steveyb

looking for some help, info and suggestions.
last weekend i had my track car out that i done the 1uzfe vvti conversion on and had an engine failure
so im looking to know is there anything i can do on the cooling of the vvti version engine to allow coolant flow more easily around the engine?
basically the engine started to put up pressure in the coolant system.
for cooling i have a large capacity koyo alloy rad fitted with 2 spal racing fans, so cooling should be more than enough.
the issue i think is that the coolant system is pushing water out of the engine and out the overflow of the header tank.

billydpowe

iTrader: (1)

if you cant get a larger radiator, get a higher pressure cap if your radiator can handle it, and run your heater wide open...

timmy0tool

iTrader: (7)

where is your radiator placement versus the engine? is the engine overheating? what car is the motor in?

i believe the issue here is pressure management since your motor is seeing higher RPMs thus pumping water around the engine at a higher rate. i am with billy in suggesting to get a higher pressure radiator cap first and try again.

steveyb

i have this engine in a ford sierra cosworth running with a manual gearbox.
ill try get some pics of it at the weekend
the radiator is a large 52mm core alloy rad so should have good enough cooling.
the alloy rad has good space around it with no aircone rad or anything like that in front of it and bonnet is also vented. there are no engine splash guards under the car and the exhaust manifolds are heat wrapped.

i will try with higher press rad cap when i rebuild the engine. but at this stage i would like to be looking more into how to open the engine more to allow coolant flow around the engine better as it may be designed to keep engine temp up for emissions. as its a track car getting high reving this wouldnt be suited.
also as the engine is difficult to bleed the coolant system this is leading to these issues.

when you say run heater wide open, is there a valve somewhere on the engine controlling what goes to heater matrix?

billydpowe

iTrader: (1)

without some knowledge of your setup, that is an impossible question... IF I put that engine in a ford I would know where the heater control valve was... I am just guessing at possible solutions.. BUT on an LS400 the heater is an integral part of the cooling system... sounds like you have it sort of chopped up... our friends in Japan did not build a hot engine and then build a car around it, they designed a complete car... and that is what this forum is about... I am not into "race cars" so I will bow out, I am sure some of the guys on here might be able to help you out.. good luck ...

timmy0tool

iTrader: (7)

only you can tell us if you ran coolant lines to the heater core residing inside the car. the valve is separate from the engine, and most likely you would be running the ford valve if you plumbed the heater. it is unknown to me what the effects are when bypassing the heater lines.

you still did not answer my question if the engine is actually overheating? i think the coolant flow is decent but then again my engine doesn't see high revs like yours. i would look in to other solution like water wetter or the like to get a better heat transfer. you already have a bigger radiator.

Kingsoup

A lot of unknowns with it being in a Sierra now. How long can you run at race speed before it starts to overheat? air pockets in the cooling system? running a tray under the motor for airflow direction? heat extractors on the sides?

Making a car run cool on a track day is tough, its usually got to be setup really nice even with a huge rad and powerful fans like you have.

steveyb

well for the set up it really just the ls400 v8 engine sitting in my engine bay with rad in front with the two main rad hoses going to top and bottom of the radiator as it would in the ls400.
im also using the standard ls400 header tank and hose to top of the radiator.

the reason i asked about the heater valve is if there was something else under the inlet manifold that i may have missed? i am not running any valves on the ford side of things. its simply hose in and back out of heater matrix. - only thing i need to check on this is the height i have my heater matrix compared to the one in an ls400.

when you say it sounds like i have it chopped up, im not sure what you mean by this, but its an engine conversion into a different car so its not a factory build. where possible i have kept everything as standard ls400 form as i can.

steveyb

yes sorry i should have stated that, i have run the two heater hoses into and out of the heater core/matrix in side car, straight in straight out with no valves.

yes the engine was over heating. yes i think the high reving is maybe causing the issue.
but basically when car was started from cold and left sitting to warm up for 15 to 20 min then driven around to warm gear oil and diff oil it started Pressurising the system and venting coolant out the overflow pipe. at this stage the engine wasn't that hot as it had only been running about 30 min and under normal driving.
What it seemed like to me is that the thermos stat hadn’t opened and had maybe a build up of air behind it or something and the system was bubbling/venting air?
I had tested the thermostat and it was working as it should, but again it may have failed since that, but I don’t think it would have? Ill not know until I get it opened up an see.
so i let it sit a while and then topped up the system with coolant, bleeding air out and went onto track. went ok for a short while and then started pressurising and venting water again. rad was going hot then cold, hot then cold and so on.

steveyb

hopefully i have covered a lot of the unknowns above now? to be honest not very long on one lap about 1.5-2km i would have to take half the 2nd lap for a cool down. so after a few laps i noticed a power drop so called it a day.

air pockets is what i think is causing it, but its how to stop the air pockets from starting in the first place is what i want to look into. as the last day i was able to go nearly all day with no issues on same track with same weather temp etc.

So maybe when the system cools down it is creating air pockets some where?
If this is the case I would like to open the cooling system up more to allow coolant flow easily around it? Im no expert when it comes to building a track car, its built for fun and reliability was the intensions by running in stock form bar the ally rad for cooling. i don’t want to run with no thermostat as in my view it should be kept.

steveyb

ill do a compression test this evening and see what that shows up. Then remove the engine and get working on it.
The other thing I need to look into is how much actual differences there are between the older non vvti and the newer vvti cooling systems as I know a few people running them with no issues like what Im having.