Block question???

[JonnyZ(Socal)]

Ok so I was in the process of tearing down the block so I can have a bore/hone done to the cylinders! Well after hours of work I finally get the pistons and crankshaft out. Well my little brother had a hammer in his hands and dropped it on the block surface! So my question is what should I do?
My head has already had a lot of material taken off of it and i don't think it can have anymore removed, so can I have some material taken off the block and compensate with a thicker HG? Here is a pic of the damage!
Sorry for the crappy pic, it was dark when this happened!

 

[IJ.]

BHG waiting to happen, first I'd smack your bro between the eyes with the hammer then I'd try and measure just how deep the ding is.

I'd then measure the block to see if it's been surfaced before, based on all that I'd make a decision to get it surfaced or find another block and keep the hammer spaz away from it.

 

[hvyman]

If your rebuilding you should be using a mhg which needs both the block and head to be machined to about 30ra or smoother. Cometic calls for 50ra and hks calls for 30ra but the smoother the better.

Basically both the head and block should look like a mirror after.

So yes you should defiinality have the block machined.

 

[JonnyZ(Socal)]

Wow, I have never got replies so quickly on this forum before :]
How can I check if the block can be machined anymore! Thanks for the replies too!

 

[hvyman]

Either measure it and find specs/measure points or drop it off at a quality machine shop and have them inspect it.(id go with the second part)

 

[IJ.]

Wow, I have never got replies so quickly on this forum before :]
How can I check if the block can be machined anymore! Thanks for the replies too!

From memory an uncut block is 198.5mm from deck to Main tunnel saddle.

 

[JonnyZ(Socal)]

I guess I'll take it to a shop, hopefully they can tell me what to do and I hope it's not to expensive, as I am already over my budget!
If anyone can help me on deciding what size HG that would also be great

 

[IJ.]

I guess I'll take it to a shop, hopefully they can tell me what to do and I hope it's not to expensive, as I am already over my budget!
If anyone can help me on deciding what size HG that would also be great

You need the measurements I mentioned earlier BEFORE choosing a HG anyone that tells you different shouldn't be listened to.

 

[JonnyZ(Socal)]

You need the measurements I mentioned earlier BEFORE choosing a HG anyone that tells you different shouldn't be listened to.

Ok, sorry it's been a long day... I don't want to seem annoying! I really appreciate the help, now lets just hope that the machine shop knows what they are doing!

 

[IJ.]

Ok, sorry it's been a long day... I don't want to seem annoying! I really appreciate the help, now lets just hope that the machine shop knows what they are doing!

LOL don't worry I'll let ya know when I'm annoyed

Good luck with it all and don't hesitate to ask if there's anything you need to know.

 

[JonnyZ(Socal)]

LOL don't worry I'll let ya know when I'm annoyed

Good luck with it all and don't hesitate to ask if there's anything you need to know.

Ok, there is more I need to know
I'm on my gf's comp so I don't have the TSRM on me... I called the machine shop and asked if they would be able to tell me what I need done and what size HG to go with after they do the inspection. They told me that I need the specs for the head and block. From what you told me the block should measure 198.5mm from deck to Main tunnel saddle. So what about my head because, It's been machined twice before I even owned it and none of the prev. owners got the specs on how much was done... I hope I'm not confusing I'm just trying to get things done properly as I don't want to have to rebuild the motor again! Thanks for all the help so far, you guys have been very useful!

 

[hvyman]

Any good machine shop should have the specs on hand.

 

[JonnyZ(Socal)]

Any good machine shop should have the specs on hand.

I guess the ones in my city don't :/

 

[CyFi6]

http://www.supramania.com/forums/showthread.php?97552-Head-Gasket-thickness-selection&

Has all the info you need

 

[IJ.]

http://www.supramania.com/forums/showthread.php?97552-Head-Gasket-thickness-selection&

Has all the info you need

Thanks

 

[JonnyZ(Socal)]

http://www.supramania.com/forums/showthread.php?97552-Head-Gasket-thickness-selection&

Has all the info you need

Thank you sir! You are good peoples :]
Also I read that changing piston size affects compression ratio, I assume it makes the ratio lower right as I'm going .5 over right?
If so how much does this change the ratio, it shouldn't be a big deal anyways if memory serves me correct because lower compression is better for turbos! Correct me if I'm wrong, as stated I just want to make sure I do this right and I really appreciate all the help!

 

[IJ.]

CR will increase with bigger pistons as the combustion chamber doesn't change and you're squeezing a bigger volume into the same space.

http://www.csgnetwork.com/compcalc.html

 

[JonnyZ(Socal)]

CR will increase with bigger pistons as the combustion chamber doesn't change and you're squeezing a bigger volume into the same space.

http://www.csgnetwork.com/compcalc.html

Hmm, I thought that have the cylinders bored would make the combustion chamber larger, but now that I think about it when the piston hit TDC the combustion chamber is the same, so it makes sense!

 

[JonnyZ(Socal)]

Also, does anyone know how much material can be taken off from the head before its bad. I wanna know that if you max out the material you take off the head if you can still remove material from the block!

 

[IJ.]

About 20 thou is as much as I'd feel safe removing if it was going to be a performance build (ie:450+rwhp)

The heads aren't that thick in the Deck and you'll be getting close to the valve seats.