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Atlaskrukvaxt

camshafts for upgraded XU10J4R

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Atlaskrukvaxt

Hello!

 

Sorry if this is not the right place but I didn't think it approperiate to post in the engine maintainance and upgrades forum as I don't have the physical engine (yet).

Anyway this became longer than I had imagined.

 

For clarification I will be mainly speaking of 4 different engines by their short engine codes as I can't be bothered to type out the whole engine name.
XU10J4R RFV 99kW fitted in the 406, xantia and 806 etc
XU10J4RS RFS 122kW fitted in Xara VTS, 306GTI6 etc
XU10J4D RFT 110 kW fitted in 306 s16, 405 MI16 etc

XU10J4L RFY 112 kW fitted in 405MI16 and 306s16 etc

(according to wikipedia, lol)

 

As the RFT, RFS and RFY engines are quite rare to find by themselves or mounted in cars that are affordable/not worth keept running (where I live) I'm looking at a RFV engine upgrade for my 405 (that you may have seen).

However, I've spoken with another user briefly about the engine a month or so ago and he said getting performance cams to work in the engine is basically not possible. I don't know specifically which cams he had tried, I have asked but he hasn't responded

From what I've gathered from the threads I've read the engines have;
-different compression ratios due to a different size dish in the pistons and even different pistons,
-slightly different port sizes, 
-different intake manifold designs,
-some variations of (at least) the RFV doesn't have oil squirters

-floating pins vs presfitted pins

-double valve springs in e.g. the RFS

-same conrod length on RFV and RFS but different to RFT (and RFY?)

I'm then wondering, since they have so similar architecture could one not just fit stock RFS, RFT or RFY cams in the RFV engine and get somewhat similar performance? I get that clearance might be an issue but since the engines ought to be so similar (in my mind) I have a hard time imagining why. To my plebian brain fitting a slightly thicker gasket or removing 1mm from the pistons ought to fix this, or?

if it is of interest to you I'm basically looking to take the RFV engine and
-make a custom intake manifold with larger and straight pipes,
-mount a 70 ish mm throttle body and 200-300ccm injectors from a 2,5L volvo 960, 
-put a sport catalytic converter on it, stick with the original 2 inch exhaust or maybe upgrade the pipes to 2,5 inches but keep the mufflers as I'm a cheap.

(A lot of NA volvo tuners make their exhausts 2,5 inches since 3 is too big and doesn't create enough back pressure when going just over 200bhp.)

- MAXXECU street or sport depending on what my aquaintance has a spare of, he is the local reseller of the ecu system.

 

I'll answer some questions/comments I fear might pop up, at the risk of sounding arrogant. Sorry.

 

Why am I manufacturing parts when e.g. gti6 manifolds are available? Well, I'm a cheap and we have the technology and materials to make manifolds.

"this is so expensive for little gain" well, most of the parts I already have and the ECU is the most expensive part which can retroactively be modified to fit another project.

"Just buy a used X engine and.. " No. 

P.s. Is the amount of ticking on my currently fitted XU10J2C (RFX) engine too much, if so what might be the cause? I've tried with starter spray all over the intake manifold but no difference so it's not leaking there.

I'd much appreciate your thoughts/feedback/comments on anything and everything. 
Thank you for reading! 

Edited by Atlaskrukvaxt

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DamirGTI
2 hours ago, Atlaskrukvaxt said:

P.s. Is the amount of ticking on my currently fitted XU10J2C (RFX) engine too much, if so what might be the cause? I've tried with starter spray all over the intake manifold but no difference so it's not leaking there.

 

 

Look around the exhaust manifold for cracks , leaky head-to-ex. manifold gaskets , leaky ex. manifold-to-down pipe cone mesh ring .

 

If that's all good , i'd whip off the valve cover and check the valve clearances .. these are adjustable , there's shims beneath the buckets .

 

 

The story with the XU10J4R RFV engine is kinda same as with the XU10J2TE - "de-tuned" from factory with crap camshafts , crap inlet and exhaust manifolds .

 

XU10J4R head is very much similar to the XU10J4 and XU10J4RS , big wide ports and similar valve sizes .. but mild camshafts , soft valve springs , restrictive inlet and exhaust on the XU10J4R .

 

Try google search trough the forum : XU10J4R site:205gtidrivers.com  .... as there's a lot of info written about these engine during the years , pretty much all you wish to know about them .

 

D

 

Edited by DamirGTI

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petert

 A long question deserves a long response. XU9J4(D6C) and XU10J4(RFY) heads are similar architecture. They share the same valve train and you can swap cams between them easily. XU10J4R and XU10J4RS are similar architecture. However, they don't share ANY of the same parts. Whilst an XU10J4RS cam will fit into a bare XU10J4R head, you shouldn't do it.

 

The XU10J4R has integral valve seals/spring bases and single beehive springs. The XU10J4RS has normal spring bases, separate seals and double springs.

 

The XU10J4RS camshaft has 0.395" max lift. If you observe the rule of allowing for 0.007" between each coil at full lift, you risk spring bind by fitting the RS cam into the R head. Maximum safe lift in an R head is approx. 0.380".

 

The R head has the same size valves and ports as the earlier D6C and RFY heads, so it flows really well. However, the valve train is the limiting factor.

 

Additionally, R cams are very small. ie 195º duration @ 0.050" lift, compared to 205º for the RS and 218º for the XU9J4 & XU10J4. Thus it's impossible to regrind anything useful onto an R camshaft. You can buy aftermarket RS cams, but they'll all have too much lift for the standard beehive springs.

 

The cost of upgrading the seals and spring bases is prohibitive compared to buying a used RS head.

 

Thus you are snookered, unless you can find some better beehive springs or cams with less than 0.380" lift.

 

Perfect engine for a turbo or supercharger however.

Edited by petert

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Atlaskrukvaxt

Thank you both for reading and commenting! I'll go through your responses bit by bit and answer.

Quote

Look around the exhaust manifold for cracks , leaky head-to-ex. manifold gaskets , leaky ex. manifold-to-down pipe cone mesh ring .

 

If that's all good , i'd whip off the valve cover and check the valve clearances .. these are adjustable , there's shims beneath the buckets .

When I had the top removed and fitted a new headgasket I forgot to inspect the mesh so it could probably be that then. I didn't remove the manifold when I had the head out so i don't think the exhaust gasket is bad, unless it was also bad when I got it. But Thank you! I'll see what I can find to put between the manifold and downpipe.

Quote

XU10J4R head is very much similar to the XU10J4 and XU10J4RS , big wide ports and similar valve sizes .. but mild camshafts , soft valve springs , restrictive inlet and exhaust on the XU10J4R .

 

Try google search trough the forum : XU10J4R site:205gtidrivers.com .... as there's a lot of info written about these engine during the years , pretty much all you wish to know about them .

I had done quite a bit of search through the forum but I wasn't finding what I wanted to know but thank you for informing about the difference between the valve springs.

 

Quote

The XU10J4R has integral valve seals/spring bases and single beehive springs. The XU10J4RS has normal spring bases, separate seals and double springs.

[...]

You can buy aftermarket RS cams, but they'll all have too much lift for the standard beehive springs.

[...]

The cost of upgrading the seals and spring bases is prohibitive compared to buying a used RS head. Thus you are snookered, unless you can find some better beehive springs or cams with less than 0.380" lift.

Thank you! This was what I was missing from my search of the forum. Do you happen to have more information about the springs at hand for both the RFS and RFV engine? I'll still research about the springs on the forum to see what I can find.
As I said in my original message finding the RFS engine or parts for it is very difficult. Cars with RFV engines regularly sold for 200€ and the cheapest RFS I've seen was 1200€.

 

 

All in all i gather that putting RFS cams should be possible if one changes out the spring set, or am I still mistaken?

Spring kits seems to be about 150-360€ for single/double springs for the RFS, seal kits are another 30€. I guess followers are needed too? 

If I'm lucky the spring dimensions could be similar to some old volvo stuff we have laying around. 

Quote

Perfect engine for a turbo or supercharger however.

 Lmao, my brother is so against tuning NA engines. If he finds this out I'll be in trouble :p

 

Thank you for reading and replying. 

Edited by Atlaskrukvaxt

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petert

I have both springs in the shed, but eRacing is on TV.  What do you want to know?

 

You can upgrade to RFS springs, but you'll need to machine the head to accept the spring base. Unsure if the RFS seal will push on.

 

Standard RFS cams have too much lift for RFV springs.

 

Hydraulic lifters are probably the same part.

 

Put an add in the Wanted section for 2nd hand springs/retainers/springs/bases/locks. Find a pair of RFS cams and get someone to grind them. I can do this but return postage may be prohibitive.

Edited by petert

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Atlaskrukvaxt

Thanks you for the fast reply! You shouldn't stress yourself with this. I'm not in a hurry either so enjoy your racing :D

 

But...
I think the spring constant, height outer diameter and gauge are the most crucial ones for both springs. 


F = -kx

where X is the displacement

F is the resulting force

and K is the spring constant

(hooke's law)

 

For the RFV the smallest OD and the largest OD would also be interesting.

 

edit: Dimensions of both spring bases would also be of interest.
 

Thank you so very much.

Edited by Atlaskrukvaxt

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petert

RFV spring

7.4 turns

FL = 44.3mm

d = 3.6mm

Base OD = 26.2mm

Top OD = 22.4mm

Retainer spring ID = 14.4mm

 

Sorry, I can't find any RFS springs. Somebody else on here will have the data.

XU10J4R valve spring and base.JPG

Edited by petert
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petert

Another short coming of the RFV head is the of a lack cam sensor mounting hole.

Edited by petert

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DamirGTI

11.JPG

22.JPG

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Atlaskrukvaxt

Something doesn't add up here. The data sheet provided by DamirGTI doesn't match the numbers from your spring petert. 

 

Judging from the datasheet I'd say the RFS outer spring should fit right on to the RFV base based on the OD of the RFV being 1,4mm larger than the RFS OD according to the data sheet. 

The inner diameter on the RFV is 20,4 and RFS is slightly smaller at 20,2 (without the inner spring) so that could cause a problem there. 

 

Or am I completely mistaken?

 

Edit: seems I'm partially mistaken at least. The full height can very well be what you have suggested as H1 is 35,5 at 300 N force

Edited by Atlaskrukvaxt

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petert

The RFV spring base is Ø16.4, quite loose.

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welshpug

I've got rfs spring seats and retainers to hand, and stem seals, Is the top of the valve guide the same as rfv?

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petert

That is the million dollar question. I only have an RFV head here at present. I'll take a pic though.

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petert

The inner RFS spring is never going to fit on the RFV base.

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Atlaskrukvaxt

This whole situation is quite confusing.. 

5 hours ago, petert said:

The inner RFS spring is never going to fit on the RFV base.

No, but will the RFS spring base fit the RFV head?

 

you posted earlier 

Quote

You can upgrade to RFS springs, but you'll need to machine the head to accept the spring base. Unsure if the RFS seal will push on.

 

but In this thread we find the following

Quote

 

XU10j4r (306 2.0 xsi) head and valves

 

XU10j4rs (gti6) cams, double valve springs

[...]

I'm also using the gti6 XU10j4rs stem seals which fit perfectly on the XU10j4r valve guides.. Which is nice :D

So to me it seems the valve guide could be the same,

RFS seals fit the RFV valves,

RFS base plates in the RFV head is questionable due to conflicting information currently.

Did Calvin modify his head to fit the RFS bases? I didn't find any follow up for it.

 

I took the liberty of drawing up the RFS spring base in solidworks as described in the other thread by welshpug to get a clearer overview of the situation. Could you post the same measurements for the RFV seal/base?

1282108664_RFSspringbase.thumb.JPG.cd2532d387ea26930d42e10e50e1e772.JPG

 

 

Edited by Atlaskrukvaxt

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Atlaskrukvaxt

Petert, I guess in this post you mean the top picture is the RFS head and the bottom one is the RFV head?
If you still have the head could you take a closer picture of the cylinder going in to the block on the spring side?

 

Damir, you mentioned in the same thread you have a book with a lot of things in it, does it have the sizes and dimensions of the cylindrical cut outs where the springs go?

Edited by Atlaskrukvaxt

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DamirGTI
3 hours ago, Atlaskrukvaxt said:

Damir, you mentioned in the same thread you have a book with a lot of things in it, does it have the sizes and dimensions of the cylindrical cut outs where the springs go?

 

Nothing related to that i'm afraid ... i certainly haven't seen any info about that for other engines either  , as it's not common "serviceable" area as such , thus there's usually no info about measurement's etc. .

 

I have some data for the valve guides i you want .

 

D

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petert
5 hours ago, Atlaskrukvaxt said:

Petert, I guess in this post you mean the top picture is the RFS head and the bottom one is the RFV head?

Top head is RFY,  bottom is RFV.

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Atlaskrukvaxt

I found a thread on 306cc.co.uk with some interesting stuff (no doubt some of you guys are on that forum too) .

 

Surfing a bit further on the web I found some, what I assume are, performance springs for the RFV head. That based on the fact that they are advertised as having 11mm valve lift which is over the "maximum safe 9.65mm" that I've seen in so many places by now. Dbilas also seem to have a selection of camshafts for the RFV engine.

 

Thoughts?

Edited by Atlaskrukvaxt

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calvinhorse

Before this guy orders gti6 valve stem seals are the valve stems in a gti6 not thinner than the xu10j4r? 
 

happy to be told I’m wrong I just don’t want him ordering the wrong stuff 

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DamirGTI

Valve guides are :

 

RFY/RFT :

 

Lenght - 40 mm

ID - 7.01 mm

OD - 12.06 mm

 

RFS :

 

Lenght - 41 mm

ID - 6 (5.98) mm

OD - 12.06 mm

 

So yes , the RFS stem seals are 6mm while RFY/RFT are 7mm ID .

 

 

D

Edited by DamirGTI

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Atlaskrukvaxt
1 hour ago, DamirGTI said:

Valve guides are :

 

RFY/RFT :

 

Lenght - 40 mm

ID - 7.01 mm

OD - 12.06 mm

 

RFS :

 

Lenght - 41 mm

ID - 6 (5.98) mm

OD - 12.06 mm

 

So yes , the RFS stem seals are 6mm while RFY/RFT are 7mm ID .

 

 

D

But this thread focuses on RFV and RFS not RFY and RFT

RFS and RFV should be the same 

"RS stems are not smaller than R, they are smaller than the old J4, Mi16."

by welshpug in the thread I linked to in the previous post. 

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Atlaskrukvaxt
2 hours ago, calvinhorse said:

Before this guy orders gti6 valve stem seals are the valve stems in a gti6 not thinner than the xu10j4r? 
 

happy to be told I’m wrong I just don’t want him ordering the wrong stuff 

so if the material in the other thread is to be believed I'd say you're wrong. But I'd also like to be enlightened.

Edited by Atlaskrukvaxt

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DamirGTI

My bad ! misread the question pointing on the "j4r" rather than the "j4"

 

But makes no difference anyhow  , the above is all the same for these three - RFY , RFT and RFV too (D6C/DFW as well) ... only RFS is different - smaller .

 

With the exception of the RFV also having bigger 8mm stem variant and different valve guides .. no idea which are which , possibly early and late RFV engine difference .

 

 

D

 

 

IMG_8853.JPG

IMG_8854.JPG

Edited by DamirGTI

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petert

RFV is 6mm, the same as RFS. There may be a 7mm version of the RFV head, but I haven't seen one.

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