overheating
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simpson_eh
- Posts: 633
- Joined: Mon Sep 28, 2009 1:27 pm
- Location: south wales
overheating
editing for a reason
Last edited by simpson_eh on Sat Jul 11, 2015 10:40 pm, edited 1 time in total.
If you see an MR2 with a raised engine cover, the bottom line is it's probably faster than your car.
Re: overheating
From what I've seen on here its a possibility your block is cracked.
Are you losing any coolant?
Are you losing any coolant?
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simpson_eh
- Posts: 633
- Joined: Mon Sep 28, 2009 1:27 pm
- Location: south wales
Re: overheating
only through the overflow and its a 5sgte
If you see an MR2 with a raised engine cover, the bottom line is it's probably faster than your car.
Re: overheating
Possibly headgasket blown.
Btw: You shouldn't lose coolant through the expansion tank! Coolant that is forced into the tank by too much pressure is sucked back into the system when pressure is back to atmospheric.
Can you get the coolant CO tested to see if any exhaust gasses are present?
Btw: You shouldn't lose coolant through the expansion tank! Coolant that is forced into the tank by too much pressure is sucked back into the system when pressure is back to atmospheric.
Can you get the coolant CO tested to see if any exhaust gasses are present?
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simpson_eh
- Posts: 633
- Joined: Mon Sep 28, 2009 1:27 pm
- Location: south wales
Re: overheating
its back in the garage now so he can check i hope its not the block as that would be bloody costly being a 5s
If you see an MR2 with a raised engine cover, the bottom line is it's probably faster than your car.
Re: overheating
That is a sign of a cracked block.
If the compression ratio is too high for the fuel and boost being used the tuners just back off the timing to stop knock. What this does as well as losing a lot of power it brings the max cylinder pressure down into the bore where it is not designed to be and it is this pressure that cracks the block.
If the compression ratio is too high for the fuel and boost being used the tuners just back off the timing to stop knock.
What this does as well as losing a lot of power it brings the max cylinder pressure down into the bore where it is not designed to be and it is this pressure that cracks the block.Designer for turbo set ups on F1 cars, and Nitrous Oxide Systems of the USA in the 80s
Re: overheating
bobhatton wrote:That is a sign of a cracked block.
If the compression ratio is too high for the fuel and boost being used the tuners just back off the timing to stop knock.
Exactly the same symptoms I had last year.
Off boost/flat roads, car was perfectly fine. Acceleration/up hill/on boost.....Temp went into the red. 
Cracked block.
Head off, piston number 1 had been steam cleaned by combustion pressure/coolant!Re: overheating
bobhatton wrote:
If the compression ratio is too high for the fuel and boost being used the tuners just back off the timing to stop knock.
^This! This is one of the root causes for lots of cracked blocks with higher power builds - nevermind wall thickness or overheating, i'm certain that 85-90% of the time it's the tuner/owner retarding timing to far on knock.-
simpson_eh
- Posts: 633
- Joined: Mon Sep 28, 2009 1:27 pm
- Location: south wales
Re: overheating
hope not as it was mapped by ryan who put it on the safe side whilst waiting to install another fuel pump and camsit is running a 1.65mm headgasket on 8.5.1 pistons so shouldnt have cracked the block and only running 12psi of boost
If you see an MR2 with a raised engine cover, the bottom line is it's probably faster than your car.
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MR2 Turbo Boy
- Posts: 1052
- Joined: Wed Aug 15, 2012 8:03 pm
- Location: Definitely NOT at Pete Gibbens garage
Re: overheating
Ive the same with mine... 5S-GTE.. 
.. 5S-GTE.. Re: overheating
simpson_eh wrote:
it is running a 1.65mm headgasket on 8.5.1 pistons so shouldnt have cracked the block and only running 12psi of boost
Mapping on the safe side may well mean not having much timing advance.
The piston to head clearance should be no greater than 1mm.
Any larger will give an amount of charge that will burn very fast and give lots of knock.
If your pistons only come to the top of the block you now have an area of 0.65 to hold charge making the engine very prone to knock.
The correct way to design an engine is with the correct piston to head clearance and the pistons made with the correct compression ratio for the fuel and boost
that will be used.Fitting a thicker head gasket to lower the compression ratio may well end up giving greater problems, it is the wrong thing to do.
Designer for turbo set ups on F1 cars, and Nitrous Oxide Systems of the USA in the 80s
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simpson_eh
- Posts: 633
- Joined: Mon Sep 28, 2009 1:27 pm
- Location: south wales
Re: overheating
The head was skimmed so hence the bigger gasket
If you see an MR2 with a raised engine cover, the bottom line is it's probably faster than your car.
Re: overheating
I thought the 5 block was indestructible hence why ppl go for it.
This is the first I've heard
This is the first I've heard
Re: overheating
My car has this exact same issue. Head is now off and the head gasket has not failed but the block looks fine. The head is now being sent for pressure testing.
In people's experience is a cracked block usually visible to the eye?
Head is now off and the head gasket has not failed but the block looks fine. The head is now being sent for pressure testing.In people's experience is a cracked block usually visible to the eye?
Re: overheating
Adam86 wrote:My car has this exact same issue.
In people's experience is a cracked block usually visible to the eye?
Could simply be a hairline crack.
Needs crack testing by a machine shop.Re: overheating
I really hope the head fails the pressure test.