I'm new here, so I would like to start by saying hello. I have been leaching off most of these forums for a while just reading but I can't seem to find a solution and I need to learn more and what better way than people on forums. So here is the deal.
I have a 87 Thunderbird TC 2.3 Turbo on top of a BW T5 5 speed manual. It seems like I don't have an exhaust leak pre-turbo, I checked the WG and it seems to be functioning properly but I can't get my turbo to spool over 6 pounds with my MBC's and it only boosts to 15 pounds@5000rpm with the WG vacuum line unplugged. With it unplugged the turbo should be screaming maxed out at 4000rpms. It still has the factory IHI turbo with internal WG. The only mods to the car is a MBC and a 3" down pipe, 3"high flow cat, 3" to dual 2.5" Y pipe and a pair of Jones Full boar turbo tube lers. It worked fine @ 15 pounds with no exhaust and just the stock 2.25 downpipe. I checked all of my vacuum lines, no leaks. No intake leaks. There is a very slight valve cover leak and my valves need to be tightened down a little, but only because they tick, nothing to bad.
So with a BC on it's capped at 6 pounds... no BC it can boost just extremely slow. Please, any insight would help. I'm at my wits end.
If it's not over-boosting with the WGA vacuum line disconnected, then your wastegate isn't functioning properly. It's possibly not closing all the way.
Also, the valves are not adjustable on the 2.3 (at least with the stock hydraulic HLAs), so it's unlikely you're hearing valvetrain noise. Most likely you're hearing the injectors. If it *is* valvetrain noise, you have other issues.
It's either a wastegate issue, or a large boost leak.
OK the waste gate does not work by Vacuum. It works with BOOST. The more boost going to the diaphragm the lower the engines BOOST. So if you disconnect the hose on the Diaphragm and you have low boost you either have a BAD turbo a bad waste gate or a big LEAK. Check to make sure the WG diaphragm mounting bolts are TIGHT. I have seen many loose and restrict the boost levels of the turbo. Just a shot in the dark. Also check the spring tension in the diaphragm. It should be very hard to move. I have seen a couple with broken springs Good luck
Yes, we know this. If it makes you feel better. I'll call it the boost reference hose that runs to the WGA.
If it's not over-boosting with the WGA vacuum line disconnected, then your wastegate isn't functioning properly.
I'll call it the boost reference hose that runs to the WGA.
Call it whatever you want it works on BOOST NOT VACUUM thats all i was saying.
Lets call the line the charge air side to the wastegate actuator HOSE. Thats its OFFICIAL NAME, This makes me FEEL BETTER.
Just curious was my post WRONG ????
By the way i use your products and i like them very much. No hard feelings i hope.
Thanks for the feed back guys, I'll go over all of these tomorrow. I had the turbo off not to long ago and the shaft had no play and the turbines spun like they should. I looked over the housing and it didn't have any cracks. I didn't really look at the WG that thoroughly though so I will definitely check it out tomorrow a few hours after I get home from work. My guess would be the WG is stuck open or the actuator could be bad. I'm also going to replace the vast majority of my Vacuum/boost hoses.
On to the tick. If you are familiar with the tick that Isuzu troopers make after around 60k miles, that's what it sounds like. I know you can't "adjust" them, per say, but I'm pretty sure they have a specific torque to be tightened to and I'm hoping they're loose. I'm going to replace the entire intake gasket sets so I might as well take a look at the valves. How would I go about checking my injectors? I plan to do compression tests as well. I have only had the car for about a year and it's my daily driver, so working on it is extremely limited. I have a lot of work to do on it, so any tips and not well known but common issues would be fantastic. Thanks again for all the replies guys.
The HLA'S are shimable not adjustable and they do not get TORQUED.
Mischeif, you need to check that tick out as soon as you can. The stock Ford slider cam has a really nasty reputation of lobes going flat on them. You do not want to let it go, as it will start throwing metal into the motor as the lobes get worse. Ask me how I know. If you've got significant milage on your motor, inspect the cam and followers. If they've gone bad, and you're short on dollars (who isn't right now?) pick up a cheap ranger roller cam and followers and swap them in.
The little 2.3 Ford with a stock slider cam isn't very tolerant of bad valvetrain setup/tolerances.
The ranger roller conversion is on the list of things to do. I guess it just got a priority boost. Thanks for the info.
I'll keep that in mind Tom, I didn't know that.... obviously. I'm still reletively new to these motors and just learning as I go. I have been a fan of fox bodies for a very long time.
An update. The tick starts about 5 seconds of idling after the car is started. A family friend who also happens to be a mechanic said it sounds like a lifter. I'm going to make a vid of it today and throw it on Youtube. I'll post a link later today.
NO problem just wanted to clear that up. Once you pull the valve cover you will see how it works. Sliders are BAD. Even years ago when the oils had loads of ZINC they went FLAT. Its important to use ONLY a ROLLER cam in a 2.3 PERIOD. Personally i would not use a Ranger Roller CAM. They are smaller than a stock cam and its power band is not very GOOD. Other than being cheap to buy i would not use one. Save up for a better cam like a 1.9 BO PORT ETC. Basically since i have been building 2.3 motors since they came out in the PINTO in 1974 they have been eating cams. And the early motors burnt pistons like CRAZY. Good Luck
Is the ranger roller a good performance cam? Not really. It is an ecnomical choice for replacing a worn slider cam? Yes. Have people made decent power with one? Yes. Do people still use slider cams in their 2.3's? Yes. Can a quality slider cam survive when the valve train is properly set up? Yes.
My next cam will be a reground ranger roller, as I can't justify laying out $350-$400 for a cam for my daily driver/work car.
Here, you can hear my nasty ping here (http://"http://www.youtube.com/watch?v=QGh90RmK6Qg").
I'm going to do the ranger cam swap for now, but this will eventually become a project toy. I truly love this car and want to restore it. If you care to give a listen and let me know, the exhaust sounds great, I'll put a vid up of the exhaust shortly.
The exhaust. You can still hear the tick, but considering that it's a stock engine it sounds pretty good. It kills me that my turbo isn't spooling up though. Perhaps this will also help some one tell me what's wrong? http://www.youtube.com/watch?v=iZiCdWKitHI
I now know why the turbo wouldn't boos. I took the turbo off again and the T3 gasket was missing it's bottom left corner. This is the second time in 6 months it has done this. Anyways, I'm waiting for the new gasket to get here, it has to come to TN from Ohio. Do you guys know any tricks to keep them from blowing out?
Well without a DOUGHT that cam is SHOT. Better replace it. And do not use a slider. You seem to be leaning twords a RR cam. That is a big mistake but its your car. Why go through all the work for a cam that will make your car less performance orientated. I would also replace the springs and valve seals with the cam change just me . I am also going to say that i have never trusted a slider cam no matter who sets it up. Setting up the cam means nothing for its reliability. Like i stated before a slider cam will go flat and they did even when OILS were FULL OF ZYNC. The Good part about a slider cam was i made a FORTUNE on them and piston replacement and my rod modification to fix the 2.3. Good luck and change out that cam ITS SHOT.
Well that means either the manifold is not true or the turbo is not true. But their is a replacement gasket that can fix that. Get a gasket from a CAT dealer they are twice as thick and they are triple layered. I have used them with good results when the s were warped. Or have the turbo and manifold ground or machined FLAT. Good luck
Well, if you're missing a big chunk of your turbo to manifold gasket, that right there could be your tick. Replace that before you decide if the cam is dead or not.
What gasket are you using? I use the ones that actually deform/compress when you install them to better seal. They're a multi-layer stainless one. Single use, but if you use the proper fasteners to hold the turbo to the manifold, they don't come loose, and thus only need to be replaced when your pull the turbo off the manifold.
The RR cam isn't really an upgrade in the performance sense, but more to the fact that it's a roller vs the slider, and today oil blends are nicer to it, as the rollers don't need the zinc that the slider cams to for lubrication. You can buy ZDDP additives should you decide to stay with a slider cam.
IF you need to pull the cam, as mentioned at the very least replace the valve seals (FelPro full-metal-jacketed ones) and look into the springs. Bo (of Boport) offers a nice drop in set with a higher pressure.
Fix the exhaust leak first, then look decide if you still have a noise.
Sorry about taking so long to reply, the gasket was because the manifold had a small piece that at first glance looked like it was missing but in fact, the original factory gasket, from all appearances, has become one with the . I took the exhaust manifold and turbo to a machine shop and the turbo was fine. That had to shave quite a bit off of the manifold to get it smooth though, now I don't even run a gasket. They broke three studs and not having any decent auto parts stores, I resorted to using M10.2 bolts and a lockwasher. Worked beautifully. The bolts are much higher quality than any studs I can get being Hardened steel.
The tick was not actually the cam, but rather a rocker arm. A nut backed off and it was tapping against the valve cover. Every one locally swore it would be the cam as well, with the exception of my grandfather, who shocked me when he told me he used to have a SVO Mustang and made my day with his wellspring of knowledge.
Oh, I was busy being rude and not saying thank you for your imput. :) I also forgot to ask what cam you would suggest as I do want to ditch the slider. I would rather do the RR swap as opposed to what is in there now. I can get a better cam at a later date, but if I were to shop for a cam, what would you guys suggest.
Before I make any choices, I'm really debating taking on this task...
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=190563963440&viewitem=&sspagename=STRK%3AMEWAX%3AIT#ht_979wt_1165
I have built endless 2.3 engines in my life and fail to envision a nut in the upper valve train other than the cam plate posi screws. Could you post a photo??????? Of this NUT. Unless the timing gear BOLT was loose. But i have never experienced that. Reason being is the bolt goes into the oil feed cavity of the cam and oil would have poured out like crazy. Their are no nuts under that VALVE cover or valve train that i know of.
Here is a photo of a 100% stock SVO head. As you can see their is no NUT under the valve cover anywhere. Please photo this nut i would be interested in seeing it. Unless your car has a SOLID CAM. If it has a solid lifter cam and the adjuster nut LOOSENED up that would cause the NOIZE. And in fact you did not mention if the car had a mechanical CAM. The STOCK SVO HAS HYDRAULICS. So as i listened to your video and if in fact your car has a solid cam and they loosened up that sounds exactly like a bad CAM. Not being on site its hard to tell what a noize IS. But what washiznitting the VALVE COVER. This is something i would like to see in a PHOTO.
http://i740.photobucket.com/albums/xx46/proguns/001-61.jpg
Well, I just got back inside from taking my car apart. A friend of my GF was the one who diagnosed the problem and I hadn't gotten around to fixing it yet. Now that I have taken off the Valve cover I see what you're saying. Her friend is an idiot, the cam is toast. For the time being I'm just going to replace it with a stock cam, I don't feel like messing with the head at this point and just need the car to get me to and from work for another two weeks when I get the other Turbo Coupe. Sorry for doubting you as I am here because you, after all, are more the expert than I. The second and fifth lobes are done. Not to far from flat actually. I haven't had much time from my jobs to do this myself, and now I wish I had. I'm still exploring this engine, one cover, bolt and part at a time. It's a lot different from the engines I have worked with in the past. Thanks again for your input... and being right. :)
Not a problem at all. When i heard your VIDEO i knew exactly what happened . That cam as i posted is TOAST. I have heard that NOISE 500 times in my life and its very DISTINCT. I knew it was not an exhaust leak. When you have built endless 2.3 motors and i specialize in them you know the difference. Years ago i worked with ford on an internal engine failure on the 2.3. Dont ask me the details. Some do not believe i actually did this work with Ford years ago. It got me thrown off many a site and if you are interested i will PM you on the details. One tip of advice DO NOT INSTALL A SLIDER CAM. You must install a ROLLER. If cost is a factor the cheapest cam in roller configuration is the RR cam. The cam SUCKS performance wise but it is a good cheap replacement unit. Its smaller than the stock cam but it works OK for a DD. Thanks Tom
I would not take on this project without help from someone that is firmilliar with this kind of MOD. Its not something for the NOVICE thats for sure. The price is OK but you have to fabricate many parts and special pistons are a MUST.
http://www.stinger-performance.com/suspensionparts.html
The pistons. They're expensive, but it's a project in the long run. I will do a roller swap eventually but I'm not in a position where I have the time do really dig in to the head so a RR swap or any other roller swap is out of the question right now. I am picking up another 87 TC that has every option and it will be my daily driver. I have no problems playing with the "Folvo" despite being a novice with these engines because it will be a project/toy once I get the other TC. It may take a while, but the best things always do, the short stroke 412 I had in a 91 Camaro took us forever. I enjoy a challenge, I love working on my car when I have the time and I enjoy building things that are unique and stand out. The Lima block has won me over. I am in love with Fox bodies, I have always preferred Borg Warner transmission and have a pretty awesome foundation, so needless to say I'm excited.
More to my point, no time to pull the head and change the valves, so no roller swap. I'm throwing a stock Melling cam in it, it just has to hold out long enough for me to put a better cam in the other TC and get it road ready.
You know you can use roller followers on a slider cam!!
To start with, you do not need to pull the head and change the valves to run a roller setup in your TC. It's no more difficult than putting a stock cam in it. For that matter, you can pickup a RR and roller followers cheaper than a new slider cam and followers.
As for custom pistons being a MUST HAVE for a Folvo swap, that's . If you're doing a complete rebuild, then yes, by all means purchase the Folvo swap pistons. If you have a good condition short block, you can either take the stock pistons out and have .080 milled off them to get the static compression ratio back down closer to 8.2:1 , or some people have even run them unmodified and had no troubles.
Personally if you want to go the VOLVO head swap using old TC pistons is not wise. The whole idea is to make HP and to cut the domes of old pistons is something you can do i do it all the time on NEW PISTONS. But starting out fresh i would true up the BORES with a MIN cut and OS pistons for the VOLVO SWAP. Just me i like everything new and in speck. But i firmly believe a BO PORT head is a better way to go. Just me as usual i could be wrong.
http://i740.photobucket.com/albums/xx46/proguns/006-7.jpg
Here is a set of pistons i machined down for a special application. Some might know why i did this if they are real SHARP and KNOW 2.3 Fords
I would think machined down pistons would lower compression allowing you to safely run higher boost, but aside from that I'm clueless on the subject, I would, however, like to know why. Tom, you should write a book on Turbo Fords. I would buy it, lol. Def be a one up to a Haynes or Chiltons.
Also, what do you think about the 2.5 lima head? And I would still like to know your opinion on what the best upgrade cam would be for me. What would be your Preference Tom? And you as well Jangus.
http://racerwalsh.zoovy.com/product/RWA1401/23-Turbo-roller-hyd-cam-400.html
http://racerwalsh.zoovy.com/product/RWA1431R/Racer-Walsh-Stage-1-Hyd-roller-camshaft-Ford-23L-OHC.html
I found these little guys, took me a while to find the site but once I found it I googled it and it seems fairly well spoken of. Just thought I would check for an opinion.
Tom, I would also recommend new pistons when going with a clean, ground up build. However, if you have a good condition short block, I'd still either cut the stockers, or not touch them, depending on my goals. As for a Boport head making more power, I'll have to argue that point. I truly don't think anyone has ever truly tapped the full potential of the Volvo head in a turboford application. I do know that the most power made with a Boport IRON head was 597rwhp. I believe, with the same amount of port work and reground cams, the Volvo head would surpass that number.
The pistons in your link are Sealed Power/Federal Mogul flat tops. I'd have to say you cut them to drop the static compression ratio down to a turbo-tolerant level. I'm curious why you didn't setup a rotary talble on your mill and duplicate the factory dish shape, thereby retaining the factory quench area? BTW, I really wish Sealed Power/Federal Mogul, or whoever owns them now, would start making those forged slugs again. It was alot easier to pony up $260 than the $400+ it takes to buy quality pistons now.
To address the OP's cam question: If you're going to go drop that much coin on a cam, go BOPORT. They're are other manufacturers that make a roller cam for the 2.3T, but the amount of work and testing that Bo's put into his cams specifically for the turbo applications, is probably unmatched.
From what I understand Bo is awol. So Bo-port is out of the question. What's second on the list?
Where did you hear Bo is AWOL? I know he's a busy guy, but he's always answered my questions when I've emailed him. I'd wait on a Bo cam.
On the forums. He's moving or something, this was a while ago, but his website is down as well. I guess I'll just try to hit him up on the forums then? I will probably just get a set of stock valve springs and a Crane .420 roller cam and followers from summit as this car needs to be running by Tuesday. This cam is not going to stay in this car, it will go in the other Turbo Coupe when it becomes my daily driver and THEN I will get a Boport, if I can. The cam I want to pay big bucks for I don't have a set up to support, so I will wait. It will only be about $250 for the cam and followers. http://www.summitracing.com/parts/CRN-194621/
I'm just going to get stock valve springs and replace them, as mine were stock... 24 years ago. I also discovered that my intake hose didn't have the spring in it, so it's been collapsing and sucking oil through my PCV. I'm going to clean the hell out of the PCV tonight and order a new one from Forced4 Thursday. I also get the pleasure of cleaning out my Intercooler, I'm just debating between Kerosene or alcohol as the cleaner. Alcohol would work better, but higher chance of "BOOM!" Either way it will have a few days to air out, so I'm not really worried about it.
So do you think that cam will hold up to the test of time in a daily driver? I'm not wanting a power house, but this is a decent mid band street cam and I have always respected Crane cams. Might not be quite as amazing as Boport, but for my applications it should be able to do almost as well, right?
If i am not mistaken CRANE is OUT OF BUSINESS??? But that cam is a nice choice for a DD. . I on the other hand have a different perspective of a cam. I like them NASTY to say the least. Not a bad cam for the money. It will work very nicely. Good luck
Are you sure its a ROLLER CAM. They are showing sliders on te web site. Either way you can use rollers on a slider cam i have dun it and it works.
Backstock? I thought they were too, or perhaps some one purchased them, again. Either way the cam is for sale, so I will probably pick it up. Aside from Boport, no one has given me a good second option for something I could simply buy today and have in a few days. Sitting in factory head, with stock intake/exhaust manifolds, stock VAM (soon to be the SVO VAM with CAI) Stock Valves, what cam should I be aiming for? I want to know both of your personal preferences so far as the metrics of a cam are concerned.
Well, in my stuborness I will be going with a roller cam. The one I picked out was a flat tappet, the thing that sucks is the roller followers are expensive... very expensive compared to the stock ones and other flat tappet followers. $234 worth of expensive. http://racerwalsh.zoovy.com/product/RWA1485/23L-Roller-Cam-Followers.html
The cam is actually not that bad all things considered. http://racerwalsh.zoovy.com/product/RWA1431R/Racer-Walsh-Stage-1-Hyd-roller-camshaft-Ford-23L-OHC.html
Can I use the rocker arms from the ranger swap with this cam? If so then I can pick up a set from a friend and save a few dollars.
Yes, you can use ranger roller followers on an aftermarket roller cam. Yes, new roller followers are very expensive. Bo's email and website are down. Call him @ 510-979-9211. You will glad you did if your looking to spend that on a cam.
That's the information I was wanting. :) All of it, that is. Well, Ranger roller followers, check. Valve springs, check. High temp paint for the valve cover, tomorrow. Calling Bo and finally ordering a cam, also tomorrow as he didn't answer tonight, safe to assume it's to late.
Boport Cam, lifters and valve springs will be on their way tomorrow. I got the 1.1 cam since I have nothing particularly special in my engine... yet. He told me about the exchange service they offer and after I explained what I will be doing to this car he said the 1.5 will be what I need to end with, but the 1.1 will give me the best for what I have now. My Roller rockers are on the way with an extra Ranger cam if any one wants to pick it up for cheap, lol. If not then I have a strange looking club. In the 10 minutes I spoke with Bo I learned a lot about this engine, so thank you for getting me his number. ;)
One more quick question... one more of probably many, do I need the Boport HLA's? I'm getting the ones from the Ranger as well, so will I need these?
I doubt the ones from the ranger will be the "wide band" style, which will allow you to shim them up for Bo's cam. So yes, you should use the ones Bo sends you. The oil groove in most HLA's available from the parts store's have a very narrow oil groove machined into them. The ones' Bo carries have a wider groove, which is why there refered to as "wide band". The wider groove becomes very necessary when you start shimming them up to make up for the difference in the stock cam, and one that's ground on a reduced base circle.
There is obviously more in this than I thought. I need to shim them up? Normally my grandfather always did my heads, so this is realistically my first hands on by myself head that I'm doing, so please be gentle as he is not in the physical condition any more to do what needs to be done... that and it's about time I started doing everything to my car myself. Any help, instruction or advice would be nice, this is not something I feel comfortable leaving to google. I'm going to scour Boports forums for some info as well.
Just a thought. When i first started to build HI PERFORMANCE 2.3 motors many MOONS ago the wide band lifters were not available. So i made my own by chucking them in the lathe and cutting a wide band in the body. I still do this today. But you will need wide BAND HLA'S if you shim them and BOW'S cams require shimming. Small base circle cams require this. Good luck on your venture. Now buy the valve spring tool from OTC and learn the proper shimming procedure. Once again good luck
Cam, valve springs and wide band HLA's purchased from Boport. $502 is not bad considering they will out last the life of the engine and give me the performance I want.
Ok, so Bo said it's going to be 2-3 weeks for my cam because he ran out of them. So I went ahead and put the ranger cam in it, much to my lack of desire, but I have to get to work. So I'll be driving around with the power reducing RR cam. You guys were not kidding when you said it sucks the juice out of this car, it really does. It's terrible. I did, however, discover that the tapping sound was a lifter that was broken in half, the cam probably had a little more time. I went to pull the lifter out and the wider part of it was broken about half way down. The other half was hell to get out. The ranger cam rattled for about 5 minutes but now it's quiet and hums like a sewing machine. My car sounds much more aggressive but has a lot less power, I can't wait to get that Boport cam in it. Thanks for all of your help guys, you're life savers.
The ranger cam does bring power down a bit, but not that much. Check your cam timing again. If you have an adjustable cam pulley, try advancing the cam a couple of degrees. If you don't have an adjustable cam pulley, get one.
x2
RR should have plenty of grunt down low and run out of steam around 45-5000rpm(relative to the stock slider). When I run the RR, I like to retard it 4* to help it breathe up top since they have more down low to start with.
Certainly not a performance upgrade, but an upgrade none the less, and cheap replacement to get yourself to work!
I agree with Gumby. I don't have an adjustable cam gear yet, but instead I gave my distributor a little turn to advance the timing a tidge when I got to work this morning. I noticed it was backfiring a little on back pressure and that cleared it right up. I probably set my aux gear a little off when I was putting the timing belt back on. Well, needless to say the problem is solved and it actually has more power than it did before, but obviously, with the valves in two cylinders hardly working at all I think carving a hole in the floor boards and pretending to be on the Flintstones would have been a performance increase. I'm happy for now, it serves the purpose, I just can't wait for my cam from Bo. I hate to tear it down again, but it's worth it. I think I need to replace my main bearing as well, I keep dropping oil pressure when it gets warm (did this before the cam swap) or, replace my oil pump. I didn't put this one in, but I'm pretty sure it's a high volume, and that's changing to a high pressure in a few days. Thanks for all of your input guys.
WORD OF CAUTION
DO NOT USE A HIGH PRESSURE OR HIGH VOLUME PUMP ON A 2.3 FORD. It will strip the teeth off the aux shaft and Dizzy gear faster than you can DREAM OF. As the matter of fact i use an NA pump in my builds with 10/30 oils only. Never EVER use a high volume or pressure pump. You can take that to the BANK.
Check your ignition timing properly. The RR cam is a DOG but it does make good power up to 5K. It should be at least comparable to a stock slider to some extent. If your cam timing is correct and your ignition timing is on you can retard that cam 4-6* and pick up some upper end power to some extent. Or just wait for your new cam.
Yeah, I got the power back. I'm sure my ignition timing is a little off on that aux gear so a little turn on the dist and it's good. I have it perfectly in time and I really don't feel like messing with it for a couple of weeks, so I'll just wait on the Boport cam. Thanks for the heads up on the oil pump info, that would have def pissed me off... and put me up that creek without that paddle. Some have told me that it could be a bad oil pressure switch... but it's strange.
Basically, the problem is that it holds pressure to the top of the oil pressure gauge when I first start the car. It holds this pressure till it warms up, once it's warm, if I sit at a light without bringing up the RPM's, it will bottom out on the oil gauge. The engine doesn't act any different, but of course, i don't let it sit down there either. If I keep it rev'd up to about 1700 - 2000 rpms it stays about half way up the gauge and almost all the way back up when I'm driving. If I'm moving and I push in the clutch and coast, it drops again. No major oil leaks, no burning oil. No oil in the water or vice versa. No strange sounds. I run 10/30 Mobile 1 Full Synth Extended Protection and a Mobile 1 Ext Protection filter. Before I put the Mobile change in I just ran Seafoam through a 1 week cleaning cycle in my oil (I had the pressure problems before this) with a fresh change of Castrol GTX Synth Blend 10/40 and a FRAM TG Filter (I hate fram and normally wouldn't put it on a lawn mower, but in the case that the oil and filter were coming off and out after a very light driving week, I thought it would be ok). So it's narrowed pretty well to one of these three things.
Oil Pressure Switch/Sensor
Oil Pump
Main bearing
I think I'll start at the sensor. It's 24 years old and even if it's not the problem, it may likely be part of it.... so where is it? :P
I had the same issue with the oil pressure gauge maxing out when the engine was started, and dropping to almost the bottom of the gauge when it warmed up. Changed the oil pressure sender and it was back to normal. I will be adding some real gauges to monitor the engine, so I don't have to rely on the factory ones. They're not known for their accuracy anyway.
I'm going to replace the oil pressure switch soon. I assume it's the miniature fuel filter looking thing by the driver side firewall corner of the valve cover? My oil pressure comes back up when I rev up the car or I'm driving, it only drops once the car warms up and is at idle.