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deano_90sc
01-18-2006, 12:11 AM
Hey everyone i'm new to the forum and i apologize for any thread hijacks and whatnot but i have a 1990 supercoupe with a brand new oem bottom end in it new main/rod bearings, rods, ground and polished crank, new oil pump and sending unit for the glorified idiot light to tell me if i have pressure or not and i went to work one night and after i got in my car and started it up it told me i had no oil pressure so i let it set overnight in the parking lot then my dad said to h*** with it and was going to put a new motor in it so he went and drove it home, he got halfway here and the oil pressure jumped back up to normal and i drove it for about a month after that with no troubles and tonight it did the same thing, there is a slight top end tick, not a rod knock but like a loud lifter tick even though the oil pressure goes to normal above 2k rpm but below that it has no pressure and i'm out of ideas, it has new oil pump, pressure sending unit, motorcraft filter, quakerstate 5w 30, and little over 1500 miles on it since rebuild can anyone help me find out what is causing this nightmare? any help is greatly appreciated. thanks in advance

Kevin Varnes
01-18-2006, 12:13 AM
Probably just a bad sending unit or bad connection at the sending unit. Put a real mechanical gauge on it to verify what the actual pressure is. You are probably okay.

The tick could be an exhaust leak too.

rzibilske77
01-18-2006, 12:15 AM
do your motor a favor and please use a better oil then quakerstate...:)

beeturbo
01-18-2006, 12:31 AM
hey deano !been right where u are now.. go ahead to autozone and order a melling high volume oil pump part number (M-246) for your car, change the oil and begin using either 4qts valvoline max life 20w/50 or castrol high mileage 20w/50.. ; and 1qt of lucus oil stabilizer .. its a darn good oil treatment that protects against the oil breakdown and friction as well as cushions the components that need lubricating the most.. when u change the oil fill your new oil filter with the lucus before u install it.. then ad the 4qts of oil first to the engine and the remaining lucus last since it will take longer for the lucus to drain to the bottom of the pan. stay away from the cheap oil filters especially the ones that oil change lube places use .. buy preferably the motorcraft filter i believe the part number is (FL-400s) it has special silicon valve built into the filter that works very well wit the 3.8 being that it has an external oil pump .. the filter is designed to hold the oil and not allow much to escape when the engine is shut off so its lesslikely for the oil pump to lose its prime on start up and also allows the engine to get oil quicker on cold starts with less delay of the oil to flow immediately

mywhite89
01-18-2006, 03:40 PM
how much do the hv oil pumps cost?

beeturbo
01-18-2006, 04:06 PM
the hi volume pump runs about 70-80 bucks

RBH Racing
01-18-2006, 06:28 PM
Although I TOTALLY agree with the better oil, my opinion what oil is vastly different.

I am an auto tech and have HUGE regard for sticking to design, BUT synthetic oils are the grace of the engine god. It's so worth the money in every aspect. The best side of it is if your engine still runs decent, you can let it go 6,000 miles without stretching your change limits.
My opinion, varies in the weight and additives. 20w-50 seems WAY to heavy for these engines alone, then the adding of a heavy treatment is asking for problems. It would seem that BEETURBO is doing alright with it, but heavy thick oils have a hard time returning to the bottom end of the engine at high rpm and possibly highway speeds. Engines that are designed for lighter oil have smaller return passages that can really make this an issue.

Given a thicker oil will of course give you a higher oil pressure, but that's not always good. My outlaw class drag car builds around 78psi at 8,300rpm, this is actually far to much. On the other side my 88 gmc 1 ton runs standard at 27psi.
It's all in the design man. As for your pressure problem, as the guys have said I would look to the sending unit and wiring first. Then the pump and shaft. If you have an upper engine tick on a fresh engine you should no doubt look into it before it hurts something.
Who knows they could be related. Some contaminants may have found their way around and have a lifter sticking or not building up and doing the same at the pump. I have seen more than one engine get put together with to much silicone, and die from a clogged orifice and/or pump screen.

Oh yeah, and Quakerstate is CRAP, lol! Try Mobil 1 full synthetic, killer stuff!

PHEEEEW! That was more like $.05

Let us know what you find....

Kevin Varnes
01-18-2006, 07:17 PM
Before you go tearing the engine apart at least verify the oil pressure with a gauge.

deano_90sc
01-18-2006, 10:25 PM
hey guys thanks for the advice and as for the weight of the oil which weight would you recommend other than 20 50 because my dad also thinks that it is to thick. and my motor has over 100,000 miles on it is it still ok to use full synthetic or should i go with a syn. blend? Thanks again for helping the newbie get his sc fixed and going...its given me a lot of problems but i love it to death.

RBH Racing
01-18-2006, 10:39 PM
well, I put in my nickel. I a real fan of full synthetic.

rlong
01-19-2006, 02:26 AM
i always use 5w or 10w 30 maybe in the summer if its a quart low i may add 1 quart of 20w 50 im wondering if your cam bearings are good if top end ticks but my 90 always sounded slightly noisy on top when cold compared to my 89 lucas is a good additive but i mosly only add about a pint every 2 or 3 oil changes it did fix my rear main leak

Hock
01-19-2006, 05:59 PM
hey guys thanks for the advice and as for the weight of the oil which weight would you recommend other than 20 50 because my dad also thinks that it is to thick. and my motor has over 100,000 miles on it is it still ok to use full synthetic or should i go with a syn. blend? Thanks again for helping the newbie get his sc fixed and going...its given me a lot of problems but i love it to death.

Yes you can use synthetic with that many miles and it will be fine. Go with a full synthetic oil for sure, its definitly worth it weight in gold. I also suggest the Mobil 1 sythetic, IMO its the best off the shelf oil on the market. In my SC I was running 10w40 before I tore it down, though you should be fine with 10w30.

deano_90sc
01-20-2006, 01:48 PM
Hey my dad took a good look at it last night and they came to the conclusion that a camshaft bearing has spun. Everything else is basically brand new to that motor so he asked me to ask you all if that is a possibility and if that could lead to my oil pressure problem as well. thanks again guys for all the help i will definately run full syn oil from now on....save me from future problems lol.

Hock
01-20-2006, 04:44 PM
A bad cam bearing, I would say that would cause a problem.