Heavy breathing

General Chat About Engine Build

Moderator: phpBB2 - Administrators

Post Reply
DaveEFI
Forum Contributor
Forum Contributor
Posts: 3964
Joined: Fri Feb 26, 2010 4:27 pm
Location: SW London, UK

Heavy breathing

Post by DaveEFI » Wed Jun 13, 2018 9:54 am

Think that's what our US cousins call it.
My SD1 EFI has done lots of miles. Can't be certain due to it being clocked before I got it, and a few speedo drive failures in the 30 years I've had it, but about 250,000. It still runs very well indeed - better than when near new. Things like the cam have obviously been renewed. Heads are ST1 I bought from someone on here.

I was intending doing a full re-con on a 3.9 I have lying around, but have way overspent on buying a Boxster for everyday use. So money will be tight this year.

It is leaking oil from virtually every orifice. Crank pulley, rocker covers, dumpy dizzy. Even out of the breather input on the rear of the NS rocker cover. This weekend, it popped the dipstick up, and oil dribble onto the exhaust manifold, so lots more smoke and smell. I've checked the breathers are all clear. It doesn't seem to smoke much at all from the exhaust, though.
I have lots of spares in stock including all gaskets and seals. Don't mind spending time on it, but not a lot of money at this point.
Am I right in assuming it can only be ring/bore problems? Any mods I could do to the breather system to cope with this pressure until I can afford a proper fix?


Dave
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y

garrycol
Getting There
Getting There
Posts: 307
Joined: Thu Jul 16, 2015 2:47 pm
Location: Canberra, Australia

Re: Heavy breathing

Post by garrycol » Wed Jun 13, 2018 1:18 pm

DaveEFI wrote:
Wed Jun 13, 2018 9:54 am
but have way overspent on buying a Boxster for everyday use.
DaveI didn't realise you were a hairdresser - buying a hairdresser car :lol:

Seriously though it sounds like an old engine as you have said and what you describe is classic blow by where combustion gases are getting past the rings and pressurising the lower end. I guess it is at the start as the oil control rings must still be doing their job as you are not burning oil - maybe the combustion gases going down are keeping the oil out of the combustion chamber. I guess the gases are then being sucked into the inlet manifold and burnt.

At this stage I dont think there is not a lot you can do as the job of just chucking some rings in for a quick fix is not a quick job. What you could do is try putting in what we call old engine oil - oil that is designed for old smokey engines - it is a lot thicker and reduces oil usage but also as it sticks to the rings can reduce blow by. Down side is that it is thick and may not work as an oil all that well in colder climates when the engine is worming up. But you have nothing to loose.

As it is not blowing smoke I would continue to use (especially as you are not using it to drive to your hairdressing business) and plan for the inevitable - either the other engine or a rebuild of what you have. The current engine could last a while yet before it starts polluting the atmosphere.

Good luck with it and the Boxster

Garry

DaveEFI
Forum Contributor
Forum Contributor
Posts: 3964
Joined: Fri Feb 26, 2010 4:27 pm
Location: SW London, UK

Re: Heavy breathing

Post by DaveEFI » Wed Jun 13, 2018 2:48 pm

I know why they're known as hairdresser cars. They run 'ringlets' round a 911 on the twisty bits. And 'wave' goodbye to most others on the road with an 0-60 for just over 5 seconds. :D

But seriously - was wondering if I could improve/enlarge the crank breathing in some way? Even some form of catch tank? If I have a go at stopping/minimising the leaks. Don't mind hacking about the rocker covers - have spares.
Dave
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y

sidecar
Top Dog
Top Dog
Posts: 2354
Joined: Sun Feb 04, 2007 9:52 pm

Re: Heavy breathing

Post by sidecar » Wed Jun 13, 2018 2:51 pm

It may well have blown head gaskets, they quite often allow combustion gases into the valley area of the engine, the whole engine is probably tired but the thing with these V8 lumps is that they keep on going and they don't even rattle. The usual re-build type of work would sort it out.

DaveEFI
Forum Contributor
Forum Contributor
Posts: 3964
Joined: Fri Feb 26, 2010 4:27 pm
Location: SW London, UK

Re: Heavy breathing

Post by DaveEFI » Wed Jun 13, 2018 5:29 pm

Interesting. I fitted the 'new' heads a few years ago, leaving out the outer row of bolts. They'd been planed for composite - and both their surface and the block ones looked very good. The composite gaskets came from a local place - I now know isn't renown for quality. I'd sort of ruled out head gasket problems as it goes so well.
Dave
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y

User avatar
stevieturbo
Forum Contributor
Forum Contributor
Posts: 3497
Joined: Sat Nov 18, 2006 6:22 pm
Location: Northern Ireland

Re: Heavy breathing

Post by stevieturbo » Wed Jun 13, 2018 11:43 pm

Log pressure in the crankcase just to see, and then you can make breather modifications to see if it does reduce pressure, along with reduced leaks.

If there is no significant pressure in there to cause leaks, then it may just simply be down to worn or old parts just leaking.
9.85 @ 144.75mph
202mph standing mile
http://www.youtube.com/watch?v=XgWRCDtiTQ0

DaveEFI
Forum Contributor
Forum Contributor
Posts: 3964
Joined: Fri Feb 26, 2010 4:27 pm
Location: SW London, UK

Re: Heavy breathing

Post by DaveEFI » Thu Jun 14, 2018 8:34 am

I'm guessing it has to be excess pressure, since oil is being forced out of the *inlet* breather at the back of the NS rocker cover.
Is there an easy way to test if it is a a rings problem or head gasket? A head gasket I could change. Rings would have to wait for a full overhaul.
Dave
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y

DaveEFI
Forum Contributor
Forum Contributor
Posts: 3964
Joined: Fri Feb 26, 2010 4:27 pm
Location: SW London, UK

Re: Heavy breathing

Post by DaveEFI » Wed Jun 20, 2018 2:35 pm

I've bought a leak down tester from Ebay. Looks to be of similar quality to the rad pressure tester I bought some time ago, and has done good service for DIY - perhaps the same maker. Gawd knows how they do it at the price.
I'll not be able to use it until next week, though. Will report on how it goes.
Dave
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y

User avatar
stevieturbo
Forum Contributor
Forum Contributor
Posts: 3497
Joined: Sat Nov 18, 2006 6:22 pm
Location: Northern Ireland

Re: Heavy breathing

Post by stevieturbo » Fri Jun 22, 2018 9:35 am

If it was the HG causing the issue...I'd think there would be other pretty major symptoms too ?

An RV8 deck is fairly solid...so where would combustion pressure get from the cylinder into the crankcase ?
9.85 @ 144.75mph
202mph standing mile
http://www.youtube.com/watch?v=XgWRCDtiTQ0

DaveEFI
Forum Contributor
Forum Contributor
Posts: 3964
Joined: Fri Feb 26, 2010 4:27 pm
Location: SW London, UK

Re: Heavy breathing

Post by DaveEFI » Sat Jun 23, 2018 4:31 pm

Thing is I used composite gaskets from what may have been a dodgy source.

A combustion leak into the valley is I'm told not unknown. But even one into a pushrod hole through the head would find its way into the crankcase.
Dave
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y

sidecar
Top Dog
Top Dog
Posts: 2354
Joined: Sun Feb 04, 2007 9:52 pm

Re: Heavy breathing

Post by sidecar » Sun Jun 24, 2018 8:15 am

stevieturbo wrote:
Fri Jun 22, 2018 9:35 am
If it was the HG causing the issue...I'd think there would be other pretty major symptoms too ?

An RV8 deck is fairly solid...so where would combustion pressure get from the cylinder into the crankcase ?
I've seen loads of head gaskets that are starting to fail but the engine has still been running OK, admitantly they have been tin gaskets, you can see brown stains across the gasket faces running towards to valley area of the engine, the combustion gasses then cake the valley area in black exhaust soot.

sidecar
Top Dog
Top Dog
Posts: 2354
Joined: Sun Feb 04, 2007 9:52 pm

Re: Heavy breathing

Post by sidecar » Sun Jun 24, 2018 8:17 am

sidecar wrote:
Sun Jun 24, 2018 8:15 am
stevieturbo wrote:
Fri Jun 22, 2018 9:35 am
If it was the HG causing the issue...I'd think there would be other pretty major symptoms too ?

An RV8 deck is fairly solid...so where would combustion pressure get from the cylinder into the crankcase ?
I've seen loads of head gaskets that are starting to fail but the engine has still been running OK, admitantly they have been tin gaskets, you can see brown stains across the gasket faces running towards to valley area of the engine, the combustion gasses then cake the valley area in black exhaust soot. With this sort of failure the engine does not even lose any coolant as the coolant passages are not affected, the engine just carries on chugging away and does not appear to have any issues.

Post Reply

Return to “Engines Area”