Blown 351W/351C/Clevor questions.

I have a car with a 351W that has a vintage Draw Trough Turbo on it.
( '70s Trad...)

Its fun, but I think it needs good Forged pistons and better heads to make it right.

( this is what happened with the first short block...)




So what about turning it into a Clevor by putting Cleveland heads on it?


- Pistons.

Go for forged flat top Windsor pistons, and cut them for valve clearence?

Get the specially made Clevor pistons?

Would surplus Nascar ( Yates) pistons work?


-Cam, pushrods, etc.

Does a regular Windsor cam work?
(or a blower/turbo grind )

Do you mate that with W or C pushrods, or would I need aftermarket pushrods?


Did I forget anything?
( I know there would be intake manifold issues, and that the heads and block would need some minor modifications)



Or would it make more sense to forget about the Clevor, and get Forged pistons and use GT40P ( or better) heads for the Windsor?




And what is so bad about the Cleveland bottom end?

Would a complete Cleveland fit the Windsor motormounts/bellhousing?

-Flywheel/flexplate.

I think they are the same and will interchange, is that correct?



What would make the most sense, Money/Time/Performance wise?

 

The edge of that piston looks melted, and eroded from detonation, from about 10-12 o'clock. I suspect a fuel delivery (lean or uneven) or boost problem (too much boost or compression too high), or some combination of those.

Cast or forged, the melting point of aluminum is what it is. Forged pistons will hold up better, but you still don't want detonation.

Whatever you build, I'd toss an O2 sensor in after the turbo, and keep and eye on it.

 

Whatever you put together you need to tune. That shouldnt have happened, I mean to say its not a mechanical malfunction.

 

Cleavor conversions are killer set ups.
Intake manifolds are unique - Edelbrock is now making them, or you can look for an old B&A. Another way is spacers from Price Motorsports

Cleavor specialty pistons work best.

Pushrods are custom length. I think Ford Racing still sells them. Cam stays Windsor

No changes to flexplate or flywheel with head change

As for a Cleavland, the old wives tales about bottom end problems are just that. The only guy I know that blew a bottom end was a Drag racer that ran a 6-71 and shifted at 8,000. Eventually blew the bottom end. Road Race guys who run extended high rpm have some problems as well, but top end oiling restrictors cure that.
Bell housing pattern is the same as is motor mount location.

 

The cle. swap is definatly cool, but with modern tech its not worth it. The head selection now days makes it cheaper and less work. Check out sbftech.com lots of good facts on this site.

 

I have a Innovate wideband meter on it.

I saw 15:1 mixture, but I didnt get out of it quick enough.

When I took some more carefull measurements to check the Factory Ford markings on the balancer I found ot that they were way off.
I was running 8 to 10 Deg more advance more than I thought I was.

Stock compression ratio for a 351W truck engine, 8PSI boost.

No intercooler ( draw through ), but I did put Water/Methanol injection on it after the first one blew.

Two pistons had the melting damage.

But 5 out of the 8 had bad cracks on the sides of the pistons.

The one in the picture was only held together by the rings ( once I took those off, a big chunk of the side fell out...)

 

That first engine is one I had rebuilt about 8 years ago.
And I had it in two of my Worktruck's.

A lot of hard miles, abuse and long burnouts...

I got my money out of that one.

The pistons with the melting damage on top, were the ones with the most cracks and breakage on the sides.

I think its possible that the damage on the sides let crank case air in and affected the mixture on those cylinders.


And maybe the pistons let go, because it was the first time ever that engine was making decent Horsepower.... ( I use a 6000RPM redline )

 

So I guess it comes down to this:

351W.

Needs pistons ( About $400), heads ( $250 to 1200 ranging from GT40P to aftermarket )

I get to keep the Ign, intake, valvesprings that I already bought.

Could probably benifit from a cam to suit the turbo better.

Would need some work to the headers.


Clevor.

Needs pistons ( probably more expensive than 351W pistons ), heads ( $250 used, would still need springs, possible rebuild, etc )

Get to keep ign, but would benifit from cam.

Would need machine work, custom intake ( $?)or adaptors ( $200), and completely different headers.


Cleveland.

Would need custom pan to clear front suspension.

And cam, valvesprings, intake, headers, ign, and the engine itself.
(sounds like the most expensive of the 3 )



What kind of horsepower levels could I expect, with a outdated Turbo system, and budget parts?
( at 8PSI)

 

A spun balancer ring or mis-marked timing line has been a lurking nemesis of mine for years.

Yikes, 8-10 degrees too much advance is a killer on a boosted or high-compression engine..

EVERY engine I work on now gets checked, few are truly correct, although most are close. The worst was 50 degrees off. I could not even get that on started, and neither could the customer. I put the cutting torch on that balancer, lest it finds its way on another engine.

 

It wasn't spun.

0 was about where it needed to be.

But the markings were too far apart ( and not by any amount that made sense )

By the time you counted it up to the total advance it was WAY off...


Looked like piss poor quality control to me.



So that engine has run with too much advance as long as I've owned it at high RPM ( which it has seen a lot off...)

The current one has less static advance, and its locked ( it doesnt advance from that point )

 

Ahh, the new mantra of our age.

 

I wouldn't guess that you would get pistons burning like that at 15 to 1 AF ratio. If I'm wrong about this experts, please let me know. Timing. SBF balancers with bad timing marks have caused me all kinds of problems. Part of the problem can be that people pull balancers off other motors, Ford put timing marks at a few different places on the motor, so they can be wrong w/o slipping.

 

Was that a factory balancer or an aftermarket? Just seems totally unlikely that a factory one would be off like that, not with the way they are made/marked in production. Seems Odd

 

Factory.

I took care to put 0 precisely at TDC, but I never thought to check that the marks were acctually the right distances apart...

 

The best way to tell if your balancer is dead on is to mount an indicator on the #1 piston. Crank the motor by and hand till the piston reaches TDC on the compression stroke. Then check the reading on the balancer. It should read zero (TDC) with the pointer.

 

That is really surprising to me. Not that a factory could/would fuck up, but this things are stamped with the marks and I can't believe the die would even be possible to move like that. Very strange

 

Alex,

If you want power, I'd go for the Clevor. Find some 2V Aussie heads on eBay, get the custom intake - I think Edelbrock is making one now or search eBay for the B&A Track Boss (single plane) or Street Boss (dual plane), new headers, I'd change cam (get someone who knows Fords to custom grind one), & unique pushrods (Ford Racing Parts may still sell them).

If you can find a real 351C in good shape, that may be cheaper depending on condition and what you need to buy. Engine mounts and bellhousing make it a "bolt in" operation, but all the accessories and bolt-on stuff is different (cam, ignition, headers, intake, etc). If you're going to spin it, install the oil restrictors - everything you've heard about weak bottom ends is old wives tales - they just oil the top end too much & restrictors solve it. Moroso (and others) still sell the restrictor kits.

 

When you run too low of octane fuel this is what happens, DETONATION

 

Go for the Clevor, I built one for a 70 Torino wagon several years ago, real sleeper without forced air it was a handfull to drive with trac loc. in the wet.
Find the aussi info on this change over they spent a great deal of time after Nascar had moved on.. As for pistons, I ran 10.2 to 1 C/Ratio in Sacramento heat, with flat tops, great power no ping.

Your making me re-think my 351 W project, I need heads anyway and my F1 would haze the hydes like an old fueler.

 

If you go clevor...your going to need a special intake manifold.
Not to mention different headers. B & A made one back then.
But this one looks pretty affordable.

http://www.speedwaymotors.com/Edelbrock-351-Clevor-Ford-RPM-Intake-Manifold,23646.html