forged pistons recommendations

[androo007]

its ok i'm dropping it off..... and picking it up done....

[Ryan S]

its ok i'm dropping it off..... and picking it up done....

excellent!! Remember to do a build thread!

[ashley]

Sounds exciting...who's doing the work for you?

[androo007]

The southern mr2 master.... Luke @ pacific works hopefully. Had some other bits done by them before and been very impressed. Only small mistake was done by a weekend person otherwise can't fault. Always friendly and happy to talk so gets my thumbs up

[androo007]

I'll get a thread going on the progress till now....

[Ryan S]

excellent man, Never heard a bad thing about Pacific Works

[ashley]

excellent man, Never heard a bad thing about Pacific Works

http://www.imoc.co.uk/forums/viewtopic. ... sc&start=0

[Ryan S]

excellent man, Never heard a bad thing about Pacific Works

http://www.imoc.co.uk/forums/viewtopic. ... sc&start=0

I'll assume it's all good rather than read 13 pages

[ashley]

...

[Odin_S]

Luke built my car, his attention to detail is very high. Which is why I've been going to him since '08

The only other people in the MR2 world (I've deal with) with the same level of detail are Adrian from Fensport and Patrick from Rogue

[ashley]

...

[Ryan S]

Actually I remember this thread now after skipping to the last few pages. Hopefully it works out for the OP. I sometimes think this site is built to feed some of the traders/specialists on here, anytime there's a trader feedback post that's in danger of exposing a supposedly trusted specialist on here it's taken down by admin.

I will take the time to read that thread now!

To the OP, Get a contract signed by anyone carrying out any work, get timescales added to it. Sounds extreme but it may well save you a lot of heartache, time and money!

EDIT: that was some reading, Phew....No details mentioned but Moo says "Luke shafted him".

Make of that what you will as it doesn't go into any more detail than that.

[androo007]

Sure, always remember there's 2 sides to every story. Still, I'm just going from my experience and I trust Luke and his reputation is excellent so happy enough. Anyhow let's not get onto trader wars.....but appreciate the heads up.

[Ryan S]

Sure, always remember there's 2 sides to every story. Still, I'm just going from my experience and I trust Luke and his reputation is excellent so happy enough. Anyhow let's not get onto trader wars.....but appreciate the heads up.

agreed mate, for all you're having done anyway it's not like there's a lot of problems you could run into.

When are you having the work done?

[androo007]

Fingers crossed 6-8 weeks time.....!

[tehdub]

Bit late to to the party, but I have plenty to say about the arguments on here about CR. Both camps are wrong in their own way. Going for a lower CR isn't always the best approach, but neither is raising it. It's dependant on goals, and budget. A high CR build will need more work and money, but will probably yield better results. And by results I don't necessarily mean higher peak power.

All of these discussions focus on max BHP, which actually tells you nothing about an engines performance, and is only a bragging rights figure unless quoted with the RPM's and curve.

I read Sheppy's build thread, and noted the same rubbish being spouted there.

[Ryan S]

And we've all seen how that thread turned out, page after page of rubbish...There's no arguing with people on here sometimes

My argument for (slightly) higher CR than the usual 8:01/8:5:1 is that of everyone who agrees with it. We're building engines without the setback of 20+ year old fuel and fuel management! There's no real argument for lower CR other than wanting to run silly boost!

Even Toyota raised the CR on the gen4 engines. 9:0:1 I think it is.

[tehdub]

Yup, Gen4 is 9.0, but there are changes to the combustion chamber and block. I've heard that it is the strongest of the 3S blocks. The block cracking issues are to do with cooling issues, which can be sorted for little money during a rebuild.

Thread hijacking to soapbox rant, but hey, sue me!

When you engine will start detonating or pre-ignition is grounded in chamber design, plug energy/heat, cooling abilities, ignition system technology, and CR, amongst other things.

My theory is you run the absolute highest CR possible without knock.You're right about modern fueling and EM systems. But the main thing here is that the primary enemy is heat. A main cause of both pre-ignition and detonation, but its also the the loss of heat that makes power, the more of it the better.

Hence "My theory is you run the absolute highest CR possible without knock". And on that front W/M injection helps by removing hot carbon deposits, as well as using the latent heat of vaporization to reduce charge temps (which on the face of it would make less power). I'd consider it on that basis of cleaning alone. Its nigh on impossible to avoid carbon in a used engine without it, and high comp will not like that. I'd be interested in what it does to the burn time tho. Pointless running being able to run loads of retardation, if it means that the peak pressure is way after 18 degs ATDC or whatever the optimum is.

A lot of folks say its the heat that will be caused by the massive increase in pressure that will cause some form of knock.

But here's an interesting fact I got from a book:- "Boosting an engine only results in a 25% increase in peak cylinder pressure, but results in significantly larger increases in average cylinder pressure". It should there be more than feasible to run large boost with out causing massive pressure, and thus D or PI cause by excess pressure, on a higher comp engine. There's a lot of other reasons knock could occur, but high comp is unlikely to one of them, unless you go ridiculous

Its about managing all of the other factors involved. There's little you can do about chamber design, but you can coat the pistons and chamber. This is very effective. Change the ignition system to one providing precise control of spark, and lots of spark energy and allowing a larger gap for a faster, consistent burn and cooler plugs. Modify the cooling system to ensure that all cylinders get the right cooling, and make sure the chambers get cooled properly and consistently. Modify the cooling system to prevent hot spots. And inter cooling DOES matter. Ambient temperatures are a big factor. Consistent intake temps help greatly.

This is not an exhaustive list of stuff, but you get the idea.

[Ryan S]

Everything on that list is fairly standard. Couldn't agree more about the ignition, Again with the gen4...It's coil on plug. A wee thing a friend and I were talking about was when the blocks are cracking it's usually been when a car's been sat cooling down. More cases of people parking up then driving off at a later time and noticing a cracked block than the block letting go mid journey. It may just be that we've both heard the same stories of course.

Trickster on here has had a coulple let go and he reckons it's to do with the change in water temp when the thermostat opens, I'm a bit of a believer in this theory...He said he'll never use a thermostat again!

[^Trickster^]

I actually dont think having a stat makes a difference now. I think the sum of a design flaw with the casting thickness (hence the later revision blocks) and the size of the cooling system meaning the coolant is probably quite a bit cooler by the time it comes back round are both factors, on smaller systems the system saturates and maintains a temp, I have no evidence but i think the coolant probably changes temp considerably especially at speed. Its a weak spot on the 3s, and so are the cylinder walls which still crack on the later blocks with the revised pump area.

I run a thermostat still, but on a later style 5s block now

My second block cracked on the dyno during quite a few pulls, no cooldown time.

Graeme

Edit: I didnt really read the thread, but I read the post where you say it can be sorted during a rebuild - even sleeving the cylinders doesnt stop them cracking, JJ just cracked his darton sleeves, id never build another 3s based engine. Its luck of the draw with cracking them in either cylinder walls or behind the pump, but after 2 blocks doing it to me its not a chance id ever take. Good luck with your build