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Forging/modifying a high mileage engine yay or nay?
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Author:  BecauseRaceCar [ Sun Apr 10, 2016 10:13 pm ]
Post subject:  Forging/modifying a high mileage engine yay or nay?

My car has done about 167k in miles UK spec, previously commuted in.

I have nearly worked my way through it with chassis upgrades, servicing/ refurbishment and many new parts.

Eventually after a fair amount of saving and supporting modifications in place (uprated cooling system, battery relocation, ECU etc) I want to strip and rebuild the engine, with an aim for more power. having discussed the idea of forging the original engine there was an idea that the heating and cooling of the engine over 20 years may have acted like an annealing process, making the castings subtly stronger. Is this myth or is this possible?

So would it be worth me sending my block off for ultrasound testing? Or do I need to find one with that thicker section between the cylinders?

Also where is best nowadays to shop for the big components ,pistons, con rods, cams etc...

Thanks

Author:  Diceman [ Mon Apr 11, 2016 10:59 am ]
Post subject:  Re: Forging/modifying a high mileage engine yay or nay?

I can't directly comment on the age annealing of the block and if it is just heresay or truth but considering the cost of a forged rebuild; starting with a good block that requires minimal machining, minimal overbore and has good wall thickness is a very sensible place to start. The probloem is that you can invest a reasonable sum of money getting a block tested before you know if it is any good.

IMHO I would suggest that sourcing a decent used ultrasonic gauge and hiring it out may be a sensible option. They are not that expensive for cheaper models but not having actually use done yet I don't know if they are sufficient. Most cheap ones seem to be able to read 1mm or more with accuracy of 0.1mm which spec wise seems sensible.

Author:  ST185pinjo [ Tue Apr 12, 2016 5:41 pm ]
Post subject:  Re: Forging/modifying a high mileage engine yay or nay?

What kind of power?

My original engine with 225.000 [km] {140.000 [mi]} has run the last 15.000 [km] @ 280hp on the wheels(+/-350 engine), and still going strong..(apart from being not used :oops: )
But I put her away running. :lol:

So I would first check the health of the engine and set a goal for your self, power wise, and after that start looking if you need to forge the engine.

Author:  Sirius [ Tue Apr 12, 2016 11:31 pm ]
Post subject:  Re: Forging/modifying a high mileage engine yay or nay?

My view is that given that the block will be all checked/measured/machined etc it is of lesser importance how many miles it has done and greater importance that it is in good condition and is suitable.

Author:  bricktop [ Wed Apr 13, 2016 1:01 am ]
Post subject:  Re: Forging/modifying a high mileage engine yay or nay?

It might just be a load of rubbish but I seem to remember an old wives tale that the BMW 1500HP F1 turbo engines of the 80's had the block taken from an engine that had done 100k miles.

Author:  Davem45r [ Wed Apr 13, 2016 7:50 pm ]
Post subject:  Re: Forging/modifying a high mileage engine yay or nay?

Depends on your overall goals. If you're trying to build a 600bhp screamer then maybe you'd try to source a (new if still available?) late spec block and have it checked for wall thickness. With the huge cost of that type of build why take any chances?

Even then the nature of the block casting, and the inherent problems using even the highest quality instrumentation to accurately measure the thickness of a complex iron casting makes it a bit of a punt in the dark.

If your power goals are more modest I can't see the problem in stripping down the engine and checking what the condition of the block is, and if it looks OK and doesn't need much of an overbore you're probably best going with it.

Author:  BecauseRaceCar [ Thu Apr 14, 2016 1:36 pm ]
Post subject:  Re: Forging/modifying a high mileage engine yay or nay?

Thanks for the advice, my ambitions are modest working slowly over the next few years to reach 300 then onto high 300s to 400 bhp max. Would like to see that at the wheels. I'm planning ahead really will probably lay down the base layer of supporting mods before going the whole hog.

Fmic with uprated turbo, Ecu injectors, fuel pump just the main items off the top of my head. Then see where I'm at. I think it's reasonable to use the original block if it's going to be machined etc. Not skimping on cost, but as the engine probably needs a strip down anyway might as well look at rebuilding it for more power. Thanks

Author:  Davem45r [ Thu Apr 14, 2016 3:25 pm ]
Post subject:  Re: Forging/modifying a high mileage engine yay or nay?

Trying to get my head around the connection with 'modest' ambitions and a 2L engine that throws out 250bhp/litre LOL

With 500bhp at the crank power levels mentioned I'd be starting with the best block I could get my hands on.

Author:  Diceman [ Thu Apr 14, 2016 10:02 pm ]
Post subject:  Re: Forging/modifying a high mileage engine yay or nay?

Agree with Dave. 500bhp is likely to require 2 bar which is a tall order for a 3sgte.

Either reduce your goals or be very picky on wall thickness of the block. There is a known weak spot between 2&3 so ultra sounding this area is pretty quick.

Maybe look for a 98+ 5sfe block?

Author:  TrackToyFour [ Thu Apr 14, 2016 11:23 pm ]
Post subject:  Re: Forging/modifying a high mileage engine yay or nay?

Interestingly when I visited Martin Kingston last week he said he was buying new 5S-FE blocks direct from Toyota to build up 5S-GTE engines. He has also solved the oil pump/pressure issue with this hybrid spec. This opens up an alternative engine upgrade path.

Author:  Diceman [ Fri Apr 15, 2016 9:18 am ]
Post subject:  Re: Forging/modifying a high mileage engine yay or nay?

There was an oil pump/pressure issue with 5SGTE?

I'm intrigued as I thought the 5S pump was considered a high flow upgrade for the 3SGTE by some.

Author:  Davem45r [ Fri Apr 15, 2016 11:49 am ]
Post subject:  Re: Forging/modifying a high mileage engine yay or nay?

5S=GTE hybrid probably not one for a home build unless you really know what you're doing though?

Author:  Diceman [ Fri Apr 15, 2016 1:20 pm ]
Post subject:  Re: Forging/modifying a high mileage engine yay or nay?

Definitely not IMHO.
5S crank has different big end journal diameter requiring either turning down to smaller 3SGTE size or speccing custom rods. (assuming you are using the 5S crank to get the extra displacement. 5S also has larger bore so will need custom pistons or 5SGTE specific items.
5S has different flywheel bolt spacing, requires block to be ground down to fit the 3sgte gearbox/transfer box. No piston oil squirters or oil feed takeoff for turbo (all need to be drilled & tapped if you want them!)
3S oil cooler doesn't fit straight off either.

It's all doable and most parts are available but also best left to someone who knows!

That's before you get to the water pump & oil pump differences.

Author:  BecauseRaceCar [ Tue Apr 19, 2016 8:21 pm ]
Post subject:  Re: Forging/modifying a high mileage engine yay or nay?

Quote:
Trying to get my head around the connection with 'modest' ambitions and a 2L engine that throws out 250bhp/litre LOL

With 500bhp at the crank power levels mentioned I'd be starting with the best block I could get my hands on


Err I said 400BHP never mentioned 500BHP until now. I've heard 400 is modest nowadays with the knowledge we have nowadays. I'd be happy with high 300s and longevity TBH.

Author:  BecauseRaceCar [ Tue Apr 19, 2016 8:27 pm ]
Post subject:  Re: Forging/modifying a high mileage engine yay or nay?

Interestingly I spoke to a new engine builder who has "mastered" the 3sgte called Muneeb Masters, he comes highly recommended and seems to know his stuff. Having spoken to him the cost of building an engine up is half of what most people quote.

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