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ameristar2
Active Member
United States
17 Posts |
 Posted - 05/11/2009 : 2:20:21 PM
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Why does the 9.0 international V8 pop head gaskets? Is it a defect in the gasket design or do the blocks and heads have thin decks?
When you do the head gaskets, do the heads need to be trued up and tp what RA number? |
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International-9.0
Advanced Member
USA
459 Posts |
Posted - 05/11/2009 : 5:48:40 PM
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Some of the earliest 9 liters had some problems. I believe they changed the gasket/bolts/etc. The only time I've even seen blown head gaskets is when the engine has been overheated. If they aren't overheated (or lugged), they will last well beyond 200,000 miles with no major problems. The 9 liter features a 19.1:1 compression ratio, which is very high for a direct injection. Some of the IDI engines would reach 21.5:1, but these weren't subject to the same physics as a direct injection diesel. This high compression ratio is one reason why turbos were never feasible on the engine. I suspect there were other weaknesses as the heads could always have been modified for a turbo.
The engine did feature a 6 bolt head design. The 6.9 only boasted a 5 bolt design, while the DD 8.2 only had 4 bolts per head (plus an open deck design). I spose probamatic injector nozzles could cause an issue. If one cylinder gets too much fuel this could weaken the gasket around the cylinder. Lugging the engine where theres alot of vibration could cause this too. The injection pump used on the 9 liter overfueled the engine when at full throttle in the lower rpm range. This feature improved low end torque and starting. I imagine with a stick shift, you could lug the engine often and eventually where through the head gasket. 8.2s did not like to be lugged!
Another possibility is that some idiot did not torque the heads properly. There are 3 different torquing steps and each step has a different order. Not following these specifications could result in premature head gasket failure if the vehicle had been previously worked on.
Another possibility (should there be the presence of coolant in the oil that may be mistaken for a head gasket) is that the oil cooler has failed or that coolant cavitation has eaten through the cylinder walls. Cavitation isn't all that common in a parent bore engine but I spose it happens on occasion.
To be honest, other than the very early models, I've never heard of a 9 liter head gasket failing when the vehicle had not been overheated. We've had one overheat several times and luckily not enough to blow the head gasket, but it's a real gamble with those engines. I'm pretty sure the service manual says NOT to resurface the heads. We had a machine shop do ours and the engine has run fine, but I spose you better not take too much with those. They are very high compression and there isn't much clearance. |
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Trailboss
Senior Member
United States
196 Posts |
Posted - 05/12/2009 : 04:23:39 AM
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It has been along time since we have had any 9 liters. As i remember
when yhe head gaskets failed we had the heads checked,purchased a new style gasket and replaced the head bolts.After that they were a the best engine we ran. |
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second.flood
Top Member
USA
640 Posts |
Posted - 05/12/2009 : 04:52:37 AM
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| Used to have a bunch of 9.0 liters. Nearly every one had a head gasket pop. Caused by broken or stretched head bolts. New gasket and bolt kit, follow the torque sequence I-9.0 mentioned and had no more problems. |
Edited by - second.flood on 05/12/2009 04:53:37 AM |
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bsaund09
Top Member
USA
609 Posts |
Posted - 05/12/2009 : 07:29:52 AM
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| Didn't the IHC do a factory recall on those heads around the mid- 1980s seems I remember all those '84-'85 IHC having some sort of recall work on the head gaskets. I know the early Detroit Diesels in the Fords blew head gaskets all the time and I guess they try to prevent that on the IHCs by having that factory work done. anyway just a thought -- i loved driving those old Internationals nothing else like them. |
keep those buses rolling
http://www.flickr.com/photos/tags/schoolbushistory |
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ameristar2
Active Member
United States
17 Posts |
Posted - 05/12/2009 : 1:49:21 PM
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| Thank you all for the responses. I have always believed that there are no "bad" engines, just misunderstood and misused ones. I saw a hotshot out in UT that popped the head gaskets (didn't do a proper diagnostic, just assumed that that was the case), the head gaskets were recently done, motor runs fine, but antifreeze was mixing with the oil. Thanx I9.0 for the history lesson. It sounds like a set of gaskets and ARP bolts will make those engines super reliable. Another thing, what type of pump did fuel injection pump did this engine have? Was it a rotary or plunger style pump? Has anyone modified the delivery and timing on these engines to help with the overfueling issues? |
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Thomasbus24
Administrator
USA
4547 Posts |
Posted - 05/12/2009 : 3:58:39 PM
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| Haha...you've never met a Cummins V555 or VT225. BOAT ANCHORS :) |
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International-9.0
Advanced Member
USA
459 Posts |
Posted - 05/12/2009 : 5:16:45 PM
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The fuel injection pump was a Bosch PES 8A95 I believe. It is an inline pump, not a rotary. The rotary style was generally used in IDI and lesser/lighter duty diesels. It had plungers as well, but these were setup in a different fashion from the inline style pumps. There was one set of two opposed plungers and they were squeezed together by a cam ring. Then there was a distributor system on the end of the pump.
The inline style pumps were used on the premium and heavier duty diesels. I believe they had a higher cost. What I like about those is that they generally used all speed governors. The rotaries tended to use min/max type governors so it was harder to maintain a constant speed. The plungers on the inline pump used by the 9.0 are pushed by a camshaft at the bottom of the injection pump. This camshaft also runs the transfer/lift pump that is bolted to the side of the main injection pump.
I was a little bit inaccurate when I said the engines "overfuel." at low rpms. When you press the accelerator to start the engine (and you are supposed to do this, even when warm), the injection pump does overfuel the engine until it reaches an rpm of 200-500, at which the starting fuel cuts out automatically. Watch for a big black cloud as you start the engine with the accelerator down. I don't have a fueling curve in my manual that shows the fueling rate for each rpm, but it does appear there is quite a bit more black smoke in the lower rpm range when the engine is revved. Above 200 rpms (you'd never get below this unless the engine was starting anyways), I wouldn't say the engine is overfueled, but just fueled more than up in the normal operating range (above 2000 or so). Lugging the engine at less than 1500 rpms for long lengths of time is the only way you would ever have any trouble I'd think. No diesel really likes being lugged. Getting started is no problem, but continuous lugging is what does the damage, and that can also lead to overheating on hills. The engine is fueling heavy, but the water pump and fan aren't turning fast at low rpm.
Adjusting the fueling rate would require getting inside the injection pump in the valley, which is about impossible. You'd also have to be very delicate as you can mess up parts in the injection pump easily, or get the fuel way too high/low. Generally these kinds of adjustments should be made with a test stand. As far as timing, I'd thought about advancing the timing 1 or 2 degrees on mine, but that was until I saw how much work it was to do it! You have to remove just about eveything on the front of the engine to get to the injection pump cover. There's no way it's worth the work. I believe it's a little easier on the DT engines. It' too bad there was no adjustment on the pump itself for timing. As far as I know, people usually leave these engines alone. Modding is usually saved for the DT engines. If you leave he injection pump setting stock, you will be perfectly fine. If you cut the fuel back, then you will have something like an 8.2 on the low end-NOTHING. |
Edited by - International-9.0 on 05/12/2009 5:17:37 PM |
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jeepcjron
Advanced Member
USA
262 Posts |
Posted - 05/12/2009 : 5:42:07 PM
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quote:
Originally posted by Thomasbus24
Haha...you've never met a Cummins V555 or VT225. BOAT ANCHORS :)
triple nickel. thanks for reminding me those existed. time for a drink to forget now. |
its like a slinky! useless but fun to watch. |
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Thomasbus24
Administrator
USA
4547 Posts |
Posted - 05/12/2009 : 6:07:54 PM
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| Well let's make it worth drinking over shall we? LUCAS-GIRLING!!!!!!!!!!!!!!!!!!!!!!! |
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JC Theriault
Top Member
Canada
1326 Posts |
Posted - 05/12/2009 : 10:04:02 PM
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quote:
Originally posted by Thomasbus24
Well let's make it worth drinking over shall we? LUCAS-GIRLING!!!!!!!!!!!!!!!!!!!!!!!
And I read this when the beer store is closed for the night! |
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ameristar2
Active Member
United States
17 Posts |
Posted - 05/15/2009 : 3:46:28 PM
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| I could just imagine what a turbo'd 9 liter could do. Slight decompression, a couple of HX35s and a tweaked pump. Hey, it could be fun. I heard one of them run on another bus site and thought the quiet, woofly sound was cool. Thanks again for the thorough response, I seem to get more out of this bus site than most. And to think driving buses was what got me into commercial driving in the first place! Once again, thanx everybody for responding. |
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9.0 international head gasket issues
