new engine problem

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mod38-1

mod38-1

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Just put together a 408 and got it broke in. Problem is when I went to set timing it will not run with less than 40 degrees of initial timing with vacuum advance unhooked. If you try to turn it down it will just die or wants to backfire through carb. Cam was degreed when it was installed,tdc mark on balancer is correct,tried another distributer and also double checked to make sure dist drive shaft is installed correctly. Any ideas?
 
heres one: the timming tape is installed correctly??or is it scribed on the balancer?
 
Try setting the total timing. Not initial. Maybe the springs in the dist. are real loose so it's advancing as soon as it starts up giving you the impression initial timing is 40 degrees.

BTW: I have yet to have one that'll start with more than 22~23 degrees initial timing. They start kicking back on the starter about then.
 
Are you certain the firing order is correct? All 8 holes are firing? Take cylinder pressure readings from it. Tell us more about what it is.
 
It is a 360 .030 over,eagle crank,rods,kb pistons step dished and milled to a acheive a quench of .035,J heads ported,cam is a comp 20-231-4. The marks on balancer are stamped not a tape. It always starts good,does not diesel when shut off and has around 12 in vac at idle. As far as total timing I just checked it and here is something strange,if I set total to 36 than base is also 36. If I set base to 40 than total is 40 with vacuum advance unhooked. I tried 2 distributors with same results. Poss module? is orange box now. This is being checked with both a normal and advace timing light with same results.
 
sounds like the timing is locked in the dist. if you have a vacuum pump hook it up and see with the cap off if the plate moves.
 
Have tried 2 diff dist with same results
 
pump drive gear has no bearing on timing...as long as the wires are on the cap in the proper order
 
mod38-1 said:
Have tried 2 diff dist with same results
Click to expand...

Were both distributors new or used? If used it's possible they both have the timing locked out or somebody tried to re-curve them and put both light springs in them that the advance curve kit comes with. Your only supposed to install one light spring or the timing will advance as soon as it starts and that's what it sounds like might be happening.
 
Thanks for the replies,the one dist I have had since new (MP performance kit) and the other one I took out of a engine I had sitting around. I am going to try a diff module tomorrow and try cleaning all grounds because since engine was just put in,maybe there is too much paint on stuff causing a ground issue?
 
If the timing does not come back to initial(base timing) then the distributors are an issue. Take the cap off and loko down thru the advance plate... Do the wieghts move when you rotate the distributor? Can you take a pick and move them a little and they spring back? Are the springs (both of them) in place?
 
In both distributors weights move and rotor springs back,one (mp performace one) has the light springs and the other distributor is out of a stock 318 and has heavier springs in it. If I use a vacuum pump on the actuator it moves and goes back like it should in both distributors. A person I work with has a demon with the mopar electronic conversion kit in it and it does exactly the same thing,his is set at what light shows 51 degrees of timing at idle (950 rpm) with vacuum unhooked and his also does not change at 3000 rpm. He has been driving his car for a few years like this without any problems as he just sets his timing off vacuum. I just wanted to compare his to mine as I am out of ideas. I also did some online searching and this concern comes up quite a bit in diff forums but with no reason as too why? I am checking with 2 different timing lights one without advance and can not even find mark with that one and one with advance and it has to be dialed up that high to find mark.
 
Strange... I've had a few distributors and none did that unless there was something wrong with them, i.e. the springs were too light or the weights were stuck.
 
He determined he had the wrong timing cover on his engine (marks on the wrong side) so that's why his timing was reading way off.
 
fishy68 said:
Try setting the total timing. Not initial. Maybe the springs in the dist. are real loose so it's advancing as soon as it starts up giving you the impression initial timing is 40 degrees.

BTW: I have yet to have one that'll start with more than 22~23 degrees initial timing. They start kicking back on the starter about then.
Click to expand...

My Duster started up with 30 degrees initial, it was idling with what read to be 50 degrees initial with the vacuum advance hooked up!
 
Weird... i have seen the weights hang "out" on idles above 900 before with the MP or Mr Gasket light sping in place of the stock heavy. It doesnt bug me because I set my idle speeds below that anyway. I would verify TDC on the balancer with a TDC tool, then verify the oil pump drive is in properly. Something's fishy..
 
fishy68 said:
He determined he had the wrong timing cover on his engine (marks on the wrong side) so that's why his timing was reading way off.
Click to expand...
I read it as that is not the problem becuase when he checked,mark on balancer was at 0 on timing cover when piston was at tdc
redfastback said:
What side of your timing cover is the timing tab on?
Click to expand...
Timing tab is on drivers side of cover and balancer is a new summit internal balance one and I verified when piston is at tdc the 0 mark on balancer is lined up with 0 on timing tab
moper said:
Weird... i have seen the weights hang "out" on idles above 900 before with the MP or Mr Gasket light sping in place of the stock heavy. It doesnt bug me because I set my idle speeds below that anyway. I would verify TDC on the balancer with a TDC tool, then verify the oil pump drive is in properly. Something's fishy..
Click to expand...
I have verified mark on balancer and mark on cover is correct. It should not matter but I tried the oil pump gear one tooth over in both directions and it does not change anything except the way the dist housing is pointed. With the timing set where it is (40 degrees initial) it does not start hard,diesel when shut off and after it is at oper temp you can just reach in through door and car will start just fine.
 
sounds like a non issue. i,d run it a while and pull and read the plugs for any potential problem. i wonder if the m/p unit is a multiple spark like msd and has a long duration of spark therefore starting earlier.
 
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