New Motor + Hot Running = ?, Advice, help, suggestions? Options

[jhadler]

Hey all,

Starting a new thread here...

I'd like to get some advice please.

Here's the scoop:

New motor. 9:1 2056 w/ceramic coated euro race headers. Stock D-jet and stock ignition. Running on Brad Penn break-in oil.

Two shake down drives for break-in (varying rpm and load, staying out of WOT and mostly below 4k rpm), and they both have the same basic symptoms. The oil temps get too high and idle turns to cr*p.

Drive one: 75 degree ambient, 40 minutes driving. head temps vary between 250-275, never higher than 300. Oil temps climbed to 230, and once hot won't idle worth a damn.

- backed off ignition advance to stock, was running at 30 degrees. Capped vacuum retard hose, seemed to idle better without. (mistake?)

Drive two: 85 degree ambient, 25 minutes driving. Head temps vary between 250-300, never higher. Oil temp went to 250. Hot idle just plain sucked.

I know I need to get a wideband on there to figure out what the mixture is doing, but if the mixture was going lean, I'd expect to see excessive head temps right? Can the oil temp simply be a tight motor on light oil? It doesn't seem right though.

Help? Advice? Suggestions? Last thing I want to do is lunch this motor.

-Josh2

[Ferg]

Hmm, it was what 97 today? I know nothing about break in oil, but being a fresh build, I'm sure that has something to do with it.

Mine was running 230-40ish today on the highway. Needle covering the "M" on the word "temp" for console gauge with the small red area.

Anyhow, before people tell you, to retard the timing, Josh is about 5500ft elevation or more like me.

And Josh has his cooling flaps wired open.

I'm in for some replies.

Ferg

[orange914]

30 mm oil pump?

[jhadler]

30 mm oil pump?

Melling. And a Tuna Can.

-Josh2

[majkos]

What shape is the oil cooler?

[CliffBraun]

Personally I'd say trash the stock induction, but given that I don't think you have too much to worry about, temps on break in will be higher than normal operating temps for an engine with everything worn down. The oil temps are a bit higher than I'd like to see, but again, it's a break in.

I'd like an O2 sensor, but you can pull the plugs etc to see if you're running lean. I'd not worry too much about it, but be cautious.

[Jake Raby]

Those temps aren't high.. The CHT is lower than normal and with the new engine the oil temps will be higher. What oil are you using??

With the low CHT and higher oil temp I'd say that the engine needs a couple of degrees of timing to optimize it, the CHT proves you can get away with more timing and retarded timing can drive up OT easily.

[CliffBraun]

He said in the first post he's running brad penn break in oil(now I've never used this so I don't know what exactly it means).

[jhadler]

Thanks for the responses!

Jake, glad to hear that the "common" wisdom that people were telling me (backing off on the timing) was wrong. It felt like the wrong way to go, and at altitude, I would expect to run more advance anyway (running 91 octane pump gas). But I didn't know that not enough advance could contribute to high oil temps. That's really interesting, what's the mechanism that causes that?

Any idea if my plugging of the vacuum retard line was a good idea or not?

What are the "best" CHT's and Oil temps to look for. Both for break-in, regular running, and hard driving (track/DE)?

Thanks all! I'll dial in a few more degrees and see how that helps. Still need that wideband to figure out what's up with hot idle though.

-Josh2

[byndbad914]

Jake is spot on as you would expect, you need to advance the timing back up. Retarding does in fact heat oil up, water if you had a water cooled engine will heat up too. And 250deg oil temps on a hot day and a new motor just breaking in seems completely reasonable to me. The BP oil is good stuff too and will handle that temp no problem.

As for a vacuum retard, if you are talking about the vacuum line to the "can" on the distributor, that should be a vacuum advance. It is possible I guess that when you had it hooked up, and had extra overall advance, that at idle you had a lot of initial advance and the engine doesn't like it. Just a guess but would surprise me. Frankly on many a drag race motor (tho' not a VW engine so a different animal maybe) we took the advance springs completely out of the distributor and just set timing to be max all the time - point is they idled just fine with 36deg of timing, even at 1K rpm, so dunno why your car would idle differently with the advance plugged in unless your diaphragm is leaking and you created a vacuum leak plugging into it. My race car has around 18-20 deg of idle advance and 36deg overall for another example of high advance at idle working fine.

[r_towle]

The vacuum retard line comes unhooked, and plugged, from the factory.

Rich

[jhadler]

Jake is spot on as you would expect, you need to advance the timing back up. Retarding does in fact heat oil up, water if you had a water cooled engine will heat up too. And 250deg oil temps on a hot day and a new motor just breaking in seems completely reasonable to me. The BP oil is good stuff too and will handle that temp no problem.

I'm not worried about the oil per se, I'm worried about the low oil pressure that results from the hot oil. I guess I should have mentioned this earlier. When the oil gets to the 230+ mark, the oil pressure drops really low. So low as to make me nervous, and the warning light comes on near idle. Is there something wrong with the motor at this point? I'd expect a tight motor to have higher oil pressure no?

As for a vacuum retard, if you are talking about the vacuum line to the "can" on the distributor, that should be a vacuum advance.

The distributor has two ports. Vacuum advance, and vacuum retard. I have disabled the retard (no jokes, I'm being serious).

-Josh2

[jhadler]

The vacuum retard line comes unhooked, and plugged, from the factory.

Rich

D'oh!

Thanks!

-Josh2

[r_towle]

the retard hose gets connected to the throttle body.
The hose gets plugged .

The port on the distributor is left open to the air, not plugged.

If you have run it for two runs and did a classic 20 minute break in at 2000 rpms to get the camshaft seated, then I , in my humble opinion, would change out the oil now to 20/50.

I may get yelled at for this but I run the motor with the break in oil for 30 minutes, then change the oil.
Its at that early time that all the little bits of foreign matter, cleaning solvents, contaminants get mixed up in the oil....so get it hot and dump it.

I pull the sump out also, and the taco plate to get as much of the oil out as possible...

New gaskets, new oil...then drive it like you stole it.
If it is gonna break...its gonna break.

RIch

[orange914]

you need to advance the timing back up. Retarding does in fact heat oil up, water if you had a water cooled engine will heat up too.

how would retarded timing heat oil temps?, not to say it can't it just doesn't make sense to me. retarded (late) timing does in fact run engine temps. down. the more retarded the more heat/energy is blown out the exhaust. advance (early) timing drives temps up, as the combustion is in the cyl. longer. too much advance timing brings n.o.x. emmisions showing the direct corilation to the cyl. temps. going up over 2500*... even before preignition.

the reson i earlier asked if you had a 30mm h.v. oil pump was the oil heat issue. there are many threads on the extra pressure acually overideing the bypass, that consequentley bypasses the oil cooler, raising oil temp'.s. jake correct me if i'm wrong, but i've read you acually steer away from 30mm?

cylinder temp.'s normal, oil temps. high... probably running break in oil on a tight new engine under 85* normal driving. (IMG:style_emoticons/default/confused24.gif)

let us know your findings

mike

[Cap'n Krusty]

The vacuum retard line comes unhooked, and plugged, from the factory.

Rich

If we're talking about a stock D-jet equipped 1974 engine, that's not true.

The Cap'n

[Jake Raby]

Retarded timing heat soaks heads and pistons and the charge out the exhaust valve can possibly still be burning while the exhaust valve is open... retarded timing is the #1 cause of most tuning issues that cause engine failures..

People tend to be conservative with timing, thus compromising their engine due to their fear.

These engines continually prove to love 28-30* full advance @3500 RPM.

For my recommendations on temperatures see the classic thread here on 914 world.

SET MECHANICAL TIMING WITHOUT ANY VACUUM HOSES ATTACHED! This timing is all that matters, then reattach the vacuum.

Its all in the tune... Thats what I do better than anything.

[r_towle]

The vacuum retard line comes unhooked, and plugged, from the factory.

Rich

If we're talking about a stock D-jet equipped 1974 engine, that's not true.

The Cap'n

Just going on what DD said years back.
Seems some had it, some did not.

RIch

[jhadler]

Retarded timing heat soaks heads and pistons and the charge out the exhaust valve can possibly still be burning while the exhaust valve is open... retarded timing is the #1 cause of most tuning issues that cause engine failures..

That's interesting. Seemingly counter intuitive until you know the mechanism going on.

These engines continually prove to love 28-30* full advance @3500 RPM.

For my recommendations on temperatures see the classic thread here on 914 world.

SET MECHANICAL TIMING WITHOUT ANY VACUUM HOSES ATTACHED! This timing is all that matters, then reattach the vacuum.

That's what I did. I set the timing to 28 degrees, no vacuum hoses attached, 3500 rpm.

So... 30? 32? I understand that running at altitude demands more advance, is that true?

-Josh2

[Dave_Darling]

Just going on what DD said years back.
Seems some had it, some did not.

Not plugged, though--the advance fitting would be left open to the air.

--DD