Post by superflytnt on Aug 15, 2011 13:09:23 GMT -6
Hello fellow wrenchers,
Beforehand I would like to apologize for this long thread;) I have a peculiar issue with the 413cui I am currently running in my 68 Plymouth Satellite. For some reason the engine will become harder to rev up past the 2500rpm and will hardly go past 3000rpm. Here are the specs for the drivetrain:
- Chrysler 413 truck engine (thick wall 426 casting), 71 casting, standard bore, 10:1 cast pistons, new rings, balanced rotating assembly including balancer and 11 inch flywheel, 300mls since rebuild.
- Open chamber 452 heads, standard valve size
- Edelbrock 600cfm on Holley Street Dominator, 7547 size rods, 0.100" jets (one step up from standard 0.098").
- TRW TP203 hydraulic camshaft 280°/298° duration, .443"/.465" lift (in/ex)
- Standard waterpump, standard dual field alternator
- HP exhaust manifolds dumping into 2,5" dia. exhaust
- Electronic ignition w/ new regulator and orange box ECU, 16° initial advance.
- 26" standard radiator.
- A-833 manual transmission with new Centerforce dual friction clutch
- 8 3/4 rear with 3.55 gears and 31" dia. tires.
With the new MP distributor I bought in the first place I could barely reach 2200rpm at WOT. I noticed that the new Mopar distributor would not give more than 5 degrees mechanical on top of the initial advance, even after adjusting advance weights to full advance (Mallory type advance). Also, vacuum canister was inoperable.
Then I changed out the distributor for a rebuilt 'older' type with the 'radial' slots for the advance weights. Mechanical advance on this unit was 16 degrees and the vacuum canister works (non-adjustable). Now I can drive 2800 rpm at part throttle (about 70mph), but the engine has a very hard time accelerating any faster than this up to 3000 and then it stays there. Overtaking another vehicle is going painstakingly slow...
I checked the ingition cables; 5 had about 20000ohms resistance. I changed out these 5 with new cables from an incomplete set and that helped some, but the acceleration rate of the engine still decreases after 2500rpm. From idle up to 2500rpm it runs fine. It is like the distributor just stops advancing or is actually retarding the timing or it may be fuel related...
I am now thinking towards a fuel related problem (carb too small, fuel pump pushrod worn, clogged fuel filter), but without having a distributor from a known good running engine I cannot rule out an ignition problem. It is hard to start after, say, a stop at a gas station, but that may be due to the aluminium intake and carb soaking up heat from the engine (I have a 0.5" phenolic spacer installed underneath carb). I changed out the standard jets in the carb for the 0.100" jets, but I have not run the engine yet.
What are your thoughts on this?
Thanks in advance.
Beforehand I would like to apologize for this long thread;) I have a peculiar issue with the 413cui I am currently running in my 68 Plymouth Satellite. For some reason the engine will become harder to rev up past the 2500rpm and will hardly go past 3000rpm. Here are the specs for the drivetrain:
- Chrysler 413 truck engine (thick wall 426 casting), 71 casting, standard bore, 10:1 cast pistons, new rings, balanced rotating assembly including balancer and 11 inch flywheel, 300mls since rebuild.
- Open chamber 452 heads, standard valve size
- Edelbrock 600cfm on Holley Street Dominator, 7547 size rods, 0.100" jets (one step up from standard 0.098").
- TRW TP203 hydraulic camshaft 280°/298° duration, .443"/.465" lift (in/ex)
- Standard waterpump, standard dual field alternator
- HP exhaust manifolds dumping into 2,5" dia. exhaust
- Electronic ignition w/ new regulator and orange box ECU, 16° initial advance.
- 26" standard radiator.
- A-833 manual transmission with new Centerforce dual friction clutch
- 8 3/4 rear with 3.55 gears and 31" dia. tires.
With the new MP distributor I bought in the first place I could barely reach 2200rpm at WOT. I noticed that the new Mopar distributor would not give more than 5 degrees mechanical on top of the initial advance, even after adjusting advance weights to full advance (Mallory type advance). Also, vacuum canister was inoperable.
Then I changed out the distributor for a rebuilt 'older' type with the 'radial' slots for the advance weights. Mechanical advance on this unit was 16 degrees and the vacuum canister works (non-adjustable). Now I can drive 2800 rpm at part throttle (about 70mph), but the engine has a very hard time accelerating any faster than this up to 3000 and then it stays there. Overtaking another vehicle is going painstakingly slow...
I checked the ingition cables; 5 had about 20000ohms resistance. I changed out these 5 with new cables from an incomplete set and that helped some, but the acceleration rate of the engine still decreases after 2500rpm. From idle up to 2500rpm it runs fine. It is like the distributor just stops advancing or is actually retarding the timing or it may be fuel related...
I am now thinking towards a fuel related problem (carb too small, fuel pump pushrod worn, clogged fuel filter), but without having a distributor from a known good running engine I cannot rule out an ignition problem. It is hard to start after, say, a stop at a gas station, but that may be due to the aluminium intake and carb soaking up heat from the engine (I have a 0.5" phenolic spacer installed underneath carb). I changed out the standard jets in the carb for the 0.100" jets, but I have not run the engine yet.
What are your thoughts on this?
Thanks in advance.