Back after a long time/318 Guidance

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Demon_Dan

Demon_Dan

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Hey gang! Its been roughly 8 years since I've posted. I basically left off after my Demon's transmission exploded all over the road back in 2009. Since then, I bought a house and had a Son and never found the time or money to get the car moving again.. Well, Its currently in the shop getting a new transmission and should be back on the road sometime next week. I know asking a question like this is opening a can of worms , but Id like to see if anybody can figure out why my build turned out to be such a dog off the line... So much so that I cant even break the tires loose. Im going to post below, a picture of a stat sheet on my engine that my mechanic at the time printed out for me. Since this was made, I had to do away with the headers because they dragged too close to the ground and had been flattened , I have 340 manifolds on it now. I also bought an MSD Ignition for it to replace the Mopar one. Thanks, and I'ts great to be back!
IMG_20170726_145854_01.jpg
 
Gears and tire size also please.
 
Demon_Dan said:
Hey gang! Its been roughly 8 years since I've posted. I basically left off after my Demon's transmission exploded all over the road back in 2009. Since then, I bought a house and had a Son and never found the time or money to get the car moving again.. Well, Its currently in the shop getting a new transmission and should be back on the road sometime next week. I know asking a question like this is opening a can of worms , but Id like to see if anybody can figure out why my build turned out to be such a dog off the line... So much so that I cant even break the tires loose. Im going to post below, a picture of a stat sheet on my engine that my mechanic at the time printed out for me. Since this was made, I had to do away with the headers because they dragged too close to the ground and had been flattened , I have 340 manifolds on it now. I also bought an MSD Ignition for it to replace the Mopar one. Thanks, and I'ts great to be back!View attachment 1715080901
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Have you timed it, if so what is your timing?
 
dukeboy_318 said:
Have you timed it, if so what is your timing?
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I haven't played with the timing since the mechanic who installed the engine set it. These are all things I should learn for myself , but unfortunately my knowledge ends at playing with the timing until it " sounds right".
 
The thing that jumps out at me is the compression. Did you actually measure/calculate it yourself? The reason I ask is that it's mentioned that TRW flat tops were used with J-heads. If you take a flat top and install it at zero deck height, assume a 0.041" head gasket with a 4.100 bore (since most are made for 340/360)...it takes a 62cc head to get to 10.47 to 1...which a J-head is not. J-heads tend to run 68-72cc. Also, most flat tops have valve reliefs of some kind...and I know my Wiseco's are 5cc's. If you have 5cc cut outs in yours, then you now need a 57cc head to get to 10.47 compression. I don't think you can cut that much out of a J-head.

The set of J-heads I have measure at 69cc. Using THIS volume plus the above numbers, you're looking at 9.1 to 1 compression. That's a bit on the low side for the cam in the engine. I'd DOUBLE check the compression as a starting point.
 
1966DDart said:
The thing that jumps out at me is the compression. Did you actually measure/calculate it yourself? The reason I ask is that it's mentioned that TRW flat tops were used with J-heads. If you take a flat top and install it at zero deck height, assume a 0.041" head gasket with a 4.100 bore (since most are made for 340/360)...it takes a 62cc head to get to 10.47 to 1...which a J-head is not. J-heads tend to run 68-72cc. Also, most flat tops have valve reliefs of some kind...and I know my Wiseco's are 5cc's. If you have 5cc cut outs in yours, then you now need a 57cc head to get to 10.47 compression. I don't think you can cut that much out of a J-head.

The set of J-heads I have measure at 69cc. Using THIS volume plus the above numbers, you're looking at 9.1 to 1 compression. That's a bit on the low side for the cam in the engine. I'd DOUBLE check the compression as a starting point.
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To add to the above, some of the old TRW forged pistons were nowhere near zero deck height. They were well down in the hole. So perhaps even lower CR.

OP, measure your cranking compression on all 8 cylinders with the throttle propped wide open and let us know what you get; then we'll know better what you have for compression ratio.
 
1966DDart said:
The thing that jumps out at me is the compression. Did you actually measure/calculate it yourself? The reason I ask is that it's mentioned that TRW flat tops were used with J-heads. If you take a flat top and install it at zero deck height, assume a 0.041" head gasket with a 4.100 bore (since most are made for 340/360)...it takes a 62cc head to get to 10.47 to 1...which a J-head is not. J-heads tend to run 68-72cc. Also, most flat tops have valve reliefs of some kind...and I know my Wiseco's are 5cc's. If you have 5cc cut outs in yours, then you now need a 57cc head to get to 10.47 compression. I don't think you can cut that much out of a J-head.

The set of J-heads I have measure at 69cc. Using THIS volume plus the above numbers, you're looking at 9.1 to 1 compression. That's a bit on the low side for the cam in the engine. I'd DOUBLE check the compression as a starting point.
Click to expand...



And....we have a winner. That CR jumped out like a turd in a punch bowl. Unless that piston is .050 out of the bore and the head is cut .080 it's not near 10.5:1.

That doesn't help you any, the low CR.
The exhaust manifolds don't help you either.
You may need a 3.91 gear.
And a 3500 converter to make it move.
 
I would first try to get the timing curve dialed in and see where it is with a good tune up...
 
Ill be honest, if it comes down to spending a ton of money on this engine or having to upgrade too much around it, It may be worth it to just buy a mildly built 360 and call it a day. I'm not looking to race the car. I'm looking to cruise around in it , sound good doing it and occasionally smash the gas to blow my skirt up a little. I have a feeling that despite my mechanics best intentions ,his lack of knowledge made this engine a mistake from the word go.
 
Demon_Dan said:
Ill be honest, if it comes down to spending a ton of money on this engine or having to upgrade too much around it, It may be worth it to just buy a mildly built 360 and call it a day. I'm not looking to race the car. I'm looking to cruise around in it , sound good doing it and occasionally smash the gas to blow my skirt up a little. I have a feeling that despite my mechanics best intentions ,his lack of knowledge made this engine a mistake from the word go.
Click to expand...

It doesn't sound like a bad combo...

You'd be surprised how a good timing curve can wake it up...

Dial it in and see where you are...
 
Nothing wrong with a 318 done right, we used to get 500hp out of a Chevy 305. Of course this was with injection and menthol but that only accounted for about 75 hp. We could also do no head work, you bought them and bolted them on. I ran the club so we had to check every motor and seal them , that was 2010 sure there getting more now, 10 to 1 motor was max to.
 
The only flat top I'm aware of that TRW made for a 318 had a 1.759 compression height. I really doubt your compression ratio is anywhere close to 10.5-1 with the J heads.
 
Get yourself a timing light. Lots of good threads here about setting timing. Basically, you want the most initial you can get (around 20 give or take) and limit it to around 34-36 all in.
 
I ran a 318 with the old TRW forged 10.5 pistons... I put 400 k on that engine....
 
For what you want, you would probably be fine with a 340 cam or one around 268 duration. Are you sure your timing marks are really TDC? Did they degree the cam, since he said it was balanced and blueprinted. Chamber cc or piston numbers? Not really keen on the Performer manifold. Timing can be huge, and all it takes is a timing light.
 
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