Does anyone have the following 396 setup in an LT1?

350Block, .030" overbored cylinders
3.875" stroke
6.0" Rods
9.025" engine deck height(Standard LT1)
1.060" compression height Pistons(Lunati flat top 3cc dish in this case)
56.6CC Combustion volume heads.(Stock ported heads)
Should be about 11.8CR.?

If you have the same setup or simlar are you having problems with excessive oil consumption or detonation?

How did you fix the issue or plan on fixing it?

If you have the same setup or similar I would like to hear how it works and what kind of timing your running.
Timing?
Gas Octane level used?
Part specs (rod lenght, compression height ect, etc)


Shawn L

 

These questions should be asked in a gen spacific forum, moving to LT1 Tech. Thanks.

 

Hey Crazy Man, I am having a 396 built right now. Its a 4 bolt LT1 Vette block, with Pro Gram billet caps and ARP studs. I have a Callies DragonSlayer crank on hold, waiting for a weight on a custom J&E piston. The pistons will have an anti friction coating on the skirts, and only be .010 over to preserve cylinder wall thickness, since the block is in great shape. They will have a custom dish, cause the block is decked to 9.018 to equalize them. The crank and pistons are being connected by Manley Billet 6 inch rods. Also, going with an AFR 210 now with a 58 CC chamber, which will bring the compression to around 11:25 to 1 or so. I wouldnt go any higher and run pump gas. As far as excessive oil consumption, I dont see that being a problem unless the wrong type of oil controll ring was used, or some tolerance wasnt checked and left to loose. I plan to use pump gas, and full timing, and be able to drive this thing where ever the hell I want. Sounds like you need to order a little more of a piston dish to keep the compression pump gas friendly. i would also wait till your machiist had your block, to see how much of an overbore you really need, and to deck the block to determine the piston dish with the heads you will use. I hope some of this info helps, hopefully some of the other stroker guys will chime in soon.



Nick

 

thx for the post Nick, I hope more chime in soon. I'd like to hear from more people.
I had my engine built at ARE in Toronto. Despite having the brought the car back to then at least 3 times in the last 3 years for problems they have not been successful at solving.
Each time the problem was the same, the thing detonates and consumes too much oil. I can't see any black smoke but I have to top up the oil every 750 miles or so. Sometimes as mush as a quart.

<<rant on>> (to skip rant, go to <Rant Off>)
Anyway, I have given up any hope with regard to ARE fixing this, and there customer service sucks(they hardly ever return calls and when the do get the car it takes an extra month or more on top of the time agreed to be finished. Then it still is not fixed)
There solution was "its a tuning problem" and then proceded to reduice timing to about the 26-28deg level at WOT. Which no doubt removes tons of power
I'm very frustrated so I'm jumping into this by myself to make sure the problem gets fixed.
<Rant off>

The possible problems I see are:
1. Oil is causing black buildup on plug, heads and cylinder tops and thus detonation:
This could Simplly be the ring/piston combination is not correct causing oil blowby at RPM. A static compression test revealed 240-260psi tho. If this is a problem I need to tear the engine apart and re-pistron and re-ring (something I do not want to do)

2. Oil cunsumtion: Intake or heads leaking oil.
Solution is to fix that up. haven't see much proof of this yet but I did not take the valves out of heads for a closer look yet.

3. One engine builder mentioned my compression being to high for pump gas. He also said up hear in Canada the gas is not as good as in the US so I have to run a lower CR than guys are running in the US.
My ARE engine build sheet calculates an 11.3:1 CR. I when though the calculation and noticed this was incorrect, It is actually more like 11.8:1 or a bit higher. This in itself could be the problem.
Solution here: I don't know yet and since I'm on a very limited budget tearing the engine block out is not desirable although i may have too.
A. Take some metal out of the combustion chambers of my LT1 heads. How many CCs can one take out without risking too thin of a combustion chamber top?
B. take some ccs out of the Lunati pistons I have. Who knows
how much can safely be taken out?

I'm open to other solutions..