Problems and solutions for my 64 365/327 engine
05-30-2011, 01:59 PM
#1
Racer
Thread Starter
Problems and solutions for my 64 365/327 engine
My 64 365/327 has always had hard starting and hot starting problems. The idle quality left a lot to be desired and the low end torque was pitiful. The exhaust was always rich with excess fuel. With the addition of air conditioning the problems became acute. The hotter the air temp, the more fuel percolation problems and starting problems. The max rpm I could get was about 4600. I am running a TKO 500, five speed with 336 rear end gears and 26.5 inch tires. Stock rams horns, 2-1/2 exhaust system, heat riser valve blocked open. The carb list is 2818-1. The engine temp stayed around 180°F with the DeWitts radiator on very hot days.
I am running an Engle EPH25 high rpm hydraulic cam. (valve lift, w/1.5 rockers, .494/.494, duration 282°/282°, duration @ .050 236°/236°, lobe center 110°)
The pistons are flat top, de-burred, with valve reliefs. The engine is balanced. The block is decked. Deck height is zero or very close. The heads are ported, milled and cc'd to 64 cc's. I think the head gasket was around .040 thick. A compression check showed around 175 psi +/- 5 psi. At 900 rpm I have 9-10 inches of vacuum. Compression ration is about 10:1.
I added a MSD ignition but saw no improvement. These have worked well in the past on my other cars. I went through the distributor, setup the advance to factory specs with the correct vacuum can, stock springs and weights. I added a Pertronics point replacement unit. I checked the timing advance curve with an adjustable timing light and checked the plug parade with an CRT ignition analyzer. Note with the MSD you could see three distinct spark cycles at idle vs. one for the standard ignition. I replaced the nylon bushing on the advance limiting pin. The distributor has new bushings and the run out is nil. Plugs, wires, cap and rotor are new. Plugs are AC 44, gaped to .035.
I tried different valve lash adjustments thinking the valves were hanging open at higher rpms. After rebuilding the carb twice with little improvement, then replacing it with a new one with the same problems I decided to seek help from a pro.
The gentlemen shall remain unnamed but I can say he is a very successful drag racer and builds the odd pro touring car. His shop is equipped with all the tools for engine building including a pair of Sun engine analyzers and a Sun distributor machine. I brought the car to his shop and we put it on the Sun engine analyzer. We got a nice spark parade but the total advance was well over 50 degrees. We then pulled the distributor and the fun began. He pulled the distributor shaft out and welded the pin slot. He then filed it to get the profile he deemed correct. We put it back together and and retested it on the Sun distributor machine. He repeated filing and adjusting the springs, weights until he had a very smooth 40° advance curve. Note the stock weights are much better quality then the after market parts. We ended up with stock chevy springs. He also notched the vacuum can so it can be moved to adjust the position. Nice trick here. We still were getting some spark wobble at higher rpms. He called a friend who said the model Pertronics unit I had was junk. It is the unit that senses off the cam lobes. I then went and bought the type with the ring and magnets that screws to the bottom side of the rotor. In the distributor machine the new unit worked perfectly with no wobble up to 7000 rpm. We then installed distributor back on the car but we still couldn't get it to run right. Note it was about 90°F.
The Sun engine machine now said we had 40° advance at 3100 rpm and was advancing smoothly. The pro said the intake manifold and carburetor are to hot. He recommended we block off the exhaust ports to the intake manifold. This I avoided doing, but he said the carb got to hot to touch and that was causing a lot of my problems. He said they work fine on cast iron manifolds but the aluminum conducts the heat so well the carb boils. So I agreed and the next day we pulled the intake manifold off. At that time we inspected the cam and lifters and re-adjusted the valves. The valves were all in good adjustment, so I had gotten that part right. He fabricated some stainless pieces and siliconed them in place. I run the blue Felpro gaskets. Note he tossed the rubber valley seals and just used black silicone to seal the manifold to the valley.
Next was the carburetor rebuild. He dismantled it completely, including drilling out the brass plugs in the vacuum galleries. This I have never done. He inspected everything under magnification. He showed me were we had some leakage and weeping. The new power valve I installed was leaking even though the diaphragm was intact. He then drilled and tapped a couple of the vacuum galleries in the metering bodies and screwed in some very small brass orifices. He then proceeded to drill these out to his specifications. Next he took the main body and the throttle body and jig milled them flat. We ended up taking off .006 inch off the main body ends and .005 off the throttle body. He then de-burred the machined areas. He then dyed all the zymac metal back to it's original color. He also epoxied the plug on the secondary fuel bowl which was weeping. Next he opened up the vacuum bleed holes in the venturis. It was a very small amount. Next he worked on the secondary vacuum diaphragm assembly. He opened up the feed to the diaphragm and changed the spring. He glued the diaphragm to the housing. He then rebuilt the accelerator pump and housing. It to had been leaking a little, not noticeable to the naked eye but under magnification you could see it. He flatted the housing and reinstalled the diaphragm. He fabricated a new fuel feed tube from the primary to the secondaries out of aluminum tube with special end seals that don't leak. No more o rings for me. He then went to work on the float/valve assemblies. He makes his own floats that have better leverage and spring damping characteristics. This gives better fuel feed to the carb and maintains a more uniform fuel level. He uses stock Holley float valves. These can handle up to 15 psi fuel pressure. The key here is the fuel level stays uniform so the fuel feed is consistent. Every step took time. Patience is key here. Every part was washed and blown clear with air.
Next he put the carb on 350 hp engine he uses just for testing carburetors. He adjusted, the idle mixture, the accelerator pump, choke, linkage, floats, etc. until he was satisfied with the performance. That took about 10 minutes.
I then installed it back on the engine, added back the coolant, connected the hoses, retimed the distributor, and set the idle.
The first thing you notice is the car starts instantly. No need to pump the accelerator. Just turn the key. The idle can be set as low as 550 rpm but with the air I have it set at 850. On acceleration the car is smooth and pulls steady to the 6000 redline. It will pull in fifth gear from 1100 rpm up. You are lugging the engine but there is no stutter or backfiring. The car is an absolute joy to drive now. In the 45 years I have owned this car it has never been so enjoyable to drive. My hat's off to the pro.
I am running an Engle EPH25 high rpm hydraulic cam. (valve lift, w/1.5 rockers, .494/.494, duration 282°/282°, duration @ .050 236°/236°, lobe center 110°)
The pistons are flat top, de-burred, with valve reliefs. The engine is balanced. The block is decked. Deck height is zero or very close. The heads are ported, milled and cc'd to 64 cc's. I think the head gasket was around .040 thick. A compression check showed around 175 psi +/- 5 psi. At 900 rpm I have 9-10 inches of vacuum. Compression ration is about 10:1.
I added a MSD ignition but saw no improvement. These have worked well in the past on my other cars. I went through the distributor, setup the advance to factory specs with the correct vacuum can, stock springs and weights. I added a Pertronics point replacement unit. I checked the timing advance curve with an adjustable timing light and checked the plug parade with an CRT ignition analyzer. Note with the MSD you could see three distinct spark cycles at idle vs. one for the standard ignition. I replaced the nylon bushing on the advance limiting pin. The distributor has new bushings and the run out is nil. Plugs, wires, cap and rotor are new. Plugs are AC 44, gaped to .035.
I tried different valve lash adjustments thinking the valves were hanging open at higher rpms. After rebuilding the carb twice with little improvement, then replacing it with a new one with the same problems I decided to seek help from a pro.
The gentlemen shall remain unnamed but I can say he is a very successful drag racer and builds the odd pro touring car. His shop is equipped with all the tools for engine building including a pair of Sun engine analyzers and a Sun distributor machine. I brought the car to his shop and we put it on the Sun engine analyzer. We got a nice spark parade but the total advance was well over 50 degrees. We then pulled the distributor and the fun began. He pulled the distributor shaft out and welded the pin slot. He then filed it to get the profile he deemed correct. We put it back together and and retested it on the Sun distributor machine. He repeated filing and adjusting the springs, weights until he had a very smooth 40° advance curve. Note the stock weights are much better quality then the after market parts. We ended up with stock chevy springs. He also notched the vacuum can so it can be moved to adjust the position. Nice trick here. We still were getting some spark wobble at higher rpms. He called a friend who said the model Pertronics unit I had was junk. It is the unit that senses off the cam lobes. I then went and bought the type with the ring and magnets that screws to the bottom side of the rotor. In the distributor machine the new unit worked perfectly with no wobble up to 7000 rpm. We then installed distributor back on the car but we still couldn't get it to run right. Note it was about 90°F.
The Sun engine machine now said we had 40° advance at 3100 rpm and was advancing smoothly. The pro said the intake manifold and carburetor are to hot. He recommended we block off the exhaust ports to the intake manifold. This I avoided doing, but he said the carb got to hot to touch and that was causing a lot of my problems. He said they work fine on cast iron manifolds but the aluminum conducts the heat so well the carb boils. So I agreed and the next day we pulled the intake manifold off. At that time we inspected the cam and lifters and re-adjusted the valves. The valves were all in good adjustment, so I had gotten that part right. He fabricated some stainless pieces and siliconed them in place. I run the blue Felpro gaskets. Note he tossed the rubber valley seals and just used black silicone to seal the manifold to the valley.
Next was the carburetor rebuild. He dismantled it completely, including drilling out the brass plugs in the vacuum galleries. This I have never done. He inspected everything under magnification. He showed me were we had some leakage and weeping. The new power valve I installed was leaking even though the diaphragm was intact. He then drilled and tapped a couple of the vacuum galleries in the metering bodies and screwed in some very small brass orifices. He then proceeded to drill these out to his specifications. Next he took the main body and the throttle body and jig milled them flat. We ended up taking off .006 inch off the main body ends and .005 off the throttle body. He then de-burred the machined areas. He then dyed all the zymac metal back to it's original color. He also epoxied the plug on the secondary fuel bowl which was weeping. Next he opened up the vacuum bleed holes in the venturis. It was a very small amount. Next he worked on the secondary vacuum diaphragm assembly. He opened up the feed to the diaphragm and changed the spring. He glued the diaphragm to the housing. He then rebuilt the accelerator pump and housing. It to had been leaking a little, not noticeable to the naked eye but under magnification you could see it. He flatted the housing and reinstalled the diaphragm. He fabricated a new fuel feed tube from the primary to the secondaries out of aluminum tube with special end seals that don't leak. No more o rings for me. He then went to work on the float/valve assemblies. He makes his own floats that have better leverage and spring damping characteristics. This gives better fuel feed to the carb and maintains a more uniform fuel level. He uses stock Holley float valves. These can handle up to 15 psi fuel pressure. The key here is the fuel level stays uniform so the fuel feed is consistent. Every step took time. Patience is key here. Every part was washed and blown clear with air.
Next he put the carb on 350 hp engine he uses just for testing carburetors. He adjusted, the idle mixture, the accelerator pump, choke, linkage, floats, etc. until he was satisfied with the performance. That took about 10 minutes.
I then installed it back on the engine, added back the coolant, connected the hoses, retimed the distributor, and set the idle.
The first thing you notice is the car starts instantly. No need to pump the accelerator. Just turn the key. The idle can be set as low as 550 rpm but with the air I have it set at 850. On acceleration the car is smooth and pulls steady to the 6000 redline. It will pull in fifth gear from 1100 rpm up. You are lugging the engine but there is no stutter or backfiring. The car is an absolute joy to drive now. In the 45 years I have owned this car it has never been so enjoyable to drive. My hat's off to the pro.
Drive it like you stole it !
05-31-2011, 12:19 PM
#4
Le Mans Master
A true pro like that should have his name and shop listed for others to tap.
Nice write up with great information.
I am curious why he took your distributor to 40 degree's, history has told me to limit to 36-37 degree max not counting vacuum advance.
Glad it is finally purring for you.
Nice write up with great information.
I am curious why he took your distributor to 40 degree's, history has told me to limit to 36-37 degree max not counting vacuum advance.
Glad it is finally purring for you.
05-31-2011, 12:34 PM
#5
Melting Slicks
Thanks for the very interesting write up. I blocked off my exhaust X-over on the intake about 2 years ago..... best move I ever made. The only drawback was, I did not like the exhaust sound. I stopped by a muffler shop and had a H pipe installed a little behind the tranny cross member, to tie the exhaust back together again. The exhaust now sounds great, and I think I picked up a couple of extra ponies with the H pipe.
