engine advice needed

[gsxr141]

ok, so it looks like the motor i threw together last year didn't hold up. i'm looking for suggestions on how to proceed.....

i have 2 complete motors, and a spare shortblock that needs to me bored out. i also have a set of new 20 over probe forged pistons. to add to that, i have about $1500 to spend on this motor.

what would be the best way to go about doing a motor? can i use stock rods or do i need better ones to reach 450 hp?
please toss out any suggestions you guys might have. i'm pulling the motor out this weekend, and want to get started on the rebuild.
thanks......

 

[suprarx7nut]

Stock rods (and pistons for that matter) should be fine for that power level unless you have some horrible detonation/tuning.

Talk to some machine shops nearby and see who's familiar with 7Ms. They could probably tell you which block is in better shape.

You'll want a MHG which requires machining the block surface. As far as the block goes, you won't need much else. Use new bearings all around. It'd be smart to get a valve job done on the head if you haven't recently.

IMO, nothing's special on a build for that power level aside from the block surface.

 

[gsxr141]

cool. i'd like to use the probes, and stock rods. is there anything i should do to the rods besides getting arp's? what about the main caps, should i get arp's for them too?
also, the crank has some marks from a previous rod bearing failure....... will it be ok to have it turned down?

lastly, i'd like to have the head gone through. is there any benefit to getting all new parts at the power level i'm trying to reach? ... 400-450- wheel.

 

[super51fan]

What was the failure of your rebuild? If you don't know root cause take all part to machine shop. Dirt and improper cleaning is usually the cause of bearing failure. Each and every part that comes back from machine shop needs a thorough cleaning of at least brake clean and compressed air. I mean several cans of brake clean will be used.

The advice given above is good advise. Make sure you have rods checked out and redone big end .

Make sure they don't use "old school" Hot tank to clean block. It will destroy oil pump bearings. These should be inspected before anyway.

At your power level all stock parts will be ok except use of MHG. I like the cheap HKS brand . IMO of course. Make sure they have front cover for block decking. Get new oil pump also.

I would ask how much they charge to assemble the short block? Might be worth it for them to do it for you.

If a machine shop does a valve job they would replace any worn parts they find. Make sure they set valve clearance. And always double check the clearance once home.

Find out root cause of failure so problem won't be repeated. Good luck .