Got the head off...should I pull the pistons?

[Daveed]

Got the head off the motor last night and at least one of the exhaust valves has a chunk missing on cyl.#2. Pressure test indicated leaking exhaust valves on cyls. 2 and 3.

Question: How much further into this motor is it worth it to go?
I don't plan on modding it with any performance parts and the cylinder walls looked surprisingly good.

Should I pull the pistons and rods? (does this mean pulling the entire motor?)
Thanks.

 

[NOSLO2PT0]

Should I pull the pistons and rods? (does this mean pulling the entire motor?)
Thanks.

No.

 

[jasoncitrano]

Got the head off the motor last night and at least one of the exhaust valves has a chunk missing on cyl.#2. Pressure test indicated leaking exhaust valves on cyls. 2 and 3.

Question: How much further into this motor is it worth it to go?
I don't plan on modding it with any performance parts and the cylinder walls looked surprisingly good.

Should I pull the pistons and rods? (does this mean pulling the entire motor?)
Thanks.

Ok, I had pretty much the same problem. I also had a blown headgasket and my piston's were toast. It is MUCH easier to just pull the entire motor/trans all at once, becuase trying to get that damn oil pan off an awd with the engine still in the car. It just saves alot of hassles.

Honestly i'd just rebuild it becuase think about it, if you go and spend the money to buy another car you going to just be buying somebody else's problems. If you rebuild this engine you can start from scratch and take care of it from the start.

 

[jasoncitrano]

No.

yeah and if he pulls the pistons and leaves the block in there, then goes to replace the pistons the rings are going to seat correctly and he's going to end up having more problems.

 

[Daveed]

Thanks for the input guys. I've got a couple weeks before the head gets machined so I'm not in that much of a rush.

Do rod bearings on these engines tend to be a problem?

 

[NOSLO2PT0]

yeah and if he pulls the pistons and leaves the block in there, then goes to replace the pistons the rings are going to seat correctly and he's going to end up having more problems.

Why on earth would you rip the bottom end apart if an exhaust valve is bad? Might as well go change the gas tank while you are at. Whatever you just said, didn't make one bit of sense. Explain it again so we can all understand, please.

 

[jasoncitrano]

All I was saying was that since he's got head off and he's got a 1990 it might be a good idea to do the bottom end as well otherwise he's gonna end up doing it soon anyways! and since his head is going to get machined anyways why not if he's got the cash other wise could end up costing more later.

 

[Daveed]

Jason, your last post was a bit more clear and I see now what you mean.

Noslo, your dsm seems to be a pretty hot car. If i was going to "build" mine I would definitely rebuild the bottom end, however, I'm just going for stock so I wan't quite sure if it would be worth it.


How long do the bottom ends on these motors tend to last?


Mines got 150K on it right now (I don't know if it was rebuilt before now). I've driven from my car trailer to the garage and that's it.

 

[NOSLO2PT0]

Why would he need to do the bottom end? If a compression test checks out ok, leave the bottom end alone. High mileage 6 bolt bottom ends are some of the best. They are nice and broken in, they can take a lot of boost, and can survive a lot of punishment. I've got 160k miles on my stock bottom end, running 30psi. When should I rebuild it? There's a motto that many people should live by ..... "if it ain't broke, don't fix it"

 

[jasoncitrano]

Ever heard of preventive maintenance?? sure pulling a bottom end apart is a pain in the ass, but so is driving down the road and throwing a rod bearing especially when you have hot chicks in the car

I'm not telling him to do it i'm saying he's got 150k on bottom end anybody who say's a bottom end with 150k is stronger then a stock rebuilt bottom end is a fool.

Daveed i'm not telling you to build a race engine here, as stock parts do not cost much at all. Do whatever you want but when you throw a bearing don't come crying on here saying i should have built my bottom end when the head was off the car.

P.S. i threw a rod bearing at 120,000 miles, bone stock, and was never beaten. 12 psi. so it can happen anytime.

 

[Daveed]

...High mileage 6 bolt bottom ends are some of the best. They are nice and broken in, they can take a lot of boost, and can survive a lot of punishment. I've got 160k miles on my stock bottom end, running 30psi.... QUOTE]

That's the kind of example I was looking for. Thanks.

 

[Daveed]

P.S. i threw a rod bearing at 120,000 miles, bone stock, and was never beaten. 12 psi. so it can happen anytime.

This is also another example of info that is helpful. Thanks.
Real world experiences from owners the same engine.

 

[NOSLO2PT0]

P.S. i threw a rod bearing at 120,000 miles, bone stock, and was never beaten. 12 psi. so it can happen anytime.

And how do we know you didn't do any prevantitive maintenance? I've owned 5 of these cars now. Lowest mileage one has been around 117k. The last 3 I owned were all in the 150k range. They all ran like champs. Of course there's going to be one here and there that tosses a rod bearing, but I guess that's what happens when you don't change your oil very often, or don't do regular maintenance.

 

[allmotor92talon]

whats the biggest shot of nitrous you think i could use on my stock 6 bolt bottem end.i have a 3 angle valve job,stronger springs and retainers,turbo intake cam,obx header and cold air intake,cam gears.......

 

[Daveed]

go to this fAQ on nitrous and it may be there.
http://www.dsmtuners.com/forums/showthread.php?t=37223&highlight=rod