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Loola

De-stroke a EW10J4s to 1800cc. How?

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Loola

Have someone done this conversion: De-stroke a EW10J4s to 1800cc?

Or have some ideas on how to do it.

 

I have a 206 RC/GTI 180 and would like to build it to suit the regulations of the Swedish national

Rallycross class 2150cc. 2150cc refers to the max volume for a 2-valve N/A engine.

In the beginning of year 2019 there will be an extension in the regulations allowing 4-valve engines

with a max volume of 1800cc.

 

Could I start with a crank shaft from XU7 or EW7 with stroke 81,4mm, will it fit? Is one of those

better than the other?

And then re-grind it to stroke 79mm. If I have done my math, the new diameter would go from 45mm to approx. 42mm.

If that would work, what conrods to use? (this is completely blanc to me, but I would prefer long before short ones).

 

Adjustment to the deck height will probably be necessarily. Where would the limitations be (in reason) to how much

the engine block can be skimmed?

 

Original pistons will do, but if the new conrods need a different compression height, so it will be.

Any suggestions for pistons?

 

Are there any differences to the engine block of the J4S V.S. J4, or are they from the same mold?

I ask because I have a J4 lying around, who could be a test dummy if it comes down to skimming the engine block.

 

And then the fun part, increase performance within regulation specs. But that is the next issues.

The primary target is to get a working engine base.

 

See this as a project on limited budget.

 

Pretty technical questions, I know. But I see a lot of knowledge people contributing here. So maybe someone

have some answers/suggestions. Thanks in advance!

 

 

Kind regards,

 

Loola Lindgren

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welshpug

best bet is to start with the EW7 block crank and head.

 

not sure why you think you need to grind the crank.

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allanallen
45 minutes ago, welshpug said:

best bet is to start with the EW7 block crank and head.

 

not sure why you think you need to grind the crank.

I believe he’s meaning to offset grind the crank to give less throw so he can keep the 85mm pistons

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Loola
48 minutes ago, welshpug said:

best bet is to start with the EW7 block crank and head.

 

not sure why you think you need to grind the crank.

1. The regulations says that engine block and cylinder head have to come from the same type of engine, and I like to use the EW10J4S head.

2. To keep volume to max 1800cc just by de-stroke and keep the bore as is

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Loola
10 minutes ago, allanallen said:

I believe he’s meaning to offset grind the crank to give less throw so he can keep the 85mm pistons

Allanallen,

 

Yes, you are absolutely right.

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Richie-Van-GTi
Posted (edited)

doesnt the EW7 crank fit the EW10 block? Its the same bore spacing and uses the same mains bearings. If it does maybe you can hybrid the EW10 piston and rod onto EW7 crank. Can you get a scrap 1.8 engine to strip and measure? Would come out slightly over 1800 due to piston bore/swept volume. Also be low compression

Edited by Richie-Van-GTi

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Loola
3 hours ago, Richie-Van-GTi said:

doesnt the EW7 crank fit the EW10 block? Its the same bore spacing and uses the same mains bearings. If it does maybe you can hybrid the EW10 piston and rod onto EW7 crank. Can you get a scrap 1.8 engine to strip and measure? Would come out slightly over 1800 due to piston bore/swept volume. Also be low compression

About the crank, I do not know if EW7 fit. But I shure hope so, or the plan goes out the window. I will have to offset grind the crank to keep the volume below 1800cc.

And because of that, there have to be conrods with a big end approx. 42mm diameter. I feel that finding the right conrods are the real challenge at this time.

How easy this would have been if there was a "list" containing every conrod ever made, with all the measurements included :)

To be frank, I dont have a clue where to start looking for the right conrods. And that’s why I am trying with this forum. Hoping that someone has done something like this, or close to. 

If someone would have a blueprint with all measurements of an original conrod from a EW10J4S? I would be pleased to see it.

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B1ack_Mi16

You should probably either get custom conrods or custom pistons. Trying to find something that almost fits and then need machining afterwards etc. will often get expensive in the end anyway.

 

The crank I guess will fit from any XU engine also possibly? At least DW crankshafts seem to fit XU iron blocks.

 

So pistons use whatever you like, crank, try to see if there is an OE alternative either from 1.6 XU or 1.8 XU that might fit?

Order custom rods to suit, for example from Pauter.

 

It is a bit optimistic thinking it would be possible to do a custom engine like this without any sort of significant budget.

But with custom rods and machining cost of crankshaft I still think it's possible to get the bottom end ready for about 2000£.

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B1ack_Mi16

You should possibly aim for a crank throw of 79.25mm.

This will give a 1799cc engine on a 85mm bore.

 

Big end must be 42.5mm at maximum. So you better start looking for na engine with orginal big end size in the range of 40->42.5mm so you can have a big end bearing to use with the custom rods.

 

Not sure if there is a database somewhere one can search for big end diameters.

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petert

Download the ACL catalogue.

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Richie-Van-GTi

I still do not understand why not just a 1.8 bottom end? From memory the EW10 head goes straight on EW7 bottom end anyway. Someone may correct me?

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Loola
2 hours ago, Richie-Van-GTi said:

I still do not understand why not just a 1.8 bottom end? From memory the EW10 head goes straight on EW7 bottom end anyway. Someone may correct me?

The regulations says that engine block and cylinder head have to come from the same type of engine. The head and block have to belong to each other. I choose to use the EW10J4S because I think this engine got potential, and of course the fact that I have one :)

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Richie-Van-GTi

sorry misread that part, I just read something that you wanted to use your head, how tight is the ruling on same type as they are both EW series engines so technically they would be deemed as same type head and block?

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welshpug

XU5 does fit EW7 block, same size big ends also (45mm)

 

EW7 is the same series as ew10..

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Loola

Earlier I stated that the block and head have to come from the same engine. But I must have misunderstood this in my earlier contacts with the Swedish Rallycross federation. It is okay to mix part from the same engine series. And this of course opens up more possibilities. So now I will re-think this one more time (suggestion are more then welcome). And while I do that I have a question:   Does the TU5 crankshaft fit the EW block?

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dcc

I would be tempted to use an ew12 block if you can. Extra rod length due to block height.

 

87mm bore with 73mm stroke. Gives roughly 1736cc. I know nothing about engine design mind.

 

Other option is maybe 84mm bore with 81.4mm crank. Gives you 1804cc.

 

Or if youre allowed to go 1849cc or less, 85mm x 81.4 will give you 1848cc. Can use an ew10 block then

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Loola

Thanks for all input so far!

 

At this moment my strategy to reach max 1800cc with the EW10 block is this:
XU5 crank, with 73mm throw.
Use XU5 or XU7 conrods, length 150.5mm.
Bore the DW10 block to 88mm.
Wiseco pistons.
Mill the block to get the right deck height.

 

This raises some questions

1: Boring out the cylinders from 85mm to 88mm, can the block take that?

2: Adjusting the deck height with about -4mm, can the block take that (the final decision will be made after a dry fit with measuring’s)?

3: Do the XU5/XU7 conrods have press fit or floating wristpin?

 

And for those of you who like to look at numbers (me included)
Rod to stroke ratio: 2.1
Stroke to bore ratio: 0.83
For what it is worth, this is considered to be good numbers.

So off today this seems to be the best engine build.

Any comments, what so ever, are welcome!

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Loola
5 hours ago, Loola said:

Bore the DW10 block to 88mm.

Sorry, I mean: Bore the EW10 block to 88mm.

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B1ack_Mi16

I would be tempted to say that you possibly could be able to bore the DW10 to 88mm, but to bore a 85mm EW10 to 88mm I'm not sure what to think off. 

The internal cast liner design might not be up to it, but I suggest you try it and see what happens, it could work if you're lucky.

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Thijs_Rallye

4 mm decking and expanding the bore with 3 mm and on top of all that boosting the engine. I don't know if the liners are going to be up to the challenge. Would be nice if you could scrap an engine and make section cuts of the block to verify wall thicknesses.

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welshpug

I would get decent rods to save decking the block that far, I also doubt the cast in liners will go to 88mm, 87 yes, same for DW10 block, 88 has been done but is very marginal, I would not worry about reaching 1800cc absolute, there are n-a 1750cc TU engines running near 250 bhp.

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Loola

I have a EW10J4 block to do some testing on, but are this block absolutely the same as the EW10J4S (same cast) so the findings in the J4 would be the same as in the J4S?

While I am at it, anyone who knows what the C/C lenght of the EW7 conrods are?

 

 

 

 

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Loola

A little update: FYI I have now split the cylinder on a EW10J4, and that was enlightening to say the least. Thickness of the liner differs from 2.0 to 2.5 mm. So boring it out from 85 to 88 will not work. The liner got riffles to make it sit better in the aluminium. Does anyone know if there is a thicker liner in the EW12?

 

Regards

Loola

20181108_200805.jpg

20181108_200828.jpg

20181108_201209.jpg

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welshpug

couldn't say myself if the liner is thicker, however it is 86mm to start with, so 87mm should not be an issue, DCC was planning on going 87mm with an EW12 till he changed his mind, I believe Sandy Brown has built an almost 2.3 with an EW12 block.

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Thijs_Rallye

That is one piece of marvelous casting engineering imho. I love people being this thorough when building an engine!

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