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My 302 has no power, Help!


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I don't consider myself an expert, i'm a senior in high school and this is my first car. I have what I consider to be a good amount of knowledge compared to the people I know, but I don't know many car people. I just wish when I ordered everything from summit they would of asked if it was an HO or not but oh well, live and learn. Thanks for all the help and I should have it running by the weekend.

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ummm.. i would pull the cam and put in a HO cam.. the non-HO cam is a flat lifter cam.. it is not nearly agressive (lobe ramp rates) as the HO cam.. will it work w/ the non HO? yes, if you change the fireing order.

 

BTW.. i have two custom ground HO cams for sale if interested

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The cam doesn't need to be changed but the firing order needs to match the cam. The so called HO(pre roller lifter) used a 351W firing order vs the standard motor which used the earlier 289/302 firing order.Either cam can be used if the firing order matches.Post the part number of the cam and maybe the firing order can be determined.

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The Cam is meant for an HO engine, and the engine I have is a non HO engine. Since the firing order is different, I have been assuming that the crank and order the pistons would come up would be different. The firing order for the cam is 13726548. I dont understand how just simply changing the plugs would make the engine run, and when I tried, it wouldn't start and just backfired through the carb. Can someone please explain this to me. Thanks

 

Brad

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The Cam is meant for an HO engine, and the engine I have is a non HO engine. Since the firing order is different, I have been assuming that the crank and order the pistons would come up would be different. The firing order for the cam is 13726548. I dont understand how just simply changing the plugs would make the engine run, and when I tried, it wouldn't start and just backfired through the carb. Can someone please explain this to me. Thanks

 

Brad

 

DO NOT USE THAT CAM.. if its lobe ramp is designed for a roller lifter it is probably to agressive for a flat tappet.. youl probably wipe the lobes sending metal into the motor.. if it does run youll get valve float at rpm's and drop a valve on top of a piston..

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The later 5.0 roller motors had standard and H.O. cams just as the earlier pre roller motors. If your motor is a roller then you can run either a standard or H.O.firing order cam but must use roller lifters on a roller cam or flat tappet lifters on a flat tappet cam. If the motor has a roller H.O. type cam and roller lifters then it should have the firing order you listed(1-3-7-2-6-5-4-8) Take off the passenger side valve cover and crank the motor over until both the exhaust and intake valves are closed on cylinder number 1. Make sure the timing marks are about 10* and set the distributor rotor towards number one of the distributor cap.The distributor might have to be removed and reinstalled in the correct position. Route the plug wires per the firing order remembering the distributor rotates counterclockwise. It may be confusing but both firing orders can be used with the same crank as the cam dictates the firing order.

 

If you installed a roller cam and used flat tappet lifters then both the cam and lifters must now be changed.

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I used a roller cam with roller lifters, atleast I got that much right lol. Could I have put the cam in upside down? I am gonna pull the cam and re install with help from a family friend who owns three shops in the bay area so he will make sure I do it right. Hopefull this time it will be right.

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I used a roller cam with roller lifters, atleast I got that much right lol. Could I have put the cam in upside down? I am gonna pull the cam and re install with help from a family friend who owns three shops in the bay area so he will make sure I do it right. Hopefull this time it will be right.

 

If by "upsidedown" you mean the cam sprocket dot was pointing up ,not down to align with the crank sprocket dot, then yeah you could have installed it upsidedown. If that was the case my guess is there are a bunch of bent valves. Check that the distributor is installed correctly and the firing order right before pulling it apart to check the cam timing.Maybe you'll get lucky.

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It is a hydraulic roller engine, so does that mean that it is an HO? I keep getting confused, sorry.

I had the same problem the none ho cam will work perfect as well all you have to do is use flat tappet lifters and longer push rods, and the non ho firing order.

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The '83 302 HO in my 240Z has a flat tappet cam. '85 and newer 302 (5.0) HOs came with a roller cam as did some other non HO motors.

 

302ho240z

 

soooooooooo, to NOT confuse the issue.. lets call the H.O. motor a Hydro Roller motor... due to the fact that MOST people consider the HO motor to be the motor out of the 87-95.. sure the 85-86 motor was an anemic 4bbl single exhaust HO buttttt when people pull a motor from a junk yead there not pulling a pre 8x motor and trying to put a roller cam in it.. hell the lifters wout work w/o tie bars..

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soooooooooo, to NOT confuse the issue.. lets call the H.O. motor a Hydro Roller motor... due to the fact that MOST people consider the HO motor to be the motor out of the 87-95.. sure the 85-86 motor was an anemic 4bbl single exhaust HO buttttt when people pull a motor from a junk yead there not pulling a pre 8x motor and trying to put a roller cam in it.. hell the lifters wout work w/o tie bars..

 

Actually it would be the norm to differentiate the 302's as roller or non roller and leave "HO" out of it. The earlier non factory roller motors can be converted to roller cams using a retrofit reduced base circle cam which uses stock type roller lifters,dog bones and spider retainer.Link bar lifters could be used also but are more pricey.Today,the '85 and up roller motors are readily available and cheap to buy but this wasn't always the case.The yard sale 302 in my 240z has a non factory solid flat tappet cam,aftermarket aluminium heads,aftermarket intake etc and really doesn't share much with it's "HO" origin other than the basic block and rotating assembly.It will run away and hide from a factory roller HO motor.

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Got the problem fixed! This is going to make me sound like an idiot but, the cam was off by 3 teeth. When my dad and I were putting the motor together, he was teaching me how to make sure the cam was in the right spot, well he failed that lol. It could of been a lot worse though. I got it all fixed and running tonight, got the timing at 12 degrees, we let the motor warm up and we were adjusting the idle. After about 15 minutes I turn it off and as I am switching the key off the radiator hose comes apart. Coolant all over the garage and I have 2 dogs, so cleaning that up took me a while. The reason the hose came apart is because I had to piece together the hoses because the inlets and outlets are on the opposite side of the radiator. I accidently ordered a radiator for a chevy and when I realized it, I couldnt send it back. So I was wondering if there was anywhere that I could get some pre-made hoses that would work or is there any special way to do this?

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congrats on getting it running,,

 

for the radiator hose.. the cheapest way would be... get a coat hanger and open it up.. bend the shape you need and take it to the auto parts store.. see if you can find 1 or 2 to match.. you can also get 2 hoses that march what you need.. cut and couple them together.

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a small tip, if the upper opening of the radiator is at the driver side, then use an L28 lower hose from a 1977 280z, you have to cut it a bit to fit but it works good, i spent alot of time to figure out what hose to use, then i found an old lower hose from my old engine, tryed to fit it as is, i wasn't able, so i cut few inches out of it and looks like it was made for the 302 swap :)

DSC00209.jpg

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I matched 2 radiator hoses together, and I used copper couplings to connect them but the bottom didn't hold. I can't find copper piping with a large enough diameter to work, so I used couplings, but they are only about 2 or 3 inches long.

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