cduemig

I've got one of the AR Racing 383's I just dropped in. I love this engine so far, it runs perfectly exactly as advertised. I bought this off a guy that sold his vette before dropping it in so I have very little documentation on it.

So for you guys that have the same setup, how did you set it up? I set my initial timing at 12 degrees, but I've read that you should set the max initial timing you can without starting problems. My MSD has heavy springs that give 21 degrees total centrifugal that come all in around 3800 rpm according to the manual. I haven't varified this, but I will next time I'm out there. So according to that logic I should set it to 15 degrees initial for a total of 36 without vacuum assuming vacuum is no more that 16 degrees for a total of 52, right?

What should I set my redline to (both the imaginary and MSD soft rev limiter)?

BigBlockk

Setting the initial advance to 15 should be OK as long as it starts easily. The timing should be "all in" at about 2800 RPM. As far as rev limiters go set it at 5800 RPM. Your engine will love you for it.

BigBlockk

Later.....

427Hotrod

Try to find some info...maybe call AR. They have been known to use the cheaper claimer style hypereutectics unless ordered otherwise and they sure don't take to ANY detonation whatsoever. Find out how much compression it has.


JIM

GrandSportC3

I personally never set timing for initial timing.. I diconnect the vacuum advance (if the distributor has one) and then set the timing to total timing. I used to have a AR 383/465 HP and it liked 38 degrees total timing best.

tshort

Let me highlight what Jim said. They don't like ANY detonation if you got the non-forged setup. And don't worry about initial timing, it's max timing that matters. Initial timing where fall where it will based on max timing and any other factors like springs, vacuum advance, choke, etc. Put in lighter springs (I put the lightest on one side and second lightest on the other side from the MSD kit) and start initially with 36 degrees total. Then get out and drive it and put a load on it and listen for any detonation. If you get any back off your timing a tad. Here's what happens with a little too much timing and oil going past the valves:

MotorHead

T short, didn't the balancer fall off that motor when it was running ?

Real quality claimer pistons there too, top shelf stuff from those AR guys

cduemig

These are the specs per my build sheet that I have. It says I have the keith black pistons, which I know are cheaper pistons right? The rod's are GM pink, which I believe are pretty good. I'm not much of an engine guy... Would I might consider swapping the pistons?

4 bolt main

-Comp Ratio 10.1

- hp and torque peak @ 5400 rpm

-The hp and Tq numbers are exact, engine was dynoed by AR racing when it was built with 437hp & 468 Ft. Lbs torque.


Machine Work

-Select high tin block 4 bolt main. 030 over

-Align bore check run out. Full race clearances

-Mag check-Press check

-Hot Tank

-Bore Torque Plate Honed

-Clearance Block

-Shot Peen Rods

-Dynamic Balance Assembly

-File Fit Rings-Blue Print Clearance

-Press pistons to Rods

-Install Cam Bearings- freeze plugs

-Port Blue Print Cylinder heads

-Final Assemble Full Rotations and Top end

HEADS

-Kenny Duttweiler Trick Flo bowls blended Full

-2.02 / 1.60 valves

-1.25 springs 7 degree super locks

-Porting 3/8 Stud Guides

-Mild Port work

-Hi Performance roller rocker 1.6 ratio

-Comp Cam Polished+Matching Rpm Intake

-112 degree center line 487-490 Lift Corrected 1.6 ratio= 520 / 532 Lift

-226/228 dur. @0502

-2,000 Stall

PARTS

-Keith Black Hypervtecic S.I. Pistons 9.8 Tol

-Eagle Steel Crank Sized + Indexed

-Childs + Albert - 22 gapdura Moly File Fit Rings

-Durabond Cam Bearings

-GM Pink Forged Steel Rods

-ARP- wavelock- rod bolts

-Clevite Rod + Main Bearings Tri- Metal 77

-Comp Cam Lifters

-Colys True Roller set

-Comp Cam Locks

-Comp cam Xe Chrome Moly Push Rods

-Dyna Gear race oil pump

-ARP steel drive

-ARP head bolts

Fel Pro Gaskets

cduemig

Man T, that really sucks. How'd that happen? I've heard of things breaking, shooting rods out the block, etc, etc, but I've never seen a straight up broken piston...

tshort

Yes, the original balancer on that motor was cheap Chinese crap. The nose broke and fell right off in my garage.

Basically a combination of oil leaking through the valve guides and a little too much timing causing some detonation broke the piston and a couple of pushrods.

I was able to get another motor out of AR in the end but it took about a year. The second motor was much better. It had all forged internals and didn't burn oil like the first one. I also had them put on an SFI certified balancer. My take on AR is that when they were smaller and hadn't gotten into the eBay world they were a decent shop. But then the eBay sales went through the roof and they couldn't keep up and quality went down the tubes. They also got so busy that it started taking forever for them to get anything done. My motor #2 was supposed to take 1 month and it ended up taking like 11 months or so.

cduemig

I just drove it today and I've got detonation. I thought it was a loose rocker, but it's got to be detonation. It only happens under load, usually in second gear and my third gear comes in late so... My timing is set at 15 degrees initial. It's supposed to have 10 degrees vacuum, but it looks more like 12. I changed out my springs to the lights to bring in full mechanical advance at about 2800rpm. My engine has a lot of power and and don't mind detuning it at all. In fact I'm considering changing out cams to something with a little less power and idles just a little smoother.

Should I put the heavy springs back in, or just set the timing back a few degrees and try again? My 383 is supposed to be 10 to 1 comp and I'm running 93 octane. I also use Lucas upper cylinder lubricant. Any suggestions? I'll check my total timing tomorrow...

63mako

Seen this happen a lot with the KB hypers. Those are silvolite claimers but made by the same company. I and others have posted on this before. I wouldn't use them in my lawnmower. JMHO

Capella

Nothing wrong with KB Hypers when used in the right application. No piston likes detonation for very long - though forged pistons might put up with it for a bit longer.

On 93 pump gas you are going to have a tough time running much more than 9:1 in a SBC with a bunch of timing advance. Might get away with a bit more if alum heads - assuming correct valve timing is also used in either case. KB recommends no more than 34degrees total with a good quench.

MotorHead

Disconnect your vacuum advance and see if the pinging goes away. If it is already disconnected set your total mechanical advance to around 30 degrees @ 3000RPM and move it up till it pings then back it off a few degrees, don't worry about what it is at idle

cduemig

Ok so disconnecting the vacuum advance will take away about 10 -12 degrees timing, is that the reason you'd say to disconnect it? I've heard that when running in high rpm's for the gear and punching it causes detonation. This is what's happening and I'm assuming that being high in the gear would give me a really high vacuum so this would stop it temporarily, but I still want my vacuum advance connected right?

MotorHead

Just disconnect it and see if that fixes the problem. Yes it adds too much advance to motor that is on the edge. The vacuum advance was invented for fuel economy and emissions you don't need it in a high performance motor.

I know there are many members on the vacuum can bandwagon but I this is my opinion based on 35 years of playing around with this stuff. I run 11:1 cr and my cranking compression is 230psi across the board and I run 91 octane, I don't even need 94 so there must be something to what I say.

cduemig

I see someone was on the debate team I'll give that a try. If I disconnect my vacuum advance, you said to set mechanical at about 30? Where would I shoot for total timing? I'll try leaving off the vac advance and run as is, right now I have 15 degrees initial and centrifugal set around 21 degress for a total timing of 36 and including vac about 48. I need to verify though...

MotorHead

Mechanical is total timing, try it at 30 deg. first all in by 3000RPM then you can move it up from there if you want. You need to put a timing light on it and don't worry about where the timing lands at idle

cduemig

So leave the vacuum disconnected and set total timing (initial + centrifugal advance) to 30, then bump it up from there right? 30 degrees seems to be very little for full advance. Is that just a starting point to ensure no detonation, or is that ok to leave there. Isn't there adverse affects to having too little timing? Everyone is talking about 50 - 52 degrees timing w/ vac...

GrandSportC3

When I had my AR 383, I ran 38 degrees total timing and no vacuum advance.. Blocked off the vacuum advance on the distributor and carb. The engine wouldn't even idle below 1200 RPM with the vacuum advance connected.. Once I disconnected the vacuum advance, the engine would idle at 700 RPM.. My AR 383 was 9.8:1 compression with IRON heads..

tshort

I think you are misunderstanding total timing. Have someone help you and rev the engine up to about 3K rpm and set the timing to 30. From there you can continue trying 2 degrees until you get any pinging and then back it back down 2.