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Vitesse 2L Mk1 misfire on cold start, now blown head gasket.


68vitesse

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3 hours ago, NonMember said:

Actually it has nothing to do with burning unburnt fuel.

Apologies if I'm incorrect when I said 'unused fuel', that might not be the main purpose, it was a rough approximation of what it does, but basically if the fuel is cooled by the EGR gases that are recycled it makes for a more complete burn as well as disposing further of remaining combustible particles in the exhaust gases - which could be called 'unburnt fuel', if anyone wanted to be charitable.

 

 

 

 

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1 hour ago, classiclife said:

I know Nick recommends Bosch WR78 which are multi pronged. Of note and IIRC the WR78X has a wider electrode gap and is probably unsuitable for cars that use BP6ES whereas the WR78 is suitable - I'm sure Nick can confirm that either way.

It has been my consistent observation, after a chance discovery many years ago, that these old Triumph engines really like the multi-electrode plugs, originally triples (Bosch W7DTC or WR7DTC), but these days more often quad are easier to find.  My theory is that it is the side-electrode nature of these, which exposes the spark to the combustion chamber differently to conventional plugs, that is the key feature and the number of electrodes is actually irrelevant - though the multi-electrodes do last a very long time, which is their main intention.

It's also been my observation that everyone who actually tries them, notices a difference for the better.

As Richard notes, one potential problem area is gap.  The multi-electrode plugs do come with a larger gap out of the box, purely because they are sold for cars with high voltage ignitions.  If you are using any kind of electronic ignition with a sports coil, this will likely be fine, though there is some added risk of finding weakness in your HT system (leads, cap, rotor arm).  For conventional points ignition the gap will be too large.  The plugs can be re-gapped though it's trickier that conventional plugs and you use tube or wire gauges, not feeler blades.

It is possible to get triple electrode NGKs too though prefer the Bosch one myself having had a few failures with NGK.

Nick

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3 hours ago, Colin Lindsay said:

if the fuel is cooled by the EGR gases that are recycled it makes for a more complete burn

No, it doesn't. Probably the opposite on a diesel, and the reason it helps on a petrol engine is nothing to do with cooling. In fact some engines use EGR during warm-up to heat the incoming mixture! You shouldn't take this as a criticism - the workings of EGR are misunderstood by the vast majority of the motor trade, never mind the public. I have the benefit of 30 years working in engine control electronics, so I've "been put right" on several such things.

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Yeah, EGR on petrol engines brings actual efficiency benefits, with lesser contamination drawbacks.

On diesels though, knocking the NOx down is the only gain, at the expense of reduced overall efficiency, increased CO2, fewer mpg, greater particulates output, and that’s before the additional effects of the engine being choked with soot kicks in.  

Pity engine management systems from about 2002 onwards are smart enough to see when the EGR cycle has been, err, reduced.

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We have the Mercedes 3L V6 Diesel in the Motorhome, Because it also has a DPF, the ECU has a programme which forces a regeneration when it recognises (if) the DPF needs it.!. Getting it on a motorway above 2200+rpm for 1/2 an hour avoids that!. On the predecessor, (A Fiat Ducato) the EGR caused several "limp mode" events, Eventually the issue was only resolved by it`s replacement!. Typical of Fiat, of course, the "new" EGR was "improved" requiring a modified "wiring harness section". Which typically cost 1/3 of the price of the new EGR. Whilst I am resigned to the fact that "modern" engines need this to keep emmisions under some control. I still yearn for the days of KISS. (keep it simple sucker). Hence the ongoing Refurb; (5years and counting) of the 13/60.

BTW. Mercedes want £80 plus VAT to reset the ECU. This I found out when I removed a driver seat to access some fuses and relays in the seat base, and created an SRS error when the Wiring was disconected. And I now have a £200 PDI reader to diagnose / delete such issues, which has alread paid for itself!.

As and aside, I supect that many Diesel fouling issues come about from not being given a good "Italian tune" on a daily basis. White Van man does not appear to experience these issues as frequently, and as we know most drive like they just "nicked" it.

Pete

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18 hours ago, NonMember said:

No, it doesn't. Probably the opposite on a diesel, and the reason it helps on a petrol engine is nothing to do with cooling. In fact some engines use EGR during warm-up to heat the incoming mixture! You shouldn't take this as a criticism - the workings of EGR are misunderstood by the vast majority of the motor trade, never mind the public. I have the benefit of 30 years working in engine control electronics, so I've "been put right" on several such things.

It's nice to learn new things! I had always thought the point of the EGR was to reduce emissions by lowering the temperature of the gases in the engine, thereby reducing the amount of Nitrogen Oxides, and also as a lesser function to reburn anything unburnt by the first pass through the engine. All I ever really knew about it was that Landy owners say: remove it, it saps power and causes running problems... so I did. I've also found that from 2019 it's an MOT failure to remove one... but that TD5 is long gone.

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  • 4 months later...

Cold misfire has returned, on checking the spark plugs when engine cold numbers four and five appear damp rest ok. They are not oily or smell of petrol but if coolant there isn't any appreciable loss but all I can think off, engine runs well enough but cylinders four and five have the lowest compression when tested.

Has the copper head gasket for the 2L Mk1 been replaced with a composite one and has anyone used it?.

Regards

Paul

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Take it youve been through the complete ignition system Paul? New dizzy cap would be good to try (always useful to have a spare in case you drop it) and swop round the leads (ones thatll reach) to see if the faulty cylinders change...

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Dont smell of petrol though? Im wondering if Pauls right and coolant is somehow getting into the combustion chambers after stopping the engine so that on start up the plugs get wet causing poor running until they warms up and clear....

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yes but if 7psi in the coolant jacket is leaching into a bore  you would expect 1500psi combustion pressures to put gas in the coolant 

and the level starts to disappear without any signs of leakage or theres a pressure build venting via the cap  

certainly coolant in   a bore will give a miss till its vapourised out   so  is there any coolant loss   quietly   going on ???

Paul have you backed off the head nuts 1/2 turn and retorqued in normal order ???  worth a try  (42'46lbft on hd nuts and washers)  ( suggest minispares washer faced nuts  cheapest)

washer deformation is a real problem especially on the 3/8 mk1 studs   ie the nut sinks into the washer and you loose clamping of the  head  

 

Pete

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Not tried retorquing the head but did put two new plugs in four and five this morning and engine started without misfiring, also tipped a part bottle of radweld I had in, think this is just a temporary solution.

Never had the head converted for unleaded, currently thinking of spending some holiday money on getting a spare head done then a "quick" swop.

Regards

Paul

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they will run for 1000s of miles without inserts as the casting has lots of absorbed lead memory 

so do it when you have to not because some plonker says it vital   its certainly not

over the years ive always used Barrs leak pellets mainly as we fitted them to every truck on production , so availability rules applied

i used rad weld once on my first side valve Minx and coolant exploded everywhere ,  that was back in the 60s 

these products will seal a leak to air side ( hoses and such)   but not a head gasket problem 

the washers are renowned for distorting under the nuts , 

try a retorque  nothing  to loose but do back of 1/2 a turn then retorque 

and mark a nut with tippex and see how much it turns to achieve a retorque

Pete

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Probably not the cause and a long shot, though Nick Jones?, I think once mentioned he had an uncommon issue with the coolant passage through the inlet manifold. This showed a clean plug on one cylinder (this is from memory) after running for a bit maybe, rather than wet at the beginning.

Just thought I'd mention.

Dave  

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Problem with four and five is mute as gasket has blown between five and six, injecting air into plug hole six it comes out of plug hole five with rocker shaft removed and compression on both is below fourty psi. My only decision now is to install my spare engine or sort out the blown head gasket and hope that's all it is.

Keeps me busy in retirement.

Regards

Paul

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On 08/06/2021 at 18:43, daverclasper said:

Probably not the cause and a long shot, though Nick Jones?, I think once mentioned he had an uncommon issue with the coolant passage through the inlet manifold. This showed a clean plug on one cylinder (this is from memory) after running for a bit maybe, rather than wet at the beginning.

Just thought I'd mention.

Dave  

Well remembered Dave!

It was a while ago now and I’ve forgotten the finer details, but there was a small water leak from the manifold heating tube into no6 runner. I was aware no.6 plug was “different” (clean!) and I was aware that I was loosing coolant, though at a very low rate.  No running issues. The penny only dropped when I had the manifold off for an entirely unrelated reason and found coolant in the runner.

Just bypassed the manifold tube and plugged the ends so that I didn’t get an air leak instead. Already had the EFI in the works at that point.

Nick

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  • 3 weeks later...

Got around to removing the head from the problem engine, curious about staining between some of the cylinders, also might have been a local heat issue as some of the water ways have debris in them.

Next decission do I get just the head done or the whole engine.

Regards

Paul.

 

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  • 68vitesse changed the title to Vitesse 2L Mk1 misfire on cold start, now blown head gasket.

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