Engine problem...must be head gasket?

[berni29]

Hi there again.

No sooner do I get my electrical problem fixed and my headlaps and pods working really well, than the engine develops a problem on the first outing!

It is blowing oil out of the exhaust having never blown any out before. None comes out of the engine breather. No 3 plug is very oily. No 4 is a bit low on compression compared to the others. I drove over my compression tester a while back and it is now only good for relative rather than absolute (starts at 50psi and a bit bent) readings.

The water in the radiator has turned muddy brown having previously been clear blue. I have only driven the car about 500 miles since getting it. The engine had been rebuilt about 3000 miles ago apparently. It does loose a lot of oil from seemingly everywhere, so I am wondering if the head was tourqued down properly.

Anyway, it looks like head off! My plan is to just change the gasket and put it back on. I guess that I should do the water pump at the same time. Anything else a "must do"? Wish me luck.

Berni

[type26owner]

Berni,
Go buy one of those dye check kits for testing CO in the coolant. They cost about $40. Worth their weight in gold. I check my engine for any signs of leaking every 6 months now. I'll bet just about half the people that read this posting have a leaking headgasket right now and don't even know it.

Don't reinstall the old tech copper/aluminum gasket. They suck.

[Elanman99]

Keith

If I have a leaking headgasket and dont know about it then I dont see how it can be a problem!

I have not had the head off for 8 years or so and very rarely need to add coolant so I presume that I dont have a problem.

Is there a set percentage of CO in the water that is used as guide as to whether to pull the haed or not?

Ian

[type26owner]

Ian,
If you just putt around it's not much of a problem. It gets much worse quickly if drop the hammer and apply maximum power and stress the headgasket with high temps and cylinder pressure.

Since I've been plagued with blowing headgaskets on the race engine from the beginning that's why I will not soup up the Elan engine. 104hp is plenty and it's fairly reliable too.

Inspite of that I had an improperly factory-installed cylinder sleeve slide down from the headgasket in the Elan and a runaway thermal event happen that peaked about 125C. I can't really tell the actual temperature because the temp needle was pointing at the 90psi indication marker of the oil pressure side of the gauge. Nothing else bad happened. I installed a new sleeve and put new rings on the old pistons and that's what I'm taking to the Laguna Seca reacetrack in another month from now.

[type26owner]

Berni,
Engines started burning much more oil when they switched over to the overhead valve configuration. Shortly after that the valve stem seal was introduced. Why the hell stem seals did not get designed into the twinkcam from the begining is a mystery. Not necessary for a racing engine I suppose.

That blue smoke is normal. The only question is by how much. Mine after idling for two minutes would exhaust a plume that would totally obscure the car sitting behind me at the traffic light. I use to shutoff the engine until the light was about to change.

With teflon seals the answer is I get none.

[type26owner]

Berni,
Just remembered I also screwed the pooch by glazing the cylinders causing excessive oil smoke. All the advice that tells you to gently break-in the engine is total crap. Best to drop the hammer often but only for a few seconds at a time. Just call the engineer at JE Pistons if don't believe me. There are many technical articles that also support this method particularly in the aircraft world.

[berni29]

Hi Keith

My last +2 would smoke a bit. Mostly on start up and after overrun. I know that it is pretty normal for this engine. People do fit valve stem oil seals (or so I have read) to the twink, with some minor modifications. Are these the teflon seals you mention? I am going to change the valve springs, do these seals work wit the standard ones or is there more to it than that?

When I bought this green +2 I was surprised at the lack of an occasional puff of smoke . Till this afternoon that is.

A little spirited driving while running in definately helps the bedding in process. I have a friend with a 1976 Rolls Royce Silver Shadow and every so often he runs it flat out on the motorway. The car runs much better for it. Constant pussyfooting around does the car harm in the long run. One of those counter intuitive things.

Many thanks

Berni

[lotusanglia1965]

Hi Berni!
GOOD LUCK
Martin

[type26owner]

Berni,
I described the teflon seals here in the past so a search should find it. They are only possible to squeeze in on the stock .35" lift camshafts. That's my other good reason I did not soup up my Elan engine.

Many folks follow some advice to reduce the oil burning from the valves that I think is really dumb. They put a restricting orifice in the oil gallery feeding the head. This will reduce the oil smoke but at the cost of possibly starving the camshaft bearings. Small orifices tend to get plugged up eventually. The oil that gets diverted up there is not at pump pressure. There are recesses in the front journal bearing of old pushrod camshaft that get filled with pressurized oil. The original pushrod cams had just two recesses and the new ones have four now. The camshaft has to rotate another 270 degrees before the oil gallery passageway leading to the head is exposed and the oil can flow out. The oil only does this by the centrifical force of the bearing journal spinning. Bet the oil pressure there is only like 2-3 psi at 6500 rpms of the crankshaft. Oh, I forgot the orifice also reduces the oil leak from the front of the headgasket. Just use a little RTV sealant there to stop that oil leak on the headgasket. If you must reduce the oil flow then grind a groove in the bearing journal to oneside and let the oil out and escape.

As far as I know there is only one type of inner and outer valve springs for the twinkcam regardless of the usage. The racers use another .1" lift and space up the springs so the outer one is nearly coil bound when fully compressed. They tend to wearout quicker and turning over the engine every month is wise if you don't want valve float.

For the oil smoke to emerge suddenly something had to break like an oil control ring. I have also found the four oil drain holes behind the oil control ring on the Hepolite pistons tend to plug up quickly with carbon deposits if the pistons are overheated and you're running dino oil. This can be corrected possibly by pulling off the oilpan and poking through the carbon plug with a right-angled metal scriber that has a sharp point. The dead giveaway clue this has happened is if the underside of the piston head is coated with black gooey carbon. This happened to me running the stock Weber jets that were way too bloody lean.

[berni29]

Hi Keith

I started the engine this morning (heavy frost here in the UK) and there is mostly a lot of white smoke. Also once the thermostat had opened and the engine was revved, there was gas in the water as viewed down the radiator cap. Quite a lot. Enough almost to make it fizzy. The only plus point was that the engine idled beautifully. Much better than ususal. Interestingly (to me) the only choke that spat back was the No3 one that was oily yesterday. If I take the oil filler cap off with the engine running there is a definate pressure, but no smoke.

I will do a search on the seals. My engine is (as far as I know) standard and I use 15/50 Mobil 1, but only since I have owned the car. The oil smoke did suddenly start and there was a lot of it. It happened after a 10 minute run.

Thanks again

Berni

[type26owner]

White smoke after engine has warmed up is bad. That's a water leak most likely from the headgasket. This is fixable but the tolerances are very stringent and if you'd better do it correctly or it'll happen again shortly. It's highly likely that the person that did the rebuild muffed it. Shortcuts are a recipe for disaster. The surface finish and flatness of the head and block are critical. A single scratch across the combustion ring area of the headgasket and you're toast.

Recommend you use a FelPro #8360 PT-1 headgasket. I think this is for the Kent engine and some of the cooling passage holes are missing that are required for the twinkcam. You lay the old gasket ontop of this one and mark the hole locations and punch 1/4" diameter holes through with a Whitney Jr sheetmetal hole punch to modify it for the twinkcam. This a far superior fiber headgasket that does not require retorquing. These gaskets are the only ones that don't blow out on my 180hp BRM race engine. Only use a new set of ARP headbolts too.

Go here for the PowerPoint file from Payen that explains the tolerances for the headgasket. A digital handheld (mouse size) surface profiler tool to measure the finish costs about $1000. If the machine shop does have one then do not take your engine there to have any work done.
http://briefcase.yahoo.com/[email protected]

Because the CTE difference is large between the aluminum head the cast iron block that makes the surface finish so critical. The headgasket has to allow them to move but still not leak. Bet your headgasket is torn apart.

[berni29]

Hi Keith

Many thanks for the information. I was going to re-use the head bolts, but will get new ones. Someone told me that if the head is off for too long it can warp. Is this true? I would like to do the job over a few days. I will phone around and see if I can find one of those gaskets here in the UK. I have a gasket set already, but the head gasket (Coopers brand silver colour on one side copper on the other) looks a bit corroded so I will not chance it.

Thanks again

Berni

[M100]

I have also found the four oil drain holes behind the oil control ring on the Hepolite pistons tend to plug up quickly with carbon deposits if the pistons are overheated and you're running dino oil.

But run on synthetic and the "big ends spin" (allegedly!)



Berni, rather than rush the job you really need to find out why the leak occurred (and if you are doing the water pump its much, much better to pull the whole lump,

The head won't warp if left off but it may have already been warped in use. Use a knife edged straight edge and sight through to a light source to see if there is any warpage, if there is then check with a feeler gauge. I'm not sure if a figure is quoted for the twin cam but more modern aluminium head cast iron block engines have a service limit of about 7-8 thou before resurfacing is required (personally anything more than a couple of thou and I'd have the head skimmed) Similarly check the block face especially between the bores.

If the threads on the headbolts are visually ok then they can be reused, they are not "stretch" bolts. Make sure the threads in the block are clean and you lightly oil the bolt threads and under the head washers when tightening.

Stop running the engine though, you could quite easily cause more damage. I'd forget using a comression tester too. A leak down tester is much more accurate and could save time if you diagnose ring damage and so need to pull the block out as well.

[type26owner]

But run on synthetic and the "big ends spin" (allegedly!)

This seems to be highly likely if you use too heavy a viscosity of oil. Almost universally engine manufacturers recommend at least 10psi of oil pressure at idle and it rise by 10psi for every increase of a 1000 rpm of the crankshaft.

I have the high capacity, high pressure oil pump in my Elan. With the engine fully heatsoaked it has 15psi at idle and by the time it revs to 2000rpm it pegs the oil pressure at 60psi while using 10-30W Redline synthetic oil. That's not right!. Going to try 0-20W Redline next but it's not readily available at all the parts outlets.

The technical paper on Redline's website tells you to use the lightest oil possible that maintains the same oil pressure. Almost all new cars require the synthetics so matching up the oil pressure to the right weight of oil is already done for you.

My VIN plaque states that a 'touring engine' should use 30W. 'Racing engine' is 40W.

Berni,
The only point I don't agree with Martin on is the headbolts. I replace the ARP bolts everytime. It's just me being very conservative though. I find I suffer from less anxiety attacks if I just cough up the cost for the rather expensive ARP bolts.

[M100]

Keith, I was only repeating a comment from another Lotus owner, made on this very board not too long ago Me, i've been on synthetic for ages (Mobil 1 0W-40) and swear by it rather than at it!

Bearing in mind your higher ambient temperatures, rather than change the oil could you not tweak the oil pressure relief valve spring to reduce that peak pressure? Higher flow oil pumps can be useful, higher pressure usually less so.