Fuel Filter

[7783911]

I ordered a fuel filter from the host and upon receipt noticed it to be larger than the previous. The new one is MAHLE and the original is BOSCH

Question: Does the size of the fuel filter make any difference to the setup, if it does I will find the bosch version and sell the MAHLE for a pittance or give to my porsche shop and they can use where appropriate

my guess its for an 83 engine which I have but the car is a 77 Targa so the fuel supply plumbing wasnt changed during the engine swap done by PO

Thanks

Bob

[boyt911sc]

Bob,

Please identify the specific model # of the fuel filters. Simply saying Mahle and Bosch filters is too vague. There are several models available for these filter brands with different inlet/outlet fitting threads. People won’t know which one you have. Thanks.

Tony

[BoxsterGT]

Show us the filter. Most are universal in filter capability, the difference is the body diameter and with the fittings.

Early production filters were 12mm threads, later have 14mm threads....





AND, most all fittings are Loctite-ed to the filter body. Almost impossible to remove unless heated (when totally dry) with a propane torch to break the loctite bond.

Len

[7783911]

MAHLE KL 21 is the new bigger one

filter


BOSCH 0 450 905 014 is the 2 year old one




size difference





My concern with the larger filter is will that affect fuel pressure setting..everything is dialed in perfect with the older filter which only has 2 years use/5K miles


Maybe just reuse the old one until i get a matching Bosch?

ps: I am able to get the fittings off of the old filter to re-install on the new..would that require any sealant if i go that route?

[BoxsterGT]

No difference in flow capacity. Use whatever will fit.

If the fittings match you are good to go. If not, swap them, but do not forget to use a new Copper Crush Ring.

Porsche had to comply with the 5 yr/50k miles emission regs that included all fuel components, thus the increase in filter size.

Len

[7783911]

Thanks for confirming

Other than fit should be easy..but also have new larger accumulator so have to adjust both placements so s pipe matches

getting a quote from local porsche dealer re bosch 014...should be interesting to see what they charge :-)

I have many new copper crush washers in my parts bins..so no worries there...goes between fuel line ends and the filter fitting, none need for fitting to filter but perhaps some thread sealant? (suggestions welcome)

Thanks

Bob

[BoxsterGT]

Copper crush ring goes between the Fitting and Filter body.

Thread sealant in place of the Loctite should be OK, but NOT on the fittings.

Fittings are "Flare" or "Ball & Cone", good for 150 psi plus.

A SC mount to hold larger Accumulator & Filter is about $100 from Porsche. I had to buy one recently.

I do have an extra J Pipe for a SC if needed. Don't know of any fitment differences.

Len

[Flojo]

BOSCH 0 450 905 014 vs MAHLE KL 21

I have a 79 SC with new implanted former Carrera engine.
I wanted to have the filter of the Carrera system, though the SC/Bosch worked fine so far.

I just switched the lower Bosch fitting to the Mahle bottom.
Job done



Downside though: the wider Mahle doesn’t fit into the filter console for the narrower Bosch.
I’ll make up something

[Flojo]

Originally Posted by BoxsterGT

A SC mount to hold larger Accumulator & Filter is about $100 from Porsche.

Guess that’s the one(?).
Also not sure if the 3 bolt pattern matches the existing bores in the bay sidewall.
Must check

[PeteKz]

Flojo, the SC bracket above does not match the holes in the inner fender for 77 and earlier cars. BTDT. Not sure about the 78-79. I know the filters changed about then (check the Pelican online catalog). I decided to use adel clamps (with the rubber inserts) to grip the top and bottom of the J pipe, and I just screwed one of those to the inner frame rail below the J pipe, and to the inner fender up where it joins the package shelf. Simple and cheap, and seems very secure. Plus I can adapt just about any filter to work.

The picture of the bracket above shows the orientation of the studs that go into the inner fender. Check yours carefully.

[Flojo]

I will, thanks

[83_Silberpfeil]

Thought I'd add/contribute to this discussion/thread. I just swapped the fuel filter for my 83 SC.

The Part: Mahle K22
Went with Mahle K22 --- I think it was a few dollars cheaper
The unit is ~ 75 mm dia. I compared to unit I took out made by Mann - it is a few mm's wider in dia, and also noticeably lengthier. But overall fitment dims and fitting sizes all worked out w no issues. So happy camper here.



The Swap Job:
Access was fairly tight. I had to remove the air duct. Then, removed to top of filter to fuel line fitting. Two 19 mm wrenches working against each other.
Then, loosened the hose clamp holding the filter.
Then, removed the bottom of filter to fuel line fitting. This time, a 19 mm and a 17 mm (or was it 13 mm) working against each other. NOTE: this is when the residual fuel in the filter started to flow out. Did my best to contain/soak, then wipe up what was spilled.
Q: fair to say that in a few days (SoCal 55 F weather) the spilled fuel will evaporate? Would appreciate thoughts here.

Then, installed new filter. As they say --- reverse the steps.
Lesson Learned here:
1) For the fuel line that connect into top of filter, make sure to move/place it so that it can move freely and able to position and fit w filter. I didn't do this and installed the bottom fitting, only to find the other fuel line stuck behind filter. So had to remove, adjust and redo.
2) The hose clamp needs to tuck under the fixture/lip behind the filter --- didn't pay attention then realized the clamp needed to be secured to something. So, another redo here.

Old Mann Filter


New Mahle K22



I had budgeted entire afternoon to do this, but completed in ~ 90 minutes. So took time to take a peek inside the old Mann filter. A hack saw, a large clamp, and ~ 15 min of elbow grease go the aluminum shell apart.

I didn't see/find any rust metal bits. Any bits visible here are from the aluminum shell. Don't know what else to look for but am curious about the color of the filter and that wrapping strip. Is the original filter white fibers, or is the brown the original color? Would be quite worrisome if all that brown is rust.