270 GMC altered motor build part 1

It'll definitely be fast now that there's some MOPAR in her.....haha

 

all motors have a weak link some where

 

Sometimes it's the Nut behind the wheel.........

 

NICK ARIAS ? What is the story on the cam cover? I would like one for our roadster. thanks for all the info!

 

We clayed the head and valves last night , the valves cleared good , the head not so good
put it together,take it apart ,grind, clean,put it together,take it apart ,grind, clean,put it together,take it apart ,grind, clean,put it together,take it apart ,grind, clean,put it together,take it apart ,grind, clean,12:00 AM "hey it fits, wholy **** about time"

 

The one we have is the only Wayne one I have ever seen, other that in the old books
If I find another one I'll let you know

 

Can you post a pic of it?

 

Are you going to put your mag/oil pump in front or stock location?

 

The mag and fuel up front , Oil in the stock location

 

Of course with the stock oil pump in you need the bottom half of a stock distributer to drive it and the cam needs to have the stock gear machined on when it's made. If you drive an external oil pump from the boss provided for it on your new cover, you save some money on cam billets. If the maker doesn't need to cut the gear it's cheaper. I'm still a little confused about how you are driving your mag.

 

We have a SW tach drive in the hole to run the oil pump,The mag is driven off the top of the front cover.

 

Anybody here that did not see this on the Landspeed forum? Look much like a 7 main bearing girddle for a GMC?

 

For what it's worth,
Demitri Elgin made my cam for our bonneville roadster. He told me that the rifle drilled stock rods were a NO-NO. Horrible pictures to follow convincing me he his right ! Aftermarket rods going in next year's motor.

 

Puting in the rear main insert wrong ****s a lot to

 

What was the RPM's when it failed?

 

I hope this isn't a dead thread. I was getting very interested.. Subscribing.

 

http://www.youtube.com/watch?v=RIfh5TylUwg
heres a link to the motor running

 

Rocky, your Rod didn't fail...at least not first...see the black from the heat on the big end and on your crank?..you lost oil to your bearing , it then siezed and broke your rod. Fix your oiling issue before you back together with expensive rods or the same thing will happen..
Hans

 

Only one rear main insert on a GMC is drilled for oil. I don't know why. All the rest (3) both inserts are drilled. But only one rear insert. Put it in upside down, no oil to rear main or #6 rod. Result looks just like this motor. Most GMC racers find this out the hard way.

 

crying shame

 

Yes it is true,,I learned the hard way in about 1962, working at a GMC Shop my very first rebuild. I was lucky I wasn't fired,, shop foreman said it happened to him, saved me. Also it only went about 20 miles when the noise started and was shut off. Whew!!!!!

 

Seems to me the California Bill GMC speed manual from the early '50s makes a point of discussing this.

 

Could be. It's a very well known quirk of GMCs. But it still happens. Only once to most people.

 

A guy I work with did it when he rebuilt the 228 in his '46 GMC, but luckily only drove it a few miles before he figured it out.

 

Hi Marshall. I was attempting to spin it to 4500 rpm's. Went to 4000 & $%^@$%^$%^$&^$$$$$$$

 

I am going to check this !
Sorry for the hijacking !

 

Rockey - can you report back what you found? I am putting a new crank in my 270 as of this writing and noted that I had ****ed up the bearing placement while I was working in the rear main seal. I caught it during final ***y.

My original crank developed a crack that wiped out the #5 rod bearing and I caught the sound change right away and shut it down. My motor had made several excursions to 5000 rpm and lasted about 15,000 miles before the crank developed cracks.





Pretty neat eh? Glad it didn't let loose at 70 mph - I actually drove it up onto the trailer to drag it 800 miles home - then drove it up to the shop for dis***embly. I was extremely fortunate.



Let us know what you found.

 

I know this is an older thread but any updates? Also Marshall, did your 12 port come from Casper, Wyoming? I met a fellow there a couple weeks ago, Gene Novotny. He had sold one a while back, neat guy with a few hundred 12 port stories.

 

Yikes! How did I miss that pic? you are very fortunate..

 

Some one is making a girdle for a 302 gmc ,any one know who it is ,or where I can get one?
Thanks
Marshall