P79 head mod

[Reptoid Overlords]

 

So I fired this thing up and got a good test drive in our fine Washington rain today. All in all I'm pretty happy with it. The .080 head mod makes a pretty noticable difference. I must say however, that my original engine was pretty worn out, so any improvement must seem major to me.

 

I'm running the same transmission and differential that came out of the '82 that the engine came from.

 

I had removed the dash weeks ago to replace the heater hoses through the firewall, and in replacing the dash, I must've gone and knocked my temp gauge in just the right way to make it peg all the way to the top indicating total meltdown in the dash. But the meat thermometer in the radiator indicates 180deg after a 20 min drive. It feels normal if you touch the valve cover and I can see circulation too so I feel pretty good about it. The gauge read high ever since I've owned the car.

 

The only leak is a small drip from the heater hose coupler that runs along the passenger side of the engine. Easy fix.

 

I ended up running the stock flywheel, and MSA's headers and 2 1/2" exhaust. Drives and sounds good.

 

So I guess this mod works well for anyone looking to do it.

 

Now I can tear down the original motor haha.

 

 

Edit: I didn't notice any pre ignition detonation. I'll be keeping an ear out as my drives get longer. With 3k RPM cruising and 4k rpm shits I hope I don't get any. I have a tank of premium fuel in right now.

 

 

 

 

[Captain Obvious]

Awesome!  Glad it's running well.

I'm a long way behind you, but I hope mine turns out as well!

[Reptoid Overlords]

It has about 18 miles on it at this point. Tomorrow after work I'm going to recheck valve lash. Will I need to check valve lash more frequently until it has a few hundred more miles on it, or will I be okay to resume normal check/adjustment intervals after I check and reset tomorrow?

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[siteunseen]

I rechecked mine after the initial "run in", about 150 miles of varying speeds to set the rings then again at 500 miles. Haven't touched them sense. I really need to do that soon too.

Glad it all came together for you. Congratulations.

[siteunseen]

22 hours ago, Reptoid Overlords said:

 

So I fired this thing up and got a good test drive in our fine Washington rain today. All in all I'm pretty happy with it. The .080 head mod makes a pretty noticable difference. I must say however, that my original engine was pretty worn out, so any improvement must seem major to me.

 

I'm running the same transmission and differential that came out of the '82 that the engine came from.

 

I had removed the dash weeks ago to replace the heater hoses through the firewall, and in replacing the dash, I must've gone and knocked my temp gauge in just the right way to make it peg all the way to the top indicating total meltdown in the dash. But the meat thermometer in the radiator indicates 180deg after a 20 min drive. It feels normal if you touch the valve cover and I can see circulation too so I feel pretty good about it. The gauge read high ever since I've owned the car.

 

The only leak is a small drip from the heater hose coupler that runs along the passenger side of the engine. Easy fix.

 

I ended up running the stock flywheel, and MSA's headers and 2 1/2" exhaust. Drives and sounds good.

 

So I guess this mod works well for anyone looking to do it.

 

Now I can tear down the original motor haha.

 

 

Edit: I didn't notice any pre ignition detonation. I'll be keeping an ear out as my drives get longer. With 3k RPM cruising and 4k rpm shits I hope I don't get any. I have a tank of premium fuel in right now.

 

 

 

 

I apologize for being lazy but are using the stock cam and EFI on your car?

I'm wanting to pep up my 280 now after reading all you guys build threads.  I've got the stuff and the car runs great but I'm bored...

[Reptoid Overlords]

I apologize for being lazy but are using the stock cam and EFI on your car? I'm wanting to pep up my 280 now after reading all you guys build threads.  I've got the stuff and the car runs great but I'm bored...

 

Yes. I'm totally using stock EFI and stock cam. I'm using my 1980 throttle body so I can have the idle air adjustment screw(1982 screw is not on the throttle body) . I have also deleted the CSV and warming plate and all EGR equipment. It starts and runs fine in our current 55 degree temps.

 

 

 

 

 

 

[siteunseen]

Good to know!  Thank you.

I've got an N42 combo, head and block with dished pistons and some F54 flat top pistons I could put in the N42 block. I was worried about running pump gas but after watching what you did I'm not too worried about swapping out the pistons. I have some later 240 rods I'd like to use. I've read they do something better than the L28s?

[Jeff G 78]

51 minutes ago, siteunseen said:

Good to know!  Thank you.

I've got an N42 combo, head and block with dished pistons and some F54 flat top pistons I could put in the N42 block. I was worried about running pump gas but after watching what you did I'm not too worried about swapping out the pistons. I have some later 240 rods I'd like to use. I've read they do something better than the L28s?

Cliff, my street engine is a N47 with flat top pistons and it does fine on 93 pump gas.  I did the rheostat mod to add some fuel, but otherwise, it's stock EFI and cam.  I run a AZC 6-1 header on that car.  Slap the flat top pistons in with the N42 and call it a day.  Just make sure the head hasn't been milled at all.  Even a shallow clean-up cut will put you over 10:1 and it won't like pump gas.

[siteunseen]

Thanks Jeff!

I have a "volume knob" fix on my CTS. Louder=more fuel. I can flood it out.

2 things to do this winter when it's too cold out. Oh wait. I forgot about the 99 other things I punted on this summer when it was too hot. I'm getting old.

 

[Reptoid Overlords]

I took it out on the freeway for about 15 miles and got on it a little bit.  The performance increase is pretty noticeable, but I also noticed a bit of detonation under a bit of a load(I only took it to 4k rpm) on a slight incline at around 60MPH@ roughly 3kRPM.  It went away after a few seconds.  I'd guess it would be worse if i lugged the engine.  I'll have to get used to finessing the throttle to avoid it.  Maybe a bit less of a shave would prevent it.  Haven't run a compression check yet, but it sure wants to do evil stuff haha. 

[madkaw]

So what dizzy are you running and what’s your timing?

[Reptoid Overlords]

My original 1980 distributor, with ignition timing set to 10 deg.

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