camshafts for upgraded XU10J4R

[petert 586]

So 2.1mm is the total distance between valve on the seat and valve resting on the piston at TDC?

 

If so, this is not enough. From this total measurement, you need to subtract clearance. For hydraulic lifters, that size valve, that sort of engine etc., you need 0.080" ( 2.03mm). To this you would add the cam lift at TDC, say 0.040" (1mm). Thus the total you need would be 0.120" (3.0mm).

 

5.2mm on the exhaust would be ok. That's typical 4V Peugeot.

[Atlaskrukvaxt 5]

Thank you PeterT!
Just the information I've been looking for.

 

Yes, 2.1mm distance between the valve touching the piston and being retracted as far as possible in to the valve seat.

In my case that means then 2.1mm-2.03-1.75 =-1.68mm that I need to deepen the valve cutouts. 

 

I took off the head and sump today in preparation for removing the pistons and conrods. It looked kind of disgusting.

No piston cooling jets on this engine though. I was hoping perhaps the channels would have been there so I could have threaded them and put my own but nope. 

 

 

I'll see if I can find someone local that can do the cutouts for me or I'll have to make a jig and try to do it with the drill press and an old valve with a carbide cutting bit attached to it. 

 

[petert 586]

Sorry, it's worse. Your inlet cam needs 1.75mm at TDC. Thus you need a total of 1.75 + 2.0 = 3.75mm at TDC. Additionally, the piston will get closer to the inlet valve approx. 6º ATDC. Thus you really need to add another 0.010" (0.25mm) if taking a "rough" measurement at TDC.

 

ie

1.75 + 2.0 + 0.25 = 4.0mm

 

Nice pics. Now you're down the rabbit hole! Keep in mind that enlarging the pockets will reduce the CR a little bit.

Edited January 5, 2021 by petert

[Atlaskrukvaxt 5]

I can't say I'm following you now. Your calculation doesn't include the existing piston valve relief? 

 

existing 2.1mm

needed rel. 2mm

valve lift 1.75mm

margin of error 0.25mm

 

0.25+1.75+2=4

minus what I already have 4-2.1=1.9

Or am I completely out for lunch?

[petert 586]

Have the piston at TDC and drop the valve onto the piston. Did you get 2.1mm?

 

 

[Atlaskrukvaxt 5]

Correct. 

[petert 586]

That means there is 2.1mm between the inlet valve and the bottom of the piston pocket. You need 4.0mm

[Atlaskrukvaxt 5]

So I'm missing 1.9mm which is the distance I would need to deepen the pocket in the piston, right?

Edited January 5, 2021 by Atlaskrukvaxt

[petert 586]

Correct. Huge!

 

I'm surprised with your inlet measurement of 2.1mm. As that suggests there was insufficient clearance to begin with. Check it again.

Edited January 5, 2021 by petert

[Atlaskrukvaxt 5]

How does this work with your stage two regrind with 0.065",1.65mm, lift@tdc?

[petert 586]

You would need a valve drop measurement of 3.9mm

 

ie

1.65 + 2.0 + 0.25m = 3.9mm

[welshpug 1,657]

I doubt you'll be able to make them much deeper than +1mm, depends if they are much more substantial than the rfs piston or not.

[petert 586]

And given they're already dished pistons and you're going to decrease the CR further, it maybe more cost effective to just buy new flat top pistons, rather than pay someone to modify standard pistons.

[Atlaskrukvaxt 5]

On 1/6/2021 at 12:26 AM, petert said:

Correct. Huge!

 

I'm surprised with your inlet measurement of 2.1mm. As that suggests there was insufficient clearance to begin with. Check it again.

Yes, I was very surprised by the measurement as well. 

I tried measuring with zero at both the piston and the valve retracted but got about the same results. 

 

I'll slap it back together and try again right away. 
 

Has anyone got a tried and tested way of pressing out the wristpins from the pistons by the way? 

I read Peugeot recommends changing pistons if you press out the pins. Kind of bad design from a tuning perspective. 

Otherwise I'll just heat the conrod and press over a wooden jig.

22 hours ago, petert said:

And given they're already dished pistons and you're going to decrease the CR further, it maybe more cost effective to just buy new flat top pistons, rather than pay someone to modify standard pistons.

 With deeper valve pockets a thinner gasket could perhaps be used and combat the loss of compression a bit. I'm not sure the loss will be that big though.

But first I'll do the measurement again. 

[Atlaskrukvaxt 5]

I used a dummy spring for this test, 1.4mm gasket and only 4 surrounding bolts tightened to 15Nm.

Result was 0.1mm more than previous measurement. I'd say insignificant considering the circumstances. 

[petert 586]

Throw the rods and pistons in the bin. Find a set of XU10J4 (S16 or Mi16) rods and buy new pistons. The end result will be better and easier. Perhaps a tad more expensive.

 

https://www.flatlander-ipp.nl/wiseco/wisecoipp-peugeot.shtml

 

Edited January 7, 2021 by petert

[Chipboy 0]

Just get some GTi6 pistons and fit them, to your j4r rods, works a treat. Only difference between them is the dish. Fitted the extractors and shortened the exhaust neck, insulated heater pipes and away it goes,.

The ecu can manage it. the head gasket is exactly the same as well between the two, quite logical from a manufacturing pov.

Edited February 25, 2021 by Chipboy

[welshpug 1,657]

11 hours ago, Chipboy said:

Just get some GTi6 pistons and fit them, to your j4r rods,

 

not a diy job, as they're a shrink fit non bushed type, you'd just use the rod and piston assembly as is.

[Atlaskrukvaxt 5]

I've already removed the pistons from the rods and machined deeper valve pockets. They are all 3.3-3.8mm deep now according to the dial gague except for piston 1 which was the first one I made. It's only around 2.9 on one of the valves. I did it all myself so it didn't cost me a dime except helping my neighbor with his smart TV. He happens to have a shop where he used to make axles for customers, mostly trailers of different kinds. 

 

I'll post a more thorough update when I'm done with them. 

 

I bought a gti6 manifold but brexit messed up the shipment so it is lost somewhere in England. 1-7 weeks before it gets back to the seller and we'll see what to do about it. But I'll be completing the engine without gti6 parts and then dynoing it before putting on a gti6 intake manifold just to see the difference, if there is one. 

 

I think, or rather want to believe, the j4r is perfectly capable if you have the tools to work on it.

 

 

[Atlaskrukvaxt 5]

I finished the exhaust valve pockets tonight. 

I used a 8mm 32.5mm valve I got by mistake when I fixed my uncle's c4.

I welded on a sharpened drill bit and grinded it down to 35,5mm for the intake side.

When I was done I took it down to the size of the valve so the pockets are slightly oversize for the 29.5 valves the pockets being aforementioned 32.5mm. 

 

Initially I was going to 3d print a jig for the pistons and just do the work in a drillpress but I asked around a bit and my neighbor allowed me to use his milling machine for fixing his smart tv. Something about wifi connectivity. 

All valve pockets are now deepened by 3.2-3.5mm.
I got better towards the end so there is some slight variation but it should be fine. The exhaust valve pockets looks a lot better than the intake ones lol. But keep in mind this is a very amateurish job (so no bully plz). 
 

Tomorrow I'm planning on cleaning up the pistons properly and fitting the new rods.

I accidentally snagged the edge a bit on one of the pistons and I'd like to know what you guys think of it. I was thinking I'd preemptively take a jab at it with a file just so no part will brake off from it later. 

Come next paycheck I'll order the camshafts I've been planning all along, provided all the valve clearances are okay when measuring again. I finally got my hands on a proper arm so now proper testing will be easier.  

[welshpug 1,657]

that will be fine, just make sure its not sharp, Mi16 cutouts are over the edge.

[Chipboy 0]

PS cooling jets take a look at the big end on the rod and the bearing shell is a giveaway, they put pilot holes in the conrod for oil squirting, so the early engines had bars the later ones have this.

Edited February 27, 2021 by Chipboy

[Atlaskrukvaxt 5]

Got the new -03106camshafts the other day and had them installed. Did some valve clearance testing with blue tack and saw no indentations. Tried again without a gasket and this was the results. I may have overdone the valve pockets. Better safe than sorry though. Intakes were all around 2.9mm with one being an outlier and only being 2.2mm but this was as I said without a gasket. Exhausts were all around 4mm. 

Edited May 6, 2021 by Atlaskrukvaxt

[Atlaskrukvaxt 5]

I also noticed this on the intake cam after turning over the engine for two cycles. Thoughts? 

 

I'll be taking the head apart again and cleaning it just to be sure in case that broke off and is somewhere inside. 

Edited May 6, 2021 by Atlaskrukvaxt

[Chipboy 0]

On 1/6/2021 at 6:58 AM, Atlaskrukvaxt said:

 

No piston cooling jets on this engine though. I was hoping perhaps the channels would have been there so I could have threaded them and put my own but nope. 

 

 

Late to your party but take a look at the conrods you will find a hole on then and when they come to top they squirt uner the pistons, a cheapr and simpler alternative. The big end bearings themselves give this away.

 

Edited November 19, 2022 by Chipboy