Re: Blown Head Gasket Repair at 600 Miles
Posted: Sat Sep 13, 2014 10:44 am
That would suggest then there was no need for their removal.
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Ok, so what do you define as "overheating"?72Hardtop wrote:No rewording...my belief has always been that's it's critical to keep the engine in a high state of tune as much as possible. One that isn't will be working much harder combined with running hotter. One big reason VW did not put CHT gauges in these vehicles was they knew it would freak people out given the majority of people were used to seeing a gauge on a water cooled car showing far less temps.asiab3 wrote: What exactly do you define as "overheating"? I've been mulling over this quite a bit- VW does not publish data in their service manuals nor the "guesswork" series. Is there a point at which we can say yes or no to "is this engine overheating?"
Or would you change your wording to "running in the hottest conditions aided in it happening sooner?"
Keep in mind Colins experience is unlike any or most average bus owner/s (past & present) much like his attention to detail such as painting backing plates while boon docking somewhere lonely.
NAAAAaaaaah . . . They were CHEAP. They could have put in a gauge with no numbers, just pretty colors, blue and red for example. Based on the legendary reliability of air-cooled VW engines up through the 60's, they felt no need to monitor such an under-stressed engine. Now, at what point do they begin to wonder if they should? Late 60's? Early 70's? They just gritted their teeth and demanded that we follow the directions as far as state of tune. The factory always always advised against performance modifications to their engines, because they did their homework and knew that things would make it to the 100,000 mile mark OK.72Hardtop wrote:One big reason VW did not put CHT gauges in these vehicles was they knew it would freak people out given the majority of people were used to seeing a gauge on a water cooled car showing far less temps.
NAAAAAaaah, I might shine stuff and stuff, but look far and wide for anything special in the engine compartment . . . y'ain't gonna find it. I tune according to the directions and drive! You might have found a few intense moments where I had to find out an over-flycut head in the Road Warrior, or who made what mistake in Chloe (too-small exhaust valves anyone?) for example, but once everything is set up correctly, I just drive the snot out of them.72Hardtop wrote: Keep in mind Colins experience is unlike any or most average bus owner/s (past & present) much like his attention to detail such as painting backing plates while boon docking somewhere lonely.
I agree with Colin on this with regards to a 'specific overheat temp'. VW never offered one up or alluded to a specific number. One thing is certain If the engine begins to smoke and cook oil...you've reached the over heat state. At that point it's generally too late.Amskeptic wrote:NAAAAaaaaah . . . They were CHEAP. They could have put in a gauge with no numbers, just pretty colors, blue and red for example. Based on the legendary reliability of air-cooled VW engines up through the 60's, they felt no need to monitor such an under-stressed engine. Now, at what point do they begin to wonder if they should? Late 60's? Early 70's? They just gritted their teeth and demanded that we follow the directions as far as state of tune. The factory always always advised against performance modifications to their engines, because they did their homework and knew that things would make it to the 100,000 mile mark OK.72Hardtop wrote:One big reason VW did not put CHT gauges in these vehicles was they knew it would freak people out given the majority of people were used to seeing a gauge on a water cooled car showing far less temps.
NAAAAAaaah, I might shine stuff and stuff, but look far and wide for anything special in the engine compartment . . . y'ain't gonna find it. I tune according to the directions and drive! You might have found a few intense moments where I had to find out an over-flycut head in the Road Warrior, or who made what mistake in Chloe (too-small exhaust valves anyone?) for example, but once everything is set up correctly, I just drive the snot out of them.72Hardtop wrote: Keep in mind Colins experience is unlike any or most average bus owner/s (past & present) much like his attention to detail such as painting backing plates while boon docking somewhere lonely.
Colin
(p.s. overheating in a VW is pretty much "already too late". You smell oil cooking on parts, you note a loss of power when the pistons smear themselves all over the cylinder walls. Back in the day, an overhaul was as easy a new piston/cylinder and an exchange head from the dealer. Now we have "gauges" and arguments galore about what number is the "overheat number")
Per the VW tech bulletin....He's not to use them. It also includes notching the connecting rods. If you're using AMC heads they already have a step machined into the head itself. No need for the gasket.CarlosZ wrote:So what's the consensus on the head gaskets? Yeah or Nay? Reason I as is that I've read conflicting info regarding the topic. I'm having an engine built and told the builder over and over NOT to use the head gaskets as per the VW tech bulletin. Yesterday he tells me that he's almost done and used them. He says they're not used on AMC heads and confuses me with technical jargon. I have a 2.0 GD case, VW 2.0 heads and a Web73 cam. So pissed, should've built it myself as others suggested. He's closed today and looking for some good ammo if I decide to have him take it all apart tomorrow. Also, I don't really care if they can be used w/o issue. I just want to have it built properly. Thanks and flame away.
The sealing rings are NOT a weak link, and they can be used as necessary. I have never lost a sealing ring in my life.cegammel wrote:They can used without issue, but they will blow again. Did the shop notch the rods, or just new gaskets?
Ask about the rod notching and the increased piston/cylinder clearance demanded by the technical service bulletin.CarlosZ wrote:So what's the consensus on the head gaskets? Yeah or Nay? Reason I as is that I've read conflicting info regarding the topic. I'm having an engine built and told the builder over and over NOT to use the head gaskets as per the VW tech bulletin. Yesterday he tells me that he's almost done and used them. He says they're not used on AMC heads and confuses me with technical jargon. I have a 2.0 GD case, VW 2.0 heads and a Web73 cam. So pissed, should've built it myself as others suggested. He's closed today and looking for some good ammo if I decide to have him take it all apart tomorrow. Also, I don't really care if they can be used w/o issue. I just want to have it built properly. Thanks and flame away.
Piston scuffing was directly related to piston-cylinder clearance not sealing ring. The fix was for piston scuffing per VW tech bulletin was as follows:Amskeptic wrote: ↑Sat Feb 11, 2017 6:52 amAsk about the rod notching and the increased piston/cylinder clearance demanded by the technical service bulletin.CarlosZ wrote:So what's the consensus on the head gaskets? Yeah or Nay? Reason I as is that I've read conflicting info regarding the topic. I'm having an engine built and told the builder over and over NOT to use the head gaskets as per the VW tech bulletin. Yesterday he tells me that he's almost done and used them. He says they're not used on AMC heads and confuses me with technical jargon. I have a 2.0 GD case, VW 2.0 heads and a Web73 cam. So pissed, should've built it myself as others suggested. He's closed today and looking for some good ammo if I decide to have him take it all apart tomorrow. Also, I don't really care if they can be used w/o issue. I just want to have it built properly. Thanks and flame away.
Please note that the sealing rings were not prone to failing . . . they failed due to other causes. They were deleted in the TSB strictly to increase immediate heat transfer from the combustion chambers to the cylinder barrels under load to help prevent piston scuffing!
But piston/cylinder clearance changes throughout the warmup cycle! The pistons receive the bulk of combustion heat FIRST, and expand sooner and quicker. Yes, the increased clearance would help, but removing the compression gasket does increase heat transfer into the cylinder walll aiding in its thermal expansion as well. VW released this bulletin as a system. It wasn't "delete the rings." It was "delete the rings, increase the clearance, space the CR back, and notch the rods." We all know that ACVW's require complete systems to be maintained, not just one step to fix one issue.72Hardtop wrote: ↑Thu Apr 27, 2017 8:43 pmPiston scuffing was directly related to piston-cylinder clearance not sealing ring. The fix was for piston scuffing per VW tech bulletin was as follows:Amskeptic wrote: ↑Sat Feb 11, 2017 6:52 amAsk about the rod notching and the increased piston/cylinder clearance demanded by the technical service bulletin.CarlosZ wrote:So what's the consensus on the head gaskets? Yeah or Nay? Reason I as is that I've read conflicting info regarding the topic. I'm having an engine built and told the builder over and over NOT to use the head gaskets as per the VW tech bulletin. Yesterday he tells me that he's almost done and used them. He says they're not used on AMC heads and confuses me with technical jargon. I have a 2.0 GD case, VW 2.0 heads and a Web73 cam. So pissed, should've built it myself as others suggested. He's closed today and looking for some good ammo if I decide to have him take it all apart tomorrow. Also, I don't really care if they can be used w/o issue. I just want to have it built properly. Thanks and flame away.
Please note that the sealing rings were not prone to failing . . . the failed due to other causes. They were deleted in the TSB strictly to increase immediate heat transfer from the combustion chambers to the cylinder barrels under load to help prevent piston scuffing!
The TSB we're speaking of was released in May of 1990. You say that the sealing rings leaking were why VW released the tech bulletin? My speculation is that many original 2.0 Type 4 engines were just starting to hit the end of their reliable life span by then, and VW was tearing them down to remanufacture. And they found piston scuffing, so they remedied that. Nobody would bring their bus in for "I think there is piston on my cylinder wall." But don't you think VW would have seen a much larger dealership work order trend if all the sealing rings were failing like you proffer? Failed rings cause low compression, leaky noises, low power, and all that jazz. Any one of those symptoms would cause a customer to bring their car in. It seems VW was clear in the TSB to say "to eliminate seizing of pistons" but never mention "to eliminate leaking of combustion chambers" or the like.The removal of the head rings was directly related to their failure overtime. The thinness of them overtime in the combustion area (high pressure) would erode them overtime. If one overheated the bus (which was quite common) that would allow for the sealing rings to erode/burn through even faster.
Sealing rings absolutely reduce heat transfer, just like the metal spacer that VW introduced under the TS2 to extend warm up times. This time, VW removed the spacer to speed up heat transfer, which helps increase piston-to-cylinder clearance during warm up.The sealing rings do not increase heat transfer given they are metal material. The repeated cycling (movement & heat) of the engine would erode the sealing rings overtime and VW knew that removing them and lapping the heads was a much better alternative. Now with the AMC heads one has the added step that in essence takes the sealing rings place and allows for a better seal when lapping the cylinders into the heads.
I was specifically referring to dealer said work. No dealer would install over flycut heads in the face of the TSB in their hand. Never would happen. Independent shops it was up to the owner. The ones I knew would not as well (liability). The fix was later adapted to 1.7 and 1.8 engines as well.Amskeptic wrote: ↑Sat Apr 29, 2017 6:52 pm"No VW shop dealer or otherwise would go the route of installing over cut heads with sealing rings."
They absolutely would and they absolutely do. Look at Air-Cooled.Net's selection of copper head sealing rings. Look at your factory engine manuals.
Sealing rings were installed in millions! of Type 4 engines from 1970! onwards. They were not a known failure point. They were only canaries in coal mines for those engines that endured traumatic overheats (many of which arose from dealer mechanics). The TSB was for only the 2.0 engine with the 94mm cylinders that had this bumper crop of scuffed pistons that then sounded like little diesel engines once the skirts were collapsed.
"Improved heat transfer", said the bulletin. Damn right. We are talking of course, of momentary heat spikes on hills and headwinds that caused a momentary "unsynchronization" of heat expansion rates between the piston and the cylinder wall. That is all.
The thread that just won't die.
Colin
p.s.
"Anyone who had an issue with them being removed per the bulletin were turned away given no shop would do the work."
What? )