donuts2001

What compression is Premium Unleaded needed at? My Haynes manual says the compression for the EA-ED should be around 1010kPa.

I've recently done a head gasket change, put in a XR6 cam and head the recoed(which probably means shaved a bit) and my compression in most of the cylinders is around 1200kPa. Does anyone know around what compression is needed to justify the use of PULP?

Also what does Pinging sound like? I've got a weird metal rattling noise when I give the motor full acceleration when it's cold(goes away once engines heated up). Could just be the exhaust but I'm having problems locating the problem.

Cheers

mongrelEB

Hey, how does she go with the xr6 cam?
I dunno about the compressions, I generally work in ratios and am too lazy to do the maths :-)
But, the rattling sounds to me like the lifters. If it was my car, I'd whip the rockerbox off and make sure they're all good, then use a thicker oil - 20W/50 usually seems to fix rattly lifters.

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Martin

If I were you I would only be giving it full acceleration when warmed up, something like 90% of engine wear occurs when cold.

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donuts2001

I changed over from 3 speed to 4 speed at the same time i put the cam in so it's hard to say. Also I have a feeling my exhaust is leaking or something because as I said it makes a horrible death rattle noise when you give it some when it's cold... and it goes hard when the rattle noise isn't there.

I don't normally... but I shouldn't be getting any noises warm engine or not.

donuts2001

Anyone? Surely someone here must know?

Well does anyone knw the compression of the XR6 cars as they run on premium?

Martin

The compression ratio of EB-ED XR6s are 9.01:1 compared to 8.8:1 for standard.
EF XR6 is 9.35:1 and 9.30:1 for GLi
Got no idea how to convert it to kpa

If you think its pinging why dont you chuck in some premium anyway? At worst youve wasted all of $2. But generally a car wont ping when cold, and not ping when hot. Its usually the other way round as a car runs richer when cold.

More than likey its the lifters, what oil are you running?

__________________
1993 ED XR6 M5 (1 of 329)
Polynesian Green
Turbo on the way!!
1993 EBII Fairmont (Now wrecking, PM if you want any parts)
1988 Nissan R31 Skyline

donuts2001

Nah it isn't the lifters, I know what they sound like and this definately isn't the noise. This is a very loud rattley noise only when under really bad stress when the motors still cold. Somehow by loosening off the automatic transmission support bracket bolts that connect up to the block and then retightening it decreased the noise a fair bit. So I figured that it must have something to do with the exhaust hitting the support member for the transmission... but it doesn't seem to touch.

I doubt the noise I'm hearing is pinging, but it's still good to know if i should be running premium with my high compression(compared to standard at least)

SiX_iN_a_RoW

cat converter?

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ir33t

What about timing chain?

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TopGhia

Get under the car and give the cat a bit of a belt with a rubber mallet or a lump of wood. If it rattles, it's rooted.

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