Urgent - Engine first run, glowing exhaust headers? [Archive]

View Full Version : Urgent - Engine first run, glowing exhaust headers?

feistl

02-04-2016, 09:57 PM

Hey guys,

Jumping ahead as i haven't updated my build thread, but need some advice ASAP.

After LOTS of minor issues i finally got the Chev 350 started today (well at 8pm after aiming for midday), but it wasn't all smooth sailing.

As you can see in the video below (sorry its a bit long and not always focused properly but i was trying to film and deal with a number of problems) after a minute or so the exhaust headers start glowing red hot.

Now i don't know exactly how many RPM the engine was doing (no tacho) but i estimate around 2500-3000rpm.

I have a couple of theroies as to why, but looking for input.

1. Not sure what the timing is, i tried to set it to roughly 12 degrees BTDC but haven't had a timing light on it yet.
2. The exhaust headers are stainless steel and were pretty cheap... Maybe not particularly thick?
3. I have put a balance pipe just below the collectors, maybe the back pressure is really high?

Now i only ran the engine for ~8 minutes before i turned it off (was concerned about the exhaust temp), is that likely to have stuffed the cam run in process? Everywhere i have read has said 20 minutes or more.

What should i do next? Try starting it again to finish the run in process and adjust the timing?

Cheers, Errol.

https://www.youtube.com/watch?v=jv6vLxIRJR0

EDIT - Also, seems the audio on the youtube encode are really shit. Ill upload a better version shortly...

IJ.

02-04-2016, 10:00 PM

How did you set the cam timing?

feistl

02-04-2016, 10:05 PM

0 Degrees?

We lined the adjustable sprocket (that goes on the crank) to 0 degrees, and then matched the two timing dots on each gear. I might have a pic of it somewhere...

Could that be the issue?

It seemed to run pretty well just seemed the exhaust got bloody hot (The engine itself didnt seem that hot though).

Thanks for the quick reply...

Jason01

02-04-2016, 10:09 PM

I helped a young bloke out I knew many years ago on a 400 Chev he had built for him and had a similar issue when we were trying to run a flat tappet cam in. From memory the ignition timing was retarded, when we put a timing light on it and advanced it the pipes stopped glowing.

Jason

feistl

02-04-2016, 10:30 PM

Thanks Jason,

That was actually my first gut feeling... That timing was so retarded that it was blowing most of the burning mixture out the exhaust before it had fully combusted.

Question is, would that have caused any damage to the heads/exhaust?

And as above, if you only half bed the cam in does that cause issues? Or should it be ok to finish off tomorrow....

Micks

03-04-2016, 05:45 AM

Yes a retarded motor will heat exhaust valves quickly, though you only ran it for 8mins so should be ok.

BLACKVE

03-04-2016, 06:37 AM

I started up my VE after lifter replacement etc and with engine light on(I assumed timing retarded) headers went orange. On re start with light gone all good.

Check your timing

IJ.

03-04-2016, 08:11 AM

feistl

03-04-2016, 09:12 AM

Jason01

03-04-2016, 09:27 AM

Sorry Feistl, I didn't check back last night.

Although stopping and starting is not ideal when trying to run the cam in, from memory a long time ago now I've had to do it and suffered no ill effects. I can't imagine running with the timing retarded for a short time would be too much to worry about either, I think as long as you give it some advance it should be good enough to get the cam run in.

Good luck, I hope it goes well for you today.

Jason

feistl

03-04-2016, 02:59 PM

Very quick update...

It works!.

Timing was out massively... At 3000rpm it was at 8 degrees (not 34-36 as recommended).

Adjusted the timing and the engine instantly ran better (EG as i advanced the timing the engine revs picked up even as i decreased the throttle).

Exhaust header temps came down and hovered around ~250-300 degrees (vs glowing red hot earlier).

Ran the cam in for a good 15 minutes (constantly fluctuating between 2500-3500rpm) and then set the idle. Sounds fantastic.

Ill post up a video later, going to try and finish a few more things this arvo.

Thanks everyone for your help, ive learned a lot about running a motor in.

pvk308

03-04-2016, 06:10 PM

Mate now drop the oil and check it for metal make sure you distributor is definitely locked down and then recheck your valve lash and rocker gear make sure they are adjusted properly and seating well before you do anything more........Nows the time to check or other wise things if and will going wrong in a big way

Jason01

03-04-2016, 08:56 PM

Glad it went well for you Feistl, :goodjob:, some good follow up info from PVK308 there for you as well just to check a few things before you go too much further.

Jason.

Micks

04-04-2016, 05:53 AM

Thanks guys,

going to try again shortly and adjust the timing.

apparently you want 32-38 degrees (ideally 34) at 3000rpm with the vacuum advance disconnected during run in....

http://www.onallcylinders.com/2014/11/13/engine-break-guide-10-tips-help-properly-break-engine/

cheers,

Glad you got it all sorted Errol, like mentioned don't be tempted to leave the dizzy clamp a bit loose as I know how awkward the bolt is to get to on these Chev/Holden blocks.

pvk308

04-04-2016, 08:14 AM

Yep leave that clamp loose and soon as you go to start the car the cam will spin the dizzy seen it happen on a few 5lts that are especially tight or have descent compression then its start all over again....Valve gear though is the big one I always used take the rocker covers off and dribble oil over them and down the push rods before start up for the first 1000km or so... pain in the ass I know but those first moments on start up until the engine gets oil pressure on a brand new motor are when the damage gets done doesn't hurt to keep things lubricated