dohc head cc's ????

mrsleeve91 · Post by **mrsleeve91** » Thu Nov 30, 2006 11:44 pm

plus the dohc block has different webing and oil passages to feed and drain the heads vs. the 2. (hate)

crzyone · Post by **crzyone** » Fri Dec 01, 2006 12:50 am

I'm guessing it was a budget dohc engine. Its a stout engine, but complicated and heavy.

SappySE107 · Post by **SappySE107** » Fri Dec 01, 2006 2:18 am

crzyone · Post by **crzyone** » Fri Dec 01, 2006 3:18 am

Umm no, cheaper than I give them credit for.

There is no reason GM needed to use the 60* block other than to save a few $$. The Yamaha was no screamer, another detuned dohc V-6.

The N* was cool, clean sheet design and was being made around the same time the 3.4dohc was.

SappySE107 · Post by **SappySE107** » Fri Dec 01, 2006 3:26 am

crzyone · Post by **crzyone** » Fri Dec 01, 2006 3:36 am

You can bet that it was being developed during that time. Its release was the 93 model year.

Fastback86 · Post by **Fastback86** » Fri Dec 01, 2006 3:59 am

Far as I can tell, the 3.4DOHC was "what's the easiest way to put DOHC heads on this pushrod block we have sitting here?" They got the job done, but the design leaves a lot to be desired.

I always wondered why the S* never caught on. Dunno what GM has against a DOHC V6.

SappySE107 · Post by **SappySE107** » Fri Dec 01, 2006 4:05 am

Series8217 · Post by **Series8217** » Fri Dec 01, 2006 5:30 am

SappySE107 wrote:At least they didn't look at the 3800 and say "yeah, that design looks good for a V6".

You know they did make a 3800 V6 DOHC.... it was in a concept car. I think they did it the same way as the 3.4 DOHC; timing chain driving a dummy cam driving a timing belt.

SappySE107 · Post by **SappySE107** » Fri Dec 01, 2006 6:36 am

The Dark Side of Will · Fri Dec 01, 2006 9:32 am

Mach10 wrote:Be fun to remove it... If there was a better way to make it turn the cams, too :scratch:

Remote oil pump ftw? All that preoilling goodness...

The timing chain sprocket drives the belt pulley directly. All the snout of the I-shaft does is hold the two together. If there were a bearing surface in the front cover, you could lop the I-shaft off right behind the 1st cam bearing. Since there isn't a bearing surface in the front cover, you have to lop it off behind the second cam bearing... which only gets rid of 66% of it.

Yes, you'll have to plug the cam holes with something in order to keep oil pressure, but crazier things have been done with production blocks.

Mach10 · Post by **Mach10** » Fri Dec 01, 2006 10:08 am

If weight and rotating mass is a concern, I wonder how much material you could shave off the "blanks" between the cam bearings and still have it strong enough to turn the oilpump? :scratch:

Be a whole lot less complicated.

The Dark Side of Will · Fri Dec 01, 2006 10:59 am

Absolutely negligible effect on moment of inertia... diameter's too small.

Oil pump driveshaft is 3/8" or 7/16", so only slightly bigger than that would be necessary. At that point it would probably be better to make an intermediate shaft from 7/16" drill rod with a bunch of blanks for the cam bearing journals pressed onto it.

Alternatively, press blanks into the cam bearing bores in the block and press bronze bushings into those blanks. Tiny oil holes would be all that would be necessary to adequately lube the drill rod and you'd get rid of the MOI of the bearing journals.

p8ntman442 · Post by **p8ntman442** » Fri Dec 01, 2006 5:21 pm

THis would deffinatly be a problem for my proposed setup. I need to remove the cam, because the head gets the oil from the cam carrier feed. I would have to make a sealed bearing insert to hold the pulley in place. No need for brass and oil.

Series8217 · Post by **Series8217** » Fri Dec 01, 2006 8:12 pm

You can just fill in the tiny oiling holes in a set of cam bearings and install them. That will seal the oil galley with the intermediate shaft removed.

p8ntman442 · Post by **p8ntman442** » Sat Dec 02, 2006 8:50 am

cam bearings are lead, so not sure how you would fill them to stop oil flow, and Either way, my application is different, If you dig up my aluminum 2.8 build thread, you will see the cam carrier is removable.