342 replies to this topic

[Tiny]

Hey everyone,

For those who dont know my car I'll post some info and pics of it up soon.

For those who have followed my build and know what ive been chasing, my latest update is that ive FINALLY put in the 3.7 Diff that i got from Lostit last year!

Unfortunately we had to dismantle the diff to remove a pice of broken axle, so this is our first attempt ar re-assembling and setting up the diff, but so far so good! The car accelerates like a scalded cat, and its really taken some load off the engine.

The engine just wants to rev so much more freely now, and the speedo climbs like a jet fighter! I'm over the moon with the new ratio, Ive gotto get out onto the road alot more with it to see how it acts on the freeway etc and how many more revs i'm carrying at highway speeds but it should be a HEAP better off the line at the drags!

I Have uncovered one "problem" since its installation and if anyone's got any ideas.. it would be great to hear about it!

When i accelerate REALLY hard now with traction ( and therefore G forces on the car) i can watch the oil pressure guage fall from 62Psi down to around 20Psi!! The only time it regains pressure is when you get off teh gas and allow the forces to ease off.

I'm concerned that i'm suffering from oil surge ( toward the back of the sump) now that the car accelerates so hard!

For those who dont know, its a 400 Chev smallblock, Blueprinted bigblock oil pump, STANDARD HQ SUMP, windage tray, oil restrictors installed, and block has been deburred throught the valleya nd oil returns to aid in drainback.

Anyhow, Enough for now.. I'll post some pics of the car and more info for anyone who wants to know soon!
Cheers!

[Tiny]

Hey marty!
THanks for that mate, I *THINK* its the sump too and i was going to start looking at a high energy as you suggested. I was wondering if anyone else knew of any other ideas it COULD be before i just went for the sump thats was all!

Thanks mate, the gains were IMPRESSIVE to say the least! I'm wrapped! cant wait to hit the track and give it a squirt to see what she runs now!
And i havent even put on Ultrablue's carby yet!! YAY!!

Cheers!

[ToRunYa]

the poor bloody oil is running away! it dont want that sorta punishment!

[Tiny]

hehe yeah... but i'm not punishing it THAT hard! *Hides the whips and chains*

[Tiny]

Thanks Julian! I think your spot on mate.. The pressure doesnt drop when teh car is still so thats why i think it is surge!

My pressure at idle is around 20Psi and at revs is 62Psi.. so the only explaianation is that the oil is surging away from teh pickup! DAMN! ive gotto race next weekend at heathcote!

Cheers.

[gtrboyy]

Yep I would say it's the sump.Putting in shorter gears can change the car for the better.I put 3.89s in my lc & it feels like a slingshot.It also made a big difference putting 3.7s in my brother's vs maloo.

[Tiny]

Thanks guys,

I'll give steve at SEPERF a message sounds like the man i need to speak to!

Datto: I cant get rid of my centre just yet... I'm defintiely NOT leaving this bloody spool in the car.. its such a pain in the ass! I'm going to be going back to the LSD ASAP but DEFINITELY with 3.7s!

Devils: I'm really surprised at how much better the car feels! I too had an oil surge problem under hard braking luckily i watched my guage when i was slamming on teh brakes!) but yeah i had seen small signs of it under acceleration as the car WAS.. but this has just gone nuts.

For now ( to race next weekend) i'm going to have to cheat like hell and put in an extra litre of oil and keep an eagle eye on the pressure guage. Till i can get a sump and fix it once and for all!

Thanks again!

[Tiny]

LOL TLC.. love it chop... havent heard that one but your right!!

Whats worrying me now is the fact that ive got exactly one week to have this fixed... OR... i cant race it in heathcote.

My greatest fear is that the oil pressure drops on a run ( remeber.. this happened on teh street with street tyres.. not on slicks at a prepped track!) and spins a bearing and kicks a leg out of bed...

Its a worrying thought cause if that happens.. then its all over. And i mean that i CANNOT afford to build another engine.. point blank.

See my Dilemma?

Other than that.. the ford now has a 2.2 tonne tow kit and i'm prepped to go to melbourne!

ANyone got that TLC handy?

[Struggler]

Moroso make a tidy little plate that fits between the oil pump and mains cap. This acts as a baffle and stops oil running right up the back of the sump under acceleration. It is all I use and it works for me. Might be worth a try, its only worth a few dollars.

[Tiny]

Verrrry interesting! Thanks andrew! Definitely might be worth a go!

[Tiny]

if ive got the $$ for a new sump and if i can get a new sump!

If the sumps gotto come off.... ive got a whole HOST of things i wanna do.. one is a rear main seal!

*sigh*

[Tiny]

Hmm thanks alx ss! that worries me! something to check though!

[LXCHEV]

Aaaaarrrggghhhh!!!!! Tiny, dilemma's, dilemma's mate!!! Tricky situation you've managed to find yourself in here! First of all, I TOLD YOU THAT 3.7's WOULD ROCK!!!! hehehe, glad to hear it.

So what are you gonna do in the short-term? Would 1 litre extra oil solve it do you think? It's a fair call if you were gonna rip the donk out (assuming you can get hold of a new sump ASAP). As you said though, when that happens you really want to fix up that rear main, what a pain in the ass!!! Don't you hate it when that happens! Is there much involved getting your engine out and back in again. Perhaps this calls for a "sickie" this week hahahaha.

Keep us updated on how it's all going.

PS. If those gears don't see you into the 11's now, damn you're gonna be close to em!

Good luck with it all pal.

[LXCHEV]

Just read Lostit's post - some good ideas there. What oil are you using and how much does your sump actually hold from empty? I like the idea of checking the pressure with another known good gauge too - who knows.

All this talk makes we want to check mine now too - anytime I take off real hard I can't say I really look at my oil pressure gauge (sits down low under my heater). I do have an Autometer Mini Pro-Lite wired up though, but I lost oil pressure once and the bloody thing didn't even go off, couldn't believe it! Seemed to stop working temporarily and then a week or two lately it magically cleared itself and was working fine again. Maybe something was blocked up in the sender unit or something.

[Struggler]

I had the same problem with my chev, when i pulled off the sump found the pick up sitting on the bottom. Some how it snaped off and there was only a pipe trying to suck up oil. Idled perfect, cruized fine, but droped pressure at hard exelleration.

I suffered this problem a few times with my 454. The true test was a really fast stop.....this would give zero oil pressure as all the oil ran forward, away from the pickup tube. Despite what Denis says, it will idle and drive with normal oil pressure, only under extremes will it fluctuate. Adding an extra litre did get me home safely a few times though.

Hope this helps