DeTomaso Mailing List: May 1997, Message #62
     



From: Andy Poling <andy@realbig.com>

Subject: Re: Of Fuel and Ford Metalurgy

Date: Fri, 2 May 1997 01:19:30 -0400 (EDT)



(OK, so I apologized before I even sent this out.  If I only had a brain...)



Steve wrote:

> >  As for pulling an engine apart to put in hardened seats, don't do it

> unless things are coming apart anyway. It will be time and money spent

> better elsewhere. Like I say, we can thank Ford engineers for this probably

> unintentional foresight. (I've pulled apart 428's and 390's with 80K+ miles

> on them, and the cylinder walls have had from 0" to .002" taper (runnable

> for another 160K+!!), where a Chevy small block will require a ridge reamer,

> a rebore, and new pistons to get back in the game.)



On Thu, 1 May 1997, David Doddek wrote:

> I had a 69 302 that sucked 3 valves a 1/4 inch up into the head before I

> rebuilt it.  It only had about 20000 miles on it since the leadded gass was

> outlawed.  Ford heads will wear out without lead.



This is second-hand info, but my mechanic says that the "hardened layer" on

the heads as they came from Ford in the very early 70's was very thin (I

forget the actual depth he told me) and if/once you wore through it that was

that.  Like I said, it's second hand, so I don't know what it's worth.



I had hardened seats installed since the heads were already in the machine

shop (they have their own real machine shop on the premises).



Steve's comment about cylinder bore wear seems on the mark for my car.

Based upon the tiredness of the valve train (two valves had already been

(mis)replced and the guides were tired) we've upped the initial estimate of

mileage (non-original speedo) from 60k to something closer to 100k.  Yet the

cylinder bores look great!



I miss my baby while it's in the shop, but when I get it back there won't be

very much to go wrong with it.  The heads are basically good as new, the

timing chain is new and everything else checks out happy.  It's worth it for

the peace of mind...



-Andy



72 Pantera: power             91 Miata: quickness              96 A4Q: traction

84 RZ350: all the above