914-6 overheating PSA |
|
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG.
This site is not affiliated with Porsche in any way. Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners. |
|
914-6 overheating PSA |
mb911 |
May 31 2020, 07:25 PM
Post
#1
|
914 Guru Group: Members Posts: 6,854 Joined: 2-January 09 From: Burlington wi Member No.: 9,892 Region Association: Upper MidWest |
After being involved in porsche flat 6s for 20 years now and building 400 whp turbo engines this is my 1st go around with a overheating issue I couldn't put my finger on. I felt this would be very helpful for others building a 914-6 specifically.. The car in question is a 74 that last fall I put an unknown but healthy sounding 2.7 in for @jwinner . The car ran hot last fall on his drive home but ran well. We talked over the winter and decided at least under trunk oil cooler would be necessary as the car was running 250 on 50 degree day after getting off of a 20 minute highway run. We had also talked about how the engine mount as designed sits lower then I prefer as there are no way to seal the engine tins to the chassis because of the mount positioning.. That was the 1st issue that really could not be resolved easily. The second issue was we had no idea if the carbs were set correctly or the timing..
So last week happens and he brings the car down. I remove the oil tank and discover one of the porsche fittings has a crack in it but no worries going all AN fittings on this with the oil cooler.. Then put a new used engine oil cooler on (what a bitch in the car with an amber 1 piece shroud) . I button everything up after a 3 day Marathon working session completely sore head to toe and mentally done as well.. Fire it up drive around my town for 10 minutes and runs 210 no problems.. Call James to pick up the car as its ready. He drives it home and 250 happens a few minutes from his house.. He is disappointed for sure and so am I.. Now thinking ok timing issue? Jets? Electric fan? The 74 911 factory manual says 250 is ok but we were hoping for cooler temps.. So after sleeping on it and texting back and forth James decided to take out the new appbiz engine sound pad and try that.. It fixed it.. The temps went down to 190-200 max.. Absolutely incredible as I never had a mat in any 914-6 before I thought that was crazy.. So note to self before getting all crazy with front oil coolers(though still happy to sell you the GT setup) take a look at removing the sound pad if you really are dealing with cooling issues.. |
Matty900 |
May 31 2020, 07:29 PM
Post
#2
|
Senior Member Group: Members Posts: 1,269 Joined: 21-February 15 From: Oregon Member No.: 18,454 Region Association: Pacific Northwest |
Good to know. Did it have the cooling fins that hang down off of the firewall?
|
mb911 |
May 31 2020, 07:35 PM
Post
#3
|
914 Guru Group: Members Posts: 6,854 Joined: 2-January 09 From: Burlington wi Member No.: 9,892 Region Association: Upper MidWest |
|
JmuRiz |
May 31 2020, 07:43 PM
Post
#4
|
914 Guru Group: Members Posts: 5,427 Joined: 30-December 02 From: NoVA Member No.: 50 Region Association: MidAtlantic Region |
Good info!
|
mepstein |
May 31 2020, 07:47 PM
Post
#5
|
914-6 GT in waiting Group: Members Posts: 19,275 Joined: 19-September 09 From: Landenberg, PA/Wilmington, DE Member No.: 10,825 Region Association: MidAtlantic Region |
So I guess the engine pad was blocking enough air to starve the fan. Maybe it was even sucking in the pad at higher rpms. Good to know.
|
mb911 |
May 31 2020, 07:48 PM
Post
#6
|
914 Guru Group: Members Posts: 6,854 Joined: 2-January 09 From: Burlington wi Member No.: 9,892 Region Association: Upper MidWest |
I would suggest painted dyna mat as an alternative
|
Retroracer |
May 31 2020, 08:01 PM
Post
#7
|
Senior Member Group: Members Posts: 612 Joined: 7-July 13 From: Bend OR Member No.: 16,100 Region Association: Pacific Northwest |
Interesting find - thx for sharing. That gap between the firewall and the fan shroud is pretty narrow - if the pad was blocking it, then the fan was probably sucking in air from the crankshaft / fan belt area - warm air.
- Tony |
rgalla9146 |
May 31 2020, 08:02 PM
Post
#8
|
Advanced Member Group: Members Posts: 4,555 Joined: 23-November 05 From: Paramus NJ Member No.: 5,176 Region Association: None |
This was the thick foam grey one ?
Were the tabs holding the perimeter in place....was the center loose from the firewall ? Great diagnosis. |
mb911 |
May 31 2020, 08:04 PM
Post
#9
|
914 Guru Group: Members Posts: 6,854 Joined: 2-January 09 From: Burlington wi Member No.: 9,892 Region Association: Upper MidWest |
It was new last fall put on with 3M super 90.. Either way I won't ever suggest that nor the mount for a conversion moving forward unless running just headers and track oriented build.
|
roblav1 |
May 31 2020, 10:05 PM
Post
#10
|
Senior Member Group: Members Posts: 528 Joined: 18-September 12 From: KY Member No.: 14,943 Region Association: MidAtlantic Region |
This is good information Ben.
I used typical racecar thin foil matting on the rear of the firewall and a foil fronted soundpad covered by 1/4" wool felt on front. Plenty of room for the air flowing to the fan. Hopefully have it started for the first time in about a week. Electrical almost done. |
raynekat |
May 31 2020, 11:29 PM
Post
#11
|
Advanced Member Group: Members Posts: 2,158 Joined: 30-December 14 From: Coeur d'Alene, Idaho Member No.: 18,263 Region Association: Pacific Northwest |
No mat on my firewall. The 2.7 MFI RS engine so far has been running very cool (190-200F max like above example) in "normal" weather/temps. We'll see how the onboard engine cooler does this summer. I'm hopeful additional cooling/coolers won't be needed.
|
ctc911ctc |
Jun 1 2020, 06:33 AM
Post
#12
|
Senior Member Group: Members Posts: 892 Joined: 9-June 18 From: boston Member No.: 22,206 Region Association: North East States |
Running down this same issue on my 914-4.
I used the EZ-Mat Soundproof (I think that is the name) AND the Sound Mat. Perhaps I have starved the engine of air flow........Will check this out! |
mb911 |
Jun 1 2020, 07:24 AM
Post
#13
|
914 Guru Group: Members Posts: 6,854 Joined: 2-January 09 From: Burlington wi Member No.: 9,892 Region Association: Upper MidWest |
I think its likely though the 4cyl fan is not as close to the firewall as the 911 engine.
|
ConeDodger |
Jun 1 2020, 07:52 AM
Post
#14
|
Apex killer! Group: Members Posts: 23,591 Joined: 31-December 04 From: Tahoe Area Member No.: 3,380 Region Association: Northern California |
Another caveat; your engine oil temperature sender must match the gauge. Otherwise, you get dramatic gauge numbers on a perfectly happy engine. (IMG:style_emoticons/default/blink.gif)
|
mb911 |
Jun 1 2020, 07:52 AM
Post
#15
|
914 Guru Group: Members Posts: 6,854 Joined: 2-January 09 From: Burlington wi Member No.: 9,892 Region Association: Upper MidWest |
Another caveat; your engine oil temperature sender must match the gauge. Otherwise, you get dramatic gauge numbers on a perfectly happy engine. (IMG:style_emoticons/default/blink.gif) Yup been there as well. |
horizontally-opposed |
Jun 1 2020, 08:49 AM
Post
#16
|
Advanced Member Group: Members Posts: 3,432 Joined: 12-May 04 From: San Francisco Member No.: 2,058 Region Association: None |
A good PSA, and a good data point.
After hemming and hawing, we left my 73's factory mat in on the engine side. Was in nice shape and not loose anywhere. Hot 2.2 seems just fine, running 180-210° F indicated on warm or even hot days. Seems to get hottest in steady-state freeway driving. Rob's post has me wanting to double check the gauge and sender (again), as the opposite can also be true: You can get a nice reading on an unhappy engine. |
Mark Henry |
Jun 1 2020, 12:05 PM
Post
#17
|
that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
I have the stock pad, heavily modified, glued and screwed to the access hatch and I haven't had any over heat issues. Was a bit hot at first, but since I did my jets I run normal street car temps.
(IMG:style_emoticons/default/confused24.gif) One thing I could see a loose mat being sucked towards the fan like a flapper valve. |
sixnotfour |
Jun 1 2020, 01:32 PM
Post
#18
|
914 Wizard Group: Members Posts: 10,432 Joined: 12-September 04 From: Life Elevated..planet UT. Member No.: 2,744 Region Association: Rocky Mountains |
2.7 ? Does still have 5 blade fan ? (IMG:style_emoticons/default/happy11.gif) (IMG:style_emoticons/default/driving.gif)
|
914Toy |
Jun 1 2020, 01:44 PM
Post
#19
|
Senior Member Group: Members Posts: 718 Joined: 12-November 17 From: Laguna beach Member No.: 21,596 Region Association: Southern California |
My 2.7 with carbs and matching cams and 11 blade fan never gets above 200, with a front oil cooler with thermostat set at about 190, which routes the oil forward to the cooler only when high speed cruising or long uphill climbs. Check your air/fuel (A/F) ratios - high A/F's (above15) equals high engine temperatures.
|
mskala |
Jun 1 2020, 02:12 PM
Post
#20
|
R Group: Members Posts: 1,925 Joined: 2-January 03 From: Massachusetts Member No.: 79 Region Association: None |
Is this the reason the factory didn't install the pad on the 914-6?
I don't have the pad, but in upgrading from 2.0 to 2.3L -6, I went through a few experiments with temperature and there are a bunch of factors that can affect the temps, like plugging holes where HE paper hoses used to be, and regular lid vs. GT all-mesh lid, underside flaps, and of course engine tuning. Fan speed also can be changed with different fan (same blades though) with appropriate pulleys. This is where it sucks that half the pulley is part of the fan. |
Lo-Fi Version | Time is now: 19th May 2024 - 08:50 AM |
All rights reserved 914World.com © since 2002 |
914World.com is the fastest growing online 914 community! We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ... |