JoshEE

iTrader: (5)

I just got around to taking the intake manifold off the LS1 I bought to swap into my RX-7 to clean it up a little bit, and I came across a strange buildup on one of the intake valves. The buildup was only on the intake valve on the driver front side of the car, all the other valves are clean with no buildup of any kind. None of the exhaust valves look out of the ordinary.





The engine was already out of the donor car when I bought it, so I never got to hear it run or anything. Basically I'd like to know what would cause this (coolant leak somewhere, head gasket maybe?), should I be concerned, do I investigate any further? I'd appreciate any help/advice you could give.

Thanks,
Josh

vettenuts

iTrader: (4)

Cylinder 1 is close to the intake manifold port that is connected to the EVAP system, not sure if that would be a factor.

Can you see in the cylinder? Is that piston really clean?

01ssreda4

iTrader: (96)

Looks like surface rust to me.....

BIG_MIKE2005

iTrader: (116)

^^Yep, thats some rust build-up. My stock 100k mile heads didnt have that so it being close to the Evap connection isnt gonna cause this.

I'd pull that head off & inspect everything closer. Thats a little weird it only appreas on one valve. Almost looks like it sit with water in there for a while.

JoshEE

iTrader: (5)

Here's a picture of the piston and cylinder wall, what do you guys think?



More pictures here.

If it looks OK, I still need to do something about the valve right? How much would a repair on something like that cost? The local Craigslist has a set of low mileage 241's for $100 and a set of low mileage 243's for $575. Are the 243's really worth the extra ~$400+?

I also might take this opportunity to go ahead and swap in a bigger cam, easier to do it now that everything is all apart. I've been looking at the TR224, if I do that should I also do the supporting mods, LS6 ported oil pump, LS2 timing chain? What about rod bolts? I don't plan on spinning the motor at super high rpm's regularly, but I hear the stock ones are a weak point on this motor. Also are the ARP head bolts worth the extra money over the stock ones? what do they gain you?

All this stuff adds up quick, and I would like to finish my swap as quick as I can, but it seems like now is the time to do this stuff since the motor is out of the car. What do you think? I realize I'm the only one that really knows my budget, but I'd like any input you have.

Thanks

TooLateVTEC

iTrader: (2)

Nasty.

It needs to come apart and be honed, no doubt. I wouldnt run that motor like that if I was you.

Looks like water/moisture/condensation got in there and sat for a while cause that surface rust.

Probably not what you wanted to hear, but better to spend a little time and money now than a lot more later.

ae13291

iTrader: (8)

clean it up really well, hopefully the bottom end doesent look like that

vettenuts

iTrader: (4)

Ah yes, corrosion (couldn't see the photo's at work this morning).

BIG_MIKE2005

iTrader: (116)

Yep, that thing needs a tear down & cleaning. Definetly had moisture in that cylinder for a while.

JoshEE

iTrader: (5)

So I went at it with some MMO and scotch brite (lightly), and it cleaned up pretty good. I think the majority of the crap in the other picture was just stuff that fell into the cylinder from the rusted valve when I was turning over the motor to remove the torque converter bolts. The only stuff that was attached to the cylinder wall at all was a ring less than 1 cm high around the top of the cylinder, and that came off with a light scrubbing with the scotch brite pad. I'm still gonna pull the oil pan and check out the bottom end this weekend to make sure everything looks alright in there. What do you guys think?

TooLateVTEC

iTrader: (2)

It looks good now, but there was still moisture in there and im sure the piston rings didnt like it just as much as the cylinder wall didnt.

You can polish a terd, but its still a terd.

JoshEE

iTrader: (5)

Ya a friend who has built a couple of engines before is going to help me inspect the bottom end and pull the #1 piston and check out the rings. Hopefully it'll look alright, if not I'll fix whatever needs fixing, I don't want to build a time bomb here.

ae13291

iTrader: (8)

you already have the motor out, replace the rings man its simple enough. then if you replace the rings you should replace the rod bearings after that main bearings etc, at the minimum replace the rod bolts to eliminate the single weak point in the bottom end of these engines. if you do decide to do rings, bearings, then machining might get costly but really its up to you

JoshEE

iTrader: (5)

So could I just replace the rings with stock ones? I guess I would need to hone the cylinders if I replace the rings? As far as replacing the rod bearings and main bearings, would I just replace with the stock size or what? What machining would be necessary? How much would all this end up costing (ballpark)?

As you can see I'm pretty new to all the internal engine stuff, I'm pretty mechanically inclined but just haven't had the chance to do any of this stuff yet. I'll start doing some searching, but in the meantime do you have any links or resources I should look at that may be helpful?

Austinma62

Try a search on Engine rebuild or bottom end Engine rebuild. Surely someone has done this before.

ae13291

iTrader: (8)

if you are going to replace all the other things you might as well hone the cylinders. you need to have the machinist measure all the bearings and crank journals to give you the correct measurement to buy. you could spend close to $700 on machining or even more depends on who does it.

chpmnsws6

iTrader: (70)

If it was mine-
Pull the piston/rod
Stuff a rag at the bottom of the bore
Tape off engine around effected cylinder
Dingleberry hone the cylinder
Clean the piston/rings
Clean engine
inspect the rod bearings
If they are good, put them back in
Install piston/rod
Check for coolant leak
Have head checked out (might need a valve job on that cylinder)
Run it like you stole it
Compression and leakdown test to make sure all is still well