Seven days under the car, Need oil pressure advice Options

[worn]

I was planning a road trip that turned into an engine swap.
After seven straight days spent crawling around uder the car, I have the new engine transmission etc attached and adjusted. So maiden voyage around the block: this is sweet. A couple of miles later the oil pressure falls to green light at idle. U turn for a mile home at 20 psi, keeping the revs at 2000. Ahem, this is the problem I built the engine for to solve!

Please help. This makes me want British sports cars for their reliability... (IMG:style_emoticons/default/headbang.gif) (IMG:style_emoticons/default/icon8.gif) (IMG:style_emoticons/default/headbang.gif) (IMG:style_emoticons/default/icon8.gif)

[Black22]

Same sender and gauge as previous engine?

[worn]

Same sender and gauge as previous engine?

Sort of. Yes, but I added a mechanical gauge on a tee at the engine, and it seems to confirm. Both VDO - I used to like their stuff, but that is certainly fading, because I have had failures with their products recently.

[76-914]

What is the mech gage reading when the idiot light is lit? Are you using a type 4 oil pump. Is this the original oil pump?

[brant]

it sounds like you just built this engine?

if so is this the very first time its ran?
what machine work did you do, and not do

there are a few things to check
brant

[worn]

it sounds like you just built this engine?

if so is this the very first time its ran?
what machine work did you do, and not do

there are a few things to check
brant

Thanks to both. I did build the engine. The first start ups had 30 - 40 psi at idle, driven by a new aluminum 26 mm type 1 pump. I did not machine the case, but did a lot of measuring and straight edging. Well actually I tapped and plugged the oil passages. I was careful lining up the oil pump with the case holes and made a spacer ring to pull it out about 40 thousandths to match better.
I have 1.7 case, and two liter heads. The new p and cs are 2056. CR is set at 8.4. The cam is type 73 with modifications (I am told it has some similarities to a Raby 9550). I am choosing my words carefully her J.R.
The rockers are Porsche elephants feet, and I set chromoly pushrods to length.

Sadly, the electronic and mechanical gauges show 9 psi at idle of 950 rpm.

Engine runs well, but as I expected goes way lean when the throttle opens. The oil has me spooked. All new Mahler bearings and I did a lot of micrometer work. All journals were at least up to new spec, not the wear limits.

Oh, head temp under the plug was at about 290-300 degrees vdo.

[brant]

it sounds like you did a good job
I built 2 engines with the same problem you are describing
oil pressure was too low for my comfort after 20 minuetes of warm up
things to check are:

1) - did you case line bore?
2) - were the rod big ends rebuilt?
- per the rod question above.... basically is there anywhere that the bearings could be allowing that oil pressure to escape when the tolerances widen from operating temp.
3) - did you change the oil piston relief valves?... some times (although very rare) the pistons can hang in the bore and create a situation where they are not closing and thus are allowing the pressure to relief off when you don't want them to. Also take some bluing compound and put it on the face of the valve. use a dowel rod in the bottom of the same piston and push the piston up into the bore. Check for sealing with the blueing compound at the interface of the piston face and top of the bore. My builder had a motor that didn't make this seal and allowed the bypass of oil pressure.... shrapnel from the previous engine demise had implanted itself into this sealing face of the bore preventing the piston from full closure
4) - did you blue print the new oil pump? what was the measurement of the pump face to the cover plate. Any gaskets in there?
5) - case sealents.... which did you use. how thick... one of my autopsy's showed too thick of a case sealant application that essentially kept the case halves from sealing tight enough to allow the bearing shells to be tight enough to build oil pressure when expanded at full operating temperature...... (essentially like having worn out bearings with too big of a tolerances allowing oil pressure to bleed off after everything warmed up)


There are probably a few more
this is a start
what can you add in response to the above questions?

[reharvey]

Sounds like you have to large a clearance in the bearings somewhere.

[r_towle]

I did not see anywhere what type of oil you are using?
What viscosity.

I would also suspect the oil pump itself, I like type4 pumps, they seem to last.

rich

[worn]

I did not see anywhere what type of oil you are using?
What viscosity.

I would also suspect the oil pump itself, I like type4 pumps, they seem to last.

rich

Thanks Rich,
I went with mobile 1 15-50. I find it hard to choose between seating the rings and protecting the cam. The type iv oil pump shaft had backed out. I could have fixed it, but decided not too. Opinions seem to vary. Yeah the oil is going somewhere and it could be the bearings, but I triple check everything, and still i do screw up. Still, out of alignment is more likely than out of size for journals and bearings. I used plastigauge where I could.

Thing I don,t quite get is what changed only a few minutes after startup. I know that viscosity and clearance change with heat, but this seems sort of like an all or none sort of deal.

[nathansnathan]

The shadek pump body is notoriously small. I have been living with low oil pressure at idle, I think on account of that for awhile. - it just slides right in, where the stock one you have to loosen case bolts - o-ringing it would be the ticket I guess.

[r_towle]

Again, pump.

Also check the relief springs and valves to make sure you did those right...
See the diagram in the manual and pull them out to verify.

I would not run it till you figure this out.
It may be simple, could be the pump...might be something internal.

Those type 1 pumps are mass produced and do have tolerance issues.
No opinion on that, just a fact.

For my money, I would replace that pump ASAP and see what happens.

You are a perfectionist, pull the pump and blueprint it.
It may just be to far out of spec to blueprint properly, and you will know quickly if the pump is suspect by going through that process.


Rich

[SirAndy]

Also check the relief springs and valves to make sure you did those right...

(IMG:style_emoticons/default/agree.gif)

I don't know much about building engines, but that seems like a good starting point.
(IMG:style_emoticons/default/smash.gif)

[worn]

Also check the relief springs and valves to make sure you did those right...

(IMG:style_emoticons/default/agree.gif)

I don't know much about building engines, but that seems like a good starting point.
(IMG:style_emoticons/default/smash.gif)

I simply cleanedthem to shiny new and put them back. Problemo you think? Engine coming back out? (IMG:style_emoticons/default/huh.gif)

[brant]

it sounds like you did a good job
I built 2 engines with the same problem you are describing
oil pressure was too low for my comfort after 20 minuetes of warm up
things to check are:

1) - did you case line bore?
2) - were the rod big ends rebuilt?
- per the rod question above.... basically is there anywhere that the bearings could be allowing that oil pressure to escape when the tolerances widen from operating temp.
3) - did you change the oil piston relief valves?... some times (although very rare) the pistons can hang in the bore and create a situation where they are not closing and thus are allowing the pressure to relief off when you don't want them to. Also take some bluing compound and put it on the face of the valve. use a dowel rod in the bottom of the same piston and push the piston up into the bore. Check for sealing with the blueing compound at the interface of the piston face and top of the bore. My builder had a motor that didn't make this seal and allowed the bypass of oil pressure.... shrapnel from the previous engine demise had implanted itself into this sealing face of the bore preventing the piston from full closure
4) - did you blue print the new oil pump? what was the measurement of the pump face to the cover plate. Any gaskets in there?
5) - case sealents.... which did you use. how thick... one of my autopsy's showed too thick of a case sealant application that essentially kept the case halves from sealing tight enough to allow the bearing shells to be tight enough to build oil pressure when expanded at full operating temperature...... (essentially like having worn out bearings with too big of a tolerances allowing oil pressure to bleed off after everything warmed up)


There are probably a few more
this is a start
what can you add in response to the above questions?

what are your answers to the above 5 questions?

[ThePaintedMan]

it sounds like you did a good job
I built 2 engines with the same problem you are describing
oil pressure was too low for my comfort after 20 minuetes of warm up
things to check are:

1) - did you case line bore?
2) - were the rod big ends rebuilt?
- per the rod question above.... basically is there anywhere that the bearings could be allowing that oil pressure to escape when the tolerances widen from operating temp.
3) - did you change the oil piston relief valves?... some times (although very rare) the pistons can hang in the bore and create a situation where they are not closing and thus are allowing the pressure to relief off when you don't want them to. Also take some bluing compound and put it on the face of the valve. use a dowel rod in the bottom of the same piston and push the piston up into the bore. Check for sealing with the blueing compound at the interface of the piston face and top of the bore. My builder had a motor that didn't make this seal and allowed the bypass of oil pressure.... shrapnel from the previous engine demise had implanted itself into this sealing face of the bore preventing the piston from full closure
4) - did you blue print the new oil pump? what was the measurement of the pump face to the cover plate. Any gaskets in there?
5) - case sealents.... which did you use. how thick... one of my autopsy's showed too thick of a case sealant application that essentially kept the case halves from sealing tight enough to allow the bearing shells to be tight enough to build oil pressure when expanded at full operating temperature...... (essentially like having worn out bearings with too big of a tolerances allowing oil pressure to bleed off after everything warmed up)


There are probably a few more
this is a start
what can you add in response to the above questions?

what are your answers to the above 5 questions?

I have never built an engine, but have been doing a lot of reading. Brant really seems to know these things, and has laid it out in a very logical order. From what I understand you're supposed to build (at least) 10 PSI for every 1000 RPMs, so even though you're on the low side, the engine does have *some* pressure. Though, would it be safe to assume this would probably mean a shortened engine life? Especially once the engine has some miles on it and loses some pressure over it's lifespan?

Brant, #5 is really interesting. I never would have thought of the amount of sealant affecting the clearances. How does one account for that then when the case is align bored and the initial clearances measured for the bearings?

[McMark]

Maybe you should take a minute and read brant's long post. He pretty much asked all the right questions.

Is the dash light hooked to a stock pressure switch?
Did you buy a pump modified for T4 use? Or did you just put it in?
Did you use a gasket between the pump and cover plate?

[jwc914]

Drain that oil and put it in your Honda accord. put straight 50 wt Castrol in. if you don't have 20 psi @ idle add 1 more quart. take 2 asprin and call me in the morning

[worn]

it sounds like you did a good job
I built 2 engines with the same problem you are describing
oil pressure was too low for my comfort after 20 minuetes of warm up
things to check are:

1) - did you case line bore?
2) - were the rod big ends rebuilt?
- per the rod question above.... basically is there anywhere that the bearings could be allowing that oil pressure to escape when the tolerances widen from operating temp.
3) - did you change the oil piston relief valves?... some times (although very rare) the pistons can hang in the bore and create a situation where they are not closing and thus are allowing the pressure to relief off when you don't want them to. Also take some bluing compound and put it on the face of the valve. use a dowel rod in the bottom of the same piston and push the piston up into the bore. Check for sealing with the blueing compound at the interface of the piston face and top of the bore. My builder had a motor that didn't make this seal and allowed the bypass of oil pressure.... shrapnel from the previous engine demise had implanted itself into this sealing face of the bore preventing the piston from full closure
4) - did you blue print the new oil pump? what was the measurement of the pump face to the cover plate. Any gaskets in there?
5) - case sealents.... which did you use. how thick... one of my autopsy's showed too thick of a case sealant application that essentially kept the case halves from sealing tight enough to allow the bearing shells to be tight enough to build oil pressure when expanded at full operating temperature...... (essentially like having worn out bearings with too big of a tolerances allowing oil pressure to bleed off after everything warmed up)


There are probably a few more
this is a start
what can you add in response to the above questions?

1. No
2. No
3. I cleaned the pistons and bores thoroughly, but used the original parts. Should have looked more closely at mating surfaces.
4. Yes. I lapped the pump body and gears on a granite plate. Not liking how the shradek type I pump lined up with the holes in the case, I fabbed an aluminum gasket at around 40 thou to pull the pump body out. I used permatex #4 I think. Of course I can no longer find it. It brushed on thin. The vw parts web site touted the excessive output of the 26 mm pump, but now I wish I hd gone larger.
5. Same sealer for the case, following the Wilson book.

Excuses: the rod bearings measured round and still showed honing marks. Passed with plastigauge. Same for other bearings except plastigauge less practical.

I am now at the end of my rope with the car. All winter long and all that money on parts and I am right where I started. The bright spot for sure is the help I have gotten here. Thanks.

[Mike Bellis]

Isn't Mobile 1 a synthetic oil? They always run thin and lower PSI after warm up.