compression reading

floydr · Post by **floydr** » Sat Jun 30, 2007 3:42 am

before anyone says I should have searched I did search.

I just got a diesel compression tester and I am going to be changing my glow plugs so while I am at it thought I would check the compression of my dasher.

The Dasher is a 1981 1.6 liter na with approx. 240K miles on it what should I expect to get with a engine in good shape at this mileage?

later
Floyd

ps how hard is it to take out the glow plugs behind the injector pump, I seem to recall reading that you need a 8 inch 8 mm open end wrench.

libbybapa · Post by **libbybapa** » Sat Jun 30, 2007 10:06 am

400+ psi at sea level (adjust for altitude)

Andrew

tylernt · Post by **tylernt** » Sat Jun 30, 2007 10:31 am

Glow plugs are not too bad once you get the injector lines off. A magnet-onna-stick is also useful.

floydr · Post by **floydr** » Sat Jun 30, 2007 7:11 pm

Thank you, just the information I was looking for.
400 psi +at sl, I am at 28 feet above sea level
remove injector lines, magnetic pickup tool
Later Floyd

Vincent Waldon · Post by **Vincent Waldon** » Sat Jun 30, 2007 7:55 pm

The "official" specs are:

- brand spanking new pressure: 493 psi (34 bar)
- at least 412 psi (28 bar) at each cylinder
- no more than 73 psi (5 bar) between cylinder

but many people run less than 400 psi with not much difficulty unless in a cold climate.

One other safety note: DO NOT attempt the wet compression test (tablespoon of oil down the cylinder to see if compression increases) on a diesel... because of the high pressures the oil could detonate and blow up your compression tester or worse.

One other technical note: the heat shields in front of the injectors are a 1-use only device... you'll need to replace them with four new ones after you finish your compression test.

Let us know what you find out !!

Vince

floydr · Post by **floydr** » Sat Jun 30, 2007 11:03 pm

I will be testing via the glow plug ports, since I am changing them, I really don't want to look at my injectors, I know I should, would be money ahead to replace them too since I don't know how old they are. They are probably all coked up. :(
first I need to get the new glow plugs(Duraterm ) and a slow relay.
Later floyd

coke · Post by **coke** » Sat Jun 30, 2007 11:04 pm

Why are you going to buy Duraterms and use a slow relay?

floydr · Post by **floydr** » Sat Jun 30, 2007 11:11 pm

because I run a single tank vegetable conversion the longer glow time of the slow relay helps with initial start up.
I hope this is an experiment in progress I keep refining things as it progresses.
later floyd

libbybapa · Post by **libbybapa** » Sat Jun 30, 2007 11:57 pm

The injectors don't get coked up, the metal of the needle and seat erode slightly due to the high pressure diesel flowing through them.

Andrew

coke · Post by **coke** » Sun Jul 01, 2007 12:17 am

Those duraterm plugs burn at about 2200 degrees F in about 4 seconds. I just put four of them in my car. I don't think you'd need a slow relay to be honest .. but it is of course, up to you.

tylernt · Post by **tylernt** » Sun Jul 01, 2007 12:23 am

Do the Duraterms glow faster/hotter than normal fast glow plugs? I have fast glows in my Rabbit and it takes 2-3 glow cycles when it's really cold. I'd think Duraterms with the slow relay would be the ideal setup. Just start before the light goes out if it's not too cold.

coke · Post by **coke** » Sun Jul 01, 2007 12:50 am

Yes they do. I compared a fast to the duraterm. No comparison. The duraterms are the best plugs I've ever seen. And not only that, they last longer. When my car sits overnight, All it takes is 4 seconds and boom she's fired up and ready to go.

Quantum-man · Post by **Quantum-man** » Sun Jul 01, 2007 3:48 am

floydr wrote:I will be testing via the glow plug ports, since I am changing them, I really don't want to look at my injectors, I know I should, would be money ahead to replace them too since I don't know how old they are. They are probably all coked up.
first I need to get the new glow plugs(Duraterm ) and a slow relay.
Later floyd

I'll agree with Andrew that they don't coke up as in 'block up'; however if there is an issue with the heatshields for example reusing old ones without re shaping them or fitting new ones and trapping old crud on the mating surfaces you could suffer from 'coke up yer theads' which I must say (touch wood) I haven't had the displeasure

If you are reluctant to interfere with the injectors uneccessarily; then if you have a rev counter you could turn off each injector in turn by loosening the fuel line nut on top of each injector (covering in a rag as you do so; maybe wear googles too if you're short sighted and need to get close) and check drop in revs each time and look for odd variations in speed from one compared with the others.

floydr · Post by **floydr** » Sun Jul 01, 2007 9:15 am

ok I will try the duraterm's with my fast relay I didn't realize they were that much more effective.
thanks for the heads up.
You guys are a really on at the top of your craft.
Later Floyd

floydr · Post by **floydr** » Tue Jul 03, 2007 10:57 am

picked up some bosch glow plugs today for the dasher from what I have read they only make Duraterm's anymore. But how can I be sure?
the part number on box is 80010 0 250 201 032-357 with hand written 70-757 on front of box
brass contact on top of glow plug.
scratching my head.
later floyd