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Thu Oct 09, 2025 8:41 pm

This engine works but is a bit worn. Compression is 115psi on 2 cylinders and I get bad lifter tick if it’s been sitting for a week or more.

Would it be acceptable to replace bearings, rings, lifters, and maybe jugs, with minimal or no machining?

1978 vw bus with 2.0L FI

Fri Oct 10, 2025 1:57 am

There is no short cut when it comes to making an engine run properly. Being a type 4 engine it is possible that the case doesn't need machining but you will have to tear it down completely and measure it all to know.

Have you checked the compression readings dry and wet to determine if the problem is rings or valves? How much oil does the engine use? Your compression loss could be just the valves.

As for the lifter noise, type 4 engines are known to have bad camshafts.

Fri Oct 10, 2025 2:21 am

oprn wrote:
As for the lifter noise, type 4 engines are known to have bad camshafts.
That's a sweeping statement! My Type-4 stock cam and followers are over 50 years old and still fine.

Fri Oct 10, 2025 2:27 am

Zed999 wrote: oprn wrote:
As for the lifter noise, type 4 engines are known to have bad camshafts.
That's a sweeping statement! My Type-4 stock cam and followers are over 50 years old and still fine.
Age has nothing to do with it. Oil quality and the number on the odometer are the key. My '73 Bus engine had a pretty bad cam in it. Anyone that has taken a few type 4 engines down will tell you it's rare to find a good used cam.

Fri Oct 10, 2025 3:18 am

oprn wrote: Zed999 wrote: oprn wrote:
As for the lifter noise, type 4 engines are known to have bad camshafts.
That's a sweeping statement! My Type-4 stock cam and followers are over 50 years old and still fine.
Age has nothing to do with it. Oil quality and the number on the odometer are the key. My '73 Bus engine had a pretty bad cam in it. Anyone that has taken a few type 4 engines down will tell you it's rare to find a good used cam. I had the choice of 3 good and one bad when I built mine 10 years ago, I picked the marginally best looking one. I get that there's less cam/follower contact than a type-1 but let's not just write them off without inspecting. :)
As you point out it's all about maintenance rather than age but 50 years is a long time even with good maintenance though I'd admit it's likely UK buses don't cover many miles compared to US buses, so 50 years might be 100,000 miles or even less.

Fri Oct 10, 2025 4:22 am

I have rebuilt a number of type 1 engines and have yet to buy a new camshaft for one. This was my first type 4 and it was indeed very bad with 80K miles on it. The consensus from the type 4 guys on this site at the time was "Ya that is pretty normal."

The good thing about the type 4 is you can remove the lifters and get a look at the cam lobes without splitting the case.

Fri Oct 10, 2025 7:03 am

If the end play is good and the cam doesn't look too bad you might be able to get away with just doing a top-end rebuild. My friends bus was in the same situation and we just honed the cylinders, new rings, rebuilt heads... it's still on the road running strong nearly 20 years later.

Fri Oct 10, 2025 11:10 am

oprn wrote: There is no short cut when it comes to making an engine run properly. Being a type 4 engine it is possible that the case doesn't need machining but you will have to tear it down completely and measure it all to know.

Have you checked the compression readings dry and wet to determine if the problem is rings or valves? How much oil does the engine use? Your compression loss could be just the valves.

As for the lifter noise, type 4 engines are known to have bad camshafts.

I had it checked and didn't ask. I don't know if it was wet or dry. I'm assuming by wet you mean squirting oil in the cylinders

Fri Oct 10, 2025 11:24 am

Fri Oct 10, 2025 12:40 pm

459032 wrote:
Would it be acceptable to replace bearings, rings, lifters, and maybe jugs, with minimal or no machining?

Short answer... yes, you can do a "re- seal" instead of a rebuild and maybe get away with it.

Is it a good idea? That's up to you.

Low compression often indicates the rings are towards the end of their service life. At the very least you need to hone the cylinders and replace the rings.

Again, up to you but if this was the Third World we might even re- use the rings.

But...

It's a slide down a slippery slope.

Again, up to you but do you want to make "like new" power on a bottom end that's a long way from new?

Do you want to split the case and end up with your engine in a tote when you can't find bearings?

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Fri Oct 10, 2025 1:19 pm

Zed999 wrote: oprn wrote:
As for the lifter noise, type 4 engines are known to have bad camshafts.
That's a sweeping statement! My Type-4 stock cam and followers are over 50 years old and still fine.

Does your bus have a lifter tick when not used for a while?

Fri Oct 10, 2025 1:22 pm

Dusty1 wrote: 459032 wrote:
Would it be acceptable to replace bearings, rings, lifters, and maybe jugs, with minimal or no machining?

Short answer... yes, you can do a "re- seal" instead of a rebuild and maybe get away with it.

Is it a good idea? That's up to you.

Low compression often indicates the rings are towards the end of their service life. At the very least you need to hone the cylinders and replace the rings.

Again, up to you but if this was the Third World we might even re- use the rings.

But...

It's a slide down a slippery slope.

Again, up to you but do you want to make "like new" power on a bottom end that's a long way from new?

Do you want to split the case and end up with your engine in a tote when you can't find bearings?

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I'd want to reuse as much as possible. I hadnt' considered reusing rings since I assumed they'd be the reason for the lower compression.

Are new bearing not available anymore?

Fri Oct 10, 2025 1:25 pm

buckswilde wrote: If the end play is good and the cam doesn't look too bad you might be able to get away with just doing a top-end rebuild. My friends bus was in the same situation and we just honed the cylinders, new rings, rebuilt heads... it's still on the road running strong nearly 20 years later.

I'm not entirely sure how to check endplay. I put it in neutral with engine off and cold and pushed then pulled on the crank pulley. No noticeable movement.

Fri Oct 10, 2025 1:35 pm

buckswilde wrote: If the end play is good and the cam doesn't look too bad you might be able to get away with just doing a top-end rebuild. My friends bus was in the same situation and we just honed the cylinders, new rings, rebuilt heads... it's still on the road running strong nearly 20 years later.

I'm not entirely sure how to check endplay. I put it in neutral with engine off and cold and pushed then pulled on the crank pulley. No noticeable movement.

Fri Oct 10, 2025 2:59 pm

459032 wrote: Are new bearing not available anymore?

It looks like Type 4 mains are available after a quick trip to CB's site. But... click "add to cart" a few times. Seems std / std are scarce. The Type 4 guys know better than I do. .020" case / .010" crank are available as are .020" / .020". I'd order before I tore into it which is why I have $300 worth of main bearings sitting on my kitchen table.

$300 doesn't buy as many main bearings as it used to. :roll:

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Fri Oct 10, 2025 3:20 pm

459032 wrote: Zed999 wrote: oprn wrote:
As for the lifter noise, type 4 engines are known to have bad camshafts.
That's a sweeping statement! My Type-4 stock cam and followers are over 50 years old and still fine.

Does your bus have a lifter tick when not used for a while? No, and I don't understand why leaving it for a while would cause that unless you're assuming it's hydraulic lifters?

Fri Oct 10, 2025 4:26 pm

They are hydraulic lifters

Sat Oct 11, 2025 10:05 am

Dusty1 wrote: 459032 wrote: Are new bearing not available anymore?

It looks like Type 4 mains are available after a quick trip to CB's site. But... click "add to cart" a few times. Seems std / std are scarce. The Type 4 guys know better than I do. .020" case / .010" crank are available as are .020" / .020". I'd order before I tore into it which is why I have $300 worth of main bearings sitting on my kitchen table.

$300 doesn't buy as many main bearings as it used to. :roll:

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Yes...Std/Std are getting scarce. This is because not enough being made anymore (probably) but also because for those who work on type 4 engines who are measuring crank bores...and also understand what they are measuring.....unless a type 4 engine has extreme mileage, has been abused or died violently at highway speed, its rare that they need to be align bored.

To the original poster of this thread...DO NOT...order main bearings until you hvae removed what you have and inspected their condition.....AND...measure your case with a dial bore gauge.

It is not uncommon to find that moderately worn main bearings are still better quality and tolerance than what you can currently buy.

Also, there is a common main bearing bore wear condition that most type 4 cases have. When this condition is found in softer magnesium type 1 cases, it typically occurs at FAR lower mileage than you see on a type 4 and concensus is to go ahead and align bore the case.

This condition is that when you measure a type 4 main bearing bore at 12 points with a dial bore gauge, typically you will find a low spot. I describe it as more of a "dent"....usually about 0.001" to 0.002" deep that spans an area of arc that would be equivalent to slightly less than the space between say...1 and 2 on a clock....or about 25*. If you are measuring in 12 equally spaced points.....really you are only taking 6 measurements because each measurement is between two points.

If you see some difference but not much....between two points....move your starting point over 1/2 space and start the six measurements again. You are looking for a low spot of narrow arc.

If its more than the arc in degrees that I just described...lets say it spans ~40* or more or if its deeper than 0.0025"...then yes. Align bore the case.

Outside of that, if its 30* or under and 0.0025" MAX or under....DO NOT align bore the case.

This low spot will not change a thing on a type 4 case because the type 4 has a more dense alloy. I have rebuilt more than a few engines from 411/412/914 and 1.7L bus....with miles between 85K and 150k miles max...and found this low spot from the max piston load moment and upon rebuild it causes no issues.
On two engines that had this "dent"...and then drove another 125K+ miles....on tear down to refurb a few things, they had the exact same dent. Nothing increased or changed and the bearings were pretty much still usabale at 125k miles or so.

Far too many people align bore type 4 cases that do not require it...and that takes another life out of it...and....its hard to find shops witrh the proper equipment to align bore type 4 and even harder to find people with GOOD equipment and skill. Too many align bores I have seen on type 4 are not great. Add to that bearing quality being all over the place....you may be better of staying std/std if possible. Ray