Moparts

rebuilding a 1969 NASCAR Nichels HEMI

Posted By: docford

rebuilding a 1969 NASCAR Nichels HEMI - 10/19/13 11:25 PM

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 ?

Attached picture 7893342-NichelsHEMINH-915-224.jpg
Posted By: hemi-itis

Re: rebuilding a 1969 NASCAR Nichels HEMI - 10/19/13 11:41 PM

Diamond or CP should be able to handle the task.
Posted By: autoxcuda

Re: rebuilding a 1969 NASCAR Nichels HEMI - 10/20/13 01:47 AM

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.
Posted By: Steve1118

Re: rebuilding a 1969 NASCAR Nichels HEMI - 10/20/13 03:49 AM

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.
Posted By: sunroofgtx

Re: rebuilding a 1969 NASCAR Nichels HEMI - 10/20/13 04:34 AM

Vic at Wiseco. You will not be disappointed. DISCOQUIK is his Moparts name.
Posted By: jamesc

Re: rebuilding a 1969 NASCAR Nichels HEMI - 10/20/13 05:21 AM

good lord is the bottom of that intake manifold iron?
Posted By: keith airgrabber

Re: rebuilding a 1969 NASCAR Nichels HEMI - 10/20/13 07:20 AM

Where did you find that. I always wonder where all that old stock car stuff is. Wish I had one in my car.
Posted By: dwayne welder

Re: rebuilding a 1969 NASCAR Nichels HEMI - 10/20/13 02:27 PM

The manifold base is probly magnesium and the lid is aluminum!!!
Posted By: docford

Re: rebuilding a 1969 NASCAR Nichels HEMI - 10/20/13 08:37 PM

Quote:

Diamond or CP should be able to handle the task.



thanks! I'll give them a call on Monday
Posted By: docford

Re: rebuilding a 1969 NASCAR Nichels HEMI - 10/20/13 08:39 PM

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
Posted By: docford

Re: rebuilding a 1969 NASCAR Nichels HEMI - 10/20/13 08:40 PM

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.
Posted By: docford

Re: rebuilding a 1969 NASCAR Nichels HEMI - 10/20/13 08:42 PM

Quote:

Where did you find that. I always wonder where all that old stock car stuff is. Wish I had one in my car.



It was sold via Ebay USA to a Mopar fan in southern Germany. Here is more: http://www.olympia-charger.com/2013/10/a...-sump-hemi.html
Posted By: docford

Re: rebuilding a 1969 NASCAR Nichels HEMI - 10/20/13 08:44 PM

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.
Posted By: JAKE68

Re: rebuilding a 1969 NASCAR Nichels HEMI - 10/20/13 09:26 PM

Do you have an original nascar carb for that also
Posted By: 23T Hemmee

Re: rebuilding a 1969 NASCAR Nichels HEMI - 10/21/13 02:08 AM

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...
Posted By: autoxcuda

Re: rebuilding a 1969 NASCAR Nichels HEMI - 10/21/13 06:12 AM

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.
Posted By: 23T Hemmee

Re: rebuilding a 1969 NASCAR Nichels HEMI - 10/21/13 06:29 AM

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.
Posted By: 23T Hemmee

Re: rebuilding a 1969 NASCAR Nichels HEMI - 10/21/13 08:02 PM

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.

Attached picture 7895435-P1010022.JPG
Posted By: docford

Re: rebuilding a 1969 NASCAR Nichels HEMI - 10/22/13 07:30 PM

I got a spare Dominator 1050, which is the same as on my two other HEMIs
Posted By: docford

Re: rebuilding a 1969 NASCAR Nichels HEMI - 10/22/13 07:34 PM

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 :-)
Posted By: docford

Re: rebuilding a 1969 NASCAR Nichels HEMI - 10/22/13 09:39 PM

Quote:

Diamond or CP should be able to handle the task.



I just talked to Mike Knowles at DIAMOND. It sounds like we are good to go for a new set of custom made pistons :-)
Posted By: docford

Re: rebuilding a 1969 NASCAR Nichels HEMI - 10/22/13 09:42 PM

Quote:

.... 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...



We measured the rods with more precision and they are of 7.061" length indeed.
Posted By: docford

Re: rebuilding a 1969 NASCAR Nichels HEMI - 11/01/13 08:41 PM

Would you know what seat pressure and what open pressure the springs should have for the mushroom flat tappet P3614436 camshaft that is in the motor right now ?

Attached picture 7908240-nichels426valvesprings.jpg
Posted By: dwayne welder

Re: rebuilding a 1969 NASCAR Nichels HEMI - 11/01/13 09:00 PM

Looks like two different Retainers!!!!
Posted By: docford

Re: rebuilding a 1969 NASCAR Nichels HEMI - 11/02/13 09:24 AM

Oups !!
you sure got sharp eyes
Posted By: ScottSmith_Harms

Re: rebuilding a 1969 NASCAR Nichels HEMI - 11/02/13 04:09 PM

I have a correct Holley carb for that engine. neat piece!
Posted By: docford

Re: rebuilding a 1969 NASCAR Nichels HEMI - 11/06/13 11:01 PM

Quote:

I have a correct Holley carb for that engine. neat piece!



Interesting how much different is it from the regular 1050 Dominator ?
Posted By: rickseeman

Re: rebuilding a 1969 NASCAR Nichels HEMI - 11/07/13 03:39 PM

I assume you would want Lemans float bowls. I had a
Superbird with a Hemi engine and a NASCAR air cleaner and only Lemans float bowls would fit. There was more than one NASCAR air cleaner for a HEMI. I have a spare filter element for one of them that I don't need.
Posted By: efisixpack

Re: rebuilding a 1969 NASCAR Nichels HEMI - 11/07/13 04:05 PM

rick, are you referring to the filter element that slides into the cowl area? If so could you post pics and dimensions?

Scott, any ida what an nos nascar dominator would be worth?
Posted By: rickseeman

Re: rebuilding a 1969 NASCAR Nichels HEMI - 11/07/13 09:21 PM

No it is a round one.
Posted By: docford

Re: rebuilding a 1969 NASCAR Nichels HEMI - 11/24/13 10:55 PM

Quote:

No it is a round one.



mine got a flat filter that fit on a cavity in the cowl at the end of the air cleaner
Posted By: docford

Re: rebuilding a 1969 NASCAR Nichels HEMI - 11/24/13 10:57 PM

Quote:

Quote:

Diamond or CP should be able to handle the task.



I just talked to Mike Knowles at DIAMOND. It sounds like we are good to go for a new set of custom made pistons :-)



I placed the order for new pistons at CP :-)
Posted By: docford

Re: rebuilding a 1969 NASCAR Nichels HEMI - 11/24/13 10:59 PM

Quote:

Quote:

I have a correct Holley carb for that engine. neat piece!



Interesting how much different is it from the regular 1050 Dominator ?



I plan to use a regular 1050 Dominator, as it fits fine under the air filter that I got. You can see it here:
http://www.olympia-charger.com/2006/06/our_motorvation.html
Posted By: docford

Re: rebuilding a 1969 NASCAR Nichels HEMI - 12/21/13 12:54 PM

the 4.29" pistons arrived from CP CP did the reverse engineering to fit modern type rings, 1.09" tool steel pins and the right dome and valve pockets for 11:1 compression ratio

Here is a picture http://www.olympia-charger.com/2013/12/pistons-and-valvesprings-arrived-for-our-nichels-hemi.html
© 2024 Moparts Forums