Tuning for L35 heads.

[pinellas50]

Re: Tuning for L35 heads.

Yeah, I went back to stock heads. I knew I would be getting in way over my head with tuning. I'll be the first to admit it. If the problem is still there.......well at least I know the "platform" I am working with now.

I have only let it idle in the driveway and took a small little drive around the block. I haven't even tried to get into boost yet so I don't really have an answer as to what the difference is. I'm not sure what "normal" even is on this truck any more! Actually I never really ran it with the other heads. Nothing more than about 1/2 throttle and no more than 3K rpm. So I won't be able to answer that one.

I have the turbo hooked up but the ELECTRICAL connection unplugged so I can't go over 8 psi. I'm going to make sure everything is up to par before I do any real driving in it. I don't see myself even plugging the turbo back in for full boost until I get a wide band. Honestly, I don't think I am even going to try and "test" it at 8 psi until the wide band comes along. This thing has me all sorts of paranoid now after all this.

 

[pinellas50]

Re: Tuning for L35 heads.

OK. Code 42 is gone. No other codes present. I either had a bad connection at the distributor or ECM OR I caused the code to go off again after I reset the ECM the first time. Probably the latter.

I took it for a slightly extended drive tonight. Datamaster looks like everything is doing what it should. Except the IAT temps are showing very weird numbers. It was varying between -5 and 13 degrees. I don't know what's up with that!

I drove it normally and only tipped into mabey 2 lbs boost on my drive. No weird noises or sputtering. I found the plug wire on 2 arcing every now and then between the end of the plug and the heat shield so I'll probably throw another new set of wires at it. I'm sure I'll at least pull a sampling of the plugs while I'm in there. I know they won't tell me all that much from these limited runs but I'll be looking for the very obvious.

I'm still scraping up for that wide band so the answer to is this fixed probably is still a little ways off. I'll be sure to post the final result.

Thanks everyone for their help on this!

 

[pinellas50]

Re: Tuning for L35 heads.

So the motor let go again. Feels like it dropped at least 2 cylinders. I was taking a very light drive and tried to get it up into very slight boost. That's when it happened. No funny noises, just lost a cylinder or two.

I had datamaster running when this happened as it turns out. I was just monitoring, not recording of course. But I am dead certain there was no knock when it happened.

I guess I'll do a compression test on it. If the motor is done I think I will be too.

If it is done, is this thing going to be worth more as a roller or in parts? Seriously! I will loose sleep on this one tonight.

 

[Tooky]

Re: Tuning for L35 heads.

Man that's some of the worst luck I've seen in a while... even among SyTys. Really sorry to hear of it!! It sucks to see it go up for sale but I think anyone's limits would be tested with a rout of bad luck like this.. I give you a lot of credit for all the wrenching you put into it trying to solve this problem.

 

[pinellas50]

Re: Tuning for L35 heads.

If I didn't have bad luck I would have none at all. You see why I was scared of tuning myself?

The motor did't drink the coolant this time. I'm interested to see what the compression test says. It feels a lot like the head gasket went between cylinders. Like you had happen Tooky.

Yeah, this sucks. I really wanted to make this truck work out for me. I'm not normally one to give up but damn.

 

[Ty 1885]

Re: Tuning for L35 heads.

Hey, sorry to hear all the problems you are having. Did you check the block to make sure the deck is flat, checked the heads see if they are flat, did you reuse old head bolts, what did you torck your heads at ?

 

[pinellas50]

Re: Tuning for L35 heads.

I did the best I could with a straight edge. Made sure to scrape all the old gasket material off of course. The heads are fresh from the cylinder head shop and that included milling the deck. I reused my ARP head bolts. Torqued them to the value I kept finding in all the posts since I forgot what the ARP packaging said. 65 ft lb is what sticks out in my head but I don't remember for sure. Torqued them in the correct order.

When this first happened, it started in on the chug chug thing like it used to do right after a sputtering episode. Except this time it didn't clear up. Could my cylinders be fine and I really just found the culptit I have been chasing all this time? Not likely with my luck and all.

I hope to have the compression test done in a few days.

 

[Ty 1885]

Re: Tuning for L35 heads.

I can tell you that 65 ft lb is too low, that could blow a head gasket! 75-80 ft lb is correct, depands on the type of bolt sealer you are using.
Its hard to say what is cousing your problem without seen it. When i get stuck, i try to take a break few min to few days, or weeks to get a fresh start. If you keep at it, you will find the problem. Just walk away for a while.

 

[NecroWolf]

Re: Tuning for L35 heads.

i just did arps and 65ft-lb is the lowside if you use the arp lubricant. it was like 85 for 30 weight. sounds like you migt have done in a head gasket. if you can swap heads like that it shouldn't really be an issue then to fix

 

[Tooky]

Re: Tuning for L35 heads.

I followed the ARP directions with ARP's assembly lube and ARP's thread sealant, and they said 65 FT-LB. I also contacted ARP after I had a head gasket failure and they assured me that 65 was the correct spec, but said I could go up to 70 or 75 if I wanted, but that it shouldn't be necessary.

So where what are the sources for the "80-85" figures? (I'm talking about ARP Head Bolts, not studs.)

 

[pinellas50]

Re: Tuning for L35 heads.

There may be light at the end of this tunnel. All plugs had fuel on them. Here are the compression test results:

1= 165
2= See Below
3= 150
4= 150
5= 150
6= 150

I found the cylinder that was down. The plug from #4 was black and fouled. Not oily in any way. Fuel fouled as best I can tell. The compression for that cylinder was fine.

Here is what is weird. I tested #2 early on and only came up with 20 psi the first time. I tested it 2 or 3 times and kept coming up with 20. I then went on and finished all the cylinders. At the end I decided to retest #2 for whatever reason. On the second round I came up with 100 psi on 2 tests.

I am wondering if there may be a correlation between #2 being down on compression and #4 plug fouling. They share the same intake runners. Mabey it's a coincidence.

I think I need to go in and make sure I didn't mess up when I was setting valve lash. Mabey a vlave on #2 is hanging and blowing over into 4? Mabey a little far fetched but I wouldn't put anything past this truck at this point.

 

[pinellas50]

Re: Tuning for L35 heads.

I can tell you that 65 ft lb is too low, that could blow a head gasket! 75-80 ft lb is correct, depands on the type of bolt sealer you are using.
Its hard to say what is cousing your problem without seen it. When i get stuck, i try to take a break few min to few days, or weeks to get a fresh start. If you keep at it, you will find the problem. Just walk away for a while.

I remember now. 65 is the stock bolt values. I did mine to 75 based on what I was reading on ARP's in the threads.

And I am realizing that this has gone off on quite a tangent now. I won't post anything back in here except if the stock heads fixed my issue.

 

[Ty 1885]

Re: Tuning for L35 heads.

Please keep us posted. We like to teach and to learn from others. Did you open TB all the way when you did comp test ?

 

[pinellas50]

Re: Tuning for L35 heads.

Did you open TB all the way when you did comp test ?

Yes. It was zip tied open for the test on all cylinders. The rocker studs pulled out of the head on #2. I started yet another thread about it.

 

[NecroWolf]

Re: Tuning for L35 heads.

I followed the ARP directions with ARP's assembly lube and ARP's thread sealant, and they said 65 FT-LB. I also contacted ARP after I had a head gasket failure and they assured me that 65 was the correct spec, but said I could go up to 70 or 75 if I wanted, but that it shouldn't be necessary.

So where what are the sources for the "80-85" figures? (I'm talking about ARP Head Bolts, not studs.)

the higher value was listed on the insert i got with mine and was for use if 30w motor oil was used for lube instead of arp lube.



do you have a stuck valve on your number 2 cylinder or some other valvetrin problem there? lifter collapsed, pushrod bent, etc?

 

[pinellas50]

Re: Tuning for L35 heads.

do you have a stuck valve on your number 2 cylinder or some other valvetrin problem there? lifter collapsed, pushrod bent, etc?

The push rods are straight.

Collapsed lifter...I don't think so. They were moving fine when I set lash the first time, there was no noise involved here, and oil pressure is fine. Or are you asking with the angle of the lifters are collapsed and that's why the rockers are flopping? The answer to that is absolutely not. You can easily see that these two studs are much higher than all the others. They weren't like that to begin with.

Stuck valve. It doesn't look like it. There's no way I had P/V interference with all stock parts. I still wanted to put air on that cylinder just to make absolutely sure but of course it appears that my air hose kit for this seems to be one of those things that got lent out and forgotten about. If both valves are sticking somewhere in their range of motion.....well I have no idea how to answer that without pulling the springs and what not. My assumption and educated guess is no.

 

[pinellas50]

Re: Tuning for L35 heads.

I just wanted to give a final update on this. I now have stock heads with pinned rocker studs back on the motor. Everything else is still stock except for the reliability mods I did like the Walboro.

The sputtering is gone and the thing runs strong like it used to. So, I come to no other conclusion than the L35 heads were the issue all along.

Now I know. And knowning is half the battle.

 

[4C FED]

Re: Tuning for L35 heads.

And you still have YOUR truck. Even if it was a painful exercise. :tup:

 

[Tooky]

Re: Tuning for L35 heads.

I just wanted to give a final update on this. I now have stock heads with pinned rocker studs back on the motor. Everything else is still stock except for the reliability mods I did like the Walboro.

The sputtering is gone and the thing runs strong like it used to. So, I come to no other conclusion than the L35 heads were the issue all along.

Now I know. And knowning is half the battle.

Wow, that's some serious persistence!! BIG thumbs up to you for sticking through it until you got to the very core of the problem! :tup::tup:

I get a lot of emails asking project build advice and lately I have been telling everyone with "daily driver" in mind, that once you upgrade from the stock: injectors, camshaft, or heads, the truck will not be a daily driver and WILL require a lot of custom tuning and tweaking to get it to run properly. There's no way around it, even if you follow the standard Vortec/412/50# recipe like a local friend of mine did, we still had to do a lot of chip tuning to the Ultimate Vortec/50# chip to get it to run properly at startup, idle, WOT, etc.