51 replies to this topic

[vocky]

you need to use the lsj flywheel, but otherwise it's quite an easy swap. the electrics can be done, depends how clever you are with wiring

[zezinio]

you need to use the lsj flywheel, but otherwise it's quite an easy swap.

Luckily I do have the lsj flywheel.
I will first have to prepare the engine with GM's suggestions with higher flow fuel injectors, forged pistons (I think I'll go for 10:1 CR) valve springs, ported Cylinder head ( will take me some time, last time I did one is more than 10 years ago... aie) and more agressive cams (undecided)

I may be looking at more than a year for this project....

[vocky]

this thread HERE has plenty of pics of a ported lsj/saab head

[Exmantaa]

you need to use the lsj flywheel, but otherwise it's quite an easy swap.

Luckily I do have the lsj flywheel.
I will first have to prepare the engine with GM's suggestions with higher flow fuel injectors, forged pistons (I think I'll go for 10:1 CR) valve springs, ported Cylinder head ( will take me some time, last time I did one is more than 10 years ago... aie) and more agressive cams (undecided)

I may be looking at more than a year for this project....

I somewhere read that the LSJ has the same 8 bolt pattern as the XE/LET engines? Not sure though. Have to check if my old XE flywheel fits the LSJ crank...

How much power do you intend to run? The standard LSJ pistons seem to do fine in the US till ~300 Supercharged Wheel HP. (And in that GM build book they swap to 10:0 because they also used hotter cams, which lower your dynamic compression a bit.)
That article is pre-Harrop TVS, so things have evolved a bit now.

Work on the LSJ head, valve springs & cams (have a set GMR SC-cams) are also on my to-do list. And that Harrop is soooooo tempting...

A year is long, so do it in stages and SC your 2,2 first with the Courtenay remap. Will not cost you that much and you can taste some SC-power.

[Muncher]

You're right on the bolt pattern for the flywheel.

[alanoo]

Work on the LSJ head, valve springs & cams (have a set GMR SC-cams)

Bwa, these need solid lifters, they are crap

[zezinio]

I somewhere read that the LSJ has the same 8 bolt pattern as the XE/LET engines? Not sure though. Have to check if my old XE flywheel fits the LSJ crank...

How much power do you intend to run? The standard LSJ pistons seem to do fine in the US till ~300 Supercharged Wheel HP. (And in that GM build book they swap to 10:0 because they also used hotter cams, which lower your dynamic compression a bit.)
That article is pre-Harrop TVS, so things have evolved a bit now.

Work on the LSJ head, valve springs & cams (have a set GMR SC-cams) are also on my to-do list. And that Harrop is soooooo tempting...

A year is long, so do it in stages and SC your 2,2 first with the Courtenay remap. Will not cost you that much and you can taste some SC-power.

I should be satisfied with 300hp max and not rely on too much boost to generate power. I would like for the transmission and chassis to be just as reliable as the engine so I will not go over 300hp. My breaks will also have to be changed to stop all that power.

Than hit the track and learn how to drive all over again.

I tought about putting the supercharger on the std engine but I'm afraid that I will postpone and postpone my initial project as I'm sure I will love the supercharger power.
(I better not tell my wife, she'll prefer that option )

[Exmantaa]

Work on the LSJ head, valve springs & cams (have a set GMR SC-cams)

Bwa, these need solid lifters, they are crap

Yes, I know...
That's why they're still in the box.. .

[Muncher]

Work on the LSJ head, valve springs & cams (have a set GMR SC-cams)

Bwa, these need solid lifters, they are crap

Why are they crap?

[alanoo]

Cause they need solid lifters, and there's no real reason for that...

[Exmantaa]

Work on the LSJ head, valve springs & cams (have a set GMR SC-cams)

Bwa, these need solid lifters, they are crap

Why are they crap?

Smaller base circle, what the hydro lash adjusters don't like.

(Anybody can PM me a low cost solution for this? Shims underneath the lifters does not seem to work well with the LSJ's head design. (You loose the shims according some US guys...) Not sure if valve stem caps will work on our lifters?)

[alanoo]

What I can't understand is... if it is only a smaller base circle stuff, then it will work with new hydro lifters it is exactly the same issue than with piper regrinds where you get noises if you don't change them or maybe the base circle is so much smaller than it is out of the range for the hydro lifters ?

[Muncher]

I am using comp cams, will they have a smaller base circle?

[alanoo]

no

[Exmantaa]

What I can't understand is...
if it is only a smaller base circle stuff, then it will work with new hydro lifters
it is exactly the same issue than with piper regrinds where you get noises if you don't change them

or maybe the base circle is so much smaller than it is out of the range for the hydro lifters ?

Going way off topic and opening the GM box... =>
GMR Lobe top-bottom = 34.61mm
GMR Base circle diam. = 27.96mm, giving a 6.65mm cam lift.

Could not find stock base circle data so quickly.

[alanoo]

This is "only" 11.2mm on valve lift... definitely can't see why these should be problematic... apart if the base circle is really so much smaller than on OE cams

[slindborg]

the base circle probably has shag all to do with the necessity for the solids. The ramp angles (meaning velocities) might be simply too harsh for the hydros to push against, meaning you need to convert to solids. Shimming the stems is a good way to do it (its done a lot on the 8V GM engines). OR you could weld up the hydro lifters (after taking the valves out) and then shim under them from there

[vocky]

you cannot use shims on the lsj/saab/z20net head, they would fall out

[Exmantaa]

That's exactly what I heard from the US guys, therefore my question about other solutions. Have to take a closer look to my LSJ head for this, but if the adjusters simply cannot cope with the ramp angles then I should convert to solids. Vocky, do you know the OEM cam base circle specs?

[vocky]

I have a few cams knocking about, what do you need to know ps: if you remove the retaining clip on the hydraulic lifters they will work ok with a smaller base circle. the problem is making sure they don't fall apart before the head is assembled