Line Boring


DV8

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Anyone ever had this done - had my bottom end looked over and the machinist thinks this is one of the reasons my engine failed.
 


stoo.c

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Not the cheapest thing to get done as its not very common. It may be cheaper and easier to get a different block to be honest however if you are going to get it done, make sure you get a good machine shop on the case.
 


Murray

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What was wrong with your motor? I can only assume it was crank related that failed.
Buying another block would be more expensive than line boring.
Any reputable engine builder can do this or have it done no problem.

Murray
 


stoo.c

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Depends how much you pay for a block. You should be able to get an empty b18 block for £100 or a complete one for £200 or so.
 


Rory

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With the possibility of that block needing done aswell.....

Depends how much you pay for a block. You should be able to get an empty b18 block for £100 or a complete one for £200 or so.
 


stoo.c

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yeah thats a fair point but its unlikely. I think most of this is largely irrelevant anyway without actually knowing what the problem was in the first place lol.
 


Rich777

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Don't bother, depending on how aggressive the line hone will be will determine whether or not you can use Honda's bearing systerm. Its something i wouldnt recommend, but other's may say different. How much is it out by ? Did you spin the crank by hand when you assembled the engine previously ? If it spun freely it would'nt of needed line honing.

BTW, did you fit a oil pressure gauge ? if so what was your oil pressure when the engine was built and when it failed ? Come to think about it i don't think you would of made it to the ferry let alone Germany if your mains were out of line...
 


stevenEK9

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Car sounded too smooth before hand for it to be out of line!

Really think it was the temps that killed the motor, even running my heaters blazing and with a full width koyo i saw almost 120 degrees and thats with my manifold wrapped and other cooling aids

Your car must have been running AT LEAST 140/150 degrees oil temps with the heaters set full cold / half width oem radiator and doing a couple laps at a time

Guess all we can do is speculate though

Did the oil pump fail again from swarf off the spun bearing or was it due to more leftover swarf from the engine machine work do you know??
 


Rich777

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That could of been the problem as the oil would of started to brake down. What oil was you using ? You would of needed at least a 10w 50 for those temps. What bearing clearences were you running to ?
 



DV8

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Not the cheapest thing to get done as its not very common. It may be cheaper and easier to get a different block to be honest however if you are going to get it done, make sure you get a good machine shop on the case.

What was wrong with your motor? I can only assume it was crank related that failed.
Buying another block would be more expensive than line boring.
Any reputable engine builder can do this or have it done no problem.

Murray

Depends how much you pay for a block. You should be able to get an empty b18 block for £100 or a complete one for £200 or so.

With the possibility of that block needing done aswell.....

yeah thats a fair point but its unlikely. I think most of this is largely irrelevant anyway without actually knowing what the problem was in the first place lol.

Cool, thanks guys... something to think about.

Don't bother, depending on how aggressive the line hone will be will determine whether or not you can use Honda's bearing systerm. Its something i wouldnt recommend, but other's may say different. How much is it out by ? Did you spin the crank by hand when you assembled the engine previously ? If it spun freely it would'nt of needed line honing.

BTW, did you fit a oil pressure gauge ? if so what was your oil pressure when the engine was built and when it failed ? Come to think about it i don't think you would of made it to the ferry let alone Germany if your mains were out of line...

Yeh it spun completely freely when we assembled it... glided beautifully. Nah sadly didnt have an oil pressure gauge but will def be fitting one to the next project.

Car sounded too smooth before hand for it to be out of line!

Really think it was the temps that killed the motor, even running my heaters blazing and with a full width koyo i saw almost 120 degrees and thats with my manifold wrapped and other cooling aids

Your car must have been running AT LEAST 140/150 degrees oil temps with the heaters set full cold / half width oem radiator and doing a couple laps at a time

Guess all we can do is speculate though

Did the oil pump fail again from swarf off the spun bearing or was it due to more leftover swarf from the engine machine work do you know??

Yeh that's true, it did sound sweet before. And it did get VERY hot too.

Oil pump pressure relief valve was stuck open again and the gear faces look like the moon. :(

That could of been the problem as the oil would of started to brake down. What oil was you using ? You would of needed at least a 10w 50 for those temps. What bearing clearences were you running to ?

5w 40 Fully Synth Mobil Super 3000. OEM clearances as per the honda manual - all were checked and within tolerance.

Just had my camper van engine rebore to .5 over size cost my £100 +vat

Are you on about cylinder bores or crank carrier bores? If it's crank carriers that's not bad money.

The guy at the machine shop said they would machine them to OEM honda spec by making them smaller first... still not sure if I fancy doing this though...
 


Rich777

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Try running the clearences a bit looser next time to provide extra cooling for the journals. .0017 for the mains and rods will be better if you going to be driving like a nutter... he,he
 


incy-spider

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Car sounded too smooth before hand for it to be out of line!

Really think it was the temps that killed the motor, even running my heaters blazing and with a full width koyo i saw almost 120 degrees and thats with my manifold wrapped and other cooling aids

Your car must have been running AT LEAST 140/150 degrees oil temps with the heaters set full cold / half width oem radiator and doing a couple laps at a time

Guess all we can do is speculate though

Did the oil pump fail again from swarf off the spun bearing or was it due to more leftover swarf from the engine machine work do you know??

Its not that they were out of line, some are out of round! Pinched on the sides and a bit loose on the upper and lower.. Slightly egg shaped. The engineer seems to think they could of been like this beforehand which could of caused an extra bit of stress on the bearings at a zillion RPM!!

The line boring process involves taking a tiny amount off of the cap face which makes the bore slightly smaller then honing it out to OEM specs, quite clever and if done well could potentially be better than OEM!?
 


Murray

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Try running the clearences a bit looser next time to provide extra cooling for the journals. .0017 for the mains and rods will be better if you going to be driving like a nutter... he,he

A good oil cooler setup would be more than good enough, more oil capacity and better oil and water temps.
I wish i had done this when i boosted my honda a couple years back.


Its not that they were out of line, some are out of round! Pinched on the sides and a bit loose on the upper and lower.. Slightly egg shaped. The engineer seems to think they could of been like this beforehand which could of caused an extra bit of stress on the bearings at a zillion RPM!!

The line boring process involves taking a tiny amount off of the cap face which makes the bore slightly smaller then honing it out to OEM specs, quite clever and if done well could potentially be better than OEM!?

You have to take material of both surfaces so you can hone the journals round again, or you would have to hone the cap to suit the block.

Murray
 


Rich777

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A good oil cooler setup would be more than good enough, more oil capacity and better oil and water temps.
I wish i had done this when i boosted my honda a couple years back.




You have to take material of both surfaces so you can hone the journals round again, or you would have to hone the cap to suit the block.

Murray

Yes, but there is no halm what so ever in running the clearence's a bit looser for extra insurance. Its not like i'm suggesting to run them looser than Honda's spec's. It will help keep the journals cooler which for this sort of driving is important. When building a engine you need to choose clearence's to suit the application. In this case it would be a good idea to run the looser, & yes of course the oil cooler :nice: .
 


Murray

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Nope there isnt any, just not too slack haha.
As you say improved cooling of the journals at the expense of a very slight drop in oil pressure. A trade off in any engine build.:nice:

Murray
 


Rich777

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But high oil pressure doesnt really save engine. You want "good flow" and enough pressure to produce a hydo film. .0017 won't drop the oil pressure much really, i know people that have run looser than than on boosted setups (with stock unmodified oil pumps). Remember Honda's tend to run really high oil pressure as it is :nice:
 


Murray

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But high oil pressure doesnt really save engine. You want "good flow" and enough pressure to produce a hydo film. .0017 won't drop the oil pressure much really, i know people that have run looser than than on boosted setups (with stock unmodified oil pumps). Remember Honda's tend to run really high oil pressure as it is :nice:

Indeed:cool:
 



DV8

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Do you guys know what specs they would be line bored out to (what the standard Honda specs are). Can't find them in the Honda Rebuild manual anywhere...
 


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