So i bought part of an ls/vtec swap off a guy around here and i was double checking all numbers on everything so i know what to the the people im getting a base map from... heres what i know for sure

JDM b16a head
b18b1 block
GSR pistons (p72-AO)
GRS Rods (p73)

now im having issues IDing the crank... other than the 1-4 stamped on it.. there a 4 near the number one cylinder, a K near the number four cylinder and also a B2 near the number one.

If this is an LS crank... if im figuring this right, that puts my compression around 11.5:1 which is much higher than i really want to be. Would it be better to track down a GSR crank or get low compression pistons. any other option would also be nice.

 

There's a small flat plate surface on the journal closest to where the crank pulley is. That marking helps determine which crank it is without going through all the micrometer headache.

B1-B4 = LS or B20 Crank
R= Type R Crank.
6 = B16
7 = GS-R

I stole that from TheShodan a while ago.

 

That's what I was afraid of... Suggestions of my best options?

 

I'm not sure I understand exactly what your worried about. 11.5:1 comp. ratio is not very high at all. Are you trying to build a stock engine?

 

A few things... 1. I will problally be running off a basemap from phearable for a bit. 2. 93 gas is few and far between around her. And 3. I was likin at dropping a turbo in next year... And I would say 11.5 is high for a turbo.

 

if it has gsr rods it has to be using a gsr crank. not only are the rods different lengths and would put the piston out of the hole at TDC, the rod journals are different as well.

 

If that's true, which numbers do i have wrong?

 

ok, a bit off on the rod number, but im fairly sure they are the same... they are p72 rods...

and heres a pic of the pistons at tdc

 

Any one?

 

and again? got the head back from the machine shop and really need to start assembling things

 

on a ls crank only one of the counter weights are machined and the other is rough, on vtec cranks both counterweights are machined. if you have gsr rods it should be gsr crank tho. if not it wont run for long, and gsr pistons crank and rods in a taller ls block with a b16 head that has more cc volume than the gsr isnt gona have much compression. less than a gsr,so should be good for boost if thats your plans

 

acording to this http://www.zealautowerks.com/bseries.html

i would be running 10.3:1 and thats before what they had to mill off the head

 

It wouldn't be that high. The stroke on the gsr is 87 and the ls is 89 so you are losing tourqe . It sounds like like pulled a fast one on you cause there is no reason to put that crank and rods in that block

 

looks like its definatly a LS crank, as only one of the weights are mechined .... with GSR rods and pistons... suggestions? prefeaable budget friendly ones

 

if thats the case i wouldnt run it man. the gsr and ls rods are similar in length and the big end bores are the same on both so as far as bearing clearances go but alot of peopld dont check and see that the gsr rods are a good bit narrower than the ls rods. which means that the rod end play is gona be way beyond the service limit. since you got the windage tray off get a service manual and find the service limit for it anc check to make sure. the best way is with a dial indicator but you can use feeler gauges and get a pretty acurate measurement also

 

feeler gauges, i took a look at it when i look at the counter weights.... they move a could 1/4 inch....

 

Get some eagle Ls rods and p73 JDM pistons and ur good to go

 

should also mention i had to have a good bit milled off the head... 0.024" i belive