06blackg85ss

iTrader: (1)

nice man. you can use either cams, just need to make a blockoff plate for the cam sensor housing, only 2 bolts and not a big deal at all.

slindborg

perfect! Ive got some cams of similar spec to the GM performance gind on order.

just need a head now (oh and the 2.4 inlet lol)

06blackg85ss

iTrader: (1)

as I said if all else fails, I got one for sale.

en0onmai

What is the real world benefit of a LSJ head to L61 block? Bigger openings and free-er flowing head? What about the difference of the LSJ cams VS L61 cams in the same head?

I already have the generic bolt ons done:: CAI, GMPP Manifold, SC Downpipe, full exhaust, and 2.4 intake manifold. Looking for more power in a N/A setup before going FI with a Saab turbo kit. Getting the AEM FI/C end of this year to help with the Uber-Lean conditions.

Sorry for my question in bold but lotsa people around here don't read too well.

slindborg

thanks mate. If the guys at chapman cant get an LSJ for cheap I might ahve to get you to send it to them lol.


As far as I can make out the heads must flow a similar ammount and probably have the same sized valves etc, but the head itself is made stronger as its a sand casting which tends to be a more stable cast. We have a problem in the uk where the L61 heads crack in plugs 1 or 4 if the spark plugs are done up too tight..... not a problem for most but lots of mechanics here are total fcukwits and over do the plugs thinking its needed for sealing.

Novajoe

the plugs I wouldn't be worried about too much. But all the air in it would give it a higher tendency to warp under heated conditions.

MVP

also keep inmind if you bolt a head thats normally mated up with a smaller bore engine to that of a larger bore engine your going to effectivly raise your compression ratio.

not that in this case bolting a LSJ head to a L61 block will effect the compression ratio because if i recall correctly the 2.2 and the 2.0 have the same bore size but different stroke.

Don Juan

MVP its been several months now how has the mod came and numbers yet and really noticable gains?

jperris

First part true; second part untrue. With any given head, a 2.2 will have a higher compression ratio than a 2.0, regardless of whether its a larger bore, longer stroke, or both (longer stroke in this case). A longer stroke or larger bore will both have a similar effect on compression ratio, since it is based on cylinder volume as compared to combustion volume.

Way to dig up a six-month-old thread, btw.

MVP

all it takes is a larger bore on a smaller combustion chamber to raise compression because essentially your putting more air onto a smaller space. a longer stroke would have the same effect as well. a larger bore and onger stroke with a smaller combustion chamber would have the same effect as well and then some.

some one asked a question BTW I didnt dig up the thread.

jperris

that's what I was trying to tell you, because it seemed like you were saying the opposite in your first post. but i guess i just misunderstood what you had said. my bad.

Don Juan

numbers of gains? hp? tq?

MVP

yeah i started a thread on it.

slindborg

wow blast from the past lol.

I got a Saab 1.8 turbo head, which iirc is the same head as used on the LSJ.
Just need to get some time to fully measure it up (CR, port sizes etc) and get some waisted stem inlets for it etc.

incidentally was the LSJ exhaust valve sodium filled from the factory?

Halfcent

Yes, they were.

I just noticed this thread, 6 months too late. That qoute in your very first post is mine. I was discussing how you can use L61 cams in an LSJ head as long as you put that head back on to an L61 block. It seems others discussed why due to the exhaust cam driven timing sensor. All of that of course is dependant on putting the engine back into a car that was originally equipped with an L61 and it's ECM. If you use a stand alone ECM, you can do whatever the hell you want with any cams. The reason it's an advanced modification is due to the large number of additional variables that have to be addressed as a result of the swap. The parts themselves will bolt right together no problem.

IonNinja

somewhat related...

do the LSJ and L61 heads share the same valve springs?

tru2nrtt777

iTrader: (1)

I doubt it, seems like the LSJ would need stronger higher compression springs than the 2.2.

slindborg

ohh I'm not touching the exhaust valves then (bar relapping)

so effectively if i simply take my L61 equipt car and swap only the head to an LSJ one then all should be well...?

IonNinja

anyone else have any insight on this?

Halfcent

Valve spring are identical across all platforms (L61, LSJ, LE5, LNF). This data is from the Cam info sheet available for download from GMTunerSource.com.

IonNinja

so essentially then, L61's should be good for 7K revs on stock head

Halfcent

Yup. I would say you could take the stock valve train and spin it at 7500 safetly. Any faster, or any higher lift cams, and you would need new springs.

IonNinja

sorry didn't mean to say bottom end...

not that it matters since I don't have stock valvetrain but was just curious as it was brought up on another forum that they share valve springs.

thats good to know for reference though