so i took the ol gal apart today to check on a few things. before i get into it, the engine is a benson sleeved gsr with 9.7:1 cp's and eagles. ptw was set at .0045. rod bearings plastigauged .0016 to .0018 roughly. mains were .0018 to .0021 for the #3 main. compression was 220-225psi, leakdown tests were 6 to 10%. engine has like 3200 miles.


1) burning a small amount of oil/could be seen on the top of the #4 piston through the plug hole. fairly certain its the exhaust valve seals. those 2 valves arent white like the other exhaust valves. i do have some vertical wear though on the cyls that goes from top to bottom. it doesnt catch the fingernail but just want to run it by you guys to be certain its not leaking oil into my cyls.


2) the engine would have audible but not excessive piston slap until the oil would reach 150f which i thought was a long time. here is some wear i have on the #1 cyl.



ok i also found a piece of plastic in the screen in the oil pickup. i have no clue how it got there, but it was there.

ok, here are some rod bearing pics. most of them seem to have a nice wear patch on them. does it look excessive and in need of replacement or pretty normal.







just looking for some input if i should be replacing these parts or is it relatively normal wearing and not much to be concerned with

 

The cylinder walls aren't a big deal, that's fairly normal. You do have a bit of a big PTW clearance, so it will wear a bit.

The rod bearings don't look bad, but I would replace them anyway. They are cheap and you already have them out.

 

I had an incident last year with ptw contact on the dyno so I went bigger on the tolerance this time around. I hvent taken the crank out but don't the rod bearings usually wear more than the mains

 

Looks pretty fine to me considering the power it was probably pushing out. If it was me i'd replace those rod bearings, have the cylinder's honed and fit new piston rings. Yes the rod bearings do wear more than the mains.

 

Noob question:

If the compression & leakdown are good (which they appear to be) why hone and change the rings?

thanks

BTW: the bore look shiny in the pics are they washing down ( eng running rich)?

 

Because he's got it apart and its not exactly expensive to do so. He could even purchase a flex hone and do the honing him self. This is what i'd do, its just freshs up the engine a bit. He could just leave the cylinders as they are though...

 

Yea my real debate right now is to hone or not. I do have an extra set of 84.5mm rings lying around but the engine had good compression im not sure if I want to take it apart and have it not seat the rings as well or something. Ihave rod bearings on the list of stuff to orderalong with new arp rod bolts I've used this set a few times now.

I know I should replace the rings but if I can save that set I have in case some **** happens mid season it will greatly reduce my downtime. I also need to get a ball hone just in case

 

So again, Why would you change the rings? what are you gaining or correcting?

The rings currently in the motor are working now.

In this case you only have 3K miles on the build (don't know how hard those miles were) but your compression and leakdown indicate you still have a good tight motor.

Old saying "IF it's working don't F%#K with it".

Mike

 

I would hone it since its apart.
From what I know honeing creates the cross hatch pattern allowing oil to better lubricating the entire cylinder. As the rings wear that cross hatch down lubrication decreases. Allowing more heat/friction.

 

Yes you are right about the hone and crosshatch. However even where I have the wear along the thrust surfaces the crosshatch is still there.

Theoretically, even if I chance the rodbearings as long as I don't remove the pistons from the cyls it shouldn't break the ring seal and then require a rehone, correct?

 

Slightly better compressions ??? Your right its not needed but stuff like this is standard procedure in a high output engine on tear down. Is it a big deal if he doesn't do it ? No...

 

Thanks Rich777.

Question: since 220-225 compression seems to be pretty good to me, how much "better" can it get? What is optimum compression on these engines?

Thanks-

 

I dunno man seriously... i guess it comes down to the gauge he's using and how much abuse the motor has had. Like you say its not needed, maybe wanted ?? I'd do it on a engine like this... a close to stock engine ? No...

 

Im just using one of the middle of the road gauges I got from autozone. For reference on the same gauge
vitara d16 160psi
stock ls 185 psi
stock b16 and gsr 210 psi
11.5:1 b20vtec 250psi w/cam overlap.

It seems to be relatively accurate

Rod bearings are in transit should have them this week. Still up in the air on rehoning, though unlikely ill look at it again when I replace the bearings. Motor should be together soon, but im currently getting scammed on the tuner1s I bought for it so it might take a while