Knock sensor and head replacement

[Blu90GST]

I bought a 1991 laser rs turbo for 500$. The guy told me it bent a valve but he didn't know too much about it. I pulled the head and every intake valve down the line was bent and had kissed their corresponding pistons. Tomorrow I'm cleaning up the block mating surface and using scotchbrite to clean up any high spots on the pistons. Here are my main questions.

1) will the car run decent with the pistons like this? It will be my DD.

2) the knock sensor wire broke off somewhere in the process of everything, if I splice/solder the wire back together will it work correctly?

3)I want to do a little clean up in this process, mainly vacuum lines. Should I do the vac line delete now or wait? There are probably 100 vac lines going everywhere and I honestly have no idea where half of them go.

 

[Chad1993]

As long as the valves didn't poke holes in the pistons it should be fine. My cousins subaru did the same thing and is still running.

About that knock sensor, if you solder and maybe some heat shrink it will be fine. As long as the sensor it's self is unharmed.

 

[Blu90GST]

The sensor is completely fine the wire just got snipped or something

 

[F_27stryker1]

Personally if you can, why not replace the pistons. I know not all of us have the money or time to do this, but it would be one less thing to worry about down the line

 

[Turboturd]

Personally if you can, why not replace the pistons. I know not all of us have the money or time to do this, but it would be one less thing to worry about down the line

Generally because this requires you to rehone or bore the motor, its a lot of tear down and assembly work for a $500 car . Is it a good idea, yeah, but I would say for now just clean up the pistons and go for it. If it truly is just a daily and you don't plan on modifying the car then put as little work into it as possible

 

[92AWDHX40]

Ive plenty of head damage didn't replace the pistons just some nicks replaced the valves and kept on going.

 

[Blu90GST]

I go to ICC for welding and am still in high school while working part time. Those 150$ checks aren't buying me new pistons and a hone/bore anytime soon. I do have a short block that I'm rebuilding as soon as I have money and get this laser going so I'm not gettin 10 mpg in my Chevy xD. That's the only reason in considering using these pistons. Anyone have a good way to clean up the block mating surface? I've been trying scotchbrite but it's a pain getting in those little areas by the alignment dowels.

 

[BogusSVO]

Knock off the high spots with a with some sand paper or grinding stone. This is a common thing to have to deal with after a timing belt failure.

If you search "piston dings" you will find pages of threads on the subject.

Just pull the alignment dowels out. a 1/4 drive 10mm deep socket and a pair of vise grips and you can twist them out and should be in decent enough shape to re use.

 

[Jmmahon]

if their is no cracking in the pistons then they could work, there could potentially be hot spots on the piston if there is a dent when its running, but im sure it'll be fine. now for the knock sensor just solder it, you wouldn't even need it actually it would just set a DTC.

 

[My1GLaser]

If the ECU doesn't detect a knock sensor signal on a 1g it will pull 3.2* of timing across the board and run like a pig! (It might be 3.5)

A razor scraper works well to get the difficult pieces of old HG material off the block. It's hard to hurt the surface with a single edge cheap razor blade.

 

[Blu90GST]

Like a shaving razor or one from like a box cutter?

 

[untouchablecc]

Like a shaving razor or one from like a box cutter?

Neither of those. Stick with the rough grit sanding paper. If you want a gasket scrapper go to your local parts store and look down the tool isle for one or ask the person at the counter. They aren't more then 20 bucks and usually come with blades. I prefere a sanding block and paper.

 

[Blu90GST]

Like a 150 grit?

 

[BogusSVO]

Here you go...

http://www.dsmtuners.com/forums/new...r-how-clean-block-deck-pistons-installed.html

 

[Blu90GST]

I started cleaning the block the other day with a scotchbrite pad. The block is together and everything, im somewhat paranoid about messing up my rings. Is there a way to clean all the gunk from the SB pad out without did assembly?