Rebuild or replace? Built short block on the chopping block?

[want2race]

I had the motor pulled to verify number 8 piston rings. I had oil in the cylinder, suspected bad valve guide seals but needed to make sure. It was indeed worn guides and seals. Motor had strong compression and good leak down test.

So, I bought the car with the motor work already done. Built to handle way more power than it has. Wiseco 11:1 with rings dropped .300", Manley H beam rods, Boss crank, block was bored and honed then decked. Everything done right, except... The wrong parts for a true N/A only car.

Car was never boosted, never will be. I want to go 5.2. Found a builder that is putting cross plane cranks in with oem GT350 parts.

I can either rebuild my block with lighter internals, or sell it to lower the cost of going 5.2, although it's basically a stock GT350 motor. My stage 2 heads and cams with Boss intake is going back on. Mine ran 520whp when built.

Thoughts?

 

[clinton2003]

well, your going to need a lot of work to make the flat plane crank to work... we are talking a gt350 computer (or probably aftermarket), gt350 cams, timing components. at that point, you probably should just get gt350 heads as then you wont have to do all the machine work to make the cams/followers fit your heads....

thats just off the top of my head....

If you want to go full tilt na, you want a good set of rods, i beams arent a bad idea, since it sounds like you want to spin some high RPM.

how much was block bored? .005? if so you cant bore it out again (or shouldnt anyway) as the stock sleeve is really thin.

If your block already needs a rebuild, may as well use that stuff, i'd recommend the manly "lightweight" I beams. they weight the same as the H beams but are much stronger and you wont have too much of an rpm limit (maybe 10k?)

i'd also recommend sleeving your block. doing so will make sure you dont have any sort of strength issues. At that point you can decide to punch the sleeves out to 3.700 bore (94mm 5.2 liter) or leave at stock bore 3.630. (92.2mm coyote gen1 & 2) The Gen 3 bore is actually 3.660 inches (93mm).

the voodoo motor has a SLIGHTLY longer stroke( 93mm vs 92.7mm) and 12:1 compresstion. but have issues with oiling etc...

if your running e85 or race gas, id toss 14:1 compress pistons in there without thinking about it... IF you ever plan on doing boost OR want to run regular 91/93 octane you may think of staying around 12. if not, shoot for the moon.

If i were you, i'd go get my block sleeved. Punch it out to 3.66, get a custom set of pistons for 14 or 15:1 compression. Manley or equivalent I beams for strength, toss your heads on and make some awesome power. Your going to want to get a set of cams/springs for this as well to help get the most air in/out as you possibly can. Also you should look at possibly an 18 intake, from what i have seen, a ported 18 intake is as good as a cobra jet intake, for MUCH less money, but i bet cobra jet will be better after 8000 rpm. Your also going to probably want to do some sort of aftermarket computer. that way you can get the RPM's you want. It's a good bit of money but

You're looking at 2500 for sleeves, 1000-1300 for pistons/rings, 1500 for rods, 300 for bearings, 1000ish for machine work assembly of short block, so about $6600 JUST in parts/motor work. If your short block is good, you may be able to sell that for 3-3500, and find a f150 or mustang block to sleeve. May be able to hit up Sai Li for a ready to go sleeved block, but probably in stock bore.



the reason people do boost, is its actually cheaper to get power out of... most of the time anyway. Good luck, i hope to see your car turn into an NA monster... not may of them around.

PS. sorry for the bouncing back and fourth randomness. Welcome to my brain.. haha

 

[want2race]

Cross plane crank, not flat plane. 5.2 Coyote...

 

[want2race]

It's currently at .010 over, bores are excellent. I considered sleeves but thought that was really just for boosted motors.

The 5.2 using Boss crank won't require anything special for computer. Cams stay the same too. I already have upgraded springs. Should work. The 5.2 block is stronger where it needs it, without restricting the water jacket size.

Oil squirters? I don't care if it burns oil. Do they work?

Benefit of buying complete short block is so i can sell this one to offset. Down side, all the machine work is already done on mine.

 

[biminiLX]

So you're just at needing new valve guides/seals?
Freshen yours and buy an Aluminator 5.2XS.
Then IF you want more power NA you have a better starting platform.
Plus those True Aluminator motors hold good money.
$15k shipped from Jegs and rock out, sell yours to offset.
I'm thinking of buying a 5.2XS to boost and then build/sleeve when wanting more.
-J

 

[clinton2003]

Cross plane crank, not flat plane. 5.2 Coyote...

ya, must have miss read that. saw gt350 next to it and just assumed, my B.

It's currently at .010 over, bores are excellent. I considered sleeves but thought that was really just for boosted motors. No sleeves are not just for boosted motors. if you want to bore it out, you basically have to, or get a voodoo block. which are nice, but also cannot be bored (light hone maybe...) because of the plasma liner. so if it gets messed up your back to having to sleeve it anyway. The plasma liners do offer less friction than standard steel bores, but is it worth it? (if you do go with it, make sure you get rings that are safe for the plasma lining)

The 5.2 using Boss crank won't require anything special for computer. Cams stay the same too. I already have upgraded springs. Should work. The 5.2 block is stronger where it needs it, without restricting the water jacket size. This was all going towards the FLAT plane crank. i said that in my post. I had mis read your post. Have you seen how small the water jacket holes are on the head gaskets? They are set that size for a reason.

Oil squirters? I don't care if it burns oil. Do they work? Oil Burning goes with the flat plane crank. I'd definitely keep oil squirters for a NA motor.

Benefit of buying complete short block is so i can sell this one to offset. Down side, all the machine work is already done on mine. If your ok with the 11:1 may not be a bad idea to stay with it. May not be the most powerful NA motor, but definitely will not be a slouch. You could get some decent gains off an CJ or 2018 intake. Make it feel like a whole new car.

So you're just at needing new valve guides/seals?
Freshen yours and buy an Aluminator 5.2XS.
Then IF you want more power NA you have a better starting platform.
Plus those True Aluminator motors hold good money.
$15k shipped from Jegs and rock out, sell yours to offset.
I'm thinking of buying a 5.2XS to boost and then build/sleeve when wanting more.
-J

You can build the XS motor for WAY cheaper than buying that one. It is cool, but again, can be done for much less. You DO get a slight bit of warranty which is nice.

 

[want2race]

Good info. My current motor was built to handle 1000hp. Just not the best combo for pure NA. Bearings checked out, compression was good. If i could get $3k for it, then I'm willing to try the 5.2. Not sure what the market is though. I'll confer with the shop in working with and see what they think.

I read about the difficulty with the rings. Stock GT350 pistons and rings will be used.

Interesting about the '18 intake. I'm currently using a Boss.

 

[basspro302]

So is the current short block ok?

 

[want2race]

Nothing wrong with the current block. Only reason for substituting it would be for the 5.2. I'd have the shop just reassemble and go with it, but since I've paid to have the motor pulled and torn down I might as well go big.

 

[biminiLX]

You can build the XS motor for WAY cheaper than buying that one. It is cool, but again, can be done for much less. You DO get a slight bit of warranty which is nice.

Define WAY cheaper? I've added it up before and when you consider Ford assembly, warranty, and the fact there's some serialization/value in it I'm not totally convinced.
So, say you buy all the individual parts, who do you have assemble/machine and at what quality/cost?
I'm not trying to argue this, as I'm in the market and debated the same thing.
It'd be a lot easier if they offered a sleeved block version
-J

 

[want2race]

I've been quoted $5600 for a completed 5.2 short block. All OEM GT350 parts with Boss crank to keep the coyote firing order. Doesn't include shipping so I'm close to $6k for an OEM 5.2.

 

[basspro302]

Personally i would spend the money on a cj intake maybe get the heads reported if they can and seeing if i could squeeze more power out from the heads cam intake. It will benefit from having a larger bore and larger valves. That’s mainly why the gt350 has a bigger bore that and the plasma liner.

 

[want2race]

Heads are already ported. The engine builder sees some gains to be made in a valve job so we are doing that. The initial plan was to go to lighter internals so it spins up faster. I just liked the idea of the added torque from the bigger size.

 

[Modular Racing]

Let us know if we can provide you with a quote

www.modularmotorsportsracing.com

 

[want2race]

Sent pm.

 

[clinton2003]

Nothing wrong with the current block. Only reason for substituting it would be for the 5.2. I'd have the shop just reassemble and go with it, but since I've paid to have the motor pulled and torn down I might as well go big.

If they have already taken motor apart, no point in reassembling it to sell it. I would probably stick with what you have. If bore is ok, then just a light hone, and some 12:1 comp pistons. could go custom to get lighter pistons, which would make those H beams live at higher RPM's.

Define WAY cheaper? I've added it up before and when you consider Ford assembly, warranty, and the fact there's some serialization/value in it I'm not totally convinced. your talking about almost double the money for that motor. I guess if you add it all up you get to really close to the same price for the same components. BUT you can definitely save money by cloning it. Take a used GT longblock. (3000 most places) port the heads (1500) refresh timing components, etc
So, say you buy all the individual parts, who do you have assemble/machine and at what quality/cost? I have a local machine shop i trust.
I'm not trying to argue this, as I'm in the market and debated the same thing.
It'd be a lot easier if they offered a sleeved block version being a plasma liner, it in theory it is stronger than the thin steel sleeve. plus the gt350 block is "beefed" up... remember the WAP and Teksid blocks easily hold 1500 (teksid well beyond) They coyote seems to be the "weakest" mod motor block. has good internals though.
-J

I've been quoted $5600 for a completed 5.2 short block. All OEM GT350 parts with Boss crank to keep the coyote firing order. Doesn't include shipping so I'm close to $6k for an OEM 5.2.

Not a bad price. personally i think you will gain more with compression vs a couple tenths of a liter, although more displacement usually does equal more power.

Heads are already ported. The engine builder sees some gains to be made in a valve job so we are doing that. The initial plan was to go to lighter internals so it spins up faster. I just liked the idea of the added torque from the bigger size.

If your valve guides were bad, your seats may not be round anymore. Defiitely going to need to do seats on at minimum ones the guides were worn out on.

 

[want2race]

Thanks for the response. Very good info.
The heads will get bronze guides and new seals, new springs that JPC trusts for high rpm use. Then a full valve job. Going to rebuild the short block. Changing the heavier W pistons and H rods for lighter Mahle's and I beams. Bearings, hone and balance. I asked about 12:1 and we are going with 11:1, but with the head skim, will likely raise that up to 11.5. Oh, and TSS opg and cam chain gear.

 

[clinton2003]

going to be a great all around driver you can still put 91 in it sounds like. Then toss some torco or race gas in and hammer down. Possibly even e85, but not sure if it'd be worth it.

definitely recommend changing from Boss intake. look at CJ or a ported 18. 18 mani would be cheaper because no change in throttle body, but may not handle the rpm's like the CJ would.

Of course all this could be done after the fact, especially if tuner doesnt mind changing tune stuff.

 

[twistedneck]

Question, why did the valve seal fail? that's not exactly a typical part to give up the ghost. Did you have a bent valve or something?