Velocity is good to a point,but if it goes supersonic ya can't control it. Small ports and big inches and RPM's will do that.

 

Well I don't think a 302 will have that problem at 8500rpm, especially if you can bore those ports out to about 1.25". You'd know better than me though. How big do you think those intake runners are 90cc each?

 

Hard to tell in the pictures.

 

well they are 1.1" diameter. There isn't a very good shot to gauge length though.

 

damn,...I dont want to read this anymore..

my 302 is calling from the far back of the garage....give me dohc...I will love it..

I spun that thing to 8500 with the cam in block setup...hello 10,000rpm SBC

 

Haha, at your own risk man. I just don't know about a belt driven cam moving at that speed.

 

I have to admit that I find this OHC conversion intriguing. If I understand dry sump oiling systems correctly, can't you set them up so that there is no oil pump inside the pan? What I'm thinking is that if you could eliminate the need for the crank to drive the oil pump, (in the conventional way), you could also potentially eliminate the camshaft and timing chain from the block as well. Even though you'd be robbing Peter to pay Paul in the sense that you'd still have to have an external oil pump driven from a belt on the front of the engine, it doesn't seem like the amount of parasitic drag that that pump would place on the crank would be as great as that of an in-pan pump and the energy required to turn a timing chain and cam. The crankcase vaccuum produced by the dry sump system would also allow you to use low tension rings and take that much more pressure off the rotating assembly: bonus. Of course, I realize that I could be talking completely out of my **** as I don't have any direct experience with dry sump oiling systems.


Does any of this seem even remotely plausible? (Barring expense?)

 

Well I guess it depends on which engine you are talking about. Obviously on the LT1 the cam drives more than just the Oil pump. But yeah, dry sump could have a more remote oil pump, and most people get an electric waterpump anyway. Getting a new distributor is a must for the high rpm you would turn with an OHC motor, so there is no reason to keep it in the stock position, cam driven. Of course you would also save power with a lighter valvetrain. I'm not sure if the cam/timing chain plays a big part in the belt/pulley system that drives the OHC's in Aardema's kit though. You might want to check on that first.

Jeremy

 

you could go to a coil pack system to deal with the high rpms instead of a disributor.

 

Don't you still need a distributor for the coilpacks? I can't say I know a whole lot about ignition systems.

 

i think it depends on the system but the one i was looking at(EDIS controlled by a megasquirt, i know i'm cheap) only needs a crank sensor, an EDIS module, and the appropriate number of coils packs.
more on EDIS here

 

I talked to Pete Aardema again today, I think i'm going to go ahead and try my hand at building a DOHC 302. The goal will be 450 hp and 400 lb/ft of Tq with an 8500rpm redline, anything more is just gravy.

There are still a few small details to work out (i.e. where to get a money tree).

When(if ever)i'm finished I'll start taking orders!!!

Jeremy

 

what are you going to do for cams...

how about a clone of the 30-30 dontov cam....or something with a little more lift

 

A 302 LT1 or a SBC?

 

I'm going to leave everything stock for a while, until I know I can get it running as is. Just for the sake of simplicity.

As for LT1 or SBC, I think SBC will be the way to go. It's hard enough to convert SBC heads to reverse cooling, I don't think a machinist will touch nissan heads. That along with concerns about the waterpump and distributor, as well as Mr. Aardema being more knowledgeable with the SBC, he's my tech support.

I might try an LT1 if this works though.

Jeremy