Differing oil pressue.

quote:
Originally posted by Billylll

I'm still thinking it could be resistance in a ground connection to the engines gauge with the gauge reading lower and the pinned tachometer.
Bill

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Bill I'm sorry, just noticed I mistakenly said 10,000 rpm and meant to say 1,000 rpm.
Just to clearify, the tach needle was at zero before turning the ignition on, jumped to 1,000 rpm when ignition was turned on and after starting the engine the tach worked properly through the full rpm range.
The tach was never "pinned"/stuck. My bad.
I am now tending to agree with you that my oil pressure differential is electricaly related rather than mechanical. I'm thinking that if I can find out why the tach went to 1,000 rpm when I turned the ingition switch to on without starting the engine, I'll probably solve the oil psi defference between the engines.
 
I would start by wiggling the main engine harness connector. Lots of strange things happen when the main connector gets dirty or has condensation in it.
Bill
 
Having had recent (and continuing) similar issue with starboard side, sounds like sender. I've always had some difference between engines but ECM showed perfect. Found bad ground on sender during my recent "remote oil filter debacle". LIke a jackass, I didn't fix it yet but was able to do a temp fix to see that it was in fact sender related.
 
To answer the question about why not changing to a synthetic oil in an older engine; synthetic oils usually contain much more detergent than conventional motor oils. If you switch to a synthetic oil in an older engine you might break free some of the sludge build up, that formed over the years, and possibly clog some of the finer oil passages.
 
quote:
Originally posted by Neverending

To answer the question about why not changing to a synthetic oil in an older engine; synthetic oils usually contain much more detergent than conventional motor oils. If you switch to a synthetic oil in an older engine you might break free some of the sludge build up, that formed over the years, and possibly clog some of the finer oil passages.

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Ok, I think I understand what you were saying when you said you don't use synthitics. You were speaking of old engines that had run only on dino oil and I agree with you.
As I've said though, I do believe synthitic oil superior to dino oil and run it exclusivley in my newer engines.
 
Ok, lets start from scratch. First, why is the tach now regestering 1,000 rpm when the ibnition switch is switched to on?
A few years back I did wire a green led light into the upper helms ignition switches to show when the transmissions were in neutral(safety neutral ****ch dependant). Could that be a factor in the port engine(only) now showing the tach reading when switched to on?
Here's the link to the discussion on wireing the ignition switch to light up the green led light when in nuetral. Sandy told me how to do it and it worked like a charm.
http://www.boatered.com/forum/topic.asp?TOPIC_ID=148638
Of course I don't know if this has anything to do with the tach now reading 1,000rpm when switched on or not but felt I should at least mention it.
And I still don't know why my port engine's oil pressure guage's are now showing 30psi instead of the 40 psi when winterized last fall.
 
I have the same 1985 454's and still use SAE 30 Diesel rated oil (in gallon container), no problems after owning the boat for the last 17 years. Your engine calls for 30W, you should use it or even 40W. If you want to take risks with an old engine go ahead and use multi-viscosity or Synthetic oils.

I would drain the oil and check the oil pressure. Auto parts stores should have the oil available in the gallon.
 
If you have a multi pin connector open and clean lube it
 
quote:
Originally posted by Neverending

To answer the question about why not changing to a synthetic oil in an older engine; synthetic oils usually contain much more detergent than conventional motor oils. If you switch to a synthetic oil in an older engine you might break free some of the sludge build up, that formed over the years, and possibly clog some of the finer oil passages.

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Not a real concern. All modern engine oils contain detergent and have since about the 1960's. If the OP has been changing oil regularly all along, there is no sludge to 'break free'.

It doesn't work that way anyway. That's a continuation of a wives' tale from 50 years ago, when detergent oils first appeared. There were dire warnings against switching from non-detergent oil, for the same reason you quoted. As it turned out, the sludge never 'broke away' and clogged filters. It was gradually washed away with no ill effects other than possibly increasing bearing clearances as the sludge was removed.

If the OP's engine does in fact have lower oil pressure than before (not determined yet), it'd be because of the viscosity change.

My .02
 
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