Compression testing
Compression testing
Does anyone know the right way to do a compression test on a diesel. I was going to buy one from harbor freight tomorrow. I want to check the condition of the engine in the car I'm purchasing.
I bought my diesel compression tester at Harbor Freight for $35. It has the correct adapter for the glow plugs, but I'm not sure about the injector adapter. You need one or the other. You can either use a large ratchet to turn the crank or have someone else turn the key to use the starter. If you use the starter, make sure to hold down the stop lever on the injection pump so that fuel isn't injected into the cylinders. If the fuel ignites, your compression tester will explode.
So the steps I'd follow are remove all of the glow plugs, insert the glow plug adapter and hook it up to the meter. Hold down the IP lever and have somone turn over the starter. 2-4 revs should be enough. Read the pressure and move to the next cylinder.
So the steps I'd follow are remove all of the glow plugs, insert the glow plug adapter and hook it up to the meter. Hold down the IP lever and have somone turn over the starter. 2-4 revs should be enough. Read the pressure and move to the next cylinder.
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bashibazouk
- Posts: 31
- Joined: Sep 22, 2007
- Location: Winterville (not Wienerville) NC
Compression Testing
If I was asked to provide input in the redesign of the 524td, I'd ask the engineers to figure out how to put the glow plugs on the top of the engine or maybe just redo the intake plenum so it's easier to work around.
The worst part of doing the compression test is futzing with the damned glow plug connections. How many u-joint socket adapters can you hook together?
Then, of course, it always helps to drop the nuts and washers down the side of the engine when you're hooking it back up! I found the little magnetic-picker-upper thing handy for getting them started.
Also, if you bungee the IP fuel cutout lever to the front of the car, you can crank it yourself.
Please let us know how the Harbor Freight tester worked. I found out they sold them a week after I paid $105 from another online tool place!
The worst part of doing the compression test is futzing with the damned glow plug connections. How many u-joint socket adapters can you hook together?
Then, of course, it always helps to drop the nuts and washers down the side of the engine when you're hooking it back up! I found the little magnetic-picker-upper thing handy for getting them started.
Also, if you bungee the IP fuel cutout lever to the front of the car, you can crank it yourself.
Please let us know how the Harbor Freight tester worked. I found out they sold them a week after I paid $105 from another online tool place!
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bashibazouk
- Posts: 31
- Joined: Sep 22, 2007
- Location: Winterville (not Wienerville) NC
Aiiigh!
Alright. I'll quit whining then!
I got a diesel compression test kit on Ebay for about $35. It has both the adapters for the glowplugs and the injectors. Since the Injector adapter has alot more dead volume inside of it, the reading that you get will be lower. It's best to use the glowplug adapter.
The kit said to read each cylinder after 8 compression cycles. I assume this is because of the higher compression pressures of a diesel to get a better endpoint reading. Do not, I repeat, do not add oil to the cylinder to check the 'ol worn pistons rings vs a bad valve test. You could get seriously injured.
Chirs H.
The kit said to read each cylinder after 8 compression cycles. I assume this is because of the higher compression pressures of a diesel to get a better endpoint reading. Do not, I repeat, do not add oil to the cylinder to check the 'ol worn pistons rings vs a bad valve test. You could get seriously injured.
Chirs H.
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slave2school
- Posts: 371
- Joined: Aug 23, 2007
- Location: NS, Canada
Yeah check out this post to see the differences.
http://forums.tdiclub.com/showpost.php? ... stcount=71
http://forums.tdiclub.com/showpost.php? ... stcount=71
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bashibazouk
- Posts: 31
- Joined: Sep 22, 2007
- Location: Winterville (not Wienerville) NC
Greenwood, NS?!
Nice post on the TDI forum-- replete with pictures 'n all!
Greenwood, NS?! My Mom lives a bit up the road in Mabou (Cape Breton Island). I spent a few weeks at CFB Greenwood in my youth with the RCAC (719 Stora Sqn. Pt. Hawkesbury)
But back to the manifold; was your BMW originally a 324? Did you add the turbo?
Josh
Greenwood, NS?! My Mom lives a bit up the road in Mabou (Cape Breton Island). I spent a few weeks at CFB Greenwood in my youth with the RCAC (719 Stora Sqn. Pt. Hawkesbury)
But back to the manifold; was your BMW originally a 324? Did you add the turbo?
Josh
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slave2school
- Posts: 371
- Joined: Aug 23, 2007
- Location: NS, Canada
Mine is a 324D that someone, somewhere, before me put the turbo, oil cooler, and a HUGE intercooler on 
(who knows maybe it was a whole new block and they switched some stuff over since the N/A manifold is supposedly a few percent more efficient). Then someone went and rear ended it. Now it is in my hands at a friends house getting a makeover
Last page of this thread shows a bit more detail, but it is all a good read. I probably am quite insane. http://vwdiesel.net/phpBB/viewtopic.php?t=10107&start=0
I live and work on the Base as an aviation technician. It is pretty interesting work at times.
(who knows maybe it was a whole new block and they switched some stuff over since the N/A manifold is supposedly a few percent more efficient). Then someone went and rear ended it. Now it is in my hands at a friends house getting a makeover Last page of this thread shows a bit more detail, but it is all a good read. I probably am quite insane. http://vwdiesel.net/phpBB/viewtopic.php?t=10107&start=0
I live and work on the Base as an aviation technician. It is pretty interesting work at times.
The NA manifold looks to have longer runners for more bottom end while the TD has shorter ones for a higher rpm peak HP. If you had the choice, I would use then TD one on your car with the turbo since it's also easier to reach the glowplugs as well.
The real bonus with your "D" engine is your camshaft has higher lift than the TD one for better breathing. They both have the same duration. I've been trying to procure a "D" camshaft for quite a while with no luck. Can you help? I have a spare TD intake for a trade.
Thanks,
Chris H.
The real bonus with your "D" engine is your camshaft has higher lift than the TD one for better breathing. They both have the same duration. I've been trying to procure a "D" camshaft for quite a while with no luck. Can you help? I have a spare TD intake for a trade.
Thanks,
Chris H.
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slave2school
- Posts: 371
- Joined: Aug 23, 2007
- Location: NS, Canada
TurboDan, my BMW parts is definitely trying to make a commission! I went there for the "D" camshaft and they wanted over $600. Thanks for the info.
I was trying to procure a used one from this ovide_nl guy from the Netherlands. He said he had one, but never got back to me if he had pulled it or not after several follow-ups. My understanding is this part will only add 5-10hp to a 524td.
Slave2School, do you have a 5sp since my 3.25 diff gives me 2000rpm at 75mph with my auto tranny.....
I was trying to procure a used one from this ovide_nl guy from the Netherlands. He said he had one, but never got back to me if he had pulled it or not after several follow-ups. My understanding is this part will only add 5-10hp to a 524td.
Slave2School, do you have a 5sp since my 3.25 diff gives me 2000rpm at 75mph with my auto tranny.....
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slave2school
- Posts: 371
- Joined: Aug 23, 2007
- Location: NS, Canada
Yes it is a 5spd. The 5th gear is supposedly a .80 with a 3.25 final open differential.
This will be a vast improvement IMHO over the TDI that runs 2200rpm around 60mph
(4spd auto for my wife).
When I get the money I plan on getting a pump redone by Giles in Markham, Ontario. He is an expert at extracting performance.
vwdiesel.net has several testimonials/dynos/videos posted around of his work on various pumps.
This will be a vast improvement IMHO over the TDI that runs 2200rpm around 60mph
(4spd auto for my wife).When I get the money I plan on getting a pump redone by Giles in Markham, Ontario. He is an expert at extracting performance.
vwdiesel.net has several testimonials/dynos/videos posted around of his work on various pumps.
Whoa.....600$ for a cam 
BMW sure charges a handful for new parts. I'm glad I can get used spare parts a bit cheaper in my neck' o the woods. Recently bought a complete 86. 524td for 300$ (the engine was shot), spare engine for 140$ (the head, valves and cam are redone, block is in reasonable condition), spare IP in good condition for 60$.....
BMW sure charges a handful for new parts. I'm glad I can get used spare parts a bit cheaper in my neck' o the woods. Recently bought a complete 86. 524td for 300$ (the engine was shot), spare engine for 140$ (the head, valves and cam are redone, block is in reasonable condition), spare IP in good condition for 60$.....