Big 914 that will not idle, Idle Issue Options

[joeannwh8]

I have a 72 914 that I have been working on forever, started a rebuild 15 years ago. A local machinist help me out and somehow the engine that I thought was a little bigger then 2.1L, I now calculate the size at 2366 cc (103mm x 71mm)! It has an electronic vacuum advance distributor and Solex H32/34 PD513 carbs, compression is 150 psi plus or minus 2 psi all around. Engine starts instantly warm or cold, rev's sluggishly but will quickly get to 6000 rpm easily. The issue is it will not idle below 2200 rpm.

What have I missed?

[914Mels]

I have a 72 914 that I have been working on forever, started a rebuild 15 years ago. A local machinist help me out and somehow the engine that I thought was a little bigger then 2.1L, I now calculate the size at 2366 cc (103mm x 71mm)! It has an electronic vacuum advance distributor and Solex H32/34 PD513 carbs, compression is 150 psi plus or minus 2 psi all around. Engine starts instantly warm or cold, rev's sluggishly but will quickly get to 6000 rpm easily. The issue is it will not idle below 2200 rpm.

What have I missed?

Do you mean it dies out below 2200 or does it just not idle any lower than that speed?

[sportlicherFahrer]

Plugged idle jets? Timing off? Just a couple shots in the dark, and should be fairly easy things to check.

[rhodyguy]

Back one idle speed adjustment off of the stop. How tight is the throttle cable? Any backfiring or snapping back thru the carbs?

[Mark Henry]

Sounds like a vacuum leak.
Engine that size you need webers.

[Spoke]

(IMG:style_emoticons/default/welcome.png)

Got some pictures of your 914?

[thelogo]

As mark h. Said the appropriate carbs will make a big difference ( i have spanish 44's on my 2336)

And this is not a stock 1600 or a 1.8

Big displacement needs to be dialed in more so then stock

[joeannwh8]

Ok now it will idle some what, went through the timing thing again and it now lopes at around 900 rpm. Under load it will not go above 4500rpm. Air Cooled thinks I need 44's with no head work do I really need 44 or would 40's work?

I have a new issue though, the brakes don't stop the car as well as I remember, in the last 2 years I rebuilt all (4) calipers, cleaned out the proportional valve replaced the master cylinder, replaced the rear disks and replaced the pads. Pedal feels pretty solid.

Any thoughts?

[joeannwh8]

Phew,

Bought the weber's wow what a difference. 44"s w/36 vents. Had AirCooled set them up.
Made my own pressure bleeder for the brakes out of an old blood pressure cuff and a Costco mixed nuts plastic jar, was able to get the brakes working really well again.
Burned out the electronic pick up for the distributor, Hotspark helped me out there, Kuhltek wouldn't talk to me (original distributor was bought from them)
What else, finally got the rear of my car leveled out, had a set of lowering springs laying around which helped, but was still 0.625 of an inch different left to right. Machined up an extended nut and added washers to the left rear strut and set the ride hieght to 6.625 measured at the four jack points.
Now I am back to trying to get the turn signals working, the turn indicators work it is the dash indicators that are driving me crazy, left one works great right one flashes twice correctly then both flash weakly, out side lights aren't affected?!?!!?
But just like people said early on in this thread big motors need bigger carb's, thanks all

[Tdskip]

Glad you got it (mostly) sorted.

[rick 918-S]

(IMG:style_emoticons/default/welcome.png) (IMG:style_emoticons/default/thisthreadisworthlesswithoutpics.gif)

[jhynesrockmtn]

Ok now it will idle some what, went through the timing thing again and it now lopes at around 900 rpm. Under load it will not go above 4500rpm. Air Cooled thinks I need 44's with no head work do I really need 44 or would 40's work?

I have a new issue though, the brakes don't stop the car as well as I remember, in the last 2 years I rebuilt all (4) calipers, cleaned out the proportional valve replaced the master cylinder, replaced the rear disks and replaced the pads. Pedal feels pretty solid.

Any thoughts?

If the soft lines have not been replaced I would do that. I renewed the braking system on a 1970 I bought last summer. The soft lines looked ok from the outside. The rears were literally plugged up 100%. The car had sat unused for long periods of time.

[joeannwh8]

Okay thanks to everyone that has gotten me this far! The car runs now and stops now!
The running issue was to small carbs and a flaky ignition unit, the no stoppy issue was the rear brake proportional valve set to low (operator error)
The issue now is the oil over heats very quickly, 20 minutes driving around town (Santa Clarita CA) on an 80 degree day, 10 minutes on a 100 degree day.
The motor is a type 4, 2.3L, 10.5:1 compression, mild cam, weber 44 carbs (set-up by AirCooled.net), somewhere a long the way, (I started working on this motor in 2003), I got talked into a 30mm oil pump (I think this is the issue). My plugs look like hot coco and my heads are running 240, top of engine case 250, bottom of engine case 240, oil temperature on VDO gauge 275; all temps are deg F and recorded with a laser thermometer. I ran 20w-50, switched to 5w-30 and just tried 0w-20, all with similar results cold oil pressure approaching 70 psi @2800 rpm, 50 psi @ 800 rpm, as the oil temp goes up, on the way to 275, the oil pressure starts dropping (dah!) @ idle looks like 5-6 psi @ 2800 rpm 20-40 psi.
Am I just over whelming the stock relief system and heating the oil by running it over the reliefs? I experienced this in a very different hydraulic system many years ago.

Do I replace the pump or is there a way to lower the pressure (oil volume) with out running the oil over the relief valves???

Do I have to find a stock pump, I think they are 24 mm or will a 26 mm unit lower the volume enough to get my temp's under control.

[HansJan]

Okay thanks to everyone that has gotten me this far! The car runs now and stops now!
The running issue was to small carbs and a flaky ignition unit, the no stoppy issue was the rear brake proportional valve set to low (operator error)
The issue now is the oil over heats very quickly, 20 minutes driving around town (Santa Clarita CA) on an 80 degree day, 10 minutes on a 100 degree day.
The motor is a type 4, 2.3L, 10.5:1 compression, mild cam, weber 44 carbs (set-up by AirCooled.net), somewhere a long the way, (I started working on this motor in 2003), I got talked into a 30mm oil pump (I think this is the issue). My plugs look like hot coco and my heads are running 240, top of engine case 250, bottom of engine case 240, oil temperature on VDO gauge 275; all temps are deg F and recorded with a laser thermometer. I ran 20w-50, switched to 5w-30 and just tried 0w-20, all with similar results cold oil pressure approaching 70 psi @2800 rpm, 50 psi @ 800 rpm, as the oil temp goes up, on the way to 275, the oil pressure starts dropping (dah!) @ idle looks like 5-6 psi @ 2800 rpm 20-40 psi.
Am I just over whelming the stock relief system and heating the oil by running it over the reliefs? I experienced this in a very different hydraulic system many years ago.

Do I replace the pump or is there a way to lower the pressure (oil volume) with out running the oil over the relief valves???

Do I have to find a stock pump, I think they are 24 mm or will a 26 mm unit lower the volume enough to get my temp's under control.

Yours and mine have a similar setup (cylinder and carb wise), but I have an external oil-cooler with electric fan installed underneath the rear trunk. Temps never exceed 220 deg, even in Houston's crazy temps. Also have the oil-bypass thingy from Tangerine installed.

BTW: Could you share the jet sizes (my car runs powerful, but sneezes and backfires a little on decel and low neighborhood speed).

[BeatNavy]

Do I have to find a stock pump, I think they are 24 mm or will a 26 mm unit lower the volume enough to get my temp's under control.

Stock pumps are expensive so most people go with a modified T1 pump. Big debate over 26mm vs. 30mm, particularly on Samba, and I'm not sure if there is a clear answer.

I went through this recently when I had to replace a failing pump on my 2.3 I had a 30mm that was failing (and leaking), and I wanted to replace it with a modified 26mm based on what I had read and the fact that oil temps are a concern for me as well. Problem is, nobody seems to have the pre-modified 26mm in stock right now for some reason. I didn't trust myself to do the mod process myself with everything else I was working on, so I (again) went with the 30mm from type 4 store. At least my leaks are gone.

I've been futzing with my external oil cooler / fan for about a year now, and best I can do on a hot day is keep temps down to around 210/220 when moving. My head temps are surprisingly cool and not a concern, so on a hot day I'll cruise in a higher gear/lower RPM (e.g., 2800) to focus on oil temp. Sitting still on a hot day temps will approach 240.

Unfortunately I don't have an oil pressure gauge (IMG:style_emoticons/default/dry.gif)

[Shivers]

In the old days it was 10 lbs oil pressure for every 1000 rpm's. Running at 7000 rpm's you wanted 70 lbs. I'm old like these rules so I stick to them. But, with all the advancements in oil it's not so clear any more what is right for these type 4's. If you want to run a cooler more volume will help, so stick with the 30. The pressure should be controlled by the spring in the bypass valve

[Shivers]

Okay thanks to everyone that has gotten me this far! The car runs now and stops now!
The running issue was to small carbs and a flaky ignition unit, the no stoppy issue was the rear brake proportional valve set to low (operator error)
The issue now is the oil over heats very quickly, 20 minutes driving around town (Santa Clarita CA) on an 80 degree day, 10 minutes on a 100 degree day.
The motor is a type 4, 2.3L, 10.5:1 compression, mild cam, weber 44 carbs (set-up by AirCooled.net), somewhere a long the way, (I started working on this motor in 2003), I got talked into a 30mm oil pump (I think this is the issue). My plugs look like hot coco and my heads are running 240, top of engine case 250, bottom of engine case 240, oil temperature on VDO gauge 275; all temps are deg F and recorded with a laser thermometer. I ran 20w-50, switched to 5w-30 and just tried 0w-20, all with similar results cold oil pressure approaching 70 psi @2800 rpm, 50 psi @ 800 rpm, as the oil temp goes up, on the way to 275, the oil pressure starts dropping (dah!) @ idle looks like 5-6 psi @ 2800 rpm 20-40 psi.
Am I just over whelming the stock relief system and heating the oil by running it over the reliefs? I experienced this in a very different hydraulic system many years ago.

Do I replace the pump or is there a way to lower the pressure (oil volume) with out running the oil over the relief valves???

Do I have to find a stock pump, I think they are 24 mm or will a 26 mm unit lower the volume enough to get my temp's under control.

I just caught this. 10.5:1 is going to create more heat than stock compression, especially an air-cooled. My personal opinion, if you are running in a warm to hot environment, I'd be looking at volume of oil, running to a front mounted oil cooler and a fan to a t-stat.

[BeatNavy]

Okay thanks to everyone that has gotten me this far! The car runs now and stops now!
The running issue was to small carbs and a flaky ignition unit, the no stoppy issue was the rear brake proportional valve set to low (operator error)
The issue now is the oil over heats very quickly, 20 minutes driving around town (Santa Clarita CA) on an 80 degree day, 10 minutes on a 100 degree day.
The motor is a type 4, 2.3L, 10.5:1 compression, mild cam, weber 44 carbs (set-up by AirCooled.net), somewhere a long the way, (I started working on this motor in 2003), I got talked into a 30mm oil pump (I think this is the issue). My plugs look like hot coco and my heads are running 240, top of engine case 250, bottom of engine case 240, oil temperature on VDO gauge 275; all temps are deg F and recorded with a laser thermometer. I ran 20w-50, switched to 5w-30 and just tried 0w-20, all with similar results cold oil pressure approaching 70 psi @2800 rpm, 50 psi @ 800 rpm, as the oil temp goes up, on the way to 275, the oil pressure starts dropping (dah!) @ idle looks like 5-6 psi @ 2800 rpm 20-40 psi.
Am I just over whelming the stock relief system and heating the oil by running it over the reliefs? I experienced this in a very different hydraulic system many years ago.

Do I replace the pump or is there a way to lower the pressure (oil volume) with out running the oil over the relief valves???

Do I have to find a stock pump, I think they are 24 mm or will a 26 mm unit lower the volume enough to get my temp's under control.

I just caught this. 10.5:1 is going to create more heat than stock compression, especially an air-cooled. My personal opinion, if you are running in a warm to hot environment, I'd be looking at volume of oil, running to a front mounted oil cooler and a fan to a t-stat.

I think that's a fair point. I'm running a 2.3 at about 9:1, and I think I'm on the edge of what a rear mounted cooler can accomplish and sustain, at least on hot days and when I'm not moving. At some point in the mod process I think you do have to bite the bullet and plumb something up front.

[joeannwh8]

Hansjan,

Weber 44's; 36mm vents, Emulsion: F11, Idle: 55, Main: 145, Air Correction: 200
Set-up is for 0-2000 ft elevation.

Joeannwh8
20210904

[joeannwh8]

Okay if I had gray/white plugs and high head temp's I would be worried about 10.5:1 compression but I don't, I have been reading blogs from all over the internet and it sounds to me like with a 30 mm oil pump (stock is 24 mm) you are over whelming the stock reliefs, no one is really coming out and saying that buutttt. I am a retired Mechanical Engineer, California PE who worked for Northrop Grumman and Walt Disney Imagineering for roughly 20 years each. Okay I am not a German VW/Porsche engineer but I trust old engineers they were really smart, what they figured out with slide rules is amazing. I digress, anyway to get the oil to decide to go through the cooler or not, they had to use temperature or pressure. Pressure was the easiest so cold oil high pressure opens a relief this by passes oil to the cooler until temperature lowers viscosity of the oil to a point where the pressure starts to drop closing the relief forcing more oil through the cooler. Us back yard engineers come along and decide to fix worn out bearings and seals, large clearances and wha-la we need high volume pumps.... Then suddenly we need external oil coolers to take care of high oil temperature. WHERE did the the high oil temp's come from?!?!? Hmmmm if I have high compression high out engine I run richer fuel mixture to lower temperature, (I raced off road air cooled motorcycles for years, worked on off road VW powered dune buggies, always high head temp's richer mixture, accept the water cooled trucks and pavement stock cars then bigger radiators unless they were lean then RICHER mixture) high oil temps I think (feel) are generated mostly by the work oil is doing going over a relief (I feel this because of the 5 years working on mobile hydraulic systems the systems were for concrete pumps source of heat relief valves) Anyway, the reliefs in the type 4 engine were designed to manage the volume of a 24 mm pump we are asking the stock reliefs to manage the volume of a 30 mm pump.
I think the oil cooler never gets a chance to cool the oil because the oil pressure (volume of a 30mm pump) at the relief is always holding the valve open therefore it just gets hotter and hotter until the oil looses it's viscosity and the valve closes and the oil cooler isn't able to recover. I am in the market for a stock oil pump. The Tangerine Racing solution of blocking the by pass of the oil cooler is intriguing but I worry about over pressure in the oil cooler. What ever I wish I knew for sure...I do know my original oil pump and cooler worked great for 245,500 miles until I got sold on a bigger better oil pump.