Engine Seizing Issue

[328FTW]

Cause I'm stumped.

Rundown in brief. Turboed 3sge running VR4 injectors, megasquirt and td04L turbo for a cheap setup. Problem is that it's seizing motors like clockwork, tried several tunes and everytime it locks solid then you let it cool and start it and the bigends are knackered. Tried several intake and drainback setups, oil pump relief valve mod and still siezes motor.

I'm a little lost, there is a 300hp honda with a t04E I own and it runs like clockwork on the link, this thing keeps playing dead. Oil has been full, pressure seems fine, not overboosting or cornering hard but it eats motors like crazy. 20 seconds on the gas and it'll sieze. Short blips and keeping it under 5k no detonation that I can hear and pulls like a horse. Fuel ratios at 13:1 before transition and going 12:1 low boost and 11:1 at 5+psi with peaks of 10:1 under acceleration enrichments which to me seems perfect, no stuttering or leaning out causing issues just pulls hard then seizes before lots of sear words.

The way it goes out seems mechanical but the way it cools off and starts back up is almost like a piston expanding too fast in the bore or something. It's a really annoying issue given the amount of success I've had on other motors.



Had other forums on this one and come up dry, next motor I'm going to keep n/a and try again to troubleshoot but this is kinda silly since that is back where I started. Ideas?

[strx7]

where is the oil feed to the turbo plumbed from?

is it a gen2 or gen3 motor?

[iOnic]

Insufficient cooling?

[sergei]

Have you touched the way the coolant flows?
What is the temperature like when it seizes?
Are you using same radiator?

[328FTW]

Cooling is good, turbo oil feed comes from the head where the pressure sensor goes, has an oil restrictor that is really small in line with the oil feed.

Gen 2

[sergei]

What are the oil and water temperature like when under load?

[mjrstar]

Has the motor been uprighted?
Someone may correct me but if you stand the 3S up you may need to look at the oil pick-up..

Also have you modified the oil filter housing at all?

I recall some sandwich plates have the ports set out differently so you may get good pressure at the gauge but not so flash at actually lubricating engine parts...

[strx7]

turbo oil feed comes from the head where the pressure sensor goes

that is about the lowest oil pressure point on the motor, and the last place to get oil pressure. if you were going to kill something i would have said it'd be the turbo, not the engine bearings. Can be a good couple of seconds after the motor fires up before you get oil pressure up there.

How many times has this happened? I'd be looking at the big end sizes in relation to the crank journal sizes and what size bearings have been going in. almost sounds like its a fraction tight, and putting load onto them is causing them to bind on the crank

[328FTW]

Oil system is closed so there is plenty of pressure at that point. Killing the turbo is not of concern cause it is a $50 turbo anyway. It was more of a test bed before putting the money down on a better turbo, I can get .50 trim t04E all day long for cheap through a friend that works at segedins butthere are obviously issues to sort before buying any kind of better turbo, pistons and rods.

Engines are stock, like 150k engines that have had no problems beforehand. The first one I had done a seasons hard hard racing with 260k already on it with not one issue. This setup can't go one meet on engines with perfect tolerances so something is screwy. It is just running crank trigger ignition on stock everything else bar the big injectors.

[Malcolm]

i like the way you're asking for help but dismissing everything that's mentioned.

[strx7]

so you a putting a second hand replace motor into it, giving it a thrashing and then it dies. seems to be a repeative thing happening here.................

are you trashing it around a track or what?

[328FTW]

What have I dismissed? People have asked about cooling and it's good, standard radiator and system which is really good on mr2s anyway.

I missed mjrstar's post and no engine is just as it is stock, stock pan and pickup with screen, not blocked and no mods to anything except the oil relief valve on one motor where at revs the oil pressure was a bit low IMO.

Oil temps and water temps under load were always good. Only time it would get a little hot would be if I only had one fan plugged in and was giving it hell.

Everything appears normal then it just kinda stops. Temp gauge will shoot up a bit after seizure due to the exhaust manifold head soaking back to the motor but it's still within limits of what I'd call reasonable.



This is why it weird cause I've done identical setups before and had no issues. This setup is just being a massive pain in the ass for some weird reason and it'll prolly turn out to be simple and I'll go drive headlong off a bridge in it out of anger of being so stupid

[sergei]

Temp gauge will shoot up a bit after seizure due to the exhaust manifold head soaking back to the motor but it's still within limits of what I'd call reasonable.

There isn't enough energy in exhaust manifold to heatsoak into head to cause the temp gauge to shoot up.

Here how I see it: for motor to seize to a stop and then let go later after cooling down you need to increase piston temperature dramatically. Basically something running really hot in there. Assuming that the engines haven't been rebuilt with wrong piston to bore tolerances (as you say the engine is stock), the only thing I think that will cause the engine to seize is for piston to grab the bore.
Even complete failure with oil system will not cause engine to seize and restart later: it will run bearings, perhaps break conrods and block in the way, and do that very fast.
Now back to the questions:
Have you pulled apart the seized motors?
If you did, did you inspect where it actually grabbed? That will point to the fault.

In hindsight the first engine that seized should have been pulled apart and inspected. It takes 15min for this but provides a lot of valuable information (and fun thing to do).

[MAGN1T]

Insufficient ignition timing, pistons get too hot and too big, maybe combined with not enough piston to bore clearance (although it's stock).
Insufficient timing is easy to spot because the exhaust manifold will be glowing, easy to see in the dark.

An EGT gauge would be the best investment to make.

Another way to tell would be to pull a piston and check the sides for scuffing.

Steve

[328FTW]

That's the thing, I would assume being a seizure like that I would get 4 corner catching or something but I can't see anything. The timing maps I tried were off an AEM ecu, another setup a celica guy recommended as being the best he tried and a standard 3sgte map. Also it's far from lean so piston temps shouldn't be that bad surely. This happens so fast it seems like an oiling problem but me and my friend have just started to suspect pistons as a possibility, I'd investigate sooner but he blocked an injector on the weekend and blew his race motor to shreds.

Guess I could pick up an EGT monitor but not at the moment, or at least borrow one while on the dyno.


I did pull the first motor apart and all I found was a copper coated crank from the heat of the bearings, 3 were really bad, one was kinda alright but the mains looked good apart from slight markings which I dunno if that was bits of metal going through OR the beginnings of starvation.



And yes track use, rallies etc. I will try it n/a when I have time to pull the motor and slap up a new one to get it running. Less to go wrong, way less intake charge temp and less chance of detonation or other funny going ons. The honda I have is also in need of attention as well as my rx7 doing it's first run in 4 or so years this weekend so I have motors to dial in coming out my ears.



And edit: The temp on my turbo that runs like a champ which is a proper gen 2 3sgte on stock electrics jumps temp a little if you run hard and turn it off. I don't like doing that, usually let it run down a minute on the turbo timer.

[MAGN1T]

An oiling problem will end up with big end knock, not a seizure.
unless your cams seize, then it'll probably stay dead.
Running too lean causes knock.
You can't usually hear knock on turbo motors.
Then you'll have broken ringlands on the pistons and oiled up plugs.
Pulling the timing back makes the EGT go sky high, along with a glowing exhaust manifold and glowing turbine housing.

Steve

[allencr]

Remote oil filter plumbed the wrong way, but it wouldn't seize up, a poor guess but it's all I got.
It's like there are 2 simultaneous unrelated problems, high piston temps & lack of lube.

[Dell'Orto]

Got pictures of the piston/block from one of the dead motors?

[strx7]

will it 'sieze' on a dyno or only at an event?

[evil_si]

I may have missed it, but what is happening when it siezes?
Can it be turned over by hand with a ratchet etc when it happens? Or after it has sat for awhile?
Or is the engine toast

Are the bearings welding them selves to to crank?

Are you running a remote filter?
I looked at a 3s a few years ago that ran for 10minutes then locked up, the standard 3s filter he had used was not compatable with the relocation kit