Oil pressure sending unit(s)?
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Boat Maintenance
Forum Discription: Discuss maintenance of your Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=41907
Printed Date: November-16-2024 at 12:45am
Topic: Oil pressure sending unit(s)?
Posted By: gt40KS
Subject: Oil pressure sending unit(s)?
Date Posted: September-11-2017 at 9:49pm
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I've had this question since the day I test drove the boat and it's been bugging me ever since, just hasn't been high on the priority list, Now it seems the week is starting off a bit slow here on the forum so I thought I'd ask. Don't know why someone did this, but I'm guessing, like the temp senders, there are 2 oil senders - figure one to the gauge and one to the ECM, correct me if I'm wrong. Regardless, what's got me perplexed is why they had done this:  I've seen pics of many other GT40's and don't recall ever seeing this mess. If someone can tell me which sender goes where (pics would be preferable) I'd appreciate it. ------------- JCCI 1995 Ski Nautique GT40 |
Replies:
Posted By: gun-driver
Date Posted: September-11-2017 at 10:32pm
| Yea that's not right I'll see if I can snap a photo of mine tomorrow. The bell shaped one on the end goes to the gauge. |
Posted By: gt40KS
Date Posted: September-11-2017 at 11:10pm
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Thanks. Through a bit more research I'm pretty sure the smaller one is the oil slow switch and I finally came across a couple pictures, albeit fuzzy ones, where it appears they both do go to that location. However, definitely not in that configuration - the wires are both stretched to their maximum and it makes it kind of difficult to R&R the filter. A good pic of the proper adapters and their lengths would help greatly. ------------- JCCI 1995 Ski Nautique GT40 |
Posted By: KENO
Date Posted: September-11-2017 at 11:11pm
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Here's a picture from somewhere here on CCF It looks like with a little wrench turning you could have things oriented the right way with the sending unit angled up instead of down and the slow switch also angled up. Maybe Paul's picture tomorrow will show it more clearly, but it looks like you have all the right pieces and with a little work you could have things oriented the way they should be 
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Posted By: 63 Skier
Date Posted: September-11-2017 at 11:32pm
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What is an oil slow switch? Yes, seems like with a partial turn of the block fitting you can take all the tension off the wires. ------------- '63 American Skier - '98 Sport Nautique |
Posted By: KENO
Date Posted: September-11-2017 at 11:36pm
| On low oil pressure it puts the engine into limp mode limiting rpm's to around 2500. |
Posted By: 63 Skier
Date Posted: September-11-2017 at 11:38pm
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Thanks Ken. Why do they need a 2nd sensor, couldn't they read the signal from the main sending unit? Just curious. ------------- '63 American Skier - '98 Sport Nautique |
Posted By: KENO
Date Posted: September-11-2017 at 11:50pm
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From the same old thread as the picture I think the switch is just that, at 5 psi decreasing it activates the SLOW mode and at 5.1 or so increasing it's deactivates the SLOW mode Just a make or break switch like the old "idiot lights" in cars. Probably good to have redundancy too. A bad sending unit won't cause the engine to go into limp mode and if you have a bad SLOW switch you'll be in limp mode but can verify that your oil pressure is still good and disconnect the SLOW switch to get back home at normal speeds.
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lewy2001 wrote:
Posted By: 63 Skier
Date Posted: September-11-2017 at 11:54pm
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Thank you. Now that I see that I remember seeing the acronym in either that or another thread. I can't remember s%#t these days. ------------- '63 American Skier - '98 Sport Nautique |
Posted By: gt40KS
Date Posted: September-12-2017 at 3:32am
Believe it or not, that's the first thing I tried. The main fitting on the block is bottomed out and will not turn any more and backing it out a bit loosens the threads so much in just a half turn I'm afraid it will start leaking. Seems to me that fitting is about twice too long anyway, so I figured it was a "home brew" someone came up with at some point. If it's the correct part, I suppose I'll have to try some thread sealant and back it off. It gets so loose though, does anyone have any suggestions on what product to use? ------------- JCCI 1995 Ski Nautique GT40 |
Posted By: 8122pbrainard
Date Posted: September-12-2017 at 7:02am
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Joe, The problem with using any type of sealant on the nipple adaptor is the engine block is the ground source for both the pressure sender and the low pressure switch. The best fix would be to use a die on the nipple to cut the threads slightly deeper. This would be a "trial and error" on how much thread needs to be cut so the nipple 45 end sits vertical. I suggest the die and not a tap since with tapping the block deeper there's a chance of getting metal cuttings into the oil passage. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: Duane in Indy
Date Posted: September-12-2017 at 7:24am
All pipe dies that I have used have too much of a lead in taper to cut threads up to a shoulder. The hex adapter is "bottomed out" anyway. Sounds like cutting the threads deeper even if you could would only make things worse. A different hex adapter might have the thread started differently and might orient it correctly. Cutting the external thread off of the hex piece and drilling and tapping for a common nipple is probably the easiest fix, if you have the tools. Easy fix for the correct tools and hard fix if you don't. edit, agree with Pete on no sealant ------------- Keep it as original as YOU want it 1978 Mustang (modified) |
Posted By: Duane in Indy
Date Posted: September-12-2017 at 7:39am
Zach was down the other day and was not crazy about my store bought cast iron tee for my oil pres sender. He has seen some of them break due to vibration and suggested that I replace it with a stronger piece. Made one up out of 6061-t6 billet aluminum  gt40KS If you can't figure it out then send it to me and I'll fix it. Duane ------------- Keep it as original as YOU want it 1978 Mustang (modified) |
Posted By: 8122pbrainard
Date Posted: September-12-2017 at 8:30am
Yes on the off the shelf fittings and a nipple. If you want the sender to be vertical like original, a 45 street el on the end of the tee will work.  ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: 63 Skier
Date Posted: September-12-2017 at 9:12am
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I think Joseph can just use a 2" nipple and a 45 or a street elbow if there's room to spin it in, with either just connecting to his current brass T and nipple. I guess the punchline is there's several very easy options to orient the senders in a better position. Duane, I tend to use brass fittings, should I be looking at aluminum for stuff like this instead? ------------- '63 American Skier - '98 Sport Nautique |
Posted By: Gary S
Date Posted: September-12-2017 at 9:22am
drakeautomotivegroup.com has new oil pressure sender extensions for 25.00. They are listed in the Mustang catalog on page 88 of their PDF. Keep it original Pete  ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: Duane in Indy
Date Posted: September-12-2017 at 10:05am
I lean towards aluminum because of it's light weight. I made all the fittings out of aluminum on my airplane because of the weight savings. My brackets are titanium. Brass is fine for these applications. ------------- Keep it as original as YOU want it 1978 Mustang (modified) |
Posted By: KENO
Date Posted: September-12-2017 at 10:18am
I figure that statement above is real accurate. I also think that since you don't have to worry about a mechanical fuel pump you could get the sending unit and switch further away from the oil filter and more in front of the block off plate for the fuel pump and closer to the block. It would make for easier filter changes That long fitting originally was needed to get the sending unit out far enough to clear the filter and the pump on the carbureted engines with a mechanical pump. Any decent hardware store should have everything you need, It's a combination of 1/4 and 1/8 inch pipe threads on the different fittings |
Posted By: JoeinNY
Date Posted: September-12-2017 at 10:41am
Agreed, and I wouldn't get too crazy with making this rocket science, however I did go a little too cheap in this direction once and used some cheap thinwall Chinese plumbing pieces from the hardware store that was open on a sunday and ended up with a crack that cost me a perfectly good 408 stroker with about 20 hours on it... With a switch and a sending unit on it there certainly can be some weight on the end of that lever so using hydraulic type fittings on there is probably good practice. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: gun-driver
Date Posted: September-12-2017 at 1:11pm
I need to get licenses on my pictures  That's a pic of my motor when I pulled it to replace the heads, cam and clean up and then Lewey used it to show the sensor for the thread. Can't get picture to post! this not having photobucket is killing me, I have to get set up on something for my iPad. So what everyone said above is correct it needs to be reoriented up. I'm guessing the PO replaced the brass piece or it would be painted black also. If you can't get it reoriented by taking it apart and cleaning up all the threads the brass nipple and tee from a hardware store would certainly work. You will probably have to use 1/4-1/8 reducer/bushing in the block than a 1/8" nipple and Tee as I don't think you will find a tee that is 1/4" in and 1/8" X 1/8" out. |
Posted By: gt40KS
Date Posted: September-12-2017 at 9:44pm
Wow, spend the day working outside and come back to all this!! Thanks for all the replies and ideas. I guess this is one of those brain dead things that you wonder "why didn't I think of that?" But in all honesty, since I'm very new to direct drives and CC in general, I was figuring I'd better ask first instead of screwing something up and THEN asking  ------------- JCCI 1995 Ski Nautique GT40 |
Posted By: gun-driver
Date Posted: September-12-2017 at 11:45pm
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http://imgbox.com/IBCW9WVs" rel="nofollow - http://imgbox.com/IBCW9WVs Best I could come up with |