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393 update

10K views 62 replies 21 participants last post by  davis 
#1 ·
Ran into a small issue during the dummy fit. Whomever rebuilt the block when doing the 20thou over build screwed up.

Normally during a 393 build the pistons stick out of the bore 5 thou. One side of mine is stick out 5 thou and the other side sticks out 15 thou.

The blocks being decked to square and the pistons are having 15 thou machined off the crowns. Just as well, I have a piston with a 10cc dish http://www.www.fordforums.com/images/smilies/biggrin.gif

Least I probably won't have to deck the heads http://www.www.fordforums.com/images/smilies/biggrin.gif Camshaft choice has also changed as a smaller one made more torque.

Hopefully I can get it back this week and screw what I need to screw together ready for the engine dyno.
 
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#8 ·
ch7472 said:
So this is Pavtec's doing is it.Glad they are pros??
brenx said that who ever built the previous 20th over motor made a hash of the block, and has been discovered during the dummy assemble, by either Pavtek or brenx. Thats what the dummy assembly is for :hy:
Does the machining of the pistons affect balance brenx, or is it all good?
 
#9 ·
Machining the pistons will affect the balance and will need to be corrected accordingly. Hopefully I'll have the engine back here this week or early next. Hopefully no more little issues will be encountered.

I'd kill to know who did the 20thou over build. They are definately stooges. [edit] I know the 20thou over build was done in either TAS or SA ;)
 
#11 ·
It ran pretty smooth for an engine that was running on 6cyls (camshaft had wiped lobes). I drove it home from Essendon -> Cranbourne. I could tell it wasn't a happy engine though. My requirements for it due to being a stockish were only to get the car home. As most know I removed the engine pretty swiftly.
 
#14 ·
Hey Brenx,
Is your engine a copy of the 600HP job in the Street Machine Fords mag built by Pavtec using the CHI alloy 3V heads? A lot of similarities there!

Street Machine Fords mag sells out suddenly tomorrow cause everyone wants the specs on brenxs' motor!!!!!
 
#21 ·
brenx said:
Ran into a small issue during the dummy fit. Whomever rebuilt the block when doing the 20thou over build screwed up.

Normally during a 393 build the pistons stick out of the bore 5 thou. One side of mine is stick out 5 thou and the other side sticks out 15 thou.

The blocks being decked to square and the pistons are having 15 thou machined off the crowns. Just as well, I have a piston with a 10cc dish


Least I probably won't have to deck the heads
Camshaft choice has also changed as a smaller one made more torque.

Hopefully I can get it back this week and screw what I need to screw together ready for the engine dyno.
I wouldn't call that a small issue...I'd call it a wanker job done by a total wannabe. Are they going to rebalance it, too?

Who said that a smaller camshaft made more torque? At what RPM range? Is this based on your TOO SMALL carburetor?

Jeez...I would have had them prep a new block for me before accepting that kind of crap. I'd also quit calling it "rebuilt the block" and start calling it what it is...machined the block. It sounds like the traditional carpenter's problem where they just didn't measure for JACK. To me, that is a classic indication of stupidity. Did you check all of your bores to ensure that they don't taper or elongate? Who says the same jerk didn't bore it, too? How can you trust anything from them with a screw up like that? Who did the work, their pet monkey?


:davis:
 
#22 ·
davis said:
I wouldn't call that a small issue...I'd call it a wanker job done by a total wannabe. Are they going to rebalance it, too?

Who said that a smaller camshaft made more torque? At what RPM range? Is this based on your TOO SMALL carburetor?

Jeez...I would have had them prep a new block for me before accepting that kind of crap. I'd also quit calling it "rebuilt the block" and start calling it what it is...machined the block. It sounds like the traditional carpenter's problem where they just didn't measure for JACK. To me, that is a classic indication of stupidity. Did you check all of your bores to ensure that they don't taper or elongate? Who says the same jerk didn't bore it, too? How can you trust anything from them with a screw up like that? Who did the work, their pet monkey?


:davis:

Davis before you get your knickers in a knot. Here is a few facts :

* 20 thou machine work was done by god knows who. Your guess is as good as mine. Some mob before I even bought the car. The bores still had hone marks in them. No lip either. Remember I have two 351's, not 1. The other 351 was perfectly machined but I got ripped off on what was inside.

* Pavtek are doing all the machine work. The bores will be 30thou over. Yes, it's all checked inc oil clearances blah blah.

*Yes they are rebalancing after the machine works done. As stated on a C block, I'm told the pistons stick up 5thou and this is normal. Due to the BS job done on the block before I got it. One side was miles out. They didn't deck the block square.

* Camshafts have been tested on an engine dyno. One makes max power @ 7100rpm. The other makes max power @ 6900rpm. Torque figures are better with the smaller camshaft.

Take a look @ Pavtek's website -> http://www.pavtek.com.au
They ain't no half arsed workshop. I dare say they've built more 393C's than anyone else in Vic. A 393 write up was done in Street Machine Ford. Specs 260-270ish@50 lift secret, 10:1 comp, same heads I run, 750dp hp, 599hp & 515ftlbs torque. Not far behind your own 393 with smaller components.

Before you start rambling read whats written 1st.
 
#24 ·
turbomania said:
brenx do you know for a fact that a bigger carby will as you put it [ gain ] , i would of thought that if a bigger carby would have made more power then pavtek would have used one.
You can only use what the customer gives you. In that case it was a 750. Pavtek have finished all balancing today. I watched them finish it. It's odd to watch a crank rotate at high speed. Not something you see every day. No more machine work is needed. Will be picking the engine up when I get time. Should be early to mid next week.
 
#26 ·
brenx said:
Davis before you get your knickers in a knot. Here is a few facts :

* 20 thou machine work was done by god knows who. Your guess is as good as mine. Some mob before I even bought the car. The bores still had hone marks in them. No lip either. Remember I have two 351's, not 1. The other 351 was perfectly machined but I got ripped off on what was inside.

* Pavtek are doing all the machine work. The bores will be 30thou over. Yes, it's all checked inc oil clearances blah blah.

*Yes they are rebalancing after the machine works done. As stated on a C block, I'm told the pistons stick up 5thou and this is normal. Due to the BS job done on the block before I got it. One side was miles out. They didn't deck the block square.

* Camshafts have been tested on an engine dyno. One makes max power @ 7100rpm. The other makes max power @ 6900rpm. Torque figures are better with the smaller camshaft.

Take a look @ Pavtek's website -> http://www.pavtek.com.au
They ain't no half arsed workshop. I dare say they've built more 393C's than anyone else in Vic. A 393 write up was done in Street Machine Ford. Specs 260-270ish@50 lift secret, 10:1 comp, same heads I run, 750dp hp, 599hp & 515ftlbs torque. Not far behind your own 393 with smaller components.

Before you start rambling read whats written 1st.
Tell me one thing...how do you "dummy fit" a .020" bore with a .030" piston? Also, do you remember how many 351s I have and what their various bores are? You may not remember that my 393 dyno test was nothing more than a few pulls to ensure that jetting was in the ballpark. Later, I found out that the crankcase was overfilled. Track tuning and ET results suggest somewhere above 630 HP for the engine. I don't really care what number the dyno tells me, I'm not racing the dyno. My cam is no secret either...nor is there any reason for you to be so secretive about it here...what did you do, sign a non-disclosure? <grin> I used an off-the-shelf cam as it was inexpensive and "close enough" for what I'm doing with the engine. I could have bought a custom ground cam and made more power, but it wasn't worth the added money for an engine that I knew when I built it that I'd be replacing within a few months.

If you're happy with the results you're getting, great. It just sounds to me that you are the Murphy's Law when it comes to bad luck with combinations and broken parts. If you're happy shaving the tops off of new pistons as a solution to whatever problems you're having with whatever engine block you're using, I'm happy. How much material thickness do you have in the top of it now and what happened to your dish volume? Are you sure that you're still at 10:1? Did you CC the results?

I picture this guy who gets starry-eyed watching a crank spin on an electronic balancer and ends up "ripped off" in situations where parts are involved. If my knickers are binding up, maybe it is my obviously stupid attempt to try to suggest something to you. I never once mentioned Pavtek...don't know them, don't care. If you're happy with their work, great. It sounds to me as if you're building a recipe engine based on some dyno mule that they put together and came up with the numbers you're talking about here. As someone who dabbles in creative kitchen work, the recipe tends to be a set of guidelines one uses to get close to the intended goal...or a recounting of what happened during the process. If you've followed the recipe exactly, your results are still very likely to differ slightly with engines.

I still laugh at this whole "secret" camshaft thing. I'm incredibly excited that your "smaller" parts are pushing your effort close to my numbers. Let me know what you make when you pull it off of the engine dyno...though it sounds as if you're intending to skip that measure. My engine details are an open book, including my flow numbers, dyno figures and camshaft lift, duration and everything in between. My recipe is out there for everyone to see.

Factory '72 4-bolt block filled 1" below WP
Aftermarket main caps on 2, 3, 4 w/ARP studs throughout
4.030" bore SRP 11.28:1 (calculated) flat tops
Scat 3.85" 4340 forged/profiled/lightened crankshaft
6" H-beam rods SBC sizes big/small ends w/floating pins
FMS "A3" aluminum cylinder heads with flow @28"
Lift--int-/-exh
.200 152/100
.300 217/146
.400 266/194
.500 305/217
.600 341/232
.700 357/242
2.19" titanium intake x 1.71" stainless exhaust (+.100" each)
Isky dual coil w/dampner springs, titanium retainers 10* locks
Comp Pro Magnum roller rocker arms w/Jomar stud girdle
JP Performance billet timing gear/chain set
Mechanical roller 274/274 @.050" .709"/.709" lift 105 LCA
IVO 32 IVC 62 EVO 62 EVC 32
Lunati solid roller lifters
Edelbrock aluminum waterpump w/Moroso electric drive
Professional Products SFI rated harmonic damper
Milodon oil pump driveshaft, oil pump pick up and full length wet sump pan.
Mellings HV oil pump w/Moroso oil restrictors.
ARP head studs, oil pan studs, header studs, carb studs, more
MSD billet mechanical advance distributor (advance locked out)
MSD 7AL-3, 10mm wires, Pro Power HVC coil
Motorsports B351 4150-style ported intake manifold
Holley HP 1000 CFM carburetor
Stahl 2.125" primary tube headers (open)
7500 RPM redline


RPM CBTQ CBHP
4500 443.3 379.8
4600 452.7 396.5
4700 454.8 407.0
4800 464.3 424.3
4900 472.4 440.7
5000 479.0 456.0
5100 490.0 475.8
5200 492.6 487.7
5300 492.0 496.5
5400 491.0 504.8
5500 494.5 517.9
5600 490.8 523.3
5700 490.1 531.9
5800 488.1 539.0
5900 487.5 547.6
6000 487.0 556.4
6100 484.5 562.7
6200 481.0 567.8
6300 482.1 578.3
6400 480.6 585.7
6500 475.9 589.0
6600 472.7 594.0
6700 468.4 597.5
6800 464.2 601.0
6900 458.7 602.6
7000 456.6 608.6
7100 445.6 602.4
7200 442.2 606.2
7300 435.2 604.9
7400 431.7 608.3
7500 421.3 601.6
7600 418.9 606.2


If you're doing better with less, great. Enjoy it. It isn't a contest. Not many guys in full bodied cars try to race (heads up) against me, either. Even the BBCs Super Comp cars find out that the Cleveland is "a lot quicker than they thought." My little engine experiment put me into the 7s for the first time ever. Whatever you run in your car, I hope that you achieve the same level of satisfaction with having spent your money well on something that gives you plenty of enjoyment rather than frustration.


:davis:
 
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