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Tue Jul 08, 2014 5:51 pm

In my newly registered and street legal sandrail is an 1835, the first engine the PO had ever built. I have no idea what heads are on it, the rocker geometry is... well, not good, I'm seeing oil leaks everywhere that can leak, and not so great oil pressure; about 15 psi at 1800 rpm on the street, 25 psi max. Then there is the blowby... oh god, the blowby.... I have a breather box that I built with TWO filters on it, and it still build enough pressure to blow BOTH out of the box! After replacing them twice thinking they were wiped off by a tree branch or something, I finally saw the last one of the last pair blow out under full throttle! Then there was a jet of visible smoke that rose above the box a solid foot while rolling at 25mph!!! :shock: I would think that two half inch holes in the box would let it breathe easy... guess not.

Thats the bad, now for the good!

it has a case that has been line bored and a CW 69mm crankshaft with unknown origins. I suspect empi.
The PO told me it has a near stock cam, and he put the counterweighted crank in so he could run high rpm... with stock rockers and springs. valve float limits it to about 6000 pretty well. the 009 seems to be in good shape! and the lightened flywheel is 8 dowel'd.
I currently have a pair of weber dfv 228's on it, and they work ok. not great, but ok.

My main goal is to build something that makes about 80-100 hp. I would like to reuse any good parts if possible, and plan on replacing any junk parts with decent stuff. Not gene berg, but better than empi.

Also, i am seriously considering EFI, i have a pair of crossfire corvette throttle bodies that would be just perfect for this thing, and I have enough crap laying around to fix the whole thing up with all the required sensors. If i did it, i would just use throttle body injection similar to the old chevy tbi system.

So! With the notion that this would be an engine meant for a lightweight rail, driven on the road a little and in the hills a lot, what would be a good choice for cam and compression ratio? should I be considering new carbs over the DFV's if i choose not to fuel inject it? would the fuel injection favor another type of cam over another if it is speed density?
Should I choose one cam over another based on using carbs for now and EFI in the future? Is there any real benefit to building a 1776 for a rail? shoul i plan on EFI now or is later ok?

Anyway, this is a build for winter, and it is running now so I will drive it for now and build a motor when waiting for powder coating this winter. I just want to get a plan laid down so i can save up the required coin or even start some of the stuff.

Wed Jul 09, 2014 2:04 pm

I would do Compression test, then leakdown test to see what kind of shape your rings and valves are in. Nice to know where your blowby is coming from before tearing it apart.

Your a great candidate for the thick wall 92 piston and cylinders since ur case is at the correct id already. 4.6mm thick cylinder walls are awesome for any build, and you can get a full set of these P's and C's for $200.

Fuel injection is awesome but I would not spend too much time adding to the list of things that would put it on the back burner for years. Things seem easy but end up taking longer to finish. Those crossfire throttle bodies are notorious for throttle shaft play and often times need to be rebushed, so careful if you move forward with those. If I was you I would really invest in some dual 40 webers, but too each there own I understand.

Any details on the heads? valve sizes?

Wed Jul 09, 2014 5:24 pm

jpaull wrote: Any details on the heads? valve sizes?

I am heading out to the shop right now, I'll see if I can at least get a casting number. It most likely is leaking past the rings being as it has been smoking just a tiny bit. I have no idea how much it is actually burning, the thing just dumps way too much oil to ever find out. The worst leak seems to be the pushrod tubes, the other bad one is the crank pulley, probably because of too much crankcase pressure. I am thinking of pulling the heads this weekend to replace the pushrod tube seals. If I do I will measure the displacement the combustion chambers and valve size, maybe even lap the valves.

I thought you had to have the case bored for 94mm cylinders to run the thick wall 92's. Do they just have the same base and top diameter as the thin 92 with extra meat in the finned area?