I'm done, stick a fork in me !

[jrust]

Here is a brief history. I bought this 3rd gen back in June to  use as a sometime driver. 400cu, bored to.30,  hughes camshaft lifters and adjustable pushrods, milled heads,  750 dp, summit 3" exhaust, 2500 stall. This is a rebuilt motor from the receipts I have.
This is what I'm done since then: MSD plug & play dist., 6al box, new 750 DP, NGK plugs, indexed the balancer, hv carter fuel pump, 5 core radiator, Doug's headers w/ TTI x-pipe w/ 2-1/2 exhaust system, hv water pump.
I've have gotten advice from Ron on timing and the carb adjustment which I applied to this car and this afternoon I gave it another try and this what happened.  After a full warmup, vacuum around 12*, idle screws out to 1-1/4 out, 850 rpm, timing out around 13-15*. I was running the throttle back and forth and again the damn thing backfired again, it went to 1200 rpm and wouldn't come down, after 30 seconds  the # 7 tube was RED hot so I shut it down. After this I saw that the hose on the PVC valve had been blown off.  I need some help here becasuse I'm at a point to trash this bad boy and suck the $$$$$$$ I've already made and get another motor.

[chargerman68]

dont let it get to u.if u were reading any of the help wont start i have been go on a no start motor for months..hang in here she will be worth it

[Purple440]

Do a forum search, you'll find threads on "backfire", if you haven't already.  I know what you mean about sticking a fork in it, I've been there.  Keep at it!

[jrust]

Hi Guys,  I have reseach about all the treads here & there and I come up with the same sernio.  I sit in the garage here going o

[charger Downunder]

I would say running lean turn idle screws out to two turns and try it.

[jrust]

Hi guys,  I sit here in the garage thinking about all the scenarios and it just don't add up. I 've yet  see a pipe that hot which means alto of fuel burning after the spark. I own several powerstokes with the" programmers"  and they dont get this hot.

[aifilaw]

a specific cylinder got red hot.....
have you pulled a valve cover and checked the valve geometry on that specific one...

if not, perhaps you have a clogged venturi out of the 4 on the carb which is causing one corner of the engine to run lean and produce that result.

[firefighter3931]

If it's running hot the motor is either lean or the timing is retarded. Disable the vacuum advance if you're still using it. Retime it using a vacuum guage for max idle vacuum and see if it still runs hot. The problem with stock dampners is that the outer ring can sometimes slip which throws the timing #'s off. The only way to verify this is to index the balancer.

The backfire could be timing or an incorrect power valve.

How do the plugs look ? What kind of color are You seeing ?


Is this isolated to one cylinder ? Do you have access to an infrared heat gun ?



Ron


Ps. I looked at the hughes cam specs on your stick....it should be easy to tune. That's a pretty mild cam.