 a mile from my Dad's house so I let them do it.

about the bore clearance ,ive heard of race engines having so much piston to bore clearance that the pistons will move quite alot in the bore (and sound like a ball in a bell) but then again they never get started up cold ,but its quite amazing what you can get away with ,I looked at your measurments and although I'm not an engineer ,i think they look fine ,Ive seen a few mr2 engine rebuilds in the forums and other websites and ive never seen one yet need a full rebore

The engine man reckons it is absolutely fine. I will be test fitting the piston rings later and checking the ring end gap. I was concerned about the wear at the top of No.3 piston but he has reassured me the compression will be fine. He's very very well respected and therefore I'll go with his advice.

,Ive seen a few mr2 engine rebuilds in the forums and other websites and ive never seen one yet need a full rebore

You obviously didn't read Anna & Speedy's thread then

Yes, that original rebuild was truly appalling I reckon it was done by a run of the mill garage, there's no way they knew what they were doing. It should have been done by a proper engine place ()

[crazybrightman]

yeah compression should be fine my last engine build (not a toyota mind) was on its outer wear limits (over 200k) almost to the point i hardly altered the new rig gaps and it seems fine good power, no oil burning, and good vac on the over run. must compression test it though now its run in.

[chrismanchr]

no I havent seen those threads

Ive searched for engine rebuild threads and hopefully Ive seen most of them

some have been excellent like this one ,and give others the confidence to do there own

[Speedy]

It should have been done by a proper engine place

or in a shed

[anna]

I reckon it was done by a run of the mill garage,

Lol

does that count as Tom in secret/covert mode

And yes - our Mr2 (no longer in our possession) had a rebore, but that was probably down to inept garages cocking up royally.
I cannot stress enough - knock sensors are important on standard engines, and moreso on tuned engines. Half of one really doesn't work.

[Icsunonove]

Anna, your quote is too short....

it was done by a run of the mill garage, there's no way....

Half of one really doesn't work.

Lol! Yes, it also helps if you actually have a wire running from the knock sensor back to the ECU

[chrismanchr]

I must check these items when i'm rebuilding mine ,although i have started to strip mine out and get ready for my winter build project and i have found a couple of old dodgy connections one had barewires that were twisted together

whats the date for the build back up then icunonove

[Icsunonove]

whats the date for the build back up then icunonove

Well I'm waiting on a 4AGZE piston from Japan. Should be here later this week I hope.

[crazybrightman]

whats the date for the build back up then icunonove

Well I'm waiting on a 4AGZE piston from Japan. Should be here later this week I hope.

are you putting 8.9c/r pistons in?

[Icsunonove]

No I'm not. No.3 piston suffered detonation damage so I'm definitely not going to raise the compression ratio. The head had been skimmed previously and it needs skimming again . I have been taking measurements to make sure I am at least back at 8.0 or lower. I will remove some material from the cylinder head if I need to. Will post some pics later....

[crazybrightman]

people get very hooked up on c/r when forced induction is involved with modern fuels and a knock sensor on the engine 8.9:1 c/r is very safe. im sure my saab runs about 9.3:1 c/r and will do getting on for 500bhp on standard internals with the right tunning.
any idea what caused it to detonate? where you running a cooler grade plus as im guessing like most you fitted a larger drive pulley? faueling problem? ignition? spose its hard to tell if it was a momentary fault.

[Icsunonove]

Well I have an inkling what has happened but I can't be sure.

Yes I do have a 176mm pulley and have blocked off the ABV so that I get the full boost from the big pulley. I normally see about 12psi in normal conditions. Yes I was using the correct spark plugs.

But I *think* the damage was done at a Donington Park trackday. Long story but I was running the supercharger clutchless (i.e clutch was locked solid). I was seeing over 14psi of boost and the engine was getting hot after a few laps (which it never normally does). Also I was using 95 RON fuel so I'm guessing that's where the damage was done.

I need to check my knock sensor is working and am going to flush out the intercooler and put a working clutch back on the supercharger and check the compression ratio is correct. I suppose I should check the fuel pressure and injectors as well, but I'm not exactly sure what's the best way to do this

[greglebon]

Well I have an inkling what has happened but I can't be sure.

Yes I do have a 176mm pulley and have blocked off the ABV so that I get the full boost from the big pulley. I normally see about 12psi in normal conditions. Yes I was using the correct spark plugs.

But I *think* the damage was done at a Donington Park trackday. Long story but I was running the supercharger clutchless (i.e clutch was locked solid). I was seeing over 14psi of boost and the engine was getting hot after a few laps (which it never normally does). Also I was using 95 RON fuel so I'm guessing that's where the damage was done.

I need to check my knock sensor is working and am going to flush out the intercooler and put a working clutch back on the supercharger and check the compression ratio is correct. I suppose I should check the fuel pressure and injectors as well, but I'm not exactly sure what's the best way to do this

All sounds pretty likely to me....

I trial-fitted my AE101 IC a while ago, and boost dropped compared with my custom WI manifold.
By 2 psi, to be precise.
This either points to IC pressure drop, over-reading of the boost gauge due to charge temp, or a mixture of the 2....!

When I run sans IC, I always use >97 octane fuel, either Optimax, Ultimate, or just additives...

Caning it with a big pulley, continuous SC and lowish-octane fuel is not a good recipe.......especially if the knock sensor is non-operational...!

Running 14 psi with our Roots SC will raise charge temp by around 250 degrees, so det is going to be just round the corner.........

If you fit a FP gauge it gives a lot of info: Its possibly the most informative gauge I have.....?

Using the FSE rising-rate regulator, you can set it up using the gauge.
35 psi at idle seems to work for me.

Now when I drive the car, the FP drops to around 22 off-throttle, and rises to 40-ish on boost...

The O2 sensor will do a lot of the work fine tuning: if FP is slightly too high, it will cut the duration, etc......

FP gauge......

[crazybrightman]

not really having any first hand experiance with the standard sc intercooler but it does seem that anything more than standard boost pressure would cause alot of heat soak as an intercooler is moak of a heat sink and will reach its limits quickly. a charge cooler will be able to cool continuosly so would be more ideal for track use, maybe it would be safer to fit one of these to help keep temps down and reduces chances of det in the future?
ive run my car on 95ron a few times with 1.4bar boost and no problems although it has constant knock sensing on all cylinders adjusting the ignition/fuel acordingly.
interesting you had cooling issues assuming the coolant system was in tip top shape then something must have been getting hot, having said that do the mr2sc's have oil coolers? plus they dont have oil squirters for cooling the pistons and lubricating the bore do they? might be worth tapping the block and fitting a set of oil squirters aswell along with an n/a oil cooler if it doesnt have one.

one thing to remember when adjusting the fuel pressure is the lambda can only compensate up until about half throttle when its goes open loop and runs just off the ecu map and other sensors. its only a narrow band sensor so cant read the correct mixtures for when running with more boost pressure/airmass. id recomend getting a wide band up the exhaust to check alls ok when you've re done it. if you havn't got one ive just bought one of my own at last just need to set it up and your welcome to check your car with it.

[Bender Unit]

its probably worth doing, just stick 2-3mm extra preload on the spring (by sticking a piece of something 2-3mm thick behind the spring inside the valve chamber) and it should help a little.

Small washers work perfectly

But I *think* the damage was done at a Donington Park trackday. Long story but I was running the supercharger clutchless (i.e clutch was locked solid). I was seeing over 14psi of boost and the engine was getting hot after a few laps (which it never normally does). Also I was using 95 RON fuel so I'm guessing that's where the damage was done.

Do you not run an aftermarket oil cooler? IIRC the GZE converted AE86’s usually always have external oil coolers as they are well known to run hot.

[Icsunonove]

Caning it with a big pulley, continuous SC and lowish-octane fuel is not a good recipe.......especially if the knock sensor is non-operational...!

I think the knock sensor is working but I will check it.

Running 14 psi with our Roots SC will raise charge temp by around 250 degrees, so det is going to be just round the corner.........

Well I do have K-type thermocouples fitted pre and post intercooler. I must admit I have never seen inlet temperatures anywhere near that to be honest. I suppose I should recommission the temperature measurement to make sure the intercooler is doing its job properly.

If you fit a FP gauge it gives a lot of info: Its possibly the most informative gauge I have.....?

Well I will consider fitting one but I always believed the 4AGZE runs very rich on full throttle.

a charge cooler will be able to cool continuosly so would be more ideal for track use, maybe it would be safer to fit one of these to help keep temps down and reduces chances of det in the future?

Neil, I have never had a problem before using a standard intercooler, but I will recommission my temperature measurement equipment and check that is still the case.

interesting you had cooling issues assuming the coolant system was in tip top shape then something must have been getting hot, having said that do the mr2sc's have oil coolers?

Bizarrely no they don't.

plus they dont have oil squirters for cooling the pistons and lubricating the bore do they?

On the AW11 spec 4AGZE they don't. On the AE92 / AE101 spec engines they do.

might be worth tapping the block and fitting a set of oil squirters aswell along with an n/a oil cooler if it doesnt have one.

Crikey, I'm not doing that, it would be a proper PITA.

one thing to remember when adjusting the fuel pressure is the lambda can only compensate up until about half throttle when its goes open loop and runs just off the ecu map and other sensors. its only a narrow band sensor so cant read the correct mixtures for when running with more boost pressure/airmass. id recomend getting a wide band up the exhaust to check alls ok when you've re done it. if you havn't got one ive just bought one of my own at last just need to set it up and your welcome to check your car with it.

Really? I didn't know that at all

Do you not run an aftermarket oil cooler? IIRC the GZE converted AE86’s usually always have external oil coolers as they are well known to run hot.

No and I didn't know that. I have never had a problem with my engine getting hot before Donington (when I was running the Supercharger clutchless for the first time on a trackday).

(Really need to update this thread with where I'm up to)

[crazybrightman]

fitting oil squirters is quite simple assuming the use the same castings for the later engines? you will probably find an oil gallery running along the block to feed the main bearings, if this has flats on it in the middle of every cylinder all you have to do is drill and tap these and screw some squirters in. keeps pistons temps lower and will help avoid any future problems. its always a good sign when manufactuers fit them on later models that they are a good idea as they obviously discovered it helped with reliability.

[Icsunonove]

fitting oil squirters is quite simple assuming the use the same castings for the later engines?

I don't know the answer to that but I really can't afford the time / hassle to do this.

its always a good sign when manufactuers fit them on later models that they are a good idea as they obviously discovered it helped with reliability.

The later engines (AE92/AE101) all ran at 8.9:1 compression ratio. I am definitely going to ensure my engine is running 8.0:1 or lower. Update to follow....

[Icsunonove]

Update.

One of the problems with rebuilding a 20 year old engine is that you may not know what remachining has been done previously on the head and block. The compression ratio may be out if a lot of machining has been done. This can be rectified by removing material in the cylinder head. You can tell if the block has been refaced because the bore classification stampings will be missing. You cannot easily check whether the head has been refaced as there aren't any reference dimensions in the BGB

So to be 100% sure the best way is to check it yourself. What you will need to know is:

1) The volume underneath the piston crown.
2) The height of the piston crown at TDC with respect to the block top deck.
3) The volume in the head gasket.
4) The volume in the cylinder head.

The correct compression (volumetric) ratios are:

1) AW11 spec supercharged 4AGZE = 8.0:1
2) AE92 / AE101 spec supercharged 4AGZE = 8.9:1
3) Normally aspirated 4AGE 16v = 9.4:1
4) Normally aspirated 4AGE 20v (silver top) = 10.5:1
5) Normally aspirated 4AGE 20v (black top) = 11.0:1

To measure the volume underneath the piston crown you can fit a flat cap with a small hole and fill it with water using a calibrated syringe:











For reference the volume underneath a standard AW11 spec 4AGZE piston (as shown above) is almost exactly 14cc.

EDIT:

The compressed height of the Toyota standard gasket (which starts off at 1.6mm) is 1.37 and has an internal diameter of 82mm. So that equals 7.24cc.

The piston crown protrudes the block at TDC by 0.2mm. So that equals: 1.0cc

So doing the maths I need to check / make the combustion chamber volume 3X.xxcc to obtain a 8,0:1 compression ratio.

[mr2mk1chick]

wow - thats a really neat way of checking the volume.