compression test on fiat built diesel

rrman61

Well-known Member
How do I test compression on a fiat built diesel{445 long}.I'm trying to determine if its worth putting more money into or scrapping it.I would rent a compression tester but can it be used on a diesel and if so how?It runs fine but takes starting fluid to get it going.Some one said it could be my injector pump.Also a kit is available to rebuild my pump.Anyone go that route.Thanks in advance.
 
If your engine has the CAV pump and the injectors are held in place by 2 studs with nuts on top, a couple things to keep in mind.
The compression is in the 350 lb range. Ebay has some chinese compression testers that are fairly accurate and priced reasonably.
When you say rebuild the pump, I do my own pumps.
The diesel shop in my area is part a large number of shops in the Northeast. A CAV pump to
test and replace with seal and minor parts is North of $200. A complete rebuild will be North of $1000. If you decide to do the pump yourself,
you can buy a CAV diesel pump service and overhaul manual at time on ebay. I have a manual and could email or fax you a few pages, but the pictures might not come out to clear.
Before you think about rebuilding the pump, take out the injectors and have them pop tested. They are easy to rebuild. I pay about $30 to $40 for oem tips. Springs can be shimmed up with hard steel washers to get original pressure.
If you can not find someone to test them for you,
You can find tester on ebay for $200. The Tester is made in India, but looks like a Bosch tester.
The working parts are made in Germany by Bosch.
If you go this route make sure your order the tester with a gauge that reads in psi and not bars. Although, it is easy to convert, many conversion charts on the internet.
 
When you try to start it do you have white smoke out of the exhaust? any smoke? Are they equipped with a thermo-starter like an Oliver is? Have you taken the exhaust manifold off to see if any one cylinder has more smoke than any of the other cylinders?
 
Does it use oil?

Does it breathe heavily from the crankcase breather?

Does it smoke after start up from cold?

Has it ever had a top end overhaul?

What is oil pressure like?

All good indicators of engine condition. Is it used for any arduous duties or does it just potter around? Pottering around is not good for a diesel.
 
Bought the tractor used so I don't know about it being overhauled.After it starts it smokes a little[bluish white smoke]then clears up when it warms up.Have had other engines do this on startup that had 1 bad injector.My engine runs fine,plenty of power,burns very little oil,oil pressure about 45 psi at first startup then 30 at full throttle after hot.It had some sort of pre heater in the intake,that has long been disconnected before i got it.
 
If it has been started with ether over an extended period I might suspect that the top ring and piston land are shot unless the engine is in tip top order.

But seems as though there is little else wrong with it, so worth keeping rather than scrapping, IMO.

RAB
 
To answer afew of your questions:
NO, a gas compr. tester can not be used on a diesel engine.. the guage will blow up in your face, due to the pressure difference. 300psi + vs. 150psi..
and you'll need an adaptor.. it looks like an injector, but its hollow..
IF it were mine, I would get the thermostart in operating condition, depending on your climate..
A "KIT" isn't going to solve your problem.. unless its leaking fuel.
A compression test is the way to go.. 1st. Normally they can be "rented" from your local auto parts store.
 

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