Are modified/rebuilt engines reliable?

[e8_pack]

I've always tinkered with my cars and just recently I've been shopping for another, and modified cars always catch my eye because, well it might save me some cash when I enevitably start to tinker.

However, I've also blown engines, engines built by people who think they know what they are doing. Scanning the gtr/evo forums even some of the biggest budgets also end up with blown engines from otherwise reputable engine builders.

As a manufacturing engineer the one thing that sets apart a controlled factory environment is predominantly procedure and a team of people able to solve problems and enforce quality. is it to much to ask for one loan engine builder on a remote industrial estate to replicate those conditions?

Any thoughts? Would you buy a modified car?

[XJ Flyer]

There are basically two types of engine modification.One is by increasing the specific torque/power outputs of an engine which will mean increasing the pressures within the engine and/or it's running speed.The other is to leave the specific outputs more or less the same but get the extra output by increasing the size of the engine.In general it's the latter of those ideas which is the more reliable of the two but means looking for something with engine capacity increase potential.While in the case of the former the usual race engine builders guarantee applies.IE it's guaranteed to run and it's guaranteed to blow up but what they can't guarantee is the amount of time between the two.

Edited by XJ Flyer on Sunday 25th August 14:45

Edited by XJ Flyer on Sunday 25th August 14:48

[Toltec]

It could be less to do with the build and more to do with the way you are using it. After all you are not only increasing the stress on the parts, but increasing the duration they are put under stress.

All you need is one component or system to underperform . and you can have a failure. Brief blockage in an oilway, low oil pressure due to surge in the sump, one cylinder running slightly leaner, & etc.

Ref the thread about manufacturers not mapping their engines

[ejenner]

Completely depends on the person who has done it and what they did. Not a question you can really answer with a 'yes' or 'no'

If you are spending a lot of money on a car you'd want to see invoices from reputable companies. If a cheap car (sub 5k perhaps) then take a risk, won't be the end of the world if things go wrong... obviously not what you want... but if the worst did happen then not the end of the world.

[Tango13]

My brother used to build his own 350LC race engines, he would get the barrels ported by a tuner along with the squish on the heads but the actual build was his job and his alone.

He would de-burr and inspect every part of the crankcases then grit blast the main bearing journals to ensure the main bearings didn't spin.

The crank itself was ttted with a very large mallet until it ran exactly true, when I say true I mean less than 0.001" TIR

When the engine was built up the squish was measured with the tried and tested lead solder and micrometer technique. Base gaskets were added along with a torque wrench on the head to ensure the squish was exactly 0.040" +/- 0.002 IIRC

This was back in the day of single electrode spark plugs so each plug was indexed to ensure correct burn.

Plug chops were carried out on a religious basis to confirm the jetting.

He would then replace the pistons and rings two thirds into the season just in case, every other bugger had grenaded their engine by mid point in the season.

Is a modified/rebuilt engine reliable? Google 'Tony Scott RC30' for the answer.

[JagXJR]

ejenner said:

Completely depends on the person who has done it and what they did. Not a question you can really answer with a 'yes' or 'no'

If you are spending a lot of money on a car you'd want to see invoices from reputable companies. If a cheap car (sub 5k perhaps) then take a risk, won't be the end of the world if things go wrong... obviously not what you want... but if the worst did happen then not the end of the world.

+1

[SteveSteveson]

Short answer No

Long answer Only trust one that you know what has been done, by who and if you know what you are looking at. So again, if your buying it from someone else do so with extreme care and if you have to ask if they are reliable you probably don't know enough to do it safely.

[deltashad]

Choose your mechanic with caution.
Replace the oil pump, water pump, belts, tensioners and hoses if there is any doubt in their condition.

One of my cars are having an engine rebuild at the moment. I have no concerns with the work or the result.

[crossy67]

e8_pack said:

I've always tinkered with my cars and just recently I've been shopping for another, and modified cars always catch my eye because, well it might save me some cash when I enevitably start to tinker.

However, I've also blown engines, engines built by people who think they know what they are doing. Scanning the gtr/evo forums even some of the biggest budgets also end up with blown engines from otherwise reputable engine builders.

As a manufacturing engineer the one thing that sets apart a controlled factory environment is predominantly procedure and a team of people able to solve problems and enforce quality. is it to much to ask for one loan engine builder on a remote industrial estate to replicate those conditions?

Any thoughts? Would you buy a modified car?

Did you blow your 3SGTE?

[e8_pack]

Was a few years ago, broke some since.

Car under consideration:

http://pages.ebay.com/link/?nav=item.view&id=1...

[Big Fluffy One]

Simple answer is that you buy a recon/mod engine the same way as you buy anything else. There's no reason for them not to be reliable.

You pay peanuts then you get a job done by monkeys - you go to a reputable firm then you should get a warranty.

[Big Fluffy One]

Simple answer is that you buy a recon/mod engine the same way as you buy anything else. There's no reason for them not to be reliable.

You pay peanuts then you get a job done by monkeys - you go to a reputable firm then you should get a warranty.