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View Full Version : Type 4 oil pressure and sounds like?



MartinB
15-08-2013, 10:45 PM
I am hoping that there are a few people (one or two at least!) here who have more knowledge than I do in what a type 4 engine sounds like, and if I should be concerned over the sounds of my engine!

Ok, so I had a type 4 engine that I fitted about 25 years ago, which was about the same time as I found that the chassis had rotted out. I did manage to start the engine once at that time, but it was exceptionally rough, and never did hit the road... After having moved the car to Paul's, we lost the ecu, and found that many of the sensors were no good. (In fact one of the temperature senders had had the end cut off with a hacksaw; never quite understood why someone would have done that! - but did explain why the engine ran so badly; belching out black smoke and all...)

To cut a long story short (for now anyway... `¬), this was the state of the engine after having been left outside for a considerable number of years...

http://i1231.photobucket.com/albums/ee505/MarBinz/Odds/P1050267.jpg (http://s1231.photobucket.com/user/MarBinz/media/Odds/P1050267.jpg.html)

http://i1231.photobucket.com/albums/ee505/MarBinz/Odds/P1050873.jpg (http://s1231.photobucket.com/user/MarBinz/media/Odds/P1050873.jpg.html)

http://i1231.photobucket.com/albums/ee505/MarBinz/Odds/P1050880.jpg (http://s1231.photobucket.com/user/MarBinz/media/Odds/P1050880.jpg.html)


It took a lot of searching, but eventually we managed to replace a lot of the sensors and refurbished the rest;-

http://i1231.photobucket.com/albums/ee505/MarBinz/Odds/engineSml.jpg (http://s1231.photobucket.com/user/MarBinz/media/Odds/engineSml.jpg.html)

...that was now a couple of years ago (due to health reasons), but we have now spent the last few days finishing off the fuel and engine electrics and (to my surprise) managed to get it to start at the very first attempt! ...not only that, it seemed to run far better than it had previously!

The day before, we had turned the engine over on the starter only, to get a feel for there being some oil pressure.

So the video below is of the very first time (in 25 years) we tried to fire up the engine, and both Paul and myself were very surprised at how easy it started; we had assumed it might need to be coaxed into life; especially considering the state of many of the ecu wiring harness connectors. The fuel pressure climbed to 28psi, and the engine fired straight off;- (Had serious trouble getting these vids on to youtube, so hope they work - let me know if they don't please!`¬)

http://youtu.be/zgKCnHe4Vo8

After seeing how high the oil pressure was, we removed the sender and confirmed the sender and gauge by applying a known pressure 'T'd' with a know good gauge and found it to be accurate. We then fired up the engine a second time to warm it up over a period of 30 minutes;- (I've cut a lot out)

http://youtu.be/M05_29RSYaU

The big question (three actually) is what oil pressure should I expect; the manual says 42psi @2500rpm 28psi @ idle min. I'm getting 60psi (cold) and I thought there was a releif valve that prevents the oil going to the cooler if its over 42psi, but not sure if that means I will still be able to measure a pressure that is actually higher. In the second video, near the end, the engine has been warmed up for 30 minutes, and the pressure is 30psi @ idle , but goes up to 60psi at revs... so does this mean the oil won't be cooled at revs as the pressure is over the 42psi of the releif valve? ...should I be worried over this?

The second question is what should the engine sound like at idle? I've now watched / listened to this video several times today, and am aware (more so from the video than I could hear at the time - probably due to not fitting the silencer) that there is a 'wop, wop' noise at the very low revs, (sounds a bit like a manic 'Rolf Harris Wobble Board'), it does seem to go at higher revs, but wasn't sure if this was normal for this sort of engine; or would it considered to be a 'knock'?

Thirdly, there seems to be another slightly higher pitch 'pinkly' noise that sounds like someone tapping on a hollow piece of wood (or that dripping noise you get from an overflowing gutter dripping onto something), at idle when the engine is warmed up, and I'm wondering if that is anything to worry about?

Spacenut
16-08-2013, 09:12 PM
Hi Martin - sounds like a very strong engine, with the tip-top preparation we have come to expect from your build :clapping:

My memories of the T4 are now very distant, and mine was a carburettor 411 engine, but from the sound of it, the deep "wop wop" sound is merely due to the short exhaust manifolds. As the exhaust valve closes there is a partial vacuum created behind the exhaust gasses as they exit the manifold, which results in air being sucked back into the ports. Once you have an exhaust system connected this noise will disappear.

There appears to be a slight mis-fire at medium to high revs, but again this does not appear to be anything serious. It may have a number of possible causes though, ranging from ignition (points, timing, coil breakdown, dodgy HT leads etc.) to valve gear (poor seating, clearances, coked-up combustion chambers) via fuelling (I'm afraid I have no experience of Bosch K-Jetronic so someone else will have to comment on this, but you get the picture).

The oil pressure does seem higher than usual, and if the gauge and the sender are OK (I've had problems at both ends of the sensor cable in the past) then the obvious question is oil grade (too viscous?), condition of the bearings (all new?), or as you suggest, a faulty oil pressure relief valve. This latter issue might be a distinct possibility, as I believe it is not an uncommon problem on the T4 - in fact, Nova Nigel recently had a similar issue on his latest cooking T4, which resulted in the engine blowing the seals around the oil filter. Unfortunately he hasn't got to the bottom of the issue yet, so I can't say what the prognosis was, but obviously 20 years of sitting around could result in the ball bearing/spring type pressure relief valve getting clogged with congealed oil.

If a strip-down isn't on the cards, maybe some flushing oil will get rid of the deposits?

Otherwise I would say you have done an outstanding job bringing back an EFI engine from the grave!

Lauren

MartinB
16-08-2013, 11:50 PM
Thanks Lauren! `¬) You are quite right; having now fitted the old exhaust, the 'wop, wop' has gone, and the engine runs much smoother. We should have blown out the exhaust with the air line, as there was a lot of muck in there, but the engine soon did that job for us! Paul had the oil pressure relief out earlier, and the pressure is certainly now lower, although still goes up to 52psi on revs.

The engine certainly breaths a bit better with the full exhaust, and the slight miss on revs 'seems' to be better as well - we still need to check the timing with the gun tho (we could not get an identical vac advance unit, but managed to get one that hopefully is close from Francis http://www.francistuthill.co.uk/ who I've dealt with over the years and was a great help allowing me to rummage through some old stock; found quite a few bits that were most useful to us!)

Now with the 'quite' exhaust, we can hear a slight whistle on idle which we need to track down, but pretty sure its not a big issue... I'm much happier with the sound of the engine now, but it is amazing listening back to the video how tinny it sounds off the camera footage... I'm just importing the video now, but won't post it till tomorrow... One thing that is still a bit of a surprise (made me jump!) is it still spits out some flame on the run down `¬\

We now have the head temp fitted, although not convinced as to its accuracy as there does not seem to be any cold junction correction... but it is showing 300F, which is about right I think for just idling?

The alternator and regulator are also now fitted and running too.

Anyway, thanks for your feedback, I'll post the new vid to see what you think in the morning! :cheers:

letterman7
17-08-2013, 03:19 AM
Good job Martin! Having the EFI is the only way to go - no real tuning needed. I'm running into the same issue with my oil pressure and need to check that relief valve as well.. having never had a T4 before, could you post up a step-by-step with some photos of where the relief valve is on the case?

Rick

Spacenut
17-08-2013, 08:36 AM
Top job! 52psi sounds like a better reading, is there a way of adjusting the oil pressure relief? (something to change the preload on the relief spring perhaps?)


Now with the 'quiet' exhaust, we can hear a slight whistle on idle which we need to track down

This might well be an air leak, probably from the myriad of smallbore vacuum hoses, and could be all that is causing the "miss" at high rpms.

Flames on the overrun is fairly common on short exhaust systems, and is sometimes caused by leaking gaskets at the manifold joints - if air gets in here (usually following the vacuum left by the exhaust pulse), it can mix with fuel-rich fumes and ignite in the exhaust bores. Again, nothing serious, and as you say, quite exciting to see!

Lauren

MartinB
17-08-2013, 08:27 PM
Paul had already got the regulator wired up before I got there yesterday. We then spent ages trying to fit the cylinder head temperature sender which was supposed to fit under plug 3. Sounds easy until you realise that the plugs are recessed and the connector has to bend up the side of the plug while still sealing the plug in the block (after removing the original washer from the plug). If I had thought about this before I would have bought the sender at a time when we could have bolted it to the same position as the injection head temperature sender... hindsight is a wonderful thing! `¬) I didn't think it was possible to even get it to fit, but Paul managed to take an old plug and form the sender around it such that we could get the new plug to still screw in with it underneath.

After fitting the fan belt, we started her up for the third time. I checked the CO from each cylinder more out of interest than anything, and they all varied from 1.5-3.5 over time; but this was before warmed up in any case... (and with the enrichment control on the ecu set to wherever it had been!) (pretty boring video really, but its here for completeness?)

http://youtu.be/2sYIjZ7EtE4

We then fitted the old exhaust, and as mentioned should probably have cleaned it out first! With the exhaust now quieter we can hear a whistle coming from somewhere... will need to find this; although all the pipe work is new, there must be a source of the whistle; will try and find it later with a tube to my ear... (The engine really doesn't sound as tinny in the flesh as it seems on the video?)
The flames were also exactly as Lauren says, there is a small leak in the exhaust manifold connection. The engine does run smoother at revs (7:15 on the vid) with the exhaust on, but I think there is still a small miss on occasions. We are still using the old ecu loom which has been repaired, so we do know there are some not great connections in places which doesn't help either! `¬)

We also checked out the full adjustment on the idle enrichment control which gives adjustment down to 1.5 and up to 7.5, although she really struggles on the leaner mixture at idle...

http://youtu.be/kt55sZZV1kY

So this is the last video after having fully warmed up; the idle is not as stable as I'd like, and the miss can be heard at revs again; but there are still a lot of tweaks to be made / checked, as well as tracking down the whistles etc! Needless to say, after all this time I'm simple glad to know we actually have a method of propulsion for the Nova when its finished! (which still seems a long way off!)

http://youtu.be/s-A42BlXl8Q

P.S. the exhaust system here is not the one which will be finally used, which is why it looks rather tatty compared to the rest. But it is suitable for testing at least... `¬)

I hope to get round to adding some of the 'in progress' pictures at some point, as Paul set up his own zinc plating process which was applied to quite a few of the parts, and who also sprayed other parts with Electrox ... Seeing the difference in before/after of some of the parts is quite amazing! `¬)

MartinB
17-08-2013, 08:28 PM
Good job Martin! Having the EFI is the only way to go - no real tuning needed. I'm running into the same issue with my oil pressure and need to check that relief valve as well.. having never had a T4 before, could you post up a step-by-step with some photos of where the relief valve is on the case?

Rick

Hi Rick! `¬)

Paul had already removed / refitted one of the relief valves before I got there, so I cannot give you much in the way of step by step. But I can give you the following info and hope you can find the items. The two scans below are from http://www.amazon.com/Rebuild-Volkswage ... 0895862255 (http://www.amazon.com/Rebuild-Volkswagen-air-Cooled-Engine-models/dp/0895862255) so I hope its ok to put them on here?

http://i1231.photobucket.com/albums/ee5 ... s01001.jpg (http://i1231.photobucket.com/albums/ee505/MarBinz/Odds/OilPressureReleifValves01001.jpg)
http://i1231.photobucket.com/albums/ee5 ... s02001.jpg (http://i1231.photobucket.com/albums/ee505/MarBinz/Odds/OilPressureReliefValves02001.jpg)

I didn't even think to check to see if there was a second one yesterday... I will have to do so! I do know that the first one is in the left casing underneath by the oil filter, and the second (if fitted) is in the left casing at the flywheel end. They are easy to see as they look like a giant 'plug' but with a large slotted groove in them. Paul made up a special tool to fit in the groove, as the slot domes inwards. If I go over on Sunday, I will photo the tool and locations, and remove the items to show you what they look like. (and unless Paul has also checked the second one, this will still need to be done anyway)

From reading the above, it does imply that if there is only a single relief valve, then it will not actually limit the oil pressure to 42psi, but simply diverts it away from going through the cooler when the pressure is higher and the oil is cooler. It is only if you have the second relief valve fitted that the pressure is limited once the oil is warmed up. I'm not quite sure if the mechanism is only governed by pressure, as that then implies that if the pressure is above 42psi, it will never go through the cooler in any case? (if the first valve is working), so I can only assume there must be a temperature element as well? (other than just the change in pressure that occurs when the oil warms up). (or maybe I missunderstand how it works! `¬)

I have been reading that provided everything is less than 70psi, everything should be ok. (that is only based on this http://www.headflowmasters.com/vw-oil-p ... -body.html (http://www.headflowmasters.com/vw-oil-pressure-valve-body.html) which is concerned with having a replacement in the case of a low oil pressure... and the bizarre thing is that it seems to be talking about the first relief valve, not the second one which governs the overall pressure - they talk about doing away with the second which seems confusing based on the scanned page which said it was deliberately added; but I'm no expert on this so... at least there are some pics to illustrate there!)

But it is worth checking these valves to ensure they work ok. What sort of pressure are you seeing?

@Lauren
The seem to be implying on that site above, that the pressure can be adjusted by altering the spring length... I would think this would not be a good idea on an existing spring in an engine, as the root cause of an oil pressure change needs to be identified first... i.e. if a blocked oil way exists it needs to be cleared, not compensated for by altering the pressure relief?...?

letterman7
18-08-2013, 02:26 AM
Hi Martin,
Thanks for those. I've been reading all I can about these beast engines - a good forum is here: www.shoptalkforums.com (http://www.shoptalkforums.com) under the Type4rum section (currently down for maintenance for a few hours). According to some of the gurus there, the relief valves are somewhat misnomered - the "pressure relief" is actually the limiting valve and vice-versa. In any case, the larger flat bladed one at the fan side that you removed (and I will as well - I thought it was more complicated than that) seems to be the one that actually has little to do with regulating pressure per se - it simply bypasses the cooler when the oil is cold(er) and thicker. There is some nice diagramming here: http://www.thesamba.com/vw/forum/viewto ... sc&start=0 (http://www.thesamba.com/vw/forum/viewtopic.php?t=280293&postdays=0&postorder=asc&start=0) that shows the basic routes (on a T1 Beetle, but T4 is similar) but even I'm having some issues understanding exactly what's going on, but it seems that both valves need to float freely within their bores or problems start with blowing filters and overall high pressure, which is what I'm facing. At idle, I'm pushing close to 65psi; at highway speeds it oddly drops to around 45-50psi.

My plan is to put the car back in the air to get under the engine at some point this week to check both valves to see if one or both are sticking or plugged. I'm running straight 30 weight oil, which should be more than sufficient for the engine at this time of year. I'm just wondering if I can pull the plugs without having to drain the oil again!

bobbybrown
18-08-2013, 08:46 AM
if there is only a single relief valve, then it will not actually limit the oil pressure to 42psi, but simply diverts it away from going through the cooler when the pressure is higher and the oil is cooler.
This is correct, I was reading something that touched on this subject just a few nights ago.

MartinB
18-08-2013, 10:23 AM
Hi Rick, does your pressure go back up to 65 when you return to idle? ...and does your engine sound anything like mine? (without the whistle!`¬)

letterman7
18-08-2013, 01:34 PM
Generally, yes. Mine has dual carbs, so I have rather different sounds coming from the block than you would, and my exhaust is vastly different. Your miss might be a timing issue; the block appears to be either a 2.0 or 1.8L Porsche block - the VW Bus never had the oil fill on the top at the breather and the top load dip stick, unless that was added later. According to my spec book, timing for fuel injected varied depending on year of build, 1975 required 5°ATDC; 1976 to 1979 required 7.5°BTDC. I would try both of those settings to see which "runs" better and it might clean up the flame thrower effect as well!

MartinB
20-08-2013, 06:39 PM
Rick,
Went over on Sunday, and Paul had taken some photo's when he took out the valve. I've included the pic's below, including the 'tool'!

(quote in email from Paul);-
'The slot driver bit was made from a Halfords 3/8" drive 14mm Hex Bit. The plug slot is only 2.5mm wide and about as deep in the middle but gets shallower at the ends. The blade was ground to be a tight fit. It also has a slight curve to maximise the depth in the slot. All dirt and corrosion must be removed from the slot before removal, It's imperative to use a lot of hand force to press the tool into the slot while turning to prevent it slipping out.'

http://i1231.photobucket.com/albums/ee505/MarBinz/Odds/Tool01.jpg (http://s1231.photobucket.com/user/MarBinz/media/Odds/Tool01.jpg.html)

http://i1231.photobucket.com/albums/ee505/MarBinz/Odds/RValve01.jpg (http://s1231.photobucket.com/user/MarBinz/media/Odds/RValve01.jpg.html)

Spacenut
20-08-2013, 09:18 PM
They seem to be implying on that site above, that the pressure can be adjusted by altering the spring length... I would think this would not be a good idea on an existing spring in an engine, as the root cause of an oil pressure change needs to be identified first... i.e. if a blocked oil way exists it needs to be cleared, not compensated for by altering the pressure relief?...?

Hi Martin - yes, I quite agree. Altering the relief pressure could result in a blocked oilway going unnoticed and wreaking havoc!

Judging by your photographs the spring and plunger assembly don't appear to be jammed up with congealed oil, so that is one less possible cause to consider.

Lauren

Peter
21-08-2013, 08:30 AM
You could fit an adjustable pressure relief valve, mine is set to 80psi max on a 1600 type 2.

letterman7
21-08-2013, 03:00 PM
Thanks Martin! I fiddled with the engine a couple nights ago and I used that exact tool, ground to fit. Problem was I wasn't able to break the nut loose with a ratchet or even a breaker bar. Wound up using an pneumatic impact gun, which I really didn't want to do on an alloy case. It actually broke the first bit - the bit shattered on the first impact, so a second bit was brought in and that one held enough to loosen the nut. Was able to extract the innards and found that the plunger was, indeed, stuck at the top of the bore even though there was no residue or other issue that would hang the plunger.

Haven't had the car back out to see if that solves the issue or not.. maybe this weekend!

On a side note, some of the mid year engines have a second pressure valve on the side of the engine next to the #1 cylinder. Maybe yours has that?

Peter
21-08-2013, 09:12 PM
Next to number one? my second valve is next to #3, so are the engines that different?

letterman7
22-08-2013, 12:22 AM
Yes, type 4 (Bus and Porsche 914) have a completely different case.

MartinB
22-08-2013, 04:26 PM
I shall have to check that out... as yet I have not re-removed the cooling tin underneath to see if its hidden by that, but had not thought to actually look on the other side! `¬) Will have a look this w/e... cheers!

letterman7
22-08-2013, 07:46 PM
Might not have to remove the tin. Should be visible from underneath. If you have one, it should be on the side at the "tower" that runs above the taco plate on the bottom of the engine.

MartinB
24-08-2013, 08:20 PM
Found it Rick!

http://www.ephotomotion.com/914engine/page12.html

These are some usefull pages too! (the other valve is on page 8)

letterman7
25-08-2013, 03:09 AM
Yep, that's the one. My case doesn't have that, as it's a Bus case with only one valve. That, however, seemed to be the "sticking" issue with the oil pressure. Had the car out for a good long run today and the pressure was right where it should be once the oil warmed up - around 40 at idle and 45-50 at speed, so I'm a happy bunny with that. Having the 914 case is a good thing for you Martin. If memory serves those were built slightly heavier (more/different webbing) that will take more punishment than the Bus box.

*edit* upon looking yet again at my engine, I, indeed, do have that second valve, so that put my case between a '71 and an early '75. I'll check that plunger the next oil change...