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compression test figures query http://forum.triumphdolomite.co.uk/viewtopic.php?t=36032	Page 1 of 1

Author:	Rusty47 [ Fri Jul 24, 2020 3:53 pm ]
Post subject:	compression test figures query
Hello all,can someone please give advice on this?I took the 77 1300 out for a spin of about 30 miles last week,running fine going out,but on the way back,it began to run very rough,almost cutting out,and the temperature increased just a little while running. I got to within 1/4 mile of home before it stalled and refused to start.A friend towed me home.I checked the ignition electrics,they were OK,then I checked fuel from the pump,that was OK.I removed the carb,cleaned it,blew through the jet,reset the jet height,no wear in the throttle spindle,needle central etc. I then did a head compression check,and these are the figures.No.1=142psi, No.2=152,No.3=140,and No4.=150.Would that suggest a blown headgasket,or something worse? I would be able to change the gasket,but any work on the block, not for me at my age(83).If it is the headgasket,I remember doing a couple many years ago where I used extra thick gaskets,Payen I think.Are they available now? If I cant sort this,I am afraid it will be goodbye to the Dolomite.Thanks for previous very good advice.Joe.

Author:	dollyman [ Fri Jul 24, 2020 4:09 pm ]
Post subject:	Re: compression test figures query
Those compression figures are fine Joe, leave the head where it is mate. I take it you have checked if a spark is getting through to the plugs? I would be looking at the condensor first of all. Tony.

Author:	Richard the old one [ Fri Jul 24, 2020 4:52 pm ]
Post subject:	Re: compression test figures query
I would go for the condenser as well have had several fail so do not assume that the first one you fit is any good.

Author:	Rusty47 [ Tue Jul 28, 2020 1:38 pm ]
Post subject:	Re: compression test figures query
Thanks very much Tony and Richard for your replies.I fitted new points and a condenser,but still have the starting problem,just turning over on the starter.I had fitted a new coil about 6 months ago,and new NGK plugs at the same time.There is a spark at the plugs,maybe not as strong as you would expect,so a bit baffled .I am fairly sure its not a carb issue,as there is fuel at the carb.I have plenty of experience with SUs,having owned a Spitfire,2x MGBs,and a Dolomite 1500hl,over the years,so I would be very surprised if that's the issue.The timing is fine.I was thinking if it could be a valve problem perhaps?However,with lots of time on my hands,I will check everything once again.Thanks once again for your time and advice.Joe.

Author:	dollyman [ Tue Jul 28, 2020 1:51 pm ]
Post subject:	Re: compression test figures query
Hi Joe, check the condensor and the rotor arm again Sadly there seem's to be some rubbish parts out there at the moment. Last weekend a friends 1850 would not go. Fitted a new condensor and found that was faulty as well. Finally got it running with another......We then went on to fit points and a new rotor arm. bloody thing refused to start again. Put the original rotor back on and it ran again. so that was 2 duff condensors and 1 duff rotor arm So worth checking everything again my friend... Have you also had the fuel hose off and turned it over Joe, just to make sure. Tony.

Author:	Richard the old one [ Tue Jul 28, 2020 5:47 pm ]
Post subject:	Re: compression test figures query
Hi Joe. I agree with Dollyman change the condenser again as I had two condensers that cause me problems recently. Various people have suggested that the best place to get a replacement is from the Distributor Doctor tel 01984629540 or email martin@distrubutordoctor.com or www.distributordoctor.com.

Author:	Rusty47 [ Fri Jul 31, 2020 2:29 pm ]
Post subject:	Re: compression test figures query
Thanks once again.I fitted another new condenser,a new red rotor arm,and I am waiting for a new set of plug leads.And yes,Tony,I had the fuel hose off,and the pump is working fine,but still no sign of it starting.So we will see how things work out.Joe.

Author:	dollyman [ Fri Jul 31, 2020 5:38 pm ]
Post subject:	Re: compression test figures query
There can't be much else causing the problem Joe. What make of coil did you use, have you got another that you can try? Tony.

Author:	Rusty47 [ Sun Aug 02, 2020 2:40 pm ]
Post subject:	Re: compression test figures query
Thanks Richard and Tony.About a year ago,I decided to upgrade the fitted DelcoRemy coil,though the car was running Ok,as I thought it just might be the original one fitted back in 1977.So I fitted a new coil,I cant remember where I bought it and for what car,,but it had "GCL132 ballasted "on the box).The car ran OK until a couple of weeks ago,when the car ran very rough and stalled,impossible to restart.So I thought I would check the coil on a multimeter.I am not a good auto electrics chap,but I did a test.It did not give a steady reading,going from very high,to very low.So I refitted the DelcoRemy (7192190 on it),tested it, and it showed 2.3 ohms.Correct me if I am wrong,but I believe that's an accurate reading.However,when then trying to start the car,it started ,ran very roughly for a minute and stalled.So its back to the drawing board.Thanks again for your help.Joe.

Author:	dollyman [ Sun Aug 02, 2020 3:47 pm ]
Post subject:	Re: compression test figures query
Have you checked or replaced the ballast resistor Joe? Tony.

Author:	Rusty47 [ Mon Aug 03, 2020 6:36 pm ]
Post subject:	Re: compression test figures query
It's in the wiring loom somewhere,Tony,so I am not sure how to go about checking or replacing it.Joe.

Author:	marshman [ Mon Aug 03, 2020 7:54 pm ]
Post subject:	Re: compression test figures query
To check the ballast resistor do the following: 1. Disconnect the wire from the coil -ve terminal that goes to the distributor. 2. Connect a temporary wire from the coil -ve terminal to a good earth 3. Connect your voltmeter between the coil +ve terminal and the coil -ve terminal. 4. Turn the ignition on and check the voltage. If all is well with a good ballasted coil and a good ballast resistor you should get a reading of around 6V (approximately half battery voltage). DO NOT LEAVE THE IGNITION ON FOR TOO LONG as this will damage the coil. After the test remove the temporary wire and reconnect the distributor wire from the distributor. On my car with a battery voltage of 12.6V I got a reading of 5.7V across the coil. My coil is a Lucas DLB102 and the resistance measures 1.3 Ohms (meter actually read 1.7 Ohms but the test lead resistance was 0.4 Ohms). It is better to do it this way than simply trying to measure the resistance of the ballast resistor as it is checking it under load conditions, a straight resistance check does not pass much current through any connections and therefore will not show up any faulty connections. If you do not get around 6V at the coil when tested as above then there is a problem with the ballasted supply somewhere, could be the ballast itself, the ignition feed to it or something else. Let us know what you find. Hope that all makes sense. Roger

Author:	dollyman [ Tue Aug 04, 2020 10:44 am ]
Post subject:	Re: compression test figures query
Well explained Roger Tony.

Author:	xvivalve [ Tue Aug 04, 2020 11:03 am ]
Post subject:	Re: compression test figures query
When you say there is a spark at the plugs, have you tested at the plug gap, or just the end of the HT lead? Reason I ask is I had a non starter a few years ago and tested for a spark at lead end; having fitted a set of NOS plugs there was no need to test those, was there? As it happened, there was, as all 4 plugs were duff; good spark at lead end, nothing at the plug gap. These were unused sealed cellophane packaged plugs!!

Author:	Rusty47 [ Thu Aug 06, 2020 2:40 pm ]
Post subject:	Re: compression test figures query
Thanks Roger for your time and excellent detailed explanation.The battery was 12.52v,the coil after your check was 5.78v.I used a spark plug tester between the leads and the plugs and got 4 sparks.Re the plugs Alun?,I replace the new ones of 2 weeks old,with NGK BP6ES x4,removed each and got a spark,maybe not a big one at each plug when turned over on the starter.I checked petrol at carb float bowl,plenty there.I tried to start it,it ran rough for about 15 seconds and stalled.I may be wrong,but I doubt it being a carb problem.No play in the spindle,the piston passed the 7 second test,float bowl cleaned,the jet blown out,and set at 12 flats. Anyway,I am off hiking with my grandson for a few days,so I will forget this annoying problem and come back to it next week sometime.Once again ,I cant thank you enough for your time and advice.Joe.

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