Vanagon issues...low compression...
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Vanagon issues...low compression...
Dear experienced readership...
My Vanagon has a little issue. I have driven it very, very little this year. A month ago, I checked compression, as my top end power seemed lacking. 1, 2, and 3 were all in the 125-130 range. 4 read 90 cold. Today, I checked again. 4 is down to 60 on a hot engine.
So, I adjusted the #4 valves just now. The exhaust valve stem is poking out significantly more than the intake, and with the adjustment screw all the way out, the rocker arm still touches the valve stem. So, am I looking at a rebuild? Just a valve job? A new head? Can I safely drive it with a recessed seat or stretched valve stem? I am fairly sure I replaced the exhaust valves in that head when I rebuilt the engine...fairly sure.
Any ideas as to what would cause my loss of compression?
Thanks for your help!
My Vanagon has a little issue. I have driven it very, very little this year. A month ago, I checked compression, as my top end power seemed lacking. 1, 2, and 3 were all in the 125-130 range. 4 read 90 cold. Today, I checked again. 4 is down to 60 on a hot engine.
So, I adjusted the #4 valves just now. The exhaust valve stem is poking out significantly more than the intake, and with the adjustment screw all the way out, the rocker arm still touches the valve stem. So, am I looking at a rebuild? Just a valve job? A new head? Can I safely drive it with a recessed seat or stretched valve stem? I am fairly sure I replaced the exhaust valves in that head when I rebuilt the engine...fairly sure.
Any ideas as to what would cause my loss of compression?
Thanks for your help!
- SlowLane
- IAC Addict!
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Re: Vanagon issues...low compression...
Hi. Sorry, didn't see this sooner. I'm assuming here that you have an air-cooled Vanagon.
This experienced Vanagon owner suggests that you have a dropped valve seat ( having experienced two such on two successive engines). It's not a happy situation, but at least you caught it before the seat jammed in its pocket cattywumpus and caused the valve to stick open.
You will need to replace that head at the least. You should also consider replacing the other one at the same time. What you replace them with depends on your budget and tolerance for risk. High budget, low risk is a pair of HAM heads from Len Hoffman. Low budget, high risk is a single head pulled from a junkyard donor. In between is one or two new AMC heads. You'll find many opinions on the relative merits of each option.
You should not drive the car any more, however, until you have this resolved. You've dodged a bullet so far.
This experienced Vanagon owner suggests that you have a dropped valve seat ( having experienced two such on two successive engines). It's not a happy situation, but at least you caught it before the seat jammed in its pocket cattywumpus and caused the valve to stick open.
You will need to replace that head at the least. You should also consider replacing the other one at the same time. What you replace them with depends on your budget and tolerance for risk. High budget, low risk is a pair of HAM heads from Len Hoffman. Low budget, high risk is a single head pulled from a junkyard donor. In between is one or two new AMC heads. You'll find many opinions on the relative merits of each option.
You should not drive the car any more, however, until you have this resolved. You've dodged a bullet so far.
'81 Canadian Westfalia (2.0L, manual), now Californiated
"They say a little knowledge is a dangerous thing, but it is not one half so bad as a lot of ignorance."
- Terry Pratchett
"They say a little knowledge is a dangerous thing, but it is not one half so bad as a lot of ignorance."
- Terry Pratchett
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Re: Vanagon issues...low compression...
Thanks! It will be 3 weeks before I can get the head off, so that's a bummer on the driving. For curiosity, how does a burned valve behave differently from a receding valve seat?
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- IAC Addict!
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Re: Vanagon issues...low compression...
Can't answer either of your questions...but either way you are looking at new head(s)... my two cents...
From a cost benefit analysis, if the budget is tight, I would suggest a rebuilt head from bud depot ... less risky than a used head that you would most likely buy sight unseen off of the 'net, but still a bit of a crap shoot. Or, if the budget allows, new heads from Len. Based on busdepot prices for new AMC heads the cost for Len's heads are only a few hundred bucks more if you don't do any ceramic coatings.
I have a similar situation, so thought it might be helpful to provide you the logic I used when deciding which direction to go.....
As my engine runs well, I had no desire to crack into a perfectly good running engine, however, BOTH of my heads were not rebuildable. I seriously thought about going the cheap route with rebuilt heads, but since my cores were junk, that upped the price, putting them fairly close to new AMC heads. However, Len's heads aren't really all that much more than new AMC heads, and as my wife has threatened me with divorce if I ever sold the bus, it will be a permanent part of the family. So I figured I'd splurge the few extra hundred and get top o' the line stuff while top o' the line stuff is still available... Len ain't getting any younger....
that's my thought process...not yours but hope the logic helps your decision making process
From a cost benefit analysis, if the budget is tight, I would suggest a rebuilt head from bud depot ... less risky than a used head that you would most likely buy sight unseen off of the 'net, but still a bit of a crap shoot. Or, if the budget allows, new heads from Len. Based on busdepot prices for new AMC heads the cost for Len's heads are only a few hundred bucks more if you don't do any ceramic coatings.
I have a similar situation, so thought it might be helpful to provide you the logic I used when deciding which direction to go.....
As my engine runs well, I had no desire to crack into a perfectly good running engine, however, BOTH of my heads were not rebuildable. I seriously thought about going the cheap route with rebuilt heads, but since my cores were junk, that upped the price, putting them fairly close to new AMC heads. However, Len's heads aren't really all that much more than new AMC heads, and as my wife has threatened me with divorce if I ever sold the bus, it will be a permanent part of the family. So I figured I'd splurge the few extra hundred and get top o' the line stuff while top o' the line stuff is still available... Len ain't getting any younger....
that's my thought process...not yours but hope the logic helps your decision making process
1976 VW Bus aka tripod
FI ...not leaky, and not so noisy...and she runs awesome!
FI ...not leaky, and not so noisy...and she runs awesome!
hambone wrote: There are those out there with no other aim but to bunch panties. It's like arguing with a pretzel.
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Re: Vanagon issues...low compression...
How much are Len's? Everything I have seen shows $1500 and up, while BD has them for $314...that's well more than a few bucks...
- Amskeptic
- IAC "Help Desk"
- Status: Offline
Re: Vanagon issues...low compression...
I would be most interested in more information on the Bus Depot "ad copy".
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles
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Re: Vanagon issues...low compression...
http://www.busdepot.com/071101061dx
Here's the link...It looks like AMC heads run $460 or so, and puts us more in the "few hundred" category.
I am also torn between buying one knock off head now to run on this engine, and buying two good heads to build a new engine...I hate to buy two new heads for an old engine, even though "old" means only 14k miles...
Here's the link...It looks like AMC heads run $460 or so, and puts us more in the "few hundred" category.
I am also torn between buying one knock off head now to run on this engine, and buying two good heads to build a new engine...I hate to buy two new heads for an old engine, even though "old" means only 14k miles...
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- IAC Addict!
- Location: Metro Detroit
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Re: Vanagon issues...low compression...
If you are only going to replace one head, then you may want to go with a reman head, or one new head, or better yet, if you have a good core, get yours rebuilt by a reputable shop. Below are the figures I used for making my decision:
I had to buy two heads - neither of mine are rebuildable. Therefore...
2 reman heads incl. core charge: $628 from what i've read, these are a crap shoot
2 new heads: $1050 from what i've read, better than reman, but sub par valve components
2 new Len Heads: $1425 from what i've reead, top of the line, best that is available today
Figures do not include taxes or shipping.
As I'm keeping the bus, I nixed the reman route...everything I've read is that the cores that are out there have been rebuilt so much, that it's hard to get good cores, and as mine were not rebuildable, decided I needed new. As I was going new, I felt that the $375 premium was well worth getting the best available.....and you add to the fact that who knows how much longer Len will be plying his craft, and that they may not be available in the future, the decision was almost a no brainer for me.
I too have an old engine... mileage is unknown, but I have put 20k on it so far. I figured if I got the Len heads now, I would also have them in 10k -20k miles when I do have to rebuild, and won't have to factor this into the rebuild cost.
That was my logic process for my sitution...YMMV
I had to buy two heads - neither of mine are rebuildable. Therefore...
2 reman heads incl. core charge: $628 from what i've read, these are a crap shoot
2 new heads: $1050 from what i've read, better than reman, but sub par valve components
2 new Len Heads: $1425 from what i've reead, top of the line, best that is available today
Figures do not include taxes or shipping.
As I'm keeping the bus, I nixed the reman route...everything I've read is that the cores that are out there have been rebuilt so much, that it's hard to get good cores, and as mine were not rebuildable, decided I needed new. As I was going new, I felt that the $375 premium was well worth getting the best available.....and you add to the fact that who knows how much longer Len will be plying his craft, and that they may not be available in the future, the decision was almost a no brainer for me.
I too have an old engine... mileage is unknown, but I have put 20k on it so far. I figured if I got the Len heads now, I would also have them in 10k -20k miles when I do have to rebuild, and won't have to factor this into the rebuild cost.
That was my logic process for my sitution...YMMV
1976 VW Bus aka tripod
FI ...not leaky, and not so noisy...and she runs awesome!
FI ...not leaky, and not so noisy...and she runs awesome!
hambone wrote: There are those out there with no other aim but to bunch panties. It's like arguing with a pretzel.
- Amskeptic
- IAC "Help Desk"
- Status: Offline
Re: Vanagon issues...low compression...
If customers wouldn't CANCEL on me, I could budget two sets of Len Hoffman 2.0 heads for the rest of my life. And I drive a lot! I would be a longevity test for Len Hoffman heads. As it is, I will be casting my own heads in the desert sand with melted down Diet Coke cans.
Colin : )
Colin : )
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles
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- Addicted!
- Location: Thomasville Georgia
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Re: Vanagon issues...low compression...
A further push in the Len direction: I've reviewed my 2014 notes, and it seems that this bum head is the the Reman BD head, by AVP. That means that this head has survived only 4 years and 14k miles. It has a 12k mile warranty...
I'll call Len today and see what we can do. I'm definitely thinking either 2 of his heads, or one reman. I definitely want two of Len's heads for my next ground up build.
Now the question of the day...Where did I get the head for the right side?
Maybe I should just buy two...
I'll call Len today and see what we can do. I'm definitely thinking either 2 of his heads, or one reman. I definitely want two of Len's heads for my next ground up build.
Now the question of the day...Where did I get the head for the right side?
Maybe I should just buy two...
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- Location: Thomasville Georgia
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Re: Vanagon issues...low compression...
Hamheads list theirs for $1495, plus about $465 for ceramic coatings, and $50 for temp sensor notches. The oval ports are somewhat cheaper. I think I will be getting Len's and do both heads, as I have no idea where I got my right side head...
I assume that I will be CCing heads and reevaluating deck heights...
I assume that I will be CCing heads and reevaluating deck heights...
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- IAC Addict!
- Location: Metro Detroit
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Re: Vanagon issues...low compression...
You will need to CC your old heads, but Len does that for you on the new heads and stamps the readings on said heads (I asked.. of course from prompting from Colin )
1976 VW Bus aka tripod
FI ...not leaky, and not so noisy...and she runs awesome!
FI ...not leaky, and not so noisy...and she runs awesome!
hambone wrote: There are those out there with no other aim but to bunch panties. It's like arguing with a pretzel.
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- IAC Addict!
- Location: Metro Detroit
- Status: Offline
Re: Vanagon issues...low compression...
I would be happy to start a go fund me page and donate the first $50 for an IACLenHoffmanLongevityTest for the first set of Len Heads. I only ask that 5 more people would be willing to donate by responding to this string (feel free to move Mr Admin) regardless of amount, so that I know my efforts won't go for naught...Amskeptic wrote: ↑Fri May 25, 2018 7:02 amIf customers wouldn't CANCEL on me, I could budget two sets of Len Hoffman 2.0 heads for the rest of my life. And I drive a lot! I would be a longevity test for Len Hoffman heads. As it is, I will be casting my own heads in the desert sand with melted down Diet Coke cans.
Colin : )
1976 VW Bus aka tripod
FI ...not leaky, and not so noisy...and she runs awesome!
FI ...not leaky, and not so noisy...and she runs awesome!
hambone wrote: There are those out there with no other aim but to bunch panties. It's like arguing with a pretzel.
- tommu
- Old School!
- Location: Sunny Burbank
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- Amskeptic
- IAC "Help Desk"
- Status: Offline
Re: Vanagon issues...low compression...
TrollFromDownBelow wrote: ↑Fri May 25, 2018 9:22 pmI would be happy to start a go fund me page and donate the first $50 for an IACLenHoffmanLongevityTest for the first set of Len Heads. I only ask that 5 more people would be willing to donate by responding to this string (feel free to move Mr Admin) regardless of amount, so that I know my efforts won't go for naught...Amskeptic wrote: ↑Fri May 25, 2018 7:02 amIf customers wouldn't CANCEL on me, I could budget two sets of Len Hoffman 2.0 heads for the rest of my life. And I drive a lot! I would be a longevity test for Len Hoffman heads. As it is, I will be casting my own heads in the desert sand with melted down Diet Coke cans.
Colin : )
I think Len should offer them gratis . . .
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles