TR7 oil pressure/crankcase pressure

[johnrip]

I had my TR7 engine rebuilt 5 years ago. It is USA spec, and I removed the air pump and disconnected the EGR piping. Ran great since then, and had no oil leaks (what a pleasure). Recently, after 5000 or so miles, I stated having to work on several oil leaks. Fuel pump seal, rocker oil filler cap, even once some small amount came up through dipstick tube. Lately, my spin on fuel filter adapter is leaking badly. So here is my question:
1-Could the spin on filter's small seal be non-seated, so that the oil is bypassing the filter and causing an increase in oil pressure around the adapter?
2-Is my oil pump spring stuck or is it causing too high oil pressure? (I can not check this myself, I will have my mechanic check pressure)
3-Could this be crankcase emission pressure? All piping and carbon canisters are in place?
Any ideas? I am going to reinstall the old oil canister this week, and see if that solves the leak...but I feel more is going on. I would like to solve this before I store the car for the winter. Any ideas will be appreciated...thanks JOHN

[saabfast]

Try a compression test, it may be worn rings/bores causing crankcase pressurisation. How well does the car run, does it use oil?

Alan
Saab 9000 Stg 1
Saab 9000 2.3 FPT Auto (now gone that others might live)
Saab 9000 2.3 LPT Auto
'81 TR7 DHC

[dursleyman]

I agree with saabfast, if you had oil coming up the dipstick that sounds like crankcase pressure. Could be ring/piston trouble or just a breather blocked. Check for blockages in the beather pipes and get a compression test done.
Happened to me recently when I broke a piston ring.

Russ

1980 TR7 Sprint DHC
Dursley
UK

http://tr7russ.blogspot.co.uk/

[johnrip]

The car starts and idles and runs well. It does use a very small amount of oil, but I think that it is from the leak. Also, The dipstick oil was only observed once...It may be a abnormality.

[Workshop Help]

When it comes to diagnostics of the engine condition, please use a vacuum gauge. It would fill my very being with such joy to know you have a steady needle at the 20" line at the 180 degree operating temperature. With this reading, you would need NOT to perform a compression check, or a timing check, or a carburetion check. You would know your engine condition is right where it should be.

Try it, you'll like it!

Mildred Hargis

[johnrip]

Mildred,
You have answered my questions and helped me several times in my tr7 life..thanks!
Can you give me a little bit more detail on how and where I would connect the vacuum tester? All the vacuum pipes seem to be clear, I am not sure the anti run on valve is working, so could the manifold breather that is connected to the anti run on valve cause the issue?Thanks John

[Workshop Help]

Yes. Attach the vacuum gauge hose to the spigot that feeds the flapper door vacuum line. This spigot is directly over the 1-2 intake runners on the intake manifold. Simply pull loose the line at the spigot to attach the vacuum gauge hose. By disconnecting this line, the flapper door will stay open allowing an unfettered air flow which will give a smooth constant draft thru the carburetors.

If you're the especially fussy sort of person, it is possible to attach a second identical vacuum gauge to the port feeding the vacuum signal to the brake booster. This second vacuum reading would provide a report from the two rear cylinders and any variance with the front two cylinders.

Mildred Hargis

[bmcecosse]

Be aware that oil pressure and crankcase pressurisation are not linked in any way. You need to check the breathers are clear - and a simple test for crankcase pressure is to remove the oil filler cap, and rev up the hot engine - is there a plume of smoke/fume? The oil pressure leak around the filter etc is just a poor seal there - try a new one. A compression check will tell all about general piston/ring/bore/valve seat condition. Do it on a HOT engine, all 4 plugs removed, and the throttles held open. I'm sorry 'Mildred' to disagree - but I know of absolutely no useful purpose for a vacuum gauge on a motor car engine. The readings are entirely dependent on the throttle opening and engine revs.... And if just for carb balance - then a rubber tube and my ear tell me all I need to know. I do use vacuum gauges - two of them - when I'm driving steam locomotives ! They tell me if the brakes are working........[;)]

[Workshop Help]

'There are none so blind as those who refuse to see.'

'Let there be no shame cast upon the recalcitrant as they can only learn in their own good time.'


Mildred Hargis

[johnrip]

bmcosse-I revved the warm engine and air pressure came out, but no smoke/ So what does this tell me? Could the crankcase pressure be escaping from the oil leak area at the filter?

[Hasbeen]

Hi John, I hope you enjoyed cleaning up after that. The timing chain directly under the filler cap does tend to throw a lot of oil around, when revved with the cap off.

I doubt the air coming out would tell you much, unless you know how much was coming out previous to your new oil leaks. All engines blow a little to a fair bit, even when in good condition, from the crank case, that is why they have engine breathers.

The most important thing you can do is a compression test. That will tell you if the rings are not sealing well on one or more cylinders.

To answer your questions.

1/ No. All the oil leaks back to the sump/crankcase via the various bearings it is lubricating & cooling. It introduces no sump pressure as it does so.

2/ No same as above.

3/ Yes. Do that compression test, that will tell you.

Suggestions.

Tighten the fuel pump bolts. Replace the gasket if leak persists. It can usually be done without even removing the hoses.

Oil filler cap, fit a new gasket in the cap. Buy the right thing, they are a special kind of cork, or synthetic material. They are all shot by this age.

Dip stick tube, that could be crankcase pressure. Do the compression test. Check for a breather blockage. Check the canister is not full of water/petrol/oil/charcoal mix, causing backpressure. Clean out if it is.

Fit a new spin on oil filter. The seal may have been damaged, faulty or simply not tight enough. Check the face for damage. Fit old filter canister if new spin on leaks.

Do an oil change before laying up. Use 20W 50 semisynthetic, with a can of STP in it. The STP will not only minimize any blowby of the rings, but will coat & protect from corrosion all internal surfaces while the thing is stored.

Most of all, don't worry, your problems are only little ones, & probable not worth worrying about.

Buy a bigger drip tray [:D]


Hasbeen

[bmcecosse]

There really should not be any significant 'air' blowing out the filler cap hole - I'm afraid it does show 'blow by' on the piston rings. If the breathers are clear - they should be able to cope with a certain amount. My own engine (70,000 miles and untouched as far as I know from the records with the car) has very little 'air' from the open cap - and virtually no oil splash either when I do that check! The excessive 'air' will of course tend to throw out more oil droplets - sorry if it made a mess! Do the compression tests (ideally after setting the valve gaps correctly - but I realise that's not so easy with these engines...) and come back with the results. I don't share the faith in the STP - but I don't suppose it will do any harm......

[Hasbeen]

Bmcecosse, I only go by personal experience, & I don't recommend anything lightly.

I did a Bathurst 500 in a Hillman Imp, using SAE 10 & STP. It was part of an STP promotion, & half the competitors in 1964 race used the same mix with no problems.

I then added it to the oil in the TR3A engine in the Morgan +4 I was racing. Its use extended the life of the big end bearings in that engine from one race meeting to 4 race meetings. I was using BP course, their top racing oil at that time.

Although I am quite sure the oils available to the public today are much better than the best available in 1964, I still use it in every engine I own.

A little in some oil smeared on a iron or steel component will definitely prevent corrosion, making it ideal for laid up engines. Some time back I started a hand crank 6Hp diesel engined pump. This pump sits in the open, in the paddock beside the dam permanently. It was only when I went to enter my irrigation records I realised that engine had not been started for over 2 years. If it had not been running STP I'm quite sure the bore would have had enough rust in them to prevent compression starting by hand, without squirting some thick oil into it.

As the STP patent has now expired, I suspect that Castrol Magnetic probably uses the same ionized oil system.

Hasbeen

[Cobber]

<font size="2"><font face="Comic Sans MS">And here's Hasbeen's Imp at Bathurst

Interesting line through that corner!
Is that you or your offsider driving there Hasbeen?</font id="Comic Sans MS"></font id="size2">


"Keep calm, relax, focus on the problem & PULL THE BLOODY TRIGGER"

80'Triumph TR7, 73'Land Rover (Ford 351. V8),
'89 Ford Fairlane
'98 MG-F, 69'Ford F250.
76' Ford F100

[FI Spyder]

[quote]<i>Originally posted by Cobber</i>

Interesting line through that corner!
[quote]

Correct me if I'm wrong but on loose surface I believe you enter a sharp left hand turn by starting on the left then turning right, then left, which brings the back end around to make the left hand turn under power as the car swings around the corner.

- - -TR7 Spider - - - 1978 Spitfire- - - - 1976 Spitfire - - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra - Yellow TCT