Costs for rebore/head skim etc

[m1tch]

Hi all,

I will at some point (probably next year) be getting a spare engine and gearbox to build into the engine to be used in the project car, I am fine to build up a cylinder head including valve grinding etc but would need to send the block and other machining tasks to a machine shop.

The engine build will consist of:

Forged rods
8.8:1 Wiesco pistons
ARP head studs
Very light cylinder head porting (will be FI rather than NA)
Stock crank

I know that I will need to get the block bored and honed as well as the cylinder head machined flat etc but I am just wondering about the costs, it seems that I can get Wiesco pistons which are 79.5mm (eg 0.5mm oversize) without the need to have the engine sleeved. I can see I can also get 82mm and 82.5mm pistons which will require sleeves.

How much should I budget for:

Bore and hone to 79.5mm

Bore and hone to 82mm

Fitting of Darton sleeves

Cylinder head machined flat

Ideally I would just go with a bore and hone to 79.5mm (can't get Wiesco pistons in 79mm OEM size), as stock its 1794cc, boring out to 82.5mm means a displacement of 1956cc which is tempting but wouldn't really give any chance for an overbore when it wears plus the sleeve stability might not be there.

This is the first time I will need machine work done on an engine and want to build up the engine properly - just wondering how much I should expect to pay etc.

[lamcote]

I don't have any help about costs but I have read that fitting sleeves is a delicate process that, from memory, should involve something called a torque plate(?) to mimic the pressure of the cylinder head being bolted to the block. If this method isn't used it can lead to head gasket problems so I suggest, if you go for sleeves, you don't necessarily use the cheapest option unless you are fully satisfied they will be doing it properly.

[jonbill]

I think if you want to specify the machine operations and materials yourself, you can probably get it all done for a few hundred. If you want to give someone the block, pistons and head and ask them to make it all fit right for you to assemble, then add £1000.

Torque plates are also recommended for simple reboring operations, but going on the experience of my Datsun engine, no one has the torque plates and its done without, to no serious harm. If you want one, you probably have to give up a spare head for them to make it out of.

[m1tch]

I agree with the sleeve fitting being a delicate process, I think I am going to just keep with the rehone to 79.5mm as the 82/82.5mm overbore makes it almost 2 litres - the 2zz has a stroker crank to get to 2 litres whereas the 1zz just need an overbore.

I will be fitting the pistons, rods etc myself, its just the machine work that I would need so a couple of hundred sounds perfect, will see where a local place is so that I wouldn't need to pay for shipping etc to the shop.

[weeJohn]

Measure all the bores first before buying pistons, they may well be still pretty round and you may find that you dont need a rebore, just a hone. Forged pistons sometimes swell more than OEM when hot, due to their alloy content, so it may be necessary anyway but always better to check your bore diameter before buying.

[m1tch]

Measure all the bores first before buying pistons, they may well be still pretty round and you may find that you dont need a rebore, just a hone. Forged pistons sometimes swell more than OEM when hot, due to their alloy content, so it may be necessary anyway but always better to check your bore diameter before buying.

I will be measuring the bores anyway to check for oval and taper etc, will get some T gauges and a decent caliper - I think I will need a rebore though as the aftermarket pistons are 79.5mm vs the stock bore of 79mm - so almost 20 thou larger than standard, I am not sure what the usual bore wear would be. I think if I could get stock sized forged pistons it would be ok but I think because its 0.5mm oversized then I am going to need a rebore.

Plan to get the engine at some point next year to start stripping down in the garage, I can then measure up the bores and see what I want to do, don't think I want to bore out to 82mm as I don't really need the extra displacement but I feel that I should build everything as best I can and build the engine once properly.

[Carolyn]

Hi Mitch,

Before you embark on all that machining, I suggest you give the attached a good read.  It's originally a Russian article, so the  Google translation is a little sketchy.  however it is well thought through and obviously written by an engineer with some considerable expertise.

Enjoy!

 m https://www.google.co.uk/search?q=MR2+s ... zyXxExZzXM m :

[m1tch]

Hi Mitch,

Before you embark on all that machining, I suggest you give the attached a good read.  It's originally a Russian article, so the  Google translation is a little sketchy.  however it is well thought through and obviously written by an engineer with some considerable expertise.

Enjoy!

 m https://www.google.co.uk/search?q=MR2+s ... zyXxExZzXM m :

I think that might be the incorrect link!

[Carolyn]

Hmm - That was briliiant wasn't it??

I'll try again.

 m http://toyota-club.net/files/faq/04-01- ... fe_eng.htm m

[m1tch]

Hmm - That was briliiant wasn't it??

I'll try again.

 m http://toyota-club.net/files/faq/04-01- ... fe_eng.htm m

Thanks for that, was an interesting read, especially about the valves - am I correct that I'm not really able to relap the valves due to the different valve seat?

[Carolyn]

Lap yes.  Grind - I'd be very careful.

[m1tch]

Lap yes.  Grind - I'd be very careful.

Ok, will be careful when i get around to it, just in the process of calling a local engine machining place to get a quote for the work, think I will need a rebore to 79.5mm as I doubt the wear will be 0.5mm past stock on the engine I get (again not sure how much wear is normal!).

[Carolyn]

Wear will be nowhere near .5 mm.  Why do you want the Wiseco pistons?  Lower compression for a lot of boost?  Modest boost is fine with the standard 10:1.  Standard practice is just to re-hone.

[m1tch]

Wear will be nowhere near .5 mm.  Why do you want the Wiseco pistons?  Lower compression for a lot of boost?  Modest boost is fine with the standard 10:1.  Standard practice is just to re-hone.

Indeed, going to get the 8.8:1 wiseco pistons for boosted application, they are either 79.5mm or 82 or 82.5mm. I guess I could look to get new standard pistons and better rods but I thought it best to upgrade bits whilst in there. It's a shame the aren't any standard forged pistons out there which is why I'm looking to have to rebore.

[ChrisGB]

Compression that low is going to work with high boost but could make for a poor off boost performance. Just how much boost are you looking to run?

[m1tch]

Compression that low is going to work with high boost but could make for a poor off boost performance. Just how much boost are you looking to run?

Looking to run around a bar and a half eg around 20psi, the gearbox is going to be upgraded to take the extra power. I would run stock pistons and just upgraded rods but I am not sure if the stock pistons could handle the power as I know the ring land is quite near the top of the piston for emissions. Are there any good upgraded stock sized pistons out there?

[ChrisGB]

I would think forged pistons are going to be a must at that level of boost. Gearbox wise, you'll probably need an E153.

[m1tch]

I would think forged pistons are going to be a must at that level of boost. Gearbox wise, you'll probably need an E153.

Exactly what I was thinking, doubt I could get away with running stock pistons at higher levels of boost, was looking to overengineer the engine slightly so I know it won't break - don't feel like taking the engine out more than once! Not going E153 due to the weight penalty and poor gear ratios, going with a C64 box rebuilt with uprated 3rd and 4th gears from SSC, rated to 400bhp or more - they have held to 500bhp.

[1979scotte]

I would think forged pistons are going to be a must at that level of boost. Gearbox wise, you'll probably need an E153.

Exactly what I was thinking, doubt I could get away with running stock pistons at higher levels of boost, was looking to overengineer the engine slightly so I know it won't break - don't feel like taking the engine out more than once! Not going E153 due to the weight penalty and poor gear ratios, going with a C64 box rebuilt with uprated 3rd and 4th gears from SSC, rated to 400bhp or more - they have held to 500bhp.

Bhp has bugger all to do with it.
How much torque can they handle?
I know jubu do stronger 3rd and 4th never heard of SSC.
Good on you for trying something new.
Pretty sure Matt Performance was running a stock box with uprated gears on his track car.
Not sure of the outputs or how well it lasted.

[m1tch]

I would think forged pistons are going to be a must at that level of boost. Gearbox wise, you'll probably need an E153.

Exactly what I was thinking, doubt I could get away with running stock pistons at higher levels of boost, was looking to overengineer the engine slightly so I know it won't break - don't feel like taking the engine out more than once! Not going E153 due to the weight penalty and poor gear ratios, going with a C64 box rebuilt with uprated 3rd and 4th gears from SSC, rated to 400bhp or more - they have held to 500bhp.

Bhp has bugger all to do with it.
How much torque can they handle?
I know jubu do stronger 3rd and 4th never heard of SSC.
Good on you for trying something new.
Pretty sure Matt Performance was running a stock box with uprated gears on his track car.
Not sure of the outputs or how well it lasted.

SSC are slightly cheaper than the JUBA gears but not by much, torque rating is 265 ft/lbs - its a very long term project but I am gradually working out what I need for various goals.

 m https://www.monkeywrenchracing.com/prod ... a-c60-c64/ m

[HUTTY]

Hi
Stanwood Engineering at Bawtry
Cyl head skim £41.50
Cyl block bore to 79.5 £140 but they will need the pistons
They also pick up and drop off dependant on where you are

[m1tch]

Hi
Stanwood Engineering at Bawtry
Cyl head skim £41.50
Cyl block bore to 79.5 £140 but they will need the pistons
They also pick up and drop off dependant on where you are

Awesome, thanks for the info, the nearest machine shop to me I basically almost drive past on my way to work, could easily load the bare block in the car and drop it down myself, sounds like next year I will commit to the parts I want to get for the engine and order them - need to check what else is cheaper to buy from MWR all in one go.