Glowing Exhaust manifold

Can’t log in? Having a problem with the Forums? Have a question about how something works? Get support here.
Forum rules
If you need help logging in, or have question about how something works, use the Support forum located here Support Forum
Complete set of Forum Rules Forum Rules

Topic author

Glowing Exhaust manifold

Post by flitejoc » Fri Aug 07, 2020 12:53 pm

I changed my 1915 model t over to a Z head. It began to knock on first start up. I shut her down as this happened on a friends 1925 Roadster on first start up. 2 identical start ups, 1 week apart. The exhaust manifold glowed between 2 and 3 cylinders. I changed her back to the original head and fired her up. No knock but the same glow occurred between 2 and 3 cylinders. I adjusted the mixture between lean and rich and settled on 1/2 way between; the remained. Any suggestions for a fix. Mark J

User avatar

Mark Nunn
Posts: 402
Joined: Mon Jan 07, 2019 8:01 am
First Name: Mark
Last Name: Nunn
Location: Bennington, NE
MTFCA Number: 50321
Board Member Since: 2017

Re: Glowing Exhaust manifold

Post by Mark Nunn » Fri Aug 07, 2020 1:17 pm

When you installed the Z head, did you test the head by putting it on without a gasket and with loose bolts to check for interference between the pistons and head? Hand cranking would reveal interference by lifting the head slightly. There could be interference especially if your engine block has been decked and/or if your block has a large overbore. If that is a problem the combustion chambers can be ground for clearance.

I can't help from here with the glowing manifold. Are you certain that it was not glowing before the change? You may have an exhaust gasket leak.

FYI, if you post this question in the general discussion forum will get you many more responses and advice.

User avatar

Mark Gregush
Posts: 2565
Joined: Sat Jan 05, 2019 1:57 pm
First Name: Mark
Last Name: Gregush
Location: Portland Or
Board Member Since: 1999

Re: Glowing Exhaust manifold

Post by Mark Gregush » Mon Sep 28, 2020 10:50 pm

Copy and repost on the general forum, this section is for problems with the site not car questions.

Last bumped by Anonymous on Mon Sep 28, 2020 10:50 pm.
I know the voices aren't real but damn they have some good ideas! :shock:

1921 Huckster
1925 Cut down pickup

Post Reply Previous topicNext topic