Newbie in UK !!. Plus 3800 oil pressure problems.

Hi all,

Im new to this forum, but it seems to be the only Forum on the internet for the Pontiac Trans Sport. So here i am.

I am in Reading in Berkshire ( UK ), and i have just aquired a 1993 Pontiac Trans Sport SE MPV with the 3800 Tuned Port Injection V6. IT has 131,000 miles.
The Oil pressure is very low. Approx 20psi @ 2000rpm hot, and 5psi at idle.

The engine is generally quiet at idle and when revving gently. If the engine is revved quickly you can hear bottom end rumble. Also occasionally when the engine is idling there is a Very Loud bang !. Like someone hitting the block with a massive hammer. I have only heard this only twice, the last time was last night hence i am no longer going to run the engine.

At the weekend i am going to drop the sump, god knows what i am going to find in there. My dad thinks a big end bolt has come out and a big end cap is moving and occasionally catching. I think that a Push Rod has bent and a hydraulic tappet has come out of its seat hence the drop in oil pressure.

Any advice on my notes above greatly appriciated, allthough i will know more at the weekend. I will also take the Spark Plugs out and turn the engine over by hand when i am underneith.

I would like to hear from any UK Trans Sport owners on here is there are any. I think there are probably only 60 in the entire UK, very rare indeed.


Regards,
Paul Taylor ( Berkshire AACI Area Rep, Member 677 ), Reading, Berkshire. 1987 Camaro Z28 IROC-Z. 5.0 (305) V8 TPI, Auto,75k Miles, Bright Red, 125HP Shot Wet Nitrous. B&M MegaShifter. FlowMaster Exhaust. 1/4 mile 14.249 @ 94.86mph. http://www.cardomain.com/memberpage/593110
1993 Pontiac Trans Sport SE 3800 TPI V6 with LPG conversion.

IROC -Z28, Drive it like you stole it !

The low oil pressure and the occasional loud bang makes me think of something I experienced once: a connecting rod bearing is badly toasted and the two halves pile up one upon another from time to time causing a sudden squeeze and jolt on the crank throw .. I suspect the oil filter has been changed recently and is not clogged, is it...My experience with FRAM filters is they clog very fast and then cause a considerable pressure drop, within a few, 2-3, weeks. I'm told they have a smaller area so the oil has to push across a more restrictive path. I stick with DELCO filters which let me with more pressure for a much much longer time....may be some would tell then they do not filter at all....lol....

Acutally no the oil filter is very dirty, as is the oil.
Will know more tomorrow when i drop the sump !!.

Hi all,

Today i pulled the sump on our 1993 Pontiac Trans Sport to inspect the Big ends and Main Bearings.
What a state !!!.
All the bearings are heavily pitted and some bearings even have Bearing material missing. The sump also had lots of metal flakes in the bottom. Amazingly the Crank journals look perfect, no marks or scoring at all.

So now i need to order a full Set of Big and main Bearings, but i am unsure where to go to get them. UsAutomotive UK said they can get them for about £160 for a full set but will take about 2 weeks.
Im sure someone on here said they knew a company that sold bearings in the UK ??

Here are the details.
1993 Pontiac Trans Sport SE MPV. 3800 V6 TPI. ( L27 )
Stock Connecting Rod Bearing inner diameter = 60.295 - 60.312mm
Stock Main Bearing Inner Bore diameter = 68.250 - 68.275mm

These sizes were taken from the genuine Pontiac Service manual. Also i note that Main Bearing No.2 has a Flanged Bearing. All other bearings are plain.

GMpartsdirect.com lists all the bearings @ approx $19 each, but only 1 main bearing is listed. They mention nothing of the Flanged Bearing that No.2 Journal requires, so i am a bit confused. They also dont sell a complete bearing kit. So i would rather go with someone that knows what they are doing.

Can anyone help !! Please......

Regards,
Paul Taylor.

Hi,
Have a look at www.cars-stripes.com, what I can see, they charge 129,50 euro for the bearings, and shipping from Germany to England is fast and unexpensive. Send a mail to Cars and stripes and tell them what you need, they usually answer fast and seems to give very good service.

Best regards

Niklas Martin

Well all new Big & Main bearings were fitted today.
Everyone i asked here in the UK, and on Forums in the USA said i would not be able to replace the upper Main Bearings without removing the Crank.

But removing the crank means taking the Gearbox off, removing the engine front cover and removing the timing chain. This was a big no no for me as i do not have a Garage, no Shed and just a small drive.

So i took some advice from my Dad. He told me to Slacken all Main bearing caps so they drop a few mm. Then remove one main Bearing Cap. Using a Trolly Jack handle wedge in the Block and try to pull down on the Crank. At the same time use a 0.4mm Feeler Gauge to help push out and slide the upper bearing from its Cap.

Worked a treat !!. I dont all the main Top bearings this way.
Tomorrow i will put the Sump back on. Rocker covers. Fill with oil and spin on the Starter to see if i have oil pressure. If OK then i will install new Spark Plugs and fire her up. Fingers Crossed !!.

Well the Trans Sport is all back together.
I span it over on the starter 1st to get oil pressure. It only took a few seconds and the oil light went out.

I fitted all 6 spark splug and attemped to start it.
She fired up right away. But the oil pressure is still not great. Only 20 psi at idle and 35psi @ 2000rpm.
The Pontiac Service manual says it should be 60psi @ 1850rpm.

Also if i rev the engine to 2000rpm and then let go, occasionally there is a small bang from the engine when the revs come back down.
It did this before and i thought it was a Spun Bearing. But it now has all new Big and Main Bearings.

Im now really lost for ideas and need some professional help with this car. But unfortuanately i cannot find anyone in the UK with experiance on the GM 3800 Series 1 V6.

Please Please someone Help !!!. :-(

I would bet you have a worn out oil pump. IT is an integral pump, meaning it's built into the timing cover, and cannot be replaced as an assembly. Repair involves a rebuild kit which includes new gears and pressure springs. Fix the oil pump soon, or you'll be replacing those bearings again.

Bit of an update.

Decided the current 3800 is toast. Lots of loose metal flakes floating around in the engine. Missing is probably a stuck or broken lifter.

So i managed to get hold of another 3800 engine in the UK. It has half the milage of my current one, and comes with a warranty.
So the Big engine swap starts next week !!.

Needless to say im not looking forward to it. But i am looking forward to getting this baby back on the road.

>"So the Big engine swap starts next week !!."<

Paul,

I would strongly suggest you have the auto. trans. rebuilt *if* you have to remove it to change engines. The stock 4T60E trans. has some design problems, but there are aftermarket parts/kits available to fix it right-especially the TCC/OD problem.

BTW, I shipped my 1995 3.8 Transport over to northern Italy a few years ago. There were a few others there, and they have GM dealers around Milan. It's back in the US now, with a weird intermittant electrical-ground problem I haven't been able to find yet.

Benesesso

Hi,

Well my Transmission was sweet prior to the engine dieing.
It was always very smooht and changed / locked up at the correct speeds. So im not going to touch it.

Paul Taylor.