1983 Eclat Excel - BRS 500Y

[Mart1n95]

What's the compression like on each cylinder?

Pete

I haven't thought to check that, but probably should really. I'll give that a check tomorrow I think

Forgot to add another part of my fault finding process for the electrics, its handy having a good collection of equipment at home!

86e9b942-5d57-4de7-b4e8-765c2aa3cdcfphoto.png by Martin Gunn, on Flickr

[Hawaiis0]

Stabilised power supply - yummy

[Mart1n95]

Stabilised power supply - yummy

I originally bought it so I could bench test a cassette player as it kept stopping and flipping back and forth, ended up being the tape I had in so I never ended up using the power supply. So this was its maiden voyage! Handy bit of kit to have

[Pete Boole]

Stabilised power supply - yummy

Just what I was thinking!

Pete

[Mart1n95]

What's the compression like on each cylinder?

Pete

Well Pete I must thank you a tremendous amount for suggesting this as I had not thought of doing it originally, and its a good job you said it. Todays job was..... compression testing.

As mentioned before, I was mulling over whether to concentrate on having the engine run well before starting everything else, or as I had thought the engine seemed fine just do it at the end before getting it on the road. After this suggestion I thought 'ah easy thing to do, takes no time at all!'

As with most things on this project, and with life in general sometimes, is that in order to do one simple task you have to complete mini tasks first. My first job was to hook up the compression tester, but it seemed that I did not have the right fitting. I pulled out my leak down tester and robbed that adaptor so it would all fit nicely. Then upon testing it wouldn't hold the air, and when pressing the button, oil came out the bleed hole. Oh dear...

Thinking first of all, is my cylinder bore filed with oil, this isnt good. Whipped off the compression tester hose and stuck my borescope down the hole, where I can see the train of oil, thankfully coming from the spark plug hole itself. Which means, the compression tester hose is full of oil. Blew through the hose with the airline and lots of milky oil came out, which means whoever used this last had cylinders full of oil, and a very bad time. I think I can thank my younger brother for that. Anyway the compression tester still wouldnt keep the pressure in it, so the non return valve was knackered. Managed to get a borrow of one from my mechanical friend a few garages down from mine and tested each one.

Now a very helpful member on here got in touch and sent me a copy of the service manual, so a massive thank you to them because it is now more vital than before in this project. The manual states a target of 120psi for each cylinder, so onto the results:
Cylinder 1 - 120psi

Off to a tremendous start

Cylinder 2 - 10psi, yes ten, oh dear
Cylinder 3 - 60psi
Cylinder 4 - 20psi

So the good news is that I have found the source of the idline and running problems. The bad news is, well, low compression isnt an easy fix

Time to break out the leak down tester. Whilst my compressor isnt the best, it still has just enough power to give a good indication for results
Cylinder 1 was around 80%, the rest between 20-40% which is obviously bad. However the good news is that they all leaked out the exhaust, and as far as I could tell nothing out the dipstick tube which means piston rings seem good. I can deal with valve seats being crap, piston rings would have been a show stopper for this car

Now I need to pull the head, again the service manual has been a fantastic resource for this. I have gotten as far as pulling off the intake manifold, exhaust joint at the manifold to downpipe, and the intake cam carrier. Foolishly in my haste I forgot about the valve buckets and shims, dropping both cylinder 2 buckets/shims. The rest stuck to the cam carrier thankfully

I have already dabbled in head work when building my Beetle engine, so I have valve seat cutting tools and lapping compound, so the plan is to just pull the valves and lap them back in, if not cut a new seat if needed. then just put back together and see how that goes, I'm not wanting to go down the route of 'when you're in there' as it gets expensive and its not that hard to pull the head again if I have to for whatever reason

[rbgosling]

If you're pulling the head and lapping the valves, you'll need to re-gap them when you put it back together.

We have a "valve shim library", which makes it easier to swap shims in and out until you get the right size. It's far from comprehensive at the moment, but has a reasonable range of sizes. The general principle is to use ones from the library if you can, but order replacements (from Lotusbits, QED or wherever) if the size you need isn't there - then add all your rejected ones back to the library, which should continue to grow with each use.

Library last seen with Martin ("Sirclip") - see this thread.

Also, you won't get away with just tightening the cam carrier screws down until they feel tight - I tried that and kept getting inconsistent valve gaps. Torque them down to the correct spec before each measurement. And, if you do that, you will almost certainly strip a thread or two in the head. So get a helicoil kit before you start. Helicoils aren't a bodge, they are stronger than the original thread (on the F1 engines I design for a living a number of threads are helicoiled by design, on initial build).

[Mart1n95]

If you're pulling the head and lapping the valves, you'll need to re-gap them when you put it back together.

We have a "valve shim library", which makes it easier to swap shims in and out until you get the right size. It's far from comprehensive at the moment, but has a reasonable range of sizes. The general principle is to use ones from the library if you can, but order replacements (from Lotusbits, QED or wherever) if the size you need isn't there - then add all your rejected ones back to the library, which should continue to grow with each use.

Library last seen with Martin ("Sirclip") - see this thread.

Also, you won't get away with just tightening the cam carrier screws down until they feel tight - I tried that and kept getting inconsistent valve gaps. Torque them down to the correct spec before each measurement. And, if you do that, you will almost certainly strip a thread or two in the head. So get a helicoil kit before you start. Helicoils aren't a bodge, they are stronger than the original thread (on the F1 engines I design for a living a number of threads are helicoiled by design, on initial build).

Perfect thanks very much for that info, I'll definitely be utilizing the library then! I've got a Mitutoyo micrometer so should be able to confirm the shim size before sending my old ones to the library. I assume it's worth taking a valve stem height before and after to gauge the right new shim to preempt it a bit

I've got a helicoil kit already, had to drill out and helicoil 5 out of 8 exhaust studs on my beetle heads, so more than comfortable with that! Ended up having to put in spark plug inserts on those heads too, tap out to M16 and put these inserts in, like a helicoil but an actual insert which was a nice bit of kit too

[rbgosling]

No need to request or return shims to the library, just drop Martin a PM and (assuming he's finished with it) he'll send the whole pack to you. Then you can hold onto it until the next person needs it...

[Mart1n95]

No need to request or return shims to the library, just drop Martin a PM and (assuming he's finished with it) he'll send the whole pack to you. Then you can hold onto it until the next person needs it...

Ah no worries, I'll send Martin a PM then!

[Pete Boole]

Look for play between the valve stems and guides - often a source of wear. Notice there should be no valve stem oil seals. Are you using cylinder liner clamps? Depending on the sealant previously used it's vital to stop the liners moving. Also before replacing the head check the "nip" on the liners. The original and excellent head gaskets are no longer available - it might be worth using a multi-layer steel version (Gary Kemp's) and get a small boost in compression as well (slightly thinner).

Pete

[rbgosling]

Garry Kemp's stuff for sale - it's good stuff: https://www.ebay.co.uk/str/kemphighperformanceengines

[Mart1n95]

Look for play between the valve stems and guides - often a source of wear. Notice there should be no valve stem oil seals. Are you using cylinder liner clamps? Depending on the sealant previously used it's vital to stop the liners moving. Also before replacing the head check the "nip" on the liners. The original and excellent head gaskets are no longer available - it might be worth using a multi-layer steel version (Gary Kemp's) and get a small boost in compression as well (slightly thinner).

Pete

Garry Kemp's stuff for sale - it's good stuff: https://www.ebay.co.uk/str/kemphighperformanceengines

I wasn't planning on getting liner clamps as dont plan on moving the crank, but I'd be open to getting some if you think it would be worthwhile for any other checks that would be good to do

I did see that the original head gaskets arent available anymore, and unfortunately as the world seems to be going is that aftermarket replacements arent as good a quality as original. A thinner headgasket would be fine too, I always use super unleaded so a higher compression ratio would be nice anyway. I did notice there wasnt any valve stem oil seals when I looked to see if they were available. I assume it will be the exhaust valve guides that will be the issue, common again on the beetles because they run hot, but also seen that its common on other high performance cars as well, Ferraris of the 80s & 90s I think too

[Mart1n95]

Got the head off, what a pain in the behind that was. Ended up having to unbolt both the engine mounts and jacking the engine up so that the exhaust manifold would clear the body and frame

20251009_205608743 by Martin Gunn, on Flickr

The good news is its obvious where the cause of lack of compression
The bad news is..... well it seems self explanatory
20251009_203228495 by Martin Gunn, on Flickr

On the bright side, theres no cracks in the head
20251009_205529104 by Martin Gunn, on Flickr
20251009_205533614 by Martin Gunn, on Flickr
20251009_205536509 by Martin Gunn, on Flickr
20251009_205539386 by Martin Gunn, on Flickr

Looks like the original head gasket was on, it was stainless(?) on one side? Like a steel sandwich gasket
Slights scoring in cylinder 2 as well, can jut about catch my nail on it, but I'm not bothering with that for the time being
20251009_210707098 by Martin Gunn, on Flickr20251009_210647362 by Martin Gunn, on Flickr

Standard OE pistons too I assume
20251009_210656774 by Martin Gunn, on Flickr

[rbgosling]

Yikes! Yeah, I don't think a bit of valve grinding will sort all those... New valves are available, Lotusbits also have boxes of used valves of rather varying quality, but I managed to find 8 that were not too badly pitted and came up OK with a good grinding.

I hope the valve seat isn't badly damaged by that cracked valve, it'll be interesting to see what that looks like once you've got the valves out.

I know you wanted to avoid any "while I'm in there"s, but this would be an ideal opportunity to replace the exhaust studs and nuts. On my engine the originals had rusted into barely recognisable stubs, they were a bugger to get out but they did come. You can get stainless studs, and brass nuts, that will avoid future corrosion. You DO need to use both thread lock and good new spring washers (or some other sort of locking washer) on re-assembly, otherwise they will (not might) work loose again pretty quickly. And new head to manifold gaskets at the same time, of course.

[Mart1n95]

Yikes! Yeah, I don't think a bit of valve grinding will sort all those... New valves are available, Lotusbits also have boxes of used valves of rather varying quality, but I managed to find 8 that were not too badly pitted and came up OK with a good grinding.

I hope the valve seat isn't badly damaged by that cracked valve, it'll be interesting to see what that looks like once you've got the valves out.

I know you wanted to avoid any "while I'm in there"s, but this would be an ideal opportunity to replace the exhaust studs and nuts. On my engine the originals had rusted into barely recognisable stubs, they were a bugger to get out but they did come. You can get stainless studs, and brass nuts, that will avoid future corrosion. You DO need to use both thread lock and good new spring washers (or some other sort of locking washer) on re-assembly, otherwise they will (not might) work loose again pretty quickly. And new head to manifold gaskets at the same time, of course.

Big yikes indeed

I'll probably just buy new valves, obviously quite an expense at £20 each when you need 8, hopefully valve seats are okay as well, but if it's run hot enough I can only guess that the valve guides will be toasty as well, if not the valve seats too, but that's all just a guess until I get the valves out and can actually see!

Absolutely, I'd planned on changing the manifold studs as I'll have to get the manifold off anyway, and those nuts aren't for moving at all so they'll be getting cut off, got my helicoil kit at the ready for when one or two inevitably break