BLOWN Up M7 Questions

[MRN]

Hello I blew up My m7 Yesterday as the oring on the head failed and leaked coolant into the Mag side cylinder. I am curious whats the best route to go for getting a top end kit and O rings. I believe the cylinders can just be cleaned up without boring but I was also thinking I would like to run a nitrous kit next year and was courious If maybe boring would be best to tighten up the tolerences and go with an oversized piston kit. I have read some guys are liking the SPI kits?

My questions are what are the cyl, piston and ring tolerences? and should the be tighter if I plan to run about a 40hp shot?

Whats the best forged piston kit for the money? And what should I expect to pay?

Thanks Mike

 

[sledbasher M7]

M7

The cylinders are nickasiled(?) Anyway cannot overbore the without getting them re-nicked.
I hear the 700 really like NOS.
I do have a boondocker kit,less the bottle if you are interested?

 

[kbleecker28]

I just sold my m7 and i still got a union bay 900 big bore motor for and im trying to get rid of that if your interested its got a stock m7 bottom end with the 900 big bore cylinders and comes with bmp pipe kit and boondocker let me know if your interested 7016802703

 

[rigrat]

Any good reason why the cylinders cannot be bored and sleeved instead of nikasil?

 

[MRN]

TTT anyone else have any input. Can I just bore them without the renickisel?

 

[furthur]

TTT anyone else have any input. Can I just bore them without the renickisel?

no.

If you're not going bigbore, no reason not to go back to stock bore/piston for parts availability/reliability.

 

[polarisfornow]

Sleaves are not a great option in these IMO. The nicasil does alot of things that a sleeve can't reproduce. Better heat distribution, more slippery, better lubricity characteristics. Plus you'll prob be using and iron sleeve so your mixxing metals meaning different expansion and heat rates. Just not a great way to go really. The best bang for your buck IMO is overbore to fit the stock 800 piston and run a control box. Maybe add a little compression too.

You'll have as much or more power than a stock m8 and without the danger of running nitrous. And even if you do want to run nitrous you would prob need a control box anyway. Not really any extra money to go to the 800 topend.

 

[Freeride1]

Is it really just an overbore an a replate to run the M8 pistons?

 

[spudman720]

Bore and re-nik cylinders need valve spacers and chambers opened up in the head.

 

[furthur]

Bore and re-nik cylinders need valve spacers and chambers opened up in the head.

Valve spacers or cut valves?

 

[Freeride1]

Any issues with the EFI? ANy need for a controller if it is all stock?

 

[polarisfornow]

Any issues with the EFI? ANy need for a controller if it is all stock?

yes you definitely need a controller. I use the pure logic on mine and have been very happy with it. because you will be running a stock 700 ecu on an 800 motor so fuel will need to be added via the control box.