Jump to content
HybridZ

big block Z, "across the centuries"


Recommended Posts

We hear incessantly about “the one that got away”.  That’s either the crotchety old neighbor’s garage-queen, which we’ve been hankering to buy, but the neighbor would never acquiesce… until one day the old coot dies, and his widow donates the car to some obscure charity, or outright junks it.  Or it’s our teenage love, that vehicle in which we blew our first head-gasket, in which we learned the joys of long-distance pushing (uphill, both ways, in the snow,…)… until college, a new job or a new spouse render iron demands: me, or it… and decades later, we regret…

 

As of this writing, it’s mere days until this site turns 21.  And it’s been even longer since the selfsame project has been… maturing.  Remember the 20th century, folks?  Remember the fervor over prep for the Y2K bug, how automotive ECUs were going to reverse the rotational direction of the crankshaft, and anti-lock brakes would switch to anti-release?  Our attention was rapt, and the more irreverent or quirky types were praising carburetors, as the fix for a modernity gone bonkers with surfeit of tech.

 

Well then…. my project began in 1998-1999.  It never left.  It never “got away”.  It was hardly all my doing, but instead lurched ahead when I found a fellow who could help.  It was his idea to do a firewall setback, noticing how S30 Zs have ample room, and ample distance between the firewall and the windshield lower lip.  Then, after good progress, the engine wiped its camshaft.  Back then we mostly used flat tappet cams.  Remember those?  Motor oils reputedly went weak.  The car-magazines wrote copiously about the resulting wiped cam-lobes.  Dejection followed, lassitude, a loss of interest and vim.  Years!  Subsequent efforts, some good, some purely a perfunctory self-salve, a show of sorts, too brief.

 

Now I am moving back from Ohio to Los Angeles, reprising youth’s initial sally.  The Datsun follows, on a tow-trailer.  House, career, a former marriage… they all “got away”, but the car somehow endured.  It’s only meet to mention its return.  With luck, elaborations follow. Until then, a question: is anyone still left, who’s still running a big block?

Datsun_example_ext.jpg

Edited by Michael
Link to post
Share on other sites

No offense, but some details on your own car would be more interesting.  I've only been on the forum since 2009 and I don't remember seeing any big block Z's since then.  The biggest motor I saw in a Z was BRAAP's father's Z with the Mopar 440, and that was just old pictures that he had saved.  I think that you might be the last of the big motors.  It's all LSX now.  Many of the people building fast cars on the site now probably don't really know what a "big block" Chevy is.

 

Some of the guys that were active in the few years after I joined visit now and then but activity has faded pretty rapidly.  The site almost went extinct, SuperDan was considering shutting up shop. You'll probably have to message the names you remember if you want to get some interest back up.  It's slow here now.

Link to post
Share on other sites

A “big block” was a mid-1960s development of the Chevy engine family, with larger bore-spacing than the then already-venerable small block.  The small blocks are, for those who remember, the stars of the original “Jags that run” Datsun V8 swap manual, that was popular in the 1990s.  

 

Big blocks were installed in passenger cars through at least the mid 1970s, but subsequently were limited to trucks.  Mine originally came out of a 1978 Suburban.  It had the hapless “peanut port” cylinder heads, meant for low-rpm yeoman duty.  Big blocks continued to serve in GM trucks through the 1990s, but were eventually replaced by a new generation of engine – completely different from the LS-x series, and limited to trucks.  

 

The classical big block beloved by hot-rodders is the so-called Mark-IV, and the largest mainstream displacement is 454 cubic inches: 4.25” bore and 4.00” stroke.  A 0.030” overbore, which is what I have, takes us to 461 cubic inches.  Also common is 0.060” overbore, resulting in a 468.  Beyond that, stroker cranks are available, but they get expensive, especially if the intent is to retain good rod-stroke ratio.

 

15-20 years ago, the aftermarket had a bevy of aluminum cylinder head designs.  Mine are from Brodix… the so-called “Race Rite” oval-port heads.  There were two port designs… rectangular and oval… the former for higher-rpm, higher displacement applications, and the latter for more street-oriented uses.  

 

As for the history of big blocks on HybridZ, well, as we transitioned from zcar.com, or whatever it was, there were two outstanding examples.  One, a gentleman named Brad Barkley, campaigned a big block dragster.  Another, Ron Jones, had an alternative design.  Both kept the firewall in the stock location, but back-halved the rear, installing a solid axle.  As the application was drag-racing, these design choices were eminently sensible.  In at least one of those, the front-end was also redone, maybe with a lift-off hood/fender/bumper clip. But the basic McPherson strut front suspension geometry was retained.  Ron had a stunningly powerful engine – something like a 540 cubic inch, maybe with nitrous.  Brad ran, if memory serves, a 496 – a popular combination, which is a 454 with 0.060” overbore plus a 0.25” stroker crank.  This is popular because such a crank fits in the stock block, with maybe just a tad of clearancing for the rod big-ends.  With suitable pistons, the rod-stroke ratio remains OK.

 

My idea was an all-around car, with low polar moment of inertia and nearly 50-50 weight distribution. I retained the stock Datsun rear-end, except for welding the differential spider gears (“Lincoln Locker”). Yup, stock half-shafts and everything else.  In the front however there were some changes.

 

I worked with a gifted under-the-radar custom builder named Nick Tierno, based out of Las Vegas.  Nick raced motorcycles, and built some pretty impressive custom cars.  In my case he did all of the frame-work and welding.  Details are still online, hosted on Pete Paraska’s web site (I need to find the link).  But in brief, the front clip was cut off, then the firewall and floorboards removed, and a cage built on a jig.  The cage was welded into the car, then the floorboards cut, and the floorboards and firewall welded back in, 6.25” further aft than stock.  Sheet metal was constructed to reconnect the front clip, and the whole thing was secured with diagonal members from the roll-cage to the front strut towers.

 

This was all fantastic, but the aforementioned wiped cam rudely stopped the project.  It languished for 4-5 years, in a dejected questioning of what went wrong.

Rescue was in the form of another member here; active, then, but now long-gone.  He went by “Denny411”… a semi-professional mechanic, a pillar of his local community in a smallish town hidden in Ohio’s countryside.  AAA graciously towed the Datsun to his garage, and then for some months, we’d chisel-away at the mound of granite, hoping to reveal a sculpture.  After a while the engine deigned to be restarted… but only for a while.

 

What then?  Well, I used a “Cloyes adjustable timing chain”.  The classical small and big block Chevys had a basic timing chain between the cam gear and the crank gear.  Timing was literally cast into the gears, with Woodruff keys and corresponding slots.  In some cases there were alternative keyways for advancing or retarding the cam, typically by 4 degrees.  Indeed, a common trick to render tamer an aggressive cam was to install it 4 degrees advanced.  Cloyes came up with an improvement: the cam-gear was two pieces.  One had sprockets, engaging the timing chain.  The other bolted to the cam.  Between them was a rosette of six 1/4-20 bolts, riding in slots.  To advance or retard timing, loosen the six bolts, and rotate the crank, while the cam stays fixed.  Then retighten.

 

Well, in my case, the six bolts somehow worked loose, sending the cam into its most retarded position.  Fortunately there was no piston to valve contact, but the heads of the bolts, having gotten threaded-out, worked themselves into the aluminum timing-cover, sending aluminum shavings all over the engine’s oil galley. The result was a pile of aluminum crud in the oil filter, and elsewhere.  Thus, yet another rebuild.  That was around 2009… for a car that was originally built in 2000.

 

The story continues in the next segment….
 

Link to post
Share on other sites
On 2/7/2021 at 8:41 PM, NewZed said:

No offense, but some details on your own car would be more interesting.  I've only been on the forum since 2009 and I don't remember seeing any big block Z's since then.  The biggest motor I saw in a Z was BRAAP's father's Z with the Mopar 440, and that was just old pictures that he had saved.  I think that you might be the last of the big motors.  It's all LSX now.  Many of the people building fast cars on the site now probably don't really know what a "big block" Chevy is.

 

Some of the guys that were active in the few years after I joined visit now and then but activity has faded pretty rapidly.  The site almost went extinct, SuperDan was considering shutting up shop. You'll probably have to message the names you remember if you want to get some interest back up.  It's slow here now.

@NewZed True that. THere used to be a whole lot more activity here even just like 3 years ago. Now it's a ghost town which is sad. I've always liked the community here. Sorry to hijack ha.


You truly are a rare breed these days Michael. Hope to see more on your car soon!

Link to post
Share on other sites
  • 3 weeks later...

Thanks for the kind words, fellows!

 

The Z completed its transcontinental journey on a trailer behind a Penske box-van, and is now "safe" in the general locale where it started its American life... California.  Pro tip: towing is exhausting... tough on both tow-vehicle and driver.  Our box-van was lucky to get 10 mpg, especially on hilly terrain (Missouri Ozarks, Arizona mountains).  En route, the Z received smattering of compliments at gas stations, truck stops, hotel parking lots,...

 

Here's a photo from the rear, in the car's current resting-place.  License plate is gone, but the valence-panel still sports a parking sticker, from when the car was a daily driver... back in the 20th century.  The only obvious give-away from this vantage point, regarding the car's transformation, is the exhaust system... cheap Summit Racing 3"-in/3"-out mufflers (unpleasantly loud, unfortunately) exiting in the center.  The lower control-arms are stock, but powdercoated, courtesy of Mike Kelly... Mike mentioned that those were the LCAs that he used for the adjustable custom-welded kit, that his former company made.  The more seasoned members here may recall that Mike had quite the venture with his custom parts, before the proliferation of more mass-market vendors. 

 

You may also remember how a bunch of us scrambled to find symmetric, high-tolerance factory suspension parts.  The late John Coffey noted that control arms, McPherson struts and the like, were often mismatched or otherwise askew... poor quality control from the factory.  So it was no trivial matter to source a matching pair.

20210307 rear.jpg

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...