No compression on No1

[Acole]

After an hour or so of driving my GT6 mk3 it starts to miss fire. A local classic car restorer has advised there is a loss of compression on No1 valve. 
he has given me a few short term options but has advised a full restoration of the engine is the best long term option, as most of the time when one valve starts to lose compression the others will be sure to follow. The car has been fully restored apart from the engine so it seems as good an excuse as any. 
This garage has quoted about £1k per valve, therefore for my GT6 will cost about £6k. The car has done 75k miles and apart from the compression issues runs good and doesn’t overheat etc.  Does this sound a reasonable estimate or excessive? 
I would also appreciate any recommendations for restorers in central Scotland and the highlands. 
 

Thanks

Andrew

[DanMi]

I would say excesive. Look in the TSSC shop they quote £2750 for a fully rebuilt engine £410 for just the cylinder head then you would need it removed and fitted so no more than £4000 total

[Iain T]

I would suggest to do it in stages. Take the head off and take a look at the bores. Any scoring or ridge at the top? If it looks good just get the head reconditioned and see if that solves the problem. 

Iain 

[Iain T]

However before I did anything I would splash out £20 for a compression tester and see what the results are. Make sure to warm up the engine, then take out all the plugs, disconnect the coil and turn over the engine with throttle wide open. 

Iain 

[JohnD]

Acole,

First you, or your 'mechanic', isn't clear.     "Loss of compression" may be due to a faulty valve, but also to several other causes.   Secondly, a grand a valve?  Extortion!!!

And a misfire after an hour's driving will NOT be due to a faulty valve!   Find another workshop!

Or, work on the car yourself!   A compression gauge casts about £20, and instruction on how to use it are widely available, here or elsewhere online.      You are looking for all the bores to be within 5% of each other, not to compare with anyone else's readings!     Then, if you have a low one, a teaspoonful of engine oil into the sparkplug hole and retest.     This will improve the compression reading, unless you have a valve fault.   You can't tell which one!

But please don't go back to that scoundrel you have consulted!

John

[NonMember]

I have to say, that diagnosis sounds questionable to me, and coming from someone who would quote such an outrageous price makes a second opinion (from a trusted actual Triumph specialist) well worth getting.

[Iain T]

Could this be electrical, not my strong point! Plug lead breaking down, plug etc? 

Iain 

[JohnD]

Andrew (Acole) will tell us, but maybe he's not experienced, or confident to diagnose this problem?

May I suggest, Andrew, that first you get along to the monthly meeting of one of the Scots Area Groups of the TSSC?   See: https://www.tssc.org.uk/tssc/areas_google.asp

[DanMi]

Chic Doig in Perth is probably Scotland's leading Triumph workshop. As others have said get a second opinion.

[dougbgt6]

Dan,

Chic Doig has closed his premises and now works from home. The company now comprises just Chic and his daughter. They still sell stock on Facebook, but I’m not sure they’re taking on any more projects.

I know this as one of ours at East Berks has a GT6 with Chic and it’s taking some time to resolve.

I notice Andrew is North of Inverness, so the Scottish Areas, which meet near Glasgow, may not be an option. 

Doug

 

[Pete Lewis]

agree thats £1k a valve    thats complete rip off mode  ,

and a valve wil be misfiring all the time not after a while running

when did the tappets last have a reset  as temperature on a tight clearance will get worse as it gets hotter 

but always do the simple and cheap things first   anyone you wants to empty your wallet on a whim must be avoided 

much can be done with simple tools and a few notes of guidance on here  

Pete

[DanMi]

33 minutes ago, dougbgt6 said:

Chic Doig has closed his premises and now works from home.

bit cheeky that they still have the website advertising services up. Plus sad to see another specialist go

[dougbgt6]

5 minutes ago, DanMi said:

bit cheeky that they still have the website advertising services up

Chic had half a dozen guys working for him at the old work shop and still hopes to get back to that level of business. But just him and his daughter now and a barn full of stock.

Doug

[PeteH]

Covid, did not do many small business` any favours, trading into a loss is business suicide. Pull the plug, cut your losses, pay debt, and move on, I know of at least 3 small, and not so small garages that have gone under purely as result of the drag on length of the pandemic. Most of the "survivors" went "online" early, where at all possible. There are a LOT of websites that are months out of date, some are business that no longer exist!.

Pete

[Acole]

Hi all,

 

Thank you so much for your comments and advice. I certainly thought that £1k a valve seemed excessive so glad you all agree. JohnD is correct in his assessment, I’m not experienced nor confident with working with the engine hence seeking both your combined advice as well as a specialist. I have since contacted Chic Doig who estimated between £2-3k for a full restoration of the engine. 
I have had the carbs reset and the tappers have all been checked a few months ago. Also, I’m not sure if it would be an electrical fault or anything to do with the plugs as I had an electronic ignition fitted as well as the leads and plugs all being changed a matter of months ago. 
I will certainly buy a compression test kit and give that a go. 
I have a few audio clips of the engine when it is misfiring so will see if I’m able to upload them for you to see what your thoughts are. 
I am more tempted to have a full rebuild done as I plan to keep the car for a long time and would like to use it as much as I can. And so having the engine rebuilt would give me greater piece of mind. I live a few miles from the NC500 and would love to use my GT6 driving round it. The car is wonderful to drive and always puts a smile on my face but right now I always have a little bit of dread when I take it out, wondering if or when it will begin to go wrong. 
Thanks, Andrew

[DanMi]

yes Cars sat at home and no work for many small businesses, I went to Lanzarote recently and loads of restaurants still shut as very little business for 2 years so the tourism industry was also hit very hard

 

[DanMi]

I would get the car to a competent mechanic familiar with the car, there is no point doing a complete rebuild for a burnt out valve. They can check the compression, oil pressure and crank endfloat and be able to tell if the engine is worn. If a valve needs doing then they can take the head off and rebuild it and assess the bores for wear. A worn bottom end will give plenty of warning before giving up e.g. knocking under hard acceleration from the big ends or a rumble from the mains

[Pete Lewis]

i wouldhate to have you fund a full rebuild when one carb has got the dreaded rubber slivers floating in the fuel supply hose and pipe work

if the hoses have been messed with recently thats one contender  easliy fixed for pennies 

Pete

 

[Acole]

DanMi & Peter,

You’re both right. I am awaiting a call back from Chic Doig to get it booked in to try and diagnose the problem. 
Funnily enough I spoke to my local garage who doesn’t want to do the work but who suggested most of the potential causes listed in this chat. 

Thanks again for all your input. 
Andrew

[NonMember]

55 minutes ago, Acole said:

Also, I’m not sure if it would be an electrical fault or anything to do with the plugs as I had an electronic ignition fitted as well as the leads and plugs all being changed a matter of months ago. 

I've had new plugs fail within a couple of hundred miles.

My GT6 will develop hot misfires on NGK plugs within a couple of months from new. And NGKs are some of the better ones!

I've also known EI units to develop random faults - including hot misfires - when only a couple of months old.

Do NOT discount electrical problems.

[Pete Lewis]

i take it from your earlier post it runs fine from cold and only plays up after a good few miles ???

so i repeat this is something simple and cheap  dont get carried away 

 

one simple other check is look at the coil   the two terminals are marked +  and _   older coils may have CB   and SW 

these are  to get the polarity right 

so a quick look  the white ign feed must be on the + /sw/positive  terminal    the wires to the dizzy must be on the -/CB/negative    terminal

when the coil is wired back to front it does some realy annoying things to drive you mad, you get out kick the tyres and it re starts  till it stops again 

spark plugs are also the life and soul heres a link to some of the snags of modern plugs  and never fit a plug with an R in the suffix 

 

[JohnD]

Chic Doig has a good name, and £2-3K for a complete rebuild is more sensible.  Well done for grasping the nettle and resolving to get down dirty with your car!    You will enjoy it + yes, you will!   And help always here.

John

[foshi]

just a word of caution on some classic car repair garages , spoke to a friend of a friend yesterday asking on his 72  what i thought of how much a well known garage in hampshire had charged him for the following work on his lancia fulvia sport 1972. new rear springs/ new brake pipes and flexi hoses caliper rebuild / new su electric fuel pump  back up to manual / then put through a mot which it passed. knowing the garage not the cheapest around i said proberly around 4k. he then produced the invoice a nearly fell over 10k exactly. when he questioned it they said had taken six weeks labour also the springs had to be made to order . told him to come to me next time crazy paul ,just to add he took it in said no rush for the car so did not query when he did not here from them, until he received the call to say all done you can collect  . admits he was expecting around a 5k bill having used them in the past . maybe its me out of touch as i do all my own repairs .

[Steve P]

The Work listed above is never 6 weeks,2 at the very most by an unskilled gorilla!

Just a con.

Steve

[foshi]

my thoughts , the bill was not even broken down parts labour .just work carried out and a total