620 Land Speed Record

[distributorguy]

Like I said, its not done.  Yes I had left a "wing" and part of the guide, but found nearly 6 more cfm by quickly eliminating it.  Quickly being the key word.  It needs to be blended in and polished.  The area by the plug has been cleared for the piston dome, and is actually still a tighter quench than on a stock motor with a dished piston.  The piston fits the head with no gasket, barely.  The (incorrect) plug is only in the head for flow testing (to prevent air from sucking/blowing through the hole.)

[datzenmike]

Was your gasket discussed? Copper?

[G-Duax]

Did you consider picking up a set of lightly used 6mm stem titanium ex-nascar valves off eBay ?

They can be had for under $100. And I have contact info for a guy that will cut them down to fit anything.

 

Seems that if you picked up 6 cfm by cutting the guides out, a 2mm smaller stem may gain you even more.

Of course that would mean making some custom guides.

[distributorguy]

My stems are already cut down in the port area.  Severe duty Manley - custom.  

Nismo head gasket, but port work is done to the bore size.  Nismo makes the only gasket that will hold up to boost, so it should do for me.  Never copper, unless you want leaks.  They're ok for a nitro motor that'll be torn down every 300 engine revolutions, but even then they're pretty well being phased out by anyone who needs them to seal.  Print-o-seal type gaskets reign supreme, but are not all created equal.  

[datzenmike]

Made my own copper gasket 0.020". Boughten gaskets won't have the coolant holes where I want them. The engine I'm building was decked and the head milled so the surfaces are perfectly smooth. Only 9 compression so not worried.

[distributorguy]

One trick is to use a strand of ultra-fine copper wire and make your own twisted O-rings around those passages.  Lay them down with a little monkey snot to hold them while you assemble.  Just a few thou to help seal things up.  Hopefully your block and head have the right texture for copper - it needs a little more tooth.  Perfectly smooth will blow out quickly.  Significantly more coarse than an aggressive flywheel grind.  

I'd love to see how you're building a fire ring into the copper.  Peeling them off an old gasket???

[G-Duax]

There is a comany here in the US that makes custom copper gaskets, with a wide range of thicknesses.

My other toy is a Cressida, with the original problem prone 7M engine.

They are notorious for popping head gaskets, or leaking with an all metal gasket. So I ordered up a .040" gasket, with oversize bores, and then six .047" inner rings.

 

The idea was that there would be a good crush on the inner rings.

But this place had trouble holding tollerances on the rings, and I should have stopped right there.

But I proceeded.....

The main gasket then recieved several coats of the spray-on copper, then baked, turning it into a more solid rubber, than a half sticky adheasive.

Right before it went in, it got a light fresh coat of sealer, inner rings set in place, and everything torqued down (ARP studs).

 

When the engine was fired, I heard a ticking noise from the engine.

Tore the head off, and found that 2 of the rings, when squeezed down, protruding into the bores, and making contact with the pistons.

I think it would have worked, if the rings had been made to the dimensions I had specified.

Turned out that he was trying to machine them on a CNC mill, and they had distorted.

 

Anyway, the 7M doesn't like any machine marks in the gasket surface, at all.

Comes from a block that started to life many years back as a 2 liter, but by the early '90s had been pushed out to 3 liters.

Makes for very little room between one bore to the next, and little to the nearest water passages.

 

I always lap the head surface with a 60 lb lapping plate. If a head is done by a shop that mostly deals in American V8s, it will take about 3 days worth of lapping to get all the little trenches out.

The down side of this is the head is extreamly smooth at that point.

 

I have always thought that that surface should be sand blasted to put a course texture back into it.

[distributorguy]

Stainless steel O-rings in the block would have been the right way to go, if they were made properly.  But take a bad alloy block/head and you'll always battle the same issues.  

 

Clark Copper Head Gaskets is a local company to me.  Generally speaking you get what you ask for, eventually.  Usually.  But plan on O-ringing the block  if you have any compression.  

[datzenmike]

No fire rings. Copper will not be protruding into the cylinder at all and will be set back from the edge.

[distributorguy]

I'm bored and don't feel like working this Friday afternoon, so here's a pic of the race engine as it sits.  I just can't get motivated to work on the head after putting in 70+ hours of work a week all Spring.  

[/url]">http://http://s1148.photobucket.com/user/distributorguy/media/race%20engine_zpsmphxta2r.jpg.html'>

 

Calculates out to roughly 15.2:1 at this stage, although that may change as the head is fitted and valve clearances are checked with the custom cam profile.  The head cleares the domes with no gasket in place, but it will get shaved enough to clean it up.  

[Jester]

Calculates out to roughly 15.2:1 at this stage

 

HOLY SHIT!!  How much are looking for come race time?

[distributorguy]

How much what?  HP?  Speed?  Compression?  We're going into this set to a record.  No screwing around with a half-attempt 5 years in a row.  At 4000' altitude you can get away with more compression.  At 15.2 now, it may go up or down a little if the valvetrain needs more room or has a little to give up.  This should allow us to run as low as 110 octane, although we'll dyno it on 114.  We either need 250+ hp at the flywheel, or reduced drivetrain drag to be able to beat the long-standing production class record of 129.6 due to aerodynamic issues in Production class - externally stock except for a hood scoop.  

[distributorguy]

We're off to Bonneville on Sunday.  This year the team didn't think the salt was going to cooperate (again) so most made other plans.  2 of us are going out with a "scrapbook" of critical truck photos to be inspected, so next year will be easier.  I also hope to get my rookie driver orientation over with, if we can run my wife's car (AWD Charger.)  I don't exactly know how that works, whether I need a driving suit or not for a street car run?  I'll figure it out.  

[distributorguy]

Surprisingly, tech inspectors swarmed us and our photo album of the truck build.  They came up with 5 things we should address (some are technically not rules, just advised) comprising a total of about a day's work if I take my time.  We were asked a few non-technical questions about build design, to which we received a nod and a smile, such as the BMW transmission concept.  Unfortunately while we were there, a 240Z started on fire after completing a run, but was the fire was put out in a timely manner and no one was injured.  

 

I wasn't able to get my license drivinga Charger, that's the 125 club happens at the USFRA October meet.  Oops.  

 

If anyone wants to see a few videos and pics, I have them posted on my Instagram account @jschlemmer

[frank88]

This is by far one of the best threads on here for me :) Such a professional build (obviously). Following you on instagram but I'd love to see some more shots of the interior. Well actually as many pictures as you can be bothered to post :D

[]2eDeYe]

No instagram here, would still like to see pics :D

[datzenmike]

same here.

[Stoffregen Motorsports]

 

If anyone wants to see a few videos and pics, I have them posted on my Instagram account @jschlemmer

Following.

[G-Duax]

No instagram here, would still like to see pics :D

 

+1

[distributorguy]

There are a bunch of photos here:

http://s1148.photobucket.com/user/distributorguy/library/Datsun%20project?sort=3&page=1

And here:

http://s1148.photobucket.com/user/distributorguy/library/?sort=3&page=1

 

They're not very well sorted, but plenty of interior shots.  These are the photos that we had inspected at Bonneville. Apparently the only thing in the interior that's missing besides the fire system (bottle bracket is mounted on the passenger rear roll cage) is a helmet support, forward enough to cover a side impact to the front of the helmet.  Easy fix, but it has to allow the driver room to exit.  

[distributorguy]

 

Wiring not yet completed:

[frank88]

Thanks for the links - great photos. Once I'm in the position too I'm really aiming to build a street track car in a similar fashion to this. Do you think there is enough space for 2 buckets with the cage and a 6" driver in a normal cab then? I assumed a kc would be ideal for cage but much prefer the clean look of a normal cab. It looks like you have plenty of space in these pics

[distributorguy]

Simply, no.  I can barely wedge myself in place, and I'm 5'10" tall.  Knees severely bent.  You need a KC if you want to fit in the truck with a cage, for more than 5 minutes driving.  Looks ARE deceiving.  Look closely at how far forward the bottom of the driver's seat is from the back of the cab.  Now look how low it is off the floor.  Bunched up.  

[frank88]

Cheers that's good to know!

[mcordero8]

Simply, no.  I can barely wedge myself in place, and I'm 5'10" tall.  Knees severely bent.  You need a KC if you want to fit in the truck with a cage, for more than 5 minutes driving.  Looks ARE deceiving.  Look closely at how far forward the bottom of the driver's seat is from the back of the cab.  Now look how low it is off the floor.  Bunched up.

 

He's only 6". It shouldn't be a problem. Lol