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cnewingham
Guest
I got my block assym. back and my bore is 85mm however I already bought a cometic 84mm bore gasket. I dont think this is a problem but looking for advise and opinions.
You might end up with the edges of the MHG glowplugging and causing preignition 
7M pistons pop out the bore a touch at TDC but I'm not sure if it's enough to allow them to hit the gasket.
7M pistons pop out the bore a touch at TDC but I'm not sure if it's enough to allow them to hit the gasket.
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cnewingham
Guest
Gixx: Someone posted some sonic tests on a 7M block before we were hacked and it's doable but doesn't leave much room for error.
My new block has quite a bit of core shift so I wouldn't risk it on that.
My new block has quite a bit of core shift so I wouldn't risk it on that.
Well, then my advise like the other have said would be to try to return it and get a 56mm one. Worst case, you have to try and sell the one you have and just buy a new 86mm gasket.cnewingham said:
You cant. Well, you could put it out as far as you want until it hits the next cylinder, but he will grenade the engine. The factory only sells .5mm over for a reason. 1mm can be done with precautions.
Get a new headgasket.
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cnewingham
Guest
So you think I am going to grenade the engine? I dont think so. I bought the car with rodknock (owners error) and it had been running great prior to him losing a line to the oil cooler. It was far from stock. The head is ported and polished and was running HKS cams, HKS long runner manifold with a 60 trim t04, the same forged pistons that are in there know. Etc.. as the list goes on. When I tore the block down the cylinder walls were in awesome condition so the block appeared to hold up pretty well.
Automotive wise, grenade doesnt mean to explode like a handgrenade. There isnt enough cylinder pressure to break apart the cast iron block. Grenade is just a term for ruining the engine past the point of being able to rebuild. And yes, it wont last long.
But what do I know, I have only had to do less than 200 Toyota engines, so I dont have any experience/education/knowledge on the subject.
u sure its that big of an overbore?_? looks smaller to me.cnewingham said:So you think I am going to grenade the engine? I dont think so. I bought the car with rodknock (owners error) and it had been running great prior to him losing a line to the oil cooler. It was far from stock. The head is ported and polished and was running HKS cams, HKS long runner manifold with a 60 trim t04, the same forged pistons that are in there know. Etc.. as the list goes on. When I tore the block down the cylinder walls were in awesome condition so the block appeared to hold up pretty well.
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cnewingham
Guest
I know what grenade is NickM, I am not stupid! and as far as it not lasting long you dont know what you are talking about considering how many miles (roughly 30,000) the engine already had before it got rod knock.
Yeah o.k. 200 engines and you know all. Who cares how many you have built. I ran an engine and trans repair shop and I knew mechanics that have built motors for 20 years and still didnt know what the hell they were doing. Not trying to start crap but I asked about the hg, not if you think my motor was going to last or not because it has already proven it will last.
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cnewingham
Guest
That engine in the pic has not been punched out eighty thousandths of an inch.
And I am not a mechanic, but it is your engine. Have fun with it.
And I am not a mechanic, but it is your engine. Have fun with it.
Just thought I'd post this up taken from the above pic!
Where I've put the arrow is the start of a stress riser that if left unchecked may end up as a crack from the steam hole to the headbolt hole!
I have a couple of blocks here with cracks in this location , an easy way to help prevent it is to chamfer the hole as this removes the torn edge left from decking.
You can use a dremel with a small mounted point stone to take the sharp edges off all the holes in the deck!
Where I've put the arrow is the start of a stress riser that if left unchecked may end up as a crack from the steam hole to the headbolt hole!
I have a couple of blocks here with cracks in this location , an easy way to help prevent it is to chamfer the hole as this removes the torn edge left from decking.
You can use a dremel with a small mounted point stone to take the sharp edges off all the holes in the deck!