I'm about to start my build for F/I, my build will consist of sleeved 83mm GSR block, balanced LS crank, LS eagle 3/8 bolt rods, CP 9.1 comp pistons, stock port ITR head w/ supertech flat valves..Now my question is: what motor do i order the pistons for LS or GSR?? i know the deck height of these 2 motor's are ALMOST the same, but im not sure if the pistons are the EXACT same as far as the piston skirt & wrist pin location?

also say i order pistons for an LS @ 9.1comp. what would the real compression be since id be using them in my gsr block w/ ls crank/rods and itr head??


Modified by Project_EK at 9:52 AM 6/4/2008

 

can the ls crank along with rods be used in a gsr block without any modifications?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Project_SOHC_EX &raquo;</TD></TR><TR><TD CLASS="quote">can the ls crank along with rods be used in a gsr block without any modifications? </TD></TR></TABLE>

You'd either have to modify or remove & plug the oil squirters! if your going to use forged internals i'd suggest getting the kit from golden eagle to plug them...other than that nothing else needs to be "modified"

BTW be sure to use LS rod bearings..


Modified by Project_EK at 11:38 AM 6/4/2008

 

Most manufacturers I've seen use the same piston part #'s for B18A/B and B18C. They just list different compression values based on the head/block combo.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by inspyral &raquo;</TD></TR><TR><TD CLASS="quote">Most manufacturers I've seen use the same piston part #'s for B18A/B and B18C. They just list different compression values based on the head/block combo.</TD></TR></TABLE>

 

Thanks, i just got off the phone with CP and he calculated everything for me...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Project_EK &raquo;</TD></TR><TR><TD CLASS="quote">

You'd either have to modify or remove & plug the oil squirters! if your going to use forged internals i'd suggest getting the kit from golden eagle to plug them...other than that nothing else needs to be "modified"

BTW be sure to use LS rod bearings..


Modified by Project_EK at 11:38 AM 6/4/2008</TD></TR></TABLE>

im also running a gsr with ls crank with the oil squirters pluged. but you say you can modify them to work? how do you do this and what are the cons to having them plugged? i was told it wouldn't be a problem and would give me a slightly higher oil pres. which is good but i would think that having the oil squirters to cool the pistons would definatly be helpful in a turbo application?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by got wide &raquo;</TD></TR><TR><TD CLASS="quote">

im also running a gsr with ls crank with the oil squirters pluged. but you say you can modify them to work? how do you do this and what are the cons to having them plugged? i was told it wouldn't be a problem and would give me a slightly higher oil pres. which is good but i would think that having the oil squirters to cool the pistons would definatly be helpful in a turbo application?</TD></TR></TABLE>
I believe it's mostly a clearance issue, and people who opt to keep the oil squirters with forged internals usually just bend them slightly out of the way for more clearance with the rods/piston skirts.

 

The 1.8L blocks share the same deck height (crank centerline to head mating surface). The total piston/rod height is almost the same between motors, the only thing different (besides squirter clearance) is going to be intake valve relief size (31mm vs 33mm) and the rod's small end width:

B18C1, B18C5 17.9 mm (0.705 in.)
B16A, B17A 18.0 mm (0.710 in.)
B18B 19.9 mm (0.785 in.)
B20A 23.7 mm (0.935 in.)

So a vtec piston on a B18B1 rod will fit if the pistons have greater than 20mm inside width (I think there's over 10mm of slop in OEM setups). I personally think the B18B crank/rod are better for boost, since both rod ends are wider. Wider = more load bearing surface, so less force per MM^2. Extra displacement is icing on the cake.

 

forged internals didnt have anything to do with the oil squirter clearance. it was the ls crank counter weight that was hiting them and they didnt look like they could be bent out of the way and still squirt the piston?

 

I'm running a B16B(same deck hieght as B18's) with LS Crank, Eagle LS rods and LS CP 9:1 pistons.