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Rebuilt 360 has no power
I just rebuilt my 1970 360FE. I put in new bearings of course, rings, clevite stock cam, lifters and pushrods, I got it running without any problems but when I go to drive it it has no power. I put an Offenhauser port o sonic single plane intake on it and a holley 600 cfm mechanical secondary carb. All of the spark plug wires are where they need to be. im runing a rebuilt distributor with the ignitor setup along with a 40,000 colt accel coil. My brother says its becuase of the intake but I cant see how that can be becuase when I get it up to the rpm range when the intake makes power it still acts the same. Anyone have any ideas?
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Did you check your timing with a light at 2500 RPM?
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No I only used a timing light at idle like I always do. Is there an advantage at using the light at 2500?
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Yes
If the advance in the distributor is screwed up, you would never know it. Total advance at 2500 RPM should be somewhere around 35 degrees. You said the distributor was rebuilt ... but from your description, I think the distributor advance is screwed up. |
At higher rpm that would verify if the mechanical advance is working. You are only checking 'base' timing at idle speed. It's also possible your cam is retarded or advanced in relation to the crankshaft. Major restriction on the exhaust pipe(s), ie collapsed internally, plugged up in some way?
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I ported the exhaust side of the heads. I have headers and 2 1/2" exhaust with boxed mufflers. When I put the timing chain on I double checked that the marks lined up. Im also running an adjustable vacuum advance diaphram. I tried hooking the vacuum hose at the base of the carb instead of on the side and it only made it worse. I have a stiff spring and a light spring in the mechanical advance. Should I run two stiff springs? or maybe adjust my vacuum diaphram?
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1-Check your timming
2-check compression 3-Does your camshaft fit with your intake? The 360 is not known as being a big power motor. They were good truck motors . I have Ford service manuals that cover specs on the 360 and 390fe motors. |
Vacuum advance comes into ONLY at light throttle or idle conditions, it will have virtually no impact on 'power'. Interesting that it made the engine run worse when hooked up (btw, I recommend direct intake manifold vacumm for that advance). Making the idle worse indicates you have plenty of "base" advance, so thats good. As long as you get decent MECHANICAL advance at around 2500 rpm or so thats enough to give you good power. I would NOT worry about 'tuning' the springs and 'dialing in' the distributor yet. I might even leave the vacuum advance disconnected for now.
IF indeed the motor DOES lack power (a very relative term) you have a problem bigger than 'tuning'. Valve lash to tight? Like MadDog suggested, 360 weren't great 'power' motors so maybe your expecting to much? A friend of mine has a 352 in his '64 Galaxie and complains of a 'lack of power', compared to his brothers 390 in a '64 Galaxie. He says he's tried everything, 4:11 rear gear, bigger carb, timing\tuning, etc. Well, it's a 352, it aint gonna make power like a 390 no matter what! |
I actually have already swapped out the set of pushrods I put in my motor when I put it together. The first set I used were 9.62" long which are .030" longer than what is supposed to be in my motor. So I put a set of 9.59" long one in it which are the right length . When I had my heads serviced .015" was removed from the valves and the seats and im not sure if the valve stems were trimed doown to compensate what was taken away from the valves and seats. So if thats the case I will have to get a set of 9.56" long pushrods to make everything work together. My intake makes power from 2500-6500 RPM and im runing a stock cam.
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Hmmm, what is a 'stock cam'? For the 360 truck application that would be a cam that makes a lot of TORQUE at a low rpm. I would guess a stock 360 cam makes it's power in the 1500 to 3000 range and at 4000 to 4500 it's 'done'. This could be a bad match between cam and intake.
Solid or hydraulic lifters? |
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I just got done mesing with my motor and I went to make 35 degrees on my balancer and I noticed that I marked the 6 degrees the wrong way. So I marked 6 degrees BTC and got it timed and drove it and that was my problem. I know 360s arent powerhouses. Many people have asked me why are you messing with a 360 they are only junk. I didnt build my 360 to be "race worthy" I built it to be a nice clean runing motor. I thank everyone who has put input into my problem. Is there any tuning tricks for FE's?
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360'S only came with 2bbl carbs. With a stock cam the 600 mechanical secondary carb may be a bit much.
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360’s have very low compression if built as stock; static is something like 8:1. The pistons are way down in the hole and the stock cam has minimum lift and little duration. They were designed for trucks to pull hard at low rpms and get reasonable fuel economy at speed... It would certainly be a disappointment in a car.
If you change the cam to a more aggressive pattern it may get worse because your dynamic compression will fall off even more. |
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