Super Major Compression

[Fixersteve]

Ok so I have established the correct position for the fuel pump timing mark and i am happy that the engine is timed up correctly. The problem is she still wont start, My next step is to do a compression test. What compression (PSI) would i expect to be seeing??

Best regards
Steve

[Fixersteve]

Right! so ive just done a compression test and all cylinders are showing 300psi. Is this good or bad??

[Mjg1705]

could be better - top quality compression is about 380 - did you do a complete engine rebuild ?!

[Fixersteve]

No not done anything with the engine, and its not been run properly for i dont know how long.

300psi to me doesnt sound bad considering a 2.0 tdci engine compression is 420psi.........

I shouldnt have a problem with her not starting with 300psi should I???

[Mjg1705]

Maybe that's a bit of your problem - without touching the engine - its hard to know what you pistons/rings and valves/clearances are like - that may be a part of the isssue - yeh that tdci would have more compression as the engine is smaller so to speak, but even with 300 psi it would still run if it would start ! Have you bleed through the fuel system ?! Are the injectors all working correctly ?! Ie; atomising diesel not jetting it out like a hose ! maybe you need to have a good look at the engine and see if anything may not be correct- but without having the engine next to me - I can only give "back of my mind" advice !

Regards; mike

[Fixersteve]

Thanks Mike, I have bled the fuel system up correctly and All the valve clearences have been done to the Fordson spec. Ive had her running but only after towing her around the carpark outside our workshop, I was hopeing that some one would be able to tell me what the compression should be so i can either do some work on the engine (if 300psi is poor compression) or move onto the next item which is to look at the injectors, Im waiting for a friend to drop over a injector tester so i can test them.

Cheers
Steve

[Pavel]

In your previous posts you mentioned that you had 'cleaned' the injectors. But since you are now getting a tester for them I would assume that that did not entail stripping, cleaning and re-calibrating them -- which, without proper equipment, the latter would be impossible for you to do. Carbon can, and does, form on the inside of injectors and will restrict the amount of fuel injected; hence 'whitish' smoke. Also the springs lose their tension and this, with carbon build-up, allows continuous 'dribble' to occur which results in less fuel availability for the injection process.
Internal cleaning and re-calibrating of the injectors would be a good move on your part.

Pavel

[Fixersteve]

Thanks Pavel, Im going to go with your last point and clean and recalibrate the injectors once i have got the proper tester (this weekend) fingers crossed! I think i will also stick them in an ultra sonic cleaner which one of our other workshops have got.

Best regards
Steve

[Mjg1705]

good job on getting it running - sometimes a good tow is all they need ! - yep Pavel hits the nail on the head ! Defo do the injectors - and that should help. Let us know how it works out - and maybe some pics of your restoration progress

Regards;mike

[Fixersteve]

Thanks Mike, I will take some more pictures when I get a minute and post them. Where abouts in cornwall are you??

[Mjg1705]

ok- that's fine - like to see a project in progress ! - I'm in HELSTON

[Fixersteve]

Ah beauty, im just over in Hayle

[Mjg1705]

Ooo nice one - not to far away from me then !

[Fixersteve]

OK here is an update......

I have now tested and calibrated all of the injectors and they are working perfectly on the test bench. I have reinstalled them and bled the fuel system. BUT.......... She still wont start on her own!

Has anyone got any other ideas????

What roughly should the cranking RPM be??

regards
Steve

[Dandy Dave]

An educated guess would be at least 200- 300 RPM. If your started is slow and sluggish and has a problem getting the engine over compression it will not start easy. A diesel needs to spin. Dandy Dave!

[cwayne]

Steve, When I rebuilt (including new sleeves) my Super major I had the same problems, slow starting and loads of white smoke that would burn the eyes. The compression was 330 psi with very little variation between cyl. Imformation I gathered from a diesel forum stated 300 psi was the absolute minimum. The white smoke clears as soon as the engine worms up,realy bad in the winter and no excessive smoke in the summer. It has improved with use .
As Dave said the starter has to spin the engine fast , I do not know what rpm . I have a J D loader with a very tired engine which was almost impossible to start with out starting fluid, even in mild weather. engine seemed to crank over fast enough however when i replaced the bushes and brushes in the starter it now starts on all but the cold days with out assistance .
Wayne

[Nick]

Hi fixer steve. When you tow started it, how did it run? Is the timing correct on the pump coupling? Also have you checked that the lift pump, and filters arent faulty or blocked? A major engine should run easily at 300psi, before i re-built mine, it had 280psi and it started fairly easily.

Have you checked the valve clearances?

[Fixersteve]

Hi Dave,
Yeh when she is running she run fines. Think I need to retard the timing slightly as when I go from idle to full power she chuffs out aload of white smoke. I have fitted a new lift pump, new fuel filter and they are all working right.

Im also thinking that the starter motor isnt cranking fast enough so thinking a 100ah battery is needed???

Thanks for your help dave

[Nick]

In all fairness, ive just bought a re-conditioned starter motor for mine, because it wouldnt start very well when cold. The starter turned it slowly and made it hard to start. Try a bigger battery, your starter motor could need a set of brushes, does it get hot quickly? Also does it start once warm off the battery?

[Kim]

It should start and run pretty well at 300 pounds. Just a thought--- have you checked to be sure the battery earth (ground) connection at the tractor end is good and clean?
It doesn't take a lot of corrosion to drastically reduce the power to the starter motor.

[Dandy Dave]

These tractors are suppose to have two 6 volt batterys for the extra amperage. In warm weather, a 100 amp battery in excellent will start it OK. In weather below 50 to 60 degrees F. it is a different story. If you have a half dead 12 volt battery the starter will suffer for amps. Also, if your cable have heated from low amperage the copper will break down and loose it's ability to conduct. Dandy Dave!