HIGH comp Big port carby build with MANY questions

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jondee86
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Re: HIGH comp Big port carby build with MANY questions

Postby jondee86 » Wed Jul 21, 2021 12:05 am

viewtopic.php?f=9&t=12283

Cheers... jondee86
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Re: HIGH comp Big port carby build with MANY questions

Postby nyberrg » Wed Jul 21, 2021 5:28 am

jondee86 wrote:https://www.club4ag.com//forums/viewtopic.php?f=9&t=12283

Cheers... jondee86


Yah, I read that thread and understand the basics of it. I don't really have an issue with pressure, blowing hoses, or temperature though. It's just that water dissapears. Only theory I got is that it could be a very, very minor leak...

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Re: HIGH comp Big port carby build with MANY questions

Postby jondee86 » Wed Jul 21, 2021 4:24 pm

I'm curious as to why your temperature would go up to 90 and then drop quickly when you
rev the engine. Do you have a thermostat installed ? Do you have an electric cooling fan ?

If your radiator overflow hose went all the way to the bottom of your soda can, and you fill
the radiator to the the top of the neck, the can should act pretty much like the OEM system.
You would have to partly fill the can with coolant to start with. When you first start the
engine after setting this up, the engine will blow coolant out into the can as it heats up, and
then suck coolant back into the radiator when it cools down.

If the engine overheats it will start blowing steam out the overflow and you will see bubbles
in the can and some steam being given off. If the engine has a coolant leak the level in the
can will drop slightly every the car is used until all the extra coolant gets sucked out of the
can. Shrtly after that the radiator will no longer be filled to the top of the neck and the
level inside the radiator will start to drop.

The missing coolant can only go two places (if there are no external leaks). Either into the
cylinders or into the oil. Since all engines blow a little bit of steam or condensation out the
exhaust when first started on a frosty morning, that will not make it easy to detect a
small coolant leak into a cylinder. In warm weather any steam from the exhaust just gets
absorbed into the hot exhaust and becomes invisible.

If coolant leaks into the oil, it will collect in the bottom of the pan. As the oil circulates and
the pan heats up, the water will get mixed up with the oil. As engine oil temperature is
typically higher than the coolant temperature, with extended engine operation the water
will start to boil off, turn to steam and get swept out of the engine with the blowby. This
is how it gets into your catch can.

During normal combustion there is always a small amount of water produced, and this is
what you see out the exhaust on cold mornings. A very small amount of this steam will
get past the rings with blowby and eventually find its way to the catch can. But if your can
collects 90% water that is not a good sign !!!

A second effect of water in the oil is the formation of a kind of water/oil emulsion that
will collect and condense on cooler parts of the engine. Inside the oil filler cap and inside
the cam covers for example... you will get a kind of creamy "mousse" collecting. A healthy
engine will not have any mousse inside the filler cap.

Ultimately I think you will will need to fit a new head gasket. However if the engine is
running fine it may be worth trying some kind of "stop-leak" in the radiator. Products like
this .. https://www.goldeagle.com/product/aluma ... ak-powder/
are effective on small leaks and less likely to clog heater cores etc. You don't need to add
all the product... maybe half and follow the instructions on the packaging.

Cheers... jondee86
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Re: HIGH comp Big port carby build with MANY questions

Postby nyberrg » Thu Jul 22, 2021 12:31 pm

jondee86 wrote:I'm curious as to why your temperature would go up to 90 and then drop quickly when you
rev the engine. Do you have a thermostat installed ? Do you have an electric cooling fan ?


I'm pretty sure the water doesn't circulate as well on idle cause of the radiator size. If I look in to the radiator when the car is running it pretty much doesn't move until the engine revs a bit more. Not optimal, but not really an issue imo

The headgasket could very well be an issue, but it should have blown majorly by now...

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Re: HIGH comp Big port carby build with MANY questions

Postby jondee86 » Thu Jul 22, 2021 3:35 pm

If the engine is running fine/normally then the cylinder sealing is likely OK. The water leak
is probably between the oil and water passages where they pass thru the head gasket...
https://haynes.com/en-us/tips-tutorials ... t-can-fail

Because the pressure differential is lower in this type of leak, it is not as aggressive or
destructive to the gasket as a fire ring failure. Neither does it affect engine performance.

Cheers... jondee86
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Re: HIGH comp Big port carby build with MANY questions

Postby nyberrg » Fri Jul 23, 2021 1:34 am

I've got a 3 layer 0.5mm TRD gasket laying around. But there's a reason why I didn't use that the first time around...

Engine is a big port, head is shaved a bit (just to resurface after warping, not with the intention to increase compression), stroke is standard but the pistons are some wisecos with a high dome and HKS cams with 8.3 mm lift. I know some extreme build have had issues with pistons hitting the head. I doubt my build is that extreme though..

Edit: Managed to get a new oem HG and headbolts from the local toyota dealer with quick delivery. Gonna tear the head of today. Will update on the status later

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Re: HIGH comp Big port carby build with MANY questions

Postby jondee86 » Fri Jul 23, 2021 3:12 am

MLS head gaskets generally require a finer (smoother) surface finish than than OEM
composite gaskets. If you are uncertain of the piston to head clearance, and the finish
on the head and block is not specifically prepared for a MLS gasket, you would be better
off installing a fresh OEM composite gasket.

Clean the block and head surfaces carefully and inspect for any scratches or pitting
that could affect sealing. Mist a light coat of copper spray onto both sides of the gasket,
let it tack up and then install and torque. Lightly oil the head bolt threads and oil between
the head of the bolt and the hardened washer before torquing in 3 passes.

If the surfaces of the block and head are freshly machined to the correct specs then you
don't need the copper spray. But if the surfaces are less than perfect then the spray will
improve your chances of getting a good seal.

Cheers... jondee86
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Re: HIGH comp Big port carby build with MANY questions

Postby nyberrg » Fri Jul 23, 2021 7:45 am

Well, I got the head off

Images were too large to embed...
https://i.imgur.com/t1pbo59.jpg
https://i.imgur.com/SGJHc3Z.jpg
https://i.imgur.com/P9weFH2.jpg
https://i.imgur.com/d4YcKYp.jpg

Doesn't look fantastic :lol:

One thought that popped in my head is if the oem gasket works with bigger bore pistons or if I f'ed up from the beginning. I'm pretty sure my pistons are 82 mm. The measurement in the cylinder came out at 81.8 mm but those .2 could surely come down do measurement error.

Oldeskewltoy might have some insight? Even though I know he hates the pistons I use :D

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Re: HIGH comp Big port carby build with MANY questions

Postby jondee86 » Fri Jul 23, 2021 6:03 pm

If you have the engine out of action for a while, drain the oil out of the pan and
put it in a large container. Let it sit for a few days and any water mixed with the
oil should separate out. Then very carefully and slowly decant the oil into a second
container until there is just a small amount of oil remaining in the first container.

If there is water it will be under the oil so be careful not to tilt the first container
far enough to empty any water out. Then, tip all the remaining contents from
the first container into a clear glass jar and let it sit a while. If there is water
in with the oil you will be able to see it at the bottom of the jar.

Cheers... jondee86
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Re: HIGH comp Big port carby build with MANY questions

Postby nyberrg » Sat Jul 24, 2021 5:17 am

Doesn't look like I have to worry about the oil. Cause my block is fucked either way :lol:

https://i.imgur.com/YS47KSY.jpg

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Re: HIGH comp Big port carby build with MANY questions

Postby allencr » Tue Jul 27, 2021 12:52 am

I wish I knew what that pic is.
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Re: HIGH comp Big port carby build with MANY questions

Postby jondee86 » Tue Jul 27, 2021 2:32 am

Yes... I have been waiting for some further information. Apparently that blackened area is a problem.
Without anything concrete to go on I'd guess that there is scaling or pitting there possibly caused by
water sitting in that cylinder for a long time. The piston looks like it may have been "steam cleaned"
if you compare it with the other piston top in view.

Maybe there is a crack somewhere ?

Cheers... jondee86
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Re: HIGH comp Big port carby build with MANY questions

Postby nyberrg » Tue Jul 27, 2021 3:46 am

I cleaned the piston off to check for damage, that'swhy it's so much cleaner than the other one. Although there has been water in the cylinders too for sure.

The image is cylinder #4 and it is pretty fucked. My guess is due to the ring gap being too tight, maybe? The block is done so I'm moving on. The bearings were also quite worn. My best guess is that it was caused by the watery oil or incorrect clearances. You live and you learn. :D

I've got a 7-rib/smallport block that I'm gonna refresh with new bearings and piston rings. I'll keep it oem and stick my largely stock bigport head on it as that seems to have no issues.

For the new block I ordered bearings from Toyota who told me that each block and crank has one of five specs on the bearings. My old main bearings from the 7-rib had the numbers 3, 3, 2, 4, 5 front to back. Sadly I could only order a set and not individual ones, so I got a set of #3's as that felt like the closest match for most of them.

I'll be more thorough with measuring clearance this time I suppose. But I don't really know how to do it best.

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Re: HIGH comp Big port carby build with MANY questions

Postby oldeskewltoy » Wed Jul 28, 2021 8:59 am

Wow.... away for a week.......

nyberrg wrote:Doesn't look like I have to worry about the oil. Cause my block is fucked either way :lol:

https://i.imgur.com/YS47KSY.jpg


Is that a crack in the liner on the far left...??? Looks a bit too vertical...

As far as gasket types - most of the aftermarket composite gaskets - I'm NOT a fan of.... I had a few fail on Grunt (my AE95 with a 4AFE)



I'll be more thorough with measuring clearance this time I suppose. But I don't really know how to do it best.


you want to use Plastigage

Image
OST Cyl head porting, - viewtopic.php?f=22&t=300

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Re: HIGH comp Big port carby build with MANY questions

Postby allencr » Sun Aug 01, 2021 3:13 am

nyberrg wrote: My guess is due to the ring gap being too tight, maybe?


No.
And I'll say that is not a guess, and I'll say that the amazing jondee86 & oldskewltoy would never guess that also.
Water corrosion, sure, but never seen one localized like that unless the engine was leaning over.
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Re: HIGH comp Big port carby build with MANY questions

Postby nyberrg » Thu Aug 05, 2021 2:36 am

oldeskewltoy wrote:Is that a crack in the liner on the far left...??? Looks a bit too vertical...


Maybe? I haven't inspected the block cause I have no plans on using it ever. I'm pretty sure those lines were there when I got it back from the machine shop but I couldn't feel them so I didn't really care. I'll take a look and update in the new thread!