130 replies to this topic

[zebwach]

Due to recent chemical analysis to test for a suspected leaky head gasket, I have decided to go down the full engine rebuild route while the head is off. The reasons for this are as follows: 1) I am currently running a CMS Stage 4+ map and don't trust the rods to cope with the 340lbs of torque for much longer. 2) The BHP per tone that I currently have no longer excites me the same way it used to. 3) I like to buy new shiny things for my little plastic rollerskate! The aims for the build are as follows: 1) By far the main goal for this build is massive reliability. I use this car everyday and intend to carrying on doing so, so I need it to be able to take a lot of miles on the clock without giving me any issues. Future proofing while things are in bits has also worked out as a nice money saver for me in the past. e.g putting a clutch in that can take a lot more power than you are currently producing. 2) I primarily use it as a road car and so I want as much usable power as possible. I'm not after huge BHP figures that are only accessible at the top of the rev range via shed loads of turbo lag. Lots of mid range torque and a power band as wide as possible is the aim. I have owned and driven my VXT everyday for almost four years now and apart from the common clutch slipping, exploding radiators and cold fingers in the winter, it has been a very reliable, comfortable and pleasurable car to drive. Along the way I have met a fair few of you whether it be meets, track days or from selling and buying parts. For those of you that don't know me I shall list the current spec of my car so that you know from what baseline I am starting from. Handling Nitron Street Series TD 1.2's with Toyo R1R's Uprated and stiffer ARB Scared Stiff Geo Brakes Mintex 1155's Braided Hoses ABS bypass switch Standard calipers (recently refurbished) Engine PA Radiator PA Charge Cooler PA large fuel tank Gear box breather Uprated fuel pump AET Hybrid Turbo (Up for sale soon) Miltec exhaust (now sold) Large top hat (up for sale soon) Daggles adapter! Balancer deletion kit Under drive pulley Light weight flywheel 6 paddle clutch And now for the partly purchased shopping list: Garrett TT35 turbo - with ceramic coating CMS cast manifold - with ceramic coating 3inch full de-cat exhaust - with ceramic coating Uprated stronger/lighter connection rods - cryogenicly frozen Cosworth pistons - cryogenicly frozen LET block bored out to fit larger pistons - cryogenicly frozen Uprated bearings everywhere Lightweight/knife edged crank shaft machined from a single piece of billet - Not yet confirmed CMS high flow inlet manifold Enlarged top hat and larger connecting pipe work CMS re-map The head shall be skimmed and checked for serviceability. Most of this work shall be carried out by the infamous Duncan (Duncan VXR) with certain aspects being dished out to other company's, as detailed below. Duncan has and will in affect be acting as project manager by co-ordinating and planning almost all of the work that shall be undertaken. I have set no deadline or time line and have expressed that, due to Duncans immenent baby boy, I don't mind if I dont have her back by this time next year. He is after all doing me a big favor by 'fixing my head gasket thoroughly' for me on such short notice considering he has officialy retired from VX employment. So a big thank you to Duncan for what you are about to do. Please don't change your mind! Cryogenic frezzing - http://www.frozensol...2009_01_008.htm Ceramic Coating - http://www.zircotec....rmance_white/41 Block machine work and dynamic balancing - Not yet decided. Re-mapping - http://www.courtenaysport.co.uk/ Despite there being no time line, an estimated date of "around Christmas" has been set in jelly. Duncan has also said that he will send me pictures to post as new shiny bits arrive and things become disassembled. Weights of new and old of everything shall also be included for the benefit of anyone also thinking of going down this path. From viewing what other people have achieved from similar modifications, I estimate BHP to be around 370 and torques to be approximately 350. I hope you enjoy reading about the progress of my build. Zach

[VXTyrant]

Sounds good Zach! I can't imagine the finished product being anything other than fantastic Just please don't forget my PM... please Good luck with it all!

[zebwach]

I have not forgot you, don't worry! You shall have first refusal on the AET when it goes up for sale. I forgot the most important reason for all this work. I don't want MrSimba showing me a clean pair of heels in his 911 Turbo 510bhp monster at the 2011 Midlands meets! A Quaif ATB and/or traction control may be fitted if available traction is 'found to be wanting' on dry roads.

[MrSimba]

Zach you nutter!!! So you needed a headgasket and that's your 'solution'... I salute you!!!! 'Man maths' at it's finest!!!

Edited by MrSimba, 28 October 2010 - 08:33 PM.

[kipper]

Cryogenic freezing, I'm intrigued ! Is the process applied before of after machining? How does it affect different metals in the same component. How costly is it? Dave

[danger7]

Hello, What size pistons are you specifying for your engine rebuild. Machining the bores out on an LET can lead to dangerously thin walls between the water galleries. I exploded an Z20LEH block which cracked and blew out shrapnel due to running 1.4 bar boost pressure. The max piston oversize escapes me 80. someat I'll check and cosworth is Mahle and OEM pistons on an LEH engine are very very good. I'm running an LEH cylinder head with LEH bottom end internals with a C20LET block with a Garrett G2871 bolted onto a custom exhaust manifold no AMM ecu runs off lambda and air temps. Cheers Ian

[zebwach]

Thank you for the kind-ish comments guys! The freezing takes place after machining. I only know what is stated on their website, which also states that its not horrendously expensive. I have been trying to contact them today for exact prices. Ill keep trying and post exact prices when I find out. The pistons are only over sized by .5mm in order to take up the slack from the re bore of the cylinders. I have heard about the cylinder walls being a weak point, which is why im so enthusiastic about the cryogenic freezing. I'm hoping it will help strengthen the block. I will know more when I get through to them on the phone. I have heard good things though. Prices for the 'Performance White' ceramic coating are as follows: £184 for the exhaust manifold £125 for the turbo £45 per foot of exhaust All these prices exclude VAT and shipping is £15. For the benefits and longevity that this has, especially for our application, I think this is well worth the money. Zach

[VXT Tim]

Good stuff zach. Is this the vx that is currently sat in Duncans garage?

[zebwach]

Iv just got back from the gym and im a bit giddy! The block, rods and pistons will be frozen before the block is machined. Despite it saying on their website that there will be no dimension changes. Cheers Tim. It is yes.

[zebwach]

Hello,

What size pistons are you specifying for your engine rebuild. Machining the bores out on an LET can lead to dangerously thin walls between the water galleries. I exploded an Z20LEH block which cracked and blew out shrapnel due to running 1.4 bar boost pressure. The max piston oversize escapes me 80. someat I'll check and cosworth is Mahle and OEM pistons on an LEH engine are very very good. I'm running an LEH cylinder head with LEH bottom end internals with a C20LET block with a Garrett G2871 bolted onto a custom exhaust manifold no AMM ecu runs off lambda and air temps.

Cheers
Ian

Danger, thanks for your feedback.

Are you saying that the CMS Cosworth and Mahle pistons are exactly the same and produced identically?

If I were to source a C20LET block, would this mitigate any issues of "thin walls between the water galleries"? What other implications, pro's and con's are there with substituting the block and non of the peripherals?

Zach

[Ground Effect]

Zach you nutter!!!

So you needed a headgasket and that's your 'solution'... I salute you!!!!

'Man maths' at it's finest!!!

Sounds like a 911 turbo eatin spec to me

Sam.

[Winstar]

Thank you for the kind-ish comments guys!

The freezing takes place after machining. I only know what is stated on their website, which also states that its not horrendously expensive. I have been trying to contact them today for exact prices. Ill keep trying and post exact prices when I find out.

The pistons are only over sized by .5mm in order to take up the slack from the re bore of the cylinders. I have heard about the cylinder walls being a weak point, which is why im so enthusiastic about the cryogenic freezing. I'm hoping it will help strengthen the block. I will know more when I get through to them on the phone. I have heard good things though.

Prices for the 'Performance White' ceramic coating are as follows:

£184 for the exhaust manifold
£125 for the turbo
£45 per foot of exhaust

All these prices exclude VAT and shipping is £15.

For the benefits and longevity that this has, especially for our application, I think this is well worth the money.

Zach

a couple of comments

I'd be carful, or more to the point need some reasurance, that the diferent thermal expansions of the block and liners is taken into account. Also from the papers I've read on it I'm not sure how much benifit it will be on Aluminium as the grain structure doesn't change in the same way as steel/iron.

As for ceramic coating unless you coat the internal surface of the componets then you'll increase the temperatures the metal reaches in turn increasing the stresses in the components and reducing the strength. You will however stop the heatsoak into the engine bay, but this is more of a problem with the tubular manifolds than the cast ones.

[MrSimba]

Zach you nutter!!!

So you needed a headgasket and that's your 'solution'... I salute you!!!!

'Man maths' at it's finest!!!

Sounds like a 911 turbo eatin spec to me

Sam.

Lol! Sounds like it to me too!!!

When DG's finished tinkering it will be the fastest VXT in the country I've no doubt!

Edited by MrSimba, 28 October 2010 - 10:03 PM.

[zebwach]

Thank you for the kind-ish comments guys!

The freezing takes place after machining. I only know what is stated on their website, which also states that its not horrendously expensive. I have been trying to contact them today for exact prices. Ill keep trying and post exact prices when I find out.

The pistons are only over sized by .5mm in order to take up the slack from the re bore of the cylinders. I have heard about the cylinder walls being a weak point, which is why im so enthusiastic about the cryogenic freezing. I'm hoping it will help strengthen the block. I will know more when I get through to them on the phone. I have heard good things though.

Prices for the 'Performance White' ceramic coating are as follows:

£184 for the exhaust manifold
£125 for the turbo
£45 per foot of exhaust

All these prices exclude VAT and shipping is £15.

For the benefits and longevity that this has, especially for our application, I think this is well worth the money.

Zach

a couple of comments

I'd be carful, or more to the point need some reasurance, that the diferent thermal expansions of the block and liners is taken into account. Also from the papers I've read on it I'm not sure how much benifit it will be on Aluminium as the grain structure doesn't change in the same way as steel/iron.

As for ceramic coating unless you coat the internal surface of the componets then you'll increase the temperatures the metal reaches in turn increasing the stresses in the components and reducing the strength. You will however stop the heatsoak into the engine bay, but this is more of a problem with the tubular manifolds than the cast ones.

Thanks for the feedback Winstar.

I have yet to talk to them in detail about the application of the freezing. But as it is a lardy ass'd iron block and the effect of the restructuring of the grain goes through out the metal and and not just the surface. This has to be a good thing? All the components are dipped separately so even if there were any mild expansion/contraction differences between the metals, it would be irrelevant as the block shall be bored to fit the pistons afterward.

I am aware of the stresses incurred by using thermal insulation. The main problem from this is when it is not evenly distributed, especially conman with wrap, which can cause localized stressed. This is normally when failures can happen. I am hoping to avoid this by having everything covered in a precise .3mm of the stuff. I spoke to the company about covering the internal surface also. They advice strongly against it as:

A It reduces the internal diameter of the pipe
B It is such a harsh invironment with the temperatures and flow of air, that the coating can't be guaranteed to stick indefinitely. If bits were to flake off and go through the turbo, this would not be good!

[zebwach]

Zach you nutter!!!

So you needed a headgasket and that's your 'solution'... I salute you!!!!

'Man maths' at it's finest!!!

Sounds like a 911 turbo eatin spec to me

Sam.

Lol! Sounds like it to me too!!!

When DG's finished tinkering it will be the fastest VXT in the country I've no doubt!

I wouldn't see which way you went if the road conditions aren't dry though!

I like the large power band with a big lump of mid-range torque, hence the reason for keeping OEM cams. It allows for effortless overtaking.

[Duncan VXR]

Zac I feel knackered just reading all of that work, let alone doing it Your list brings back some fun memories late into the night getting finished hehe Winster good feedback, Zac does have the temptetion to do everything to this engine but trying my best to keep him under control (only kidding Zac, love how passionate you are about this next stage of work) I am due to go to the local machine shop that was recommended to me by a good friend who uses them and from speaking to them are just the company I love to deal with. Turns out they had a vxt owner in a year ago wanting a all singing and dancing crank and flywheel machined from a billet and sitting on the shelf so depending on exactly what it is may end up in the engine at the right price, been knife edged etc also and was only going to get mild work done originally on Zac's and main area of time spend on balancing Atm we are retaining std cams to retain the extra midrange torque Zac loves but have assured him 370bhp and 350ft/lb of torque is going to be bloody quick!!!! Can't wait I know aof a lot of friends and their companys using the ceramic coating service to good effect but not aware of many doing turbos and cast manifolds so a bit more investigation needed her I feel, same as deep freeze, sounds great in theory and not silly expensive but no experiance of it at all As of this morning test to work had to talk Zac out of dry sump and be happy with a baffled one It is in the garage and part stripped ready for Sunday when its clam off, engine out, box split etc. Maybe even start to strip the engine depending on how long I stick with it. Of course will try my best to take many many pics and do wewighing of oe v's upgraded or after any work noting all tollerances etc etc DG

[siztenboots]

yet another garrett , yawn.

[Duncan VXR]

yet another garrett , yawn.

You know it makes sense Steve

[Winstar]

Thanks for the feedback Winstar.

I have yet to talk to them in detail about the application of the freezing. But as it is a lardy ass'd iron block and the effect of the restructuring of the grain goes through out the metal and and not just the surface. This has to be a good thing? All the components are dipped separately so even if there were any mild expansion/contraction differences between the metals, it would be irrelevant as the block shall be bored to fit the pistons afterward.

I am aware of the stresses incurred by using thermal insulation. The main problem from this is when it is not evenly distributed, especially conman with wrap, which can cause localized stressed. This is normally when failures can happen. I am hoping to avoid this by having everything covered in a precise .3mm of the stuff. I spoke to the company about covering the internal surface also. They advice strongly against it as:

A It reduces the internal diameter of the pipe
B It is such a harsh invironment with the temperatures and flow of air, that the coating can't be guaranteed to stick indefinitely. If bits were to flake off and go through the turbo, this would not be good!

Just looked at a few pics of the LET block and it doesn't have liners (doh!) will should be fine. I'm still dubious about how it can work on ali

The main stresses in a manifold are where the branches join and are function of the thermal expansion and the hotter it gets the more thermal expansion. Yes by keeping the metal the same temp through the thickness you reduce the bending stress component but the strength of metals also greatly reduces at very high temperature.

yet another garrett , yawn.

Holset FTW

[siztenboots]

i was thinking something like this guy has on his c20let , but packaged differently