Ok, so following on from ruining Ash's for sale thread, I have done a dry build on my engine and calculated the compression to be 15.4:1. I can get it down by a fair amount by machining the pistons but to get it into the safe zone I need a bit more, so....

Does anyone know if Pug do the standard head gaskets in any other thicknesses, and bore sizes other than the standard one? Part numbers would be useful as when I spoke to Peugeot today the guy googled it after not finding anything on the Pug systems!

Also, can anyone say with some certainty what the maximum compression ratio is for an xu10j4rs engine on good quality vpower or similar?

________________________________________

Oulton Park in a BTCC 306 vid 1
Oulton Park in a BTCC 306 vid 2
Lap of the 'ring

Send them back as theyre obviously not suitable for purpose.

________________________________________

need a part number? get on here - http://public.servicebox.peugeot.com

Bring on the Trumpets.

Use a diesel injector instead of the spark plug and add some boost

________________________________________

need a part number? get on here - http://public.servicebox.peugeot.com

Bring on the Trumpets.

err,

yeah


some of the higher power low capacity VW diesel engines only run 16-1!

________________________________________

need a part number? get on here - http://public.servicebox.peugeot.com

Bring on the Trumpets.

What size pistons are you running?

________________________________________

230 hp 2.1 16v XU 205 rallye on jenveys Project thread here
309 3dr K20 Type R

Zx 16v, j4rs engine, 1.2mm std gasket, 1.4mm repair gasket, same part number listed for the j4r engine

will drop the compression about 0.4, so yeah fat lotbof good, just send then back and buy proper pistons, thought you would have learnt by now.

________________________________________

need a part number? get on here - http://public.servicebox.peugeot.com

Bring on the Trumpets.

your f**kup from using an excessively skimmed head will not make that much difference, you're talking circa 0.30mm, which IF the combustion chamber was a full 86mm round would be 1.74cc, as its not round it will be less than that.

standard chamber total is 50.97cc, giving a compression ratio of 10.8-1 (made up of 37.5cc head vol, 7.13cc gasket volume [1.2mm thickx87mm] and a piston dish of 6.34cc)

drop 1.74cc off that and you get 11.14-1.

if they're designed for 12.2-1 and an 86mm bore, then the combustion volume should be 44.6cc, which means it SHOULD have a 0.03cc intruder on a standard 1.2mm gasket.

0.03cc does not sound like pistons with mountains on the top of them now does it....

add your excessive skim guesstimation of 1.74cc drop. (42.86cc clearance volume)

(499.55+42.86)/42.86= 12.65-1.


compression height is stated at 34mm, add to 158mm rod on 86mm stroke, that's 235mm, which is exactly the same as deck height, so you cannot run them in a decked block without them being rather close to the head...


if it has given you a ratio of 15.4-1, you would have a clearance volume of 34.69cc, you'd have a 6.06cc dome working from your overskimmed head and a standard 1.2mm gasket.


which from pictures I have seen on the web of Wossners for the RS engines, sounds perfectly feasible and you have to wonder how they got it to f**king wrong.

________________________________________

need a part number? get on here - http://public.servicebox.peugeot.com

Bring on the Trumpets.

if they are as advertised, they will have pretty much flat tops.

________________________________________

need a part number? get on here - http://public.servicebox.peugeot.com

Bring on the Trumpets.

Indeed, good work old chap.

________________________________________

"Supercharged - 454.1bhp/317.5lb/ft"
Peugeot 306 GTi-6
2000 (X), Moonstone

You're not far off there WP. Been out and double checked everything tonight and have found a few things.

1- Don't use Meths in a plastic burette, it cracks it and I think this is where the excess cc'ing has come from. I reckon it has been leaking slightly as I didn't notice the crack until I went out tonight. Done it again tonight using syringes in lieu of another burette...

2- Combustion chamber volume is 35cc so not that small really.

3- My head gasket is 86.5mm x 1.2mm, its just a standard pug MLS one. 7cc

4- Additional piston volume is 3.8cc (not the 5.2cc I thought the other day)

So cylinder volume is 505cc (86.5mm diameter). Comb chamber volume is 35+7-3.8=38.2

505+38.2/38.2=14.2

So much better than 15.4! And with a slight skim of the pistons to align them with the new block height and enough off the intruder to give me 3cc (4cc) then that brings it down to 13.2:1 (12.9:1) which I am hoping will be ok.

Quick question though, do you take the piston dome into account when calculating the cylinder volume. I haven't found any info to say that you should do, but I think you should. I mean its only 3.8cc so only alters the compression ratio by 0.1:1

________________________________________

Oulton Park in a BTCC 306 vid 1
Oulton Park in a BTCC 306 vid 2
Lap of the 'ring

That sounds a lot better Pete!

________________________________________

Team Running Engine again!
Team Negative Camber!
My Budget track engine build thread!
Now appearing at a Trackday near you!!

Are we back to Ash's for sale thread welshy??

________________________________________

Team Running Engine again!
Team Negative Camber!
My Budget track engine build thread!
Now appearing at a Trackday near you!!

Rather than opening a new thread. I’m playing with building a engine at present. With regards to piston volume - a dish I understand would be easy to measure as per the head cc, but how do you calculate a high comp piston I.e the Center is above deck and the sides below? All other measurements make sense but can’t seem to find any info online and have used pistons so no specs from manufacturer etc