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Re: rebuilding a 1969 NASCAR Nichels HEMI
[Re: docford]
#1520112
10/19/13 09:47 PM
10/19/13 09:47 PM
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Joined: Jan 2003
Posts: 27,468
So Cal
autoxcuda
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 27,468
So Cal
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Quote:
I just became the happy owner of a genuine Nichels HEMI. It was raced in NASCAR and is all complete. It has 020 oversize NASCAR HEMI pistons. It will need a rebore to the next oversize, since two bores are scratched beyond what a hone job could fix. The pistons come with 1.09 pins, which was a unique size for the NASCAR 426 HEMIs back then. Rods are of 6.86" length and crankshaft stroke is 3.75".
The domes are huge. We calculated a compression ration of almost 14:1 !!
Do you know who could make me a set of custom HEMI pistons in 4.29" bore, 1.09" pins and less dome ?
Wouldn't you take a modern appoach to the engine internals and just keep the outside visually vintage appearing??
Like take advantage of modern materials. I'm certainly no motor expert, but I'm guessing the heavy pistons, heavy rods and pins could take advantage of modern stuff and maybe make it more realiable and less stressfull on parts. 
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Re: rebuilding a 1969 NASCAR Nichels HEMI
[Re: autoxcuda]
#1520113
10/19/13 11:49 PM
10/19/13 11:49 PM
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Joined: Jan 2003
Posts: 2,763
Walton's Mountain, Pa
Steve1118
master
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master
Joined: Jan 2003
Posts: 2,763
Walton's Mountain, Pa
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Depends on what you want to do. Reliability is not really a problem with those.
It sounds like it's a 426, You can find .030, .060 TRW pistons for those hanging from trees. Most old Hemi guys probably have boxes of them around. If you had gotten a 404 or one of the destroked versions that they used you may have to look a bit harder. Those NASCAR rods have a 1/2 rod bolt...they are heavy but indestructible.
If your going to race it, maybe look at modern stuff. If you're going to putsy around with it, I'd get a set of TRW slugs, clean up the bore, it, and put together. I would look at another camshaft, though, because if it's original it probably has a mushroom tappet cam in it.
For what it's worth, I still use the old stuff in my Nostalgia SS motor.
"Old age and treachery trumps youth and enthusiasm, every time!" East Central Director / Chrysler Power Magazine www.reasbeckracing.webs.com
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Re: rebuilding a 1969 NASCAR Nichels HEMI
[Re: Steve1118]
#1520114
10/20/13 12:34 AM
10/20/13 12:34 AM
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Joined: Jul 2003
Posts: 12,129
Cleveland
sunroofgtx
I Live Here
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I Live Here
Joined: Jul 2003
Posts: 12,129
Cleveland
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Vic at Wiseco. You will not be disappointed. DISCOQUIK is his Moparts name.
Join the quickest team in motorsports. Team FireCore. CustomWiresets.com
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Re: rebuilding a 1969 NASCAR Nichels HEMI
[Re: hemi-itis]
#1520118
10/20/13 04:37 PM
10/20/13 04:37 PM
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Joined: Aug 2010
Posts: 208
Munich, Bavaria
docford
OP
enthusiast
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OP
enthusiast
Joined: Aug 2010
Posts: 208
Munich, Bavaria
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Quote:
Diamond or CP should be able to handle the task. 
thanks! I'll give them a call on Monday
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Re: rebuilding a 1969 NASCAR Nichels HEMI
[Re: jamesc]
#1520119
10/20/13 04:39 PM
10/20/13 04:39 PM
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Joined: Aug 2010
Posts: 208
Munich, Bavaria
docford
OP
enthusiast
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OP
enthusiast
Joined: Aug 2010
Posts: 208
Munich, Bavaria
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Quote:
good lord is the bottom of that intake manifold iron?
no, it is a NSACAR bathtub made out of magnesium (good thing, as the elephant is heavy enough!!) The color is from some sort of clear coat paint that has darkened over the years
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Re: rebuilding a 1969 NASCAR Nichels HEMI
[Re: dwayne welder]
#1520120
10/20/13 04:40 PM
10/20/13 04:40 PM
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Joined: Aug 2010
Posts: 208
Munich, Bavaria
docford
OP
enthusiast
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OP
enthusiast
Joined: Aug 2010
Posts: 208
Munich, Bavaria
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Quote:
The manifold base is probly magnesium and the lid is aluminum!!!
The lid is magnesium too. It is the thick version, which Maurice Petty designed after that Chrysler came up with the shallow version.
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Re: rebuilding a 1969 NASCAR Nichels HEMI
[Re: Steve1118]
#1520122
10/20/13 04:44 PM
10/20/13 04:44 PM
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Joined: Aug 2010
Posts: 208
Munich, Bavaria
docford
OP
enthusiast
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OP
enthusiast
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Posts: 208
Munich, Bavaria
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Quote:
... I would look at another camshaft, though, because if it's original it probably has a mushroom tappet cam in it.
Yes, it has a mushroom tappet cam, indeed. First time I ever saw one of these for real. We'll measure it and the decide to keep it or not. The plan is to rebuild the motor as close to its original NASCAR specs as possible.
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Re: rebuilding a 1969 NASCAR Nichels HEMI
[Re: docford]
#1520123
10/20/13 05:26 PM
10/20/13 05:26 PM
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Joined: Dec 2005
Posts: 1,495
Shelby mi.
JAKE68
pro stock
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pro stock
Joined: Dec 2005
Posts: 1,495
Shelby mi.
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Do you have an original nascar carb for that also
JAKES AUTOMOTIVE
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Re: rebuilding a 1969 NASCAR Nichels HEMI
[Re: docford]
#1520124
10/20/13 10:08 PM
10/20/13 10:08 PM
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Joined: Jan 2010
Posts: 588
Franklin, TN
23T Hemmee
mopar
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mopar
Joined: Jan 2010
Posts: 588
Franklin, TN
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Hey Doc, that sure would look good in the Charger, making laps at LeMans. Unless the cylinders won't clean up on .030", I would try like Steve said above to find some of the older Nascar/TRW pistons. Technically they wern't legal as Nascar had a 430" limit (never made sense to me as .030's gave you 431", most independents used them as they seldom got torn down anyway) but you could get the .030's in a pentroof design which would give a little more compression and usually were used on the short track engines along with a little less cam. Back then the short track cams were in the 310-312 total duration range (advertised duration) and the mushroom was the way to go as roller cams were illegal and standard lifters couldn't handle the loads near as well. I'm confused about your rod length though, the ones I had were 7.061" for the std stroke, and I know they made a 6.96 and a 7.176" which I think were for the 404 and 394 destrokers. I had a Petty 394 back in the 70's and it had 7.350" Carrillo's with a 3.480" stroke Moldex and Fordgetrue pistons so I don't know if the Petty's didn't like what the factory came up with and just came up with their own or if the factory just outsourced since a lot of the combinations were one/offs anyway as it seemed Nascar kept downsizing the restrictors on a monthly basis depending on how may races the Mopars won. Wow, sorry for the run on sentences, but I'm too tired to go back and fix it... 
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Re: rebuilding a 1969 NASCAR Nichels HEMI
[Re: docford]
#1520125
10/21/13 02:12 AM
10/21/13 02:12 AM
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Joined: Jan 2003
Posts: 27,468
So Cal
autoxcuda
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 27,468
So Cal
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Quote:
Quote:
... I would look at another camshaft, though, because if it's original it probably has a mushroom tappet cam in it.
Yes, it has a mushroom tappet cam, indeed. First time I ever saw one of these for real. We'll measure it and the decide to keep it or not. The plan is to rebuild the motor as close to its original NASCAR specs as possible.
Does it matter what's inside the motor?
Why not make more HP, or make the same HP and rev less or same HP with a combo that's easier on valvetrain.
I thought you hurt a motor recently? Its expensive and time consuming.
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Re: rebuilding a 1969 NASCAR Nichels HEMI
[Re: docford]
#1520126
10/21/13 02:29 AM
10/21/13 02:29 AM
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Joined: Jan 2010
Posts: 588
Franklin, TN
23T Hemmee
mopar
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mopar
Joined: Jan 2010
Posts: 588
Franklin, TN
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Quote:
Quote:
The manifold base is probly magnesium and the lid is aluminum!!!
The lid is magnesium too. It is the thick version, which Maurice Petty designed after that Chrysler came up with the shallow version.
Actually Doc, it was the other way around. The original lids were thinner, and after Nascar started requiring the original restrictor rings in the Dominator carbs, they (Maurice and others)started making the lids thicker to increase the plenum area to try to compensate for the decreased airflow of the restricted carbs. The restrictor rings inside each barrel were fairly straight forward but there were several different theories about how to increase and re-direct airflow once inside the bathtub, one of which was a machined tube that exited closer to the floor of the manifold. Looking at one of the pics on your link, it looks like there is a machined step under each barrel. The tubes had a corresponding step so that they dropped into each hole, with the carb then holding everything in place. Seems like there may have been three lid thickness increases, and if I remember right, the rally hood bubble on the 73? 74? charger came about primarily to gain more carb clearance as the manifold got taller with each lid mod. I've still got some of those tubes somewhere, and will try to post a pic or two soon.
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Re: rebuilding a 1969 NASCAR Nichels HEMI
[Re: 23T Hemmee]
#1520127
10/21/13 04:02 PM
10/21/13 04:02 PM
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Joined: Jan 2010
Posts: 588
Franklin, TN
23T Hemmee
mopar
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mopar
Joined: Jan 2010
Posts: 588
Franklin, TN
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Here are some of the machined tubes (not sure these were ever finished)that went into the manifold top to direct the airflow down to the lower side of the intake along with one of the original restrictor rings that were knurled and pressed into the base of a 4500 style Holley. These measure 1 11/16th and over several years as the Hemi kept winning, Nascar would reduce the size to "keep the playing field level" as they used to say. Fuzzy on the last size that finally did the Hemi in, but seems like it was 1 & 1/16th" x 4bbl.
Last edited by 23T Hemmee; 10/23/13 02:16 PM.
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Re: rebuilding a 1969 NASCAR Nichels HEMI
[Re: 23T Hemmee]
#1520129
10/22/13 03:34 PM
10/22/13 03:34 PM
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Joined: Aug 2010
Posts: 208
Munich, Bavaria
docford
OP
enthusiast
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OP
enthusiast
Joined: Aug 2010
Posts: 208
Munich, Bavaria
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Quote:
... Looking at one of the pics on your link, it looks like there is a machined step under each barrel. The tubes had a corresponding step so that they dropped into each hole, with the carb then holding everything in place. ....
yes, there is indeed some machining inside the four holes, like something was meant to be held there. So this was probably for the tubes that you mention. Thanks for the information :-)
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