XR2, stock compression and stock heads CC?

HT20 · 09-02-2009, 11:23 PM

Once again questions about this engine.

As mentioned, I`m new to it after going from a 2.5EFi and down to an XR2(Dont ask why...Long story)

So what is the stock Compression in Psi, mine has 125-130psi on a cold engine, also this reading is without the throttle att WOT.

Second question, what is the stock CC on the heads, mine are marked with 26CC and from what I remember from the 2.5EFi, that would involve a lot of compression and race gas...but that is a completely different motor.

(I also have a embarrasing third question, where tha hell does the fuel-line connect on this thing, I would expect it to be connected on to the fuelpump, stock one on the block, but that seems not to be the case...)

(I have searched and tried the manual)

Burty · 09-02-2009, 11:50 PM

1. i don't know what comps should be but i would expect at a guess they should be at approx 160psi (with throttle open)
2. Don't know but don't compatre it to a 2.5 as completely different
3. I would have thought it went straight onto the mechanical pump then straight to the carbs, if running an electric pump then just straight to carbs (XR2's dont have a fuel return like 2.5's)

larby · 10-02-2009, 08:00 AM

1, IIRC, ABOUT 130 - 140 PSI,but that depends on the year
2, not a clue, burty's right tho, they are totally different!
3, With stock pump, it goes from prime bulb (boat), to pump, to carbs, in an odd kinda way tho, at least it did on mine! Someone else will be able to confirm!

James

HT20 · 10-02-2009, 03:19 PM

Engine is made in August 95(from block), sold as a 96mod.

Pretty sure its healty, it`s been kept as a spare race-engine or something, few hours on it.
I`ll take a new Comp-test when I get it running, with lubed hot engine and throttle att WOT-results should be different.

As for the fuel-situation, on this powerhead the fuelpump on the block has a line into it, coming from the block, then it goes from the pump and into a filter located on the top of the front half, from the filter it goes down to the Carbs and is distributed out to all three..

The weird thing is this line going fom the block and into the feed-side of the pump-with no obvious place to connect the fuel-line from the tank to.
Sad to say I don`t have any pics of it, would be easier to understand for you guys.

Have abit of experience with fuelsystems from cars and other engines(as the 2.5EFi amongst others) but this one was really weird as to where to connect the line.

I`m sure someone will know.

larby · 10-02-2009, 05:56 PM

Sounds odd to me, from the pump to the carbs sounds good, but it sounds like the other end is messed up somehow. I think mine used to loop under the block, but pretty much then went straight to the tank, don't recall it going into the block at all, it would have no reason to.
Compression for a cold engine with closed throttles sounds about right, i did a comp test on a mid 90's one a little while back with a cold block but throttles open and they were all around 135psi. The most important thing is that they are all close to each other.

James

daren · 10-02-2009, 10:02 PM

Quote:

Originally Posted by HT20

(I also have a embarrasing third question, where tha hell does the fuel-line connect on this thing, I would expect it to be connected on to the fuelpump, stock one on the block, but that seems not to be the case...)

(I have searched and tried the manual)

Straight to the carbs from the electric fuel pump and/or pressure regulator

dodgy dave · 10-02-2009, 10:24 PM

on later engines fuel pump to water trap to fuel filter to carbs on earlier eng trap to filter to pulse pump on side of block to carbs . my late xrs 200hp the compression was 165 even on two power heads with a snapon gauge at full wide throttle opening warm eng . hope this helps D.D

HT20 · 10-02-2009, 10:45 PM

Got a Pm with the info I was looking for, should be a nipple on the pump-opposite side of the pump from where it goes out to the carbs, some of these supposedly were plastic, maybe it just got broken of, and I have not noticed it yet.
(in the pic below you will see the vacum-line,pump, line to filter and filter.)

The hose going down to the block for the pump is the vacum that makes it work.

Another thing, when searching for info, I found a couple of XR2-powerheads, and on all of the pics, they had som different heads than mine, seems like most of them got these older looking heads with a different look in the casting(3stripes in the cast besides the sparksplugs-just see daren`s pic above)

Mine has the smooth looking heads, how come? Difference due to older/newer engine?

Pic:

Also thanks for all the reply`s.

Techteam · 17-02-2009, 10:50 PM

26cc heads are standard, remember it's 2 litre not 2.5 less swept volume lower compression with the same combustion chamber. Early 1 piece heads are different from later ones I think they took a little while to perfect the casting early on, the early casting looked like polystyrene with flash lines round what would be the 2 piece water jacket.