383 timming issues

[Gator]

ok here it is got my 383 put together and can only set total timming at 24deg at 2000 or it wants to run hot . I installed a new mopar performance dist made sure cam was timed dot to dot on crank installed new E3 spark plugs am running 93 octane gas . Build is as follows 383 bored 040 kb 400 domed pistons comp cam 280h 452 heads new eddy 750 carb alum high flow water pump and housing new mopar dual plane intake manifold new hooker headers new summit 3000 stall converter with rebuilt tci trans i havent drove car yet as unsure what to do build was recomended by a friend but friend bailed after getting parts been asking questions and some have said defective distributor others say i need racing fuel cause comp is too high with cast heads not enough fuel through carb needs bigger jets needs alim heads so i have no idea which way to go this was built for my over buget project so funds are really getting limited now any help would be apreciated

 

[bonzoro]

total timing

Total timing seems too low, probably should be near 34-36. Do you run a vacuum advance? What proceedure did you use to install the distributor?

 

[Gator]

dont have the vacum advance hooked up . while piston was at top dead center with marks on timing chain lined up rotated engine till marks lined up again and installed dist with pointer to number one plug wire installed timming cover . I can get timming up to 34 degrees but when i adjust it to 34 the headers glow and it runs hot in about a minute

 

[burntorange70]

What is the CR? Have you tried dropping bigger jets in it?

 

[Gator]

the comp is a around 10.6 based on head 79 cc;s for the 452 head . Head cc is really unkown as this wasnt checked. i do know that the heads were surfaced dont think much was taken off .. no i havent tried to rejet the carb yet but i did buy the reprogramer kit for my eddy carb along with a dist recurve kit . will watch video that came with carb and do jets. thanks for your input

 

[bonzoro]

At what RPM are you setting the total timing? You should be at about 34 when RPM's are roughly about 2000. Vacuum Advance should be plugged. Drop it back down to Idle and HOOK UP THE VACUUM ADVANCE. Unless you are racing, a street car NEEDS a vacuum advance, I dont care what anybody says. You tool around town and are most times below 2000 rpm's.

 

[burntorange70]

May be worth doing a compression test and seeing what the cylinder presser is.

 

[71383bee]

the comp is a around 10.6 based on head 79 cc;s for the 452 head . Head cc is really unkown as this wasnt checked. i do know that the heads were surfaced dont think much was taken off .. no i havent tried to rejet the carb yet but i did buy the reprogramer kit for my eddy carb along with a dist recurve kit . will watch video that came with carb and do jets. thanks for your input

There is NO way that a set of 452 open chamber heads has a cc of 79 unless massive decking was done which means the intake face would have had to been modified too. 383's are notoriously over advertised on compression and need considerable deck work to make right. The online calculators are almost worthless because of the assumptions they make. Believe it or not but 383's are hard to get compression out of due to the lousy piston selection, low octane fuel, and everyone's obsession with boat anchor open chamber heads.

Closed chamber 516 or 915 heads are around 80 to 84 cc so again there is NO way a 452 is 79. You probably are suffering from what I had on my first 383 build with giant 906 heads and kb162 pistons. car would not hold a tune and ran like garbage. Turned out it was running at 7.9:1 CR!

With the 2nd rebuild it took a set of worked 516's, and 0.020 on the deck to just get 9.2:1.

I agree your timing is way too low. What exactly was done to the heads and deck? I would not be surprised if its running below 8.3:1 CR.

Sorry to be hard about it, but I have walked this waltz with the 383 a couple times now. They are great engines and can run real good, but need some areas of special attention to work well. It took 2 rebuilds on one of mine to get it right...

 

[Gator]

ok pulled a plug and spun engine over with throttle wide open and engine hot compression gauge shows 125 psi . installed a new temp gauge ran engine and after a few minutes it shows 230. was going to install a new mopar dist but when i compared it to the origional i noticed slot for rotor was in a different orentation so i just reinstalled the first mopar dist. ran engine again at 2000 set timming to 34 degrees with advance not plugged to carb . engine shot up to 230 backed timming to 24 and engine cooled back to 190. adjusted carb to point where engine speed incresed ran engine at 2000 shut engine off pulled spark plug and looked at it looks like its a little rich .. its brown looking . closed everything up went in the house ready to give up on this project looking for a good mopar mechanic to take it to and let them fight with this thing could have bought a dynoed crate motor ready to go for what ive spent and been riding by now with no probblems oooh well just so frustrating .. did find out that the rings on the kb pistons i installed needed to have alot more gap as when they heat up and expand they wont close completely and pull the tops off of the pistons .... what i was told at summit when asking questions .. sounds like build number two is going to be a disaster too ... ok so now that ive blown off some steam . maybe have the radiator checked but previous build didnt run hot so im inclined to think the radiator is ok . didnt try and jet carb yet maybe tomarrow if its not snowing .. just dont think thats it cause the darknes on the plugs ..be glad to see summer .. hate cold weather wit no garage to get the car in

 

[Gator]

ok just had a brain storm went out and uncapped the headers and ran engine . found that engine is running normal temp now and have timming set at total 40 degrees with advance hooked up temp seems to stay normal . guess the exhaust system that was to be temporary was restricting the exhaust too much .... guess it will be a 2 1/2 new system when its road ready . ok so a case of the brain farts lol

 

[burntorange70]

You were strangling that motor. LOL Good to here you got it running better. I say you skip the 2 1/2 and go strait to 3 inch. Should be fine for now and give you room for upgrades latter.

What size was on it?

 

[Gator]

ok note taken on the heads was just going by what i had read as heads werent ccd. will know next time to cc heads so i know the true cc. have discovered that building a true performance motor is more than someone telling you to buy these pistons and this cam ect not knowing what works ... I looked for some budget builds on the internet before buying parts and kept asking my buddy questions and all i got was it will work . After the cam whiped out in the first build i know he sugested a smaller lobe cam which doesnt have the sound i was expecting so i guess ill just live with it Ive learned alot from building these motors and decided that its not worth the head aches or lost money to build a engine like this . Just wanted the pride in doing it on my car and have a bad a$$ sounding engine that would smoke the tires when i want it to . no one posts engine builds that work just that they have a 383 or 440 or small block . Its all a secret what is in the build so you have to use a builder that has had good success after trial and error to build the engine you dream of having the first time . I wanted the most horsepower i could get without doing a stroker wanted a engine that loped and let everyone know it was bad a$$. wanted a cam that lopped like a horse as big as i could get with power brakes . was planning on a 2 1/2 inch exhaust as my old system looked like maybe 1 7/8 pipe not very big at all . will 3 inch be too big and not supply enough back pressure and affect torque . Not really planning any other upgrades on my engine except for maybe a set of alumn heads later if the cam holds up and dont know what manufacturer or cc yet . but that could change into a crate engine later or a for sale sign in the window if this gets much more expensive . I thought i had a good plan on my project paint and body first engine and trans then interior , suspension and brakes but all failed every direction i took paint and body was explained to bodyshop no short cuts whatever it needs we will do ie lower qtrs on rear and new fenders or lower qtrs whatever it needs no rust but a pin hole or two in rear qtrs and fenders wanted show quality paint car has been painted twice now and paint isnt 6 months old and have bubles comming up where they fixed rear qtrs . Got a new tci trans and it had the wrong tailhousing. then built engine with buddy and it sounded great seemed to perform good till the cam wiped out and metal locked the engine down after wiping out the bearings after just about ten gallons of gas . then all the trouble i have had so far with the second build . not to mention all the parts i got off ebay that didnt fit because the seller didnt know what he was selling i have a set of rechromed bumpers for a cuda who knows what year that look decent but dont fit a challenger seller said oh well its been one thing after another had glass installed at a glass shop they leaked and with the limited time im home they were going to be closed the next day so i threw the car on a trailer strapped it down wit 2 straps and hit the road to the glass shop . well when i jumped on the interstate got up to about 80 felt something looked in the mirror and watched the car as it left the trailer . what a sight not to mention the feeling of watching the car spin around and slide sideways then down through the median towards the guard rail .. dont know how no one hit it or it didnt hit anything . seems like that was the best luck i had this whole project . lol what a experience this ride has been so far . Cant wait for the next chapter

 

[burntorange70]

Dang. If it was not for bad luck you would have no luck at all. LOL Hope things turn around for you.

 

[Cranky]

Bad luck? Two straps isn't bad luck but bad thinking. Never two strap a car to a trailer man....and yup, you had good luck in not destroying it.

Research is the key to any build especially if you don't have the experience. First off is the cam. So many do performance builds and then they line up the cam using the 'dot' method. That's not performance building. Degree the thing into the correct placement and then you know exactly where it's at. For all you know, it could be retarded or advanced by several degrees. Production tolerance can stack up against you or the 'dots' are not in the right place. A buddy that knows better decided to 'dot' align his new big cam and ended up bending ALL of his brand new 2.14 intake valves. Heck, I even degree in a stock cam.

Reading books is cool but seems like none of them have the correct cc for stock heads. What they do list is what is in the NHRA rule book as what is allowed for stock class racing. This info comes from when this stuff was new! I've checked a lot of heads over the years and have always found stock uncut open chamber heads to be right around 90cc and closed chamber heads are right around 80. That's a long ways from what the books say.

As for your exhaust being too small....yeah, it's too small for performance engines but it's fine at low rpm and I doubt it's why it's getting hot when it's idling. Too small exhaust will keep it from it's performance potential but won't affect it while running slow unless it's full of old potatoes....

Back pressure? I want proper flow with no back pressure. Too big of pipe allows the air flow to get lazy and tumble through the pipe which increases back pressure but the right size pipe can help scavenge your engine more efficiently. You don't want the engine to be working to push the exhaust out but you want the exhaust system to pull the exhaust out. This topic can get complicated. Google fluid dynamics and you'll see how deep this subject is. I think people use the term back pressure and really don't understand what it means and what they want from it.

There's a lot of info on the net about building performance engines...you just need to be able to find it and know good info from bad. It does take time to learn but it's there...