Oil pump fixes for occasional track use

So I've been building my ZHP and I've gone down a bit of a rabbit hole and I'm doing basically the whole front and rear end + vincebar kit + cooling system, vanos. I'd really like to take it to some track days and autoX next season.

It will realistically not be a full time track car but I do like to rev the engine out to redline on the street.

The cheapest solution is to safety wire the nut, I've seen a few cases on some facebook groups of the oil pump nut backing off on a tracked ZHP.

Then there is the upgraded shaft solution from Achilles. This is $250 with a prepressed shaft on the gear.

And lastly there is an oil pump baffle which is $150 + labor for welding to oil pan.



My car has 192k ish miles and I'm not sure of the state of it. It seems fine though and when I dropped the oil pan there werent any metal shavings or funny looking milky oil.


Should I just safety wire the nut and call it a day? Or is it worth getting the upgraded pump shaft and oil pan baffle?

Anyone here track their ZHPs with just a simple safety wire + overfilling oil slightly?

I'm in a similar position as you. I track my car once a year just for fun, so nothing serious. Occasional autocross (my days of attending a full season are over) and other than that a bunch of mountain runs. I do rev out the engine on a relatively consistent basis. Here's my take based on everything I've read and seen:

Top end reinforcement for RACP is the only real fix, so you're off to a good start there. You don't need to track the car to benefit from that. I'm running the SME brace and it has been great (thanks again @ZHPizza).

I know @t.er tracked his car regularly with no oil pump upgrade. He kept it under 6k rpm and has been fine. It's a ZHP.

The nut backing off is a result of chain lash (since there is no tensioner), so what you want to do is avoid sudden RPM changes. I've redlined my non-ZHP (so not even loctite on the nut) many times, but I ALWAYS rev match 100%. That means shifting from 1 to 2 is incredibly slow due to how long it takes for the revs to drop from 6.5k to 3.5k, but it has worked for me so far. If perfectly smooth shifts every single time are not your style, look at an upgrade. ZHPizza has the Achilles one and seems to be happy with it.

There's also the option of adding a tensioner if you don't mind taking off the timing cover and drilling into the block. You can also add an overunning pulley on Bosch alternators. If you have too much money, the ATI damper helps as well. Be careful with some of the complete replacement units, in some cases when a new shaft is pressed into a used oil pump, the shaft spins during a cold start, which will eventually kill your engine. I would trust the SLG one. Not sure about others.

The wired nut might be fine for your applications, just remember that the shaft can still break. The real solution, just like a top reinforcement is the real RACP solution, would be to install the chain tensioner. My plan is to do the SLG pump and overunning pulley, simply because I don't have the time or means to remove the timing cover and drill into the block.

As for oil, definitely get the baffle. I run 8L of oil plus 0.3L of hydraulic lifter additive. That's the only way for me to prevent ticking after a track session. It's not great to overfill so the baffle is a great solution. I was planning to do that together with the oil pump, though with changing priorities I'm not sure if I'll ever get to either.

Thanks for the detailed reply Galapolis, I always appreciate the posts I see from you.

The tensioner upgrade seems a bit complex and expensive. I spoke to the tech from Achilles on the phone and he told me he doesn’t see the tensioner as an issue but I’m sure he’s biased. I think it’s down to either just safety wire or doing the shaft upgrade from Achilles for me. I have not read any failures online of the Achilles shaft failing even though they don’t have a tensioner solution. I try to rev match as much as I can (still perfecting that) but I think it might be better to go for some reinforcement if the issue is due to large rpm differences. More money to burn in the project pot, but if I safety wire the nut and the shaft shears off I’ll be kicking myself for not spending the extra $250. Also we have only about 2 months left of summer tire weather and the car has been on jackstands for a long time, and it’s mostly apart right now. It’s the best time to do all the work so I don’t have to raise the engine up again and undo everything to get to the oil pan.

For the baffle I have to see if I can find a local shop to weld aluminum. I can buy a pre baffled oil pan from moreheadspeedworks for $175 extra. It would depend on whether I can find someone to weld the oil pan for less than that. But it seems that the oil starvation is pretty common if you’re driving hard or even braking hard.


The rev limit on the ZHP is 6850 I believe. I may also get a tune and there’s an option to raise the rpm to 7K. I’m wondering if getting the upgraded oil pump shaft would allow me to easily do this or if I should hold off. I think it should be fine because the idea isn’t to stay at 7k anyway, but to give me a few more revs before I have to shift/brake. And I’m not sure if the harmonic imbalances simply get worse or it’s at a particular frequency. Been awhile since I took mechanical vibrations in school but resonance doesn’t always get worse as you increase frequency, I believe there was a sweet spot depending on material etc.

Or if it’s not due to frequency at all but chain lash it shouldn’t matter anyway, except now I have an extra 150 rpm that may increase my delta when shifting.

Quote:

---

Originally Posted by REF84

I spoke to the tech from Achilles on the phone and he told me he doesn’t see the tensioner as an issue but I’m sure he’s biased.

---

Well there is no oil pump chain tensioner on our cars, so not sure how he can see it as not an issue. :)

The Achilles solution is good either way, like I said ZHPizza has been happy with it and I trust his experiences. Even though the main issue is the lack of a tensioner, harmonics do still play a role. The M54 isn't really a high revving engine, I'm sure that even on the ZHP 6850 is already past peak power, so not sure if I would raise the limit even further.

I haven't really felt the need for more wiggle room on the track, even with a 3.38 diff and 6.5k limit. I would hold off on that until you have more track time. Remember, just because the oil pump has been reinforced, the chain slack doesn't go away. The same extreme forces are still acting on the new pump solution if the oil pump chain remains untouched (which is why the shaft can break with just a welded nut or wired nut). Raising the RPM is just asking for trouble if you ask me but I also know some people who have done that and not had issues so it's up to you.

Nailed it @Galapolis

The M54B30 is inherently unbalanced and slaps the shit out of that chain. I had the front subframe down to install headers so went ahead and did the oil pan gasket, baffle, and Achilles pump shaft to get it out of the way too. Would also prefer to add a tensioner but wasn't about to pull the engine.

If you can get a baffled pan for $175 that is 1000% worth it. I went through hell trying to weld mine and Spenser's with alumiweld sticks and eventually a tig welder. The thick aluminum pan just acts as a giant heat sink so you cannot match the heat of the surface with the thin baffle and you end up melting holes in the baffle. It's a mess, even for an experienced welder.

Thanks I was pondering it last night and went with the achilles pump shaft (pre-pressed) and the baffled oil pan from moreheadspeedworks. Tried finding some local welders to do aluminum and it was a crap shoot, there was a good guy whos done it before but was nearly 2 hours away drive.

I may also replace the oil pump chain while Im in there. It's cheap and its probably a little stretched by now if there is no tensioner.