I'm servicing a Kent iron cylinder head, question -
What are the "normal" bolt thread sizes for the intake, exhaust manifolds and thermostat housing?
I can't remember the specifics and what I'm seeing doesn't seem right.
Steve
I'm servicing a Kent iron cylinder head, question -
What are the "normal" bolt thread sizes for the intake, exhaust manifolds and thermostat housing?
I can't remember the specifics and what I'm seeing doesn't seem right.
Steve
As I recall, 5/16" UNC
Yup
Roland Johnson
San Diego, Ca
As original, all those threads are 5/16 UNC. M7 is very unusual, especially in these circumstances as it's smaller than 5/16 (which is very close to 8mm).
A common 'bodge' on this side of the pond is M8 in 5/16unf, because as well as the similar diameters, the thread pitch of the two is very similar.
I really can't think of any reason for M7?
I’ve serviced a couple of Kent heads before, and from what I remember, the intake and exhaust manifolds usually take M8 x 1.25 bolts. The thermostat housing should also be M8, but honestly, it can sometimes be a little different depending on the year or if someone replaced them before. I’d double-check the threads and lengths, especially if what you’re seeing feels off—sometimes people swap bolts around over the years.
Nope, 5/16 UNC
Stephen Adams
RF92 Van Diemen FFord
1980 Lola T540 FFord
So the best I can figure is a M7 X 1 helicoil almost fits in a 5/16-18 buggered hole and they had M7X1 stuff on hand. Only 3 of the 6 exhaust bolts holes where done this way and a M7 X 1 will tighten in a 5/16-18 hole. I was able to drill out/tap those 3 holes for 5/16-18 helicoils and repair the others so I'm good.
I've been doing this long enough to see some amazingly strange fixes that defy logic and marginal mechanical skills.
Steve
I found this single hand made M10X1.50 flat head "screw" holding the oil pump on the engine of my DB2. Apparently made from an 8.8 M10X1.50 hex bolt. When the only tool you have is a grinder you have to make do.
I went to the local Ace Hardware and bought 2 proper bolts for $4.
Steve
There are currently 8 users browsing this thread. (0 members and 8 guests)