Xu10 Head On Xu5ja

[TB_205GTI 1]

Approx. two years ago I did one of the first XU10-head-on-XU5 projects on the forum. Shortly after I sold the car to get a 106 - but I have been in contact with the owner all along, and just a few weeks ago one of my mates bought it from the gyu I sold it to. The last two years the car has been totting around without almost any problems. There has been one issue with it though. When I had it i popped one of the sparkplugs, probably due to a bad thead in the head. We gave the head a helicoil and it ran like a charm again. But when the guy I sold it to had to change the plugs, the plug with the helicoil had totally burned the tip of the plug.. futhermore the helicoil cam out with the plug. Unfortunately he replaced the three plugs and left the bad one Apart from that it has been driving perfectly - at has done about 25.000Km and some abuse. So the XU9 gasket is absolutely up to the job, allthough some criticts on this forum said it would never last 10.000 Km

 

But recently (under heavy abuse) the head gave up - at approx. 6.000 rpm the engine gave a LOUD BANG and lost compression on the third cylinder. Today the head was taken apart to see what had happened to it, at first we thought that the tip of the plug (just changed them) had come loose and had got stuck between the valve and the seat - but this was not the case. Well - the pictures speak for themselves..

 

 

I hope to get some better pictures soon..

 

On the positive side, the gasket was in very good nick, and the bottomend doesn't seem to have suffered from the valve going apart. A new XU10 head has been bought and a better cam (the old one was a "272 deg" Piper cam, the new one is a 289 deg cam. Now I just need to convince my mate about the car needing a set of webers

 

But why the **** do a valve loose some of its head? I *may* have pinked a bit - I know that it HAD to run on RON98, maybe the previous owner didn't do that??

[Gentrix 2 1 Cars]

maybe it got in contact with the tip of the first Sparkplug. It might not burnt away, but just fallen down in the Chamber.

 

 

 

 

 

 

 

andi

[welshpug 1,657]

why stop at an XU10J2.....

 

 

use a J4

[Guest ashnicholls]

Bloody hell, you had my heart beating then, I thought you were going to say that the XU10 head was no good, just after I have finished my XU10 head conversion.

 

Glad to see its running ok, and was just an abnormallity in the head and not a compatability fault.

 

Yes, Webers are needed, mine sounds ACE!

[PumaRacing 2]

Can I just confirm something? You used the 1.9 head gasket with the 2.0 head?

 

I have to say that's the way I'd probably go if fitting a 2.0 head to a 1.9 block because the 2.0 gasket doesn't overlap the 1.9 liners by much. The issue of course is that the 1.9 gasket will protude into the chamber of the 2.0 head and that's meant to be a recipe for burning the fire-ring out. If yours has survived like this then it's valuable information.

[TB_205GTI 1]

Can I just confirm something? You used the 1.9 head gasket with the 2.0 head?

 

I have to say that's the way I'd probably go if fitting a 2.0 head to a 1.9 block because the 2.0 gasket doesn't overlap the 1.9 liners by much. The issue of course is that the 1.9 gasket will protude into the chamber of the 2.0 head and that's meant to be a recipe for burning the fire-ring out. If yours has survived like this then it's valuable information.

 

 

Yes it was the 1.9 gasket I used. Originally I bought the XU10 gasket, but as you say the gasket will not have enough overlap on the two outer liners. The XU9 gasket do protrude intot the chambers, but as he bore is still 83mm I do not believe it's a massive issue. If the gasket was 83mm and the head _and_ the bore was 86mm, then I wouldn't last the drive home from the shop

 

I has been used as a daily driver for approx 2.5 years now, and it has been running like a champ all along - apart from the issues with the spark plug. I believe what has happened the the spark plug is that due to the helicoil it hasn't been able to get rid of the heat and then the tip burned away on it.

 

There a several threads on the progress when I build it in the forum, they are approx two years old by now, there I also discuss the issues with the HG

 

by the way the new head with the new cam is on, the head has been ported by "Peugeot Sport Denmark" - I would _really_ like to see the torque/horsepower it has now compared to my own porting and the "272 deg" pipercam. Just after I finished it I put it on the rollers - 125Bhp @ 6500 and 148Nm @ 5600.

[christopher 5 1 Cars]

the head has been ported by "Peugeot Sport Denmark"

 

 

 

You mean agergaard?

[Anthony 1,003]

Good to hear about the XU9 gasket surviving the test of time, although now I'm having second thoughts as to what to fit to mine - was going to use the XU10 gasket as most others have done with no problems, but the limited sealing surface on the liners with the XU10 gasket was always a nigging doubt...

 

But why the **** do a valve loose some of its head? I *may* have pinked a bit - I know that it HAD to run on RON98, maybe the previous owner didn't do that??

I've seen a couple of XU9 heads wreak an exhaust valve like that, and the engine builder that I went to get the head skimmed and the seats recut had seen a few do it as well. Not sure why it does it (can't remember what my engine builder bloke said at the time now) but it's not just a one-off on your engine...

[PumaRacing 2]

I've seen a couple of XU9 heads wreak an exhaust valve like that, and the engine builder that I went to get the head skimmed and the seats recut had seen a few do it as well. Not sure why it does it (can't remember what my engine builder bloke said at the time now) but it's not just a one-off on your engine...

 

Bad exhaust valves on XU9's seem to be like buses. I don't see any for ages and then a load turn up at once. I reconditioned a head for a friend a few weeks back which was in mint condition in all respects until I came to clean and cut the exhaust valves and one had split in several places. I asked him to bring me the valves from his spare head, also in fine condition and one of those had gone too. We finally managed to get a good set out of a third head.

 

I have no particular explanation. The valve seats were in good order, some guide wear of course but that's normal on the exhaust side. The shape and material of XU9 valves seems unremarkable compared to any other engine. Maybe it's down to tappet clearances being too tight and burning the valves out but by the time I get to see most heads they've been stripped and I don't know what the tappet clearances were. Anyway I doubt this because the factory clearance on the exhaust side is huge and would have to close up by over 50% before it became a problem.

 

The process is fairly clear though. The valves start to crack and split at the edges, these grow into V shaped channels and finally if you keep running the engine a big chunk falls off. It doesn't even seem particularly related to mileage. I've seen high mileage heads with perfect valves and low mileage ones with cracked valves. Maybe it's down to a bad batch from the factory at some time in the past. The wrong material maybe or a faulty forging process.

 

Also be aware that some of the cheap replacement valves out there aren't much good either. I've seen exhaust valves made of inlet valve steel (magnetic) and a fairly well known make I tried a few months ago had stems 1 thou undersize. TRW/AE seem to be ok.

[PumaRacing 2]

I has been used as a daily driver for approx 2.5 years now, and it has been running like a champ all along - apart from the issues with the spark plug. I believe what has happened the the spark plug is that due to the helicoil it hasn't been able to get rid of the heat and then the tip burned away on it.

 

There must be tens of thousands of engines out there running quite happily with helicoils in the plug holes so I doubt that's a reason for your plug to fail.

[TB_205GTI 1]

There must be tens of thousands of engines out there running quite happily with helicoils in the plug holes so I doubt that's a reason for your plug to fail.

 

Yes that is true, but I cannot find any other reason as to why it has burned the tip of two plugs on that cylinder. When I changed the head (from original XU5JA to XU10) I also gave it a new distributor, cables, coil and amplifier, so the ignition *should* be in good nick.

[TB_205GTI 1]

You mean agergaard?

 

Yes that's right, when he still was "Peugeot Sport DK", and was placed in Greve. Now Peugeot has stopped any official race development in Denmark, so now the company is called Scandi Engeneering.

[nickpug309tt 0]

Can I just confirm something? You used the 1.9 head gasket with the 2.0 head?

 

I have to say that's the way I'd probably go if fitting a 2.0 head to a 1.9 block because the 2.0 gasket doesn't overlap the 1.9 liners by much. The issue of course is that the 1.9 gasket will protude into the chamber of the 2.0 head and that's meant to be a recipe for burning the fire-ring out. If yours has survived like this then it's valuable information.

 

Just to add on this topic. When I fitted the XU10 to my tt engine I used the 2.0 gasket first. The Turbo soon found that to be too weak on the liners, as said due to not overlapping the liners by much.

 

I then used the XU9 gasket and never had any problems again.

[TB_205GTI 1]

Just had a quick look at my docuents, it is 3 years since I put the XU10 head on, not two as I wrote.

So it has been running perfectly for three years.