fuel filter question

[Dvldog8793]

Howdy
My 1986 Military blazer at some point had the original fuel filter removed and the large round filter installed from the earlier models. It did not have both filters installed, just the one on the firewall.

Is this sufficient? or should I replace it with a racor or back to the block type?

Thanks!

[DmaxMaverick]

What you have now may be fine, and may be OEM. There are 2 types of "military" blazers: CUCV (Mil-Spec) or stateside civilian fleet (same as other local vehicles). Most CUCV models were equipped with a (standardized) round filter, while the SCF vehicles would be equipped with the FM-80 filter (square). There were variations of them, but I don't know what specific year models were affected.

Updating (upgrading) to a modern Racor filter assembly wouldn't be a bad call, in any case. Common filter availability and initial cost would be favorable. I do not recommend using the FM-80 system.

[Dvldog8793]

Thanks Dmax.
This unit is definitely done after the fact. May have been a service mod that came out at some time.
All the CUCV that I worked on in the Corps were FM80. But we are pretty small compared to the other branches, and we tend to make as many things the same as possible. I have never seen the round firewall filter used by itself before....?
Thanks again

[joeq]

When I bought my truck, many years ago, the primary filter was missing. My father-in-law talked me into replacing it, stating how dirty diesel fuel is. An ex employee I used to work with, had this set-up, and gave it to me. I liked the fact it has a glass lens, so I can monitor the fuel in the system, and it has come in handy over the years. I thought it would be an expensive element, and be hard to procure, but found out it's very common and still available at Car Quest under P/N 86370. It's quick to change due to the spring loading clamp, and I think it runs less than 20 bucks. All you need to do is find the mount. Someone told me once they're used on tractors. Here's a pic.
http://i1206.photobucket.com/albums/bb453/tajoe/filter_zpsa1iec0we.jpg (http://s1206.photobucket.com/user/tajoe/media/filter_zpsa1iec0we.jpg.html)
just another option for anyone interested.

[DmaxMaverick]

I remember it different, but then, it's been 30 or so years.

In any case, a single good filter will be OK, whichever you choose. The FM-80 filter heads are getting hard to find, if you can at all. A Racor head that uses common filters would be my preference. For a MN truck, I'd opt for one with a heater. Also, many of them will have a priming pump, which will save a lot of starter life after a filter service (or any other reason the system was opened).