Exhaust Header Temps?

Slowly, but surely, my build is coming along. I sound like a broken record, I know, but when you put a modern, fuel injected V6 into a '42 MB, things get tight.

Wires to the starter run closer to the header than I am comfortable with. I found a thermal sleeve from DEI that should work well to shield the heat. http://www.summitracing.com/parts/dei-010403/overview/

I have also noticed my spark plug wire boots will be damn near touching the headers. The same company makes some nice protectors, but they have different temperature ratings. For a stock, '99 Chevy V6 (4.3 Vortec) what continuous temperature can I expect on the outside of the headers about an inch away from the head itself? Want to place a Summit order and make sure I get the right ones.

 

Silicone plug wires should be good to 600 degrees or so as I have read.

 

Exactly. But I don't know if the headers will be hotter than that or not, and I dont have any other vehicles with headers on them I can fire up and get a reading

 

Sgt, when I put my block hugger headers in I wrapped the wires/cable with thermal wrap and also made a heat shield out of sheet metal. It has worked very well.

Pictures are on page two, near the top. V6 Block Hugger / DIY Exhaust

 

I stuffed a V6 in a MB back in 1972. My biggest worry was keeping it away from my brother so he wouldn't return it with the starter stuffed full of mud.
No headers, My Jeep guru said to not bother with headers as the stock system works fine. The guy built Pikes Peak hill climb vehicles and airplane motors. I trusted him and never had an overheating issue with stock parts.

 

On my Chevy v6, I use Taylor spark plug wires. The heat from the headers has not caused any issues. If you can wait a day or 2 I can measure the header temps. I'm in Cannon Beach, OR so can't do it now.

 

Wish I could. But with the 4.3 Vortec, there was no way on this earth the stock manifolds would work. I tried many options, and went through a total of 4 sets of headers before I found a pair that would let me keep the exhaust inside the frame rail and avoid fenderwell headers.

That would be great. I got the plug wires installed today. 2 are lightly touching the header, 2 are closer than I would like, and 2 look acceptable. No plans on firing this up anytime in the immediate future, so I can wait. I will order some sleeves for the 4 I don't like, just wondering what rating to order. They range from 500*-1800* rating, and are priced from $20/pair all the way up to $80 for a set of 8....

 

Got home earlier today and had a few minutes to get the temps. Warmed up the engine with a short drive. The header temperatures were measured about an inch down stream of the head exhaust port. Temperatures were in the 600* to 650*F range imideately after the drive and cooled to about 550* to 600*F range while sitting at idle.

 

I don't think it's uncommon for a header to reach "glowing" status under a long, heavy load, especially right at the first bend.

Faint red is 930*
Blood red is 1075*
Dark cherry is 1175*
Medium cherry is 1275*

 

That will cook your burritos!

 

those sparkplug wire insulation sleeves are rated for max contact heat and radiant heat. if they are going to touch the headers look for some with a contact rating around 700-800* at least. you can also change the boot and contact on the plug end of the wire to a strait, 45* angle, or 90* angle to help move the wire ayaw from the pipes.

 

That's the information I ma looking for. I already swapped one straight boot for a 90* and that helped...