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Engine advice

londoner

londoner

Gold Level Sponsor
Looking for advice from you knowledgeable chaps! I recently posted a thread regarding an engine bought on eBay. Its from a series 2
I did a compression test on the engine out of the car. The numbers were low. I then placed a camera down each sparkplug hole. #4 cylinder which had a very low number seemed to show corrosion and there was a good amount of carbon on the underside of the head. The other cylinders look good still showing the Hatch marks on the walls. I was hoping to not do a rebuild! The engine has been sitting on a pallet for 3 years. should I run it up to temp and try another compression test?? Looking for some advice! Thanks John
 

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hartmandm

hartmandm

Moderator
Diamond Level Sponsor
What numbers did you see on the cylinders?
Did you check the valve lash prior to testing? You might have valves not fully closing.

Mike
 
B

beamdream

Gold Level Sponsor
It's on a stand, have you considered running it for a couple of minutes where it is, listen for ominous noises then do another compression check. Don't be fussed about not having coolant if you keep the run brief.
 
londoner

londoner

Gold Level Sponsor
Thanks for the replies. I have not checked the valve lash. The compression numbers are attached. I will give it a run fingers crossed!
 

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Tim R

Tim R

Silver Level Sponsor
You might struggle to get it to run at all with compression readings of 30 and 85.

If it was me, I'd strip it to have a thorough check through before I tried to run it. It could be a really good engine and just needs a little love to bring it back.

Tim R
 
londoner

londoner

Gold Level Sponsor
I have the origin engine as well. My hope was to put this engine in the car and work on the original one over time. The original was used to race the car in the 60s so I am hoping that it may have a little more poke!
John
 
husky drvr

husky drvr

Platinum Level Sponsor
John,

I'm not wanting to be a naysayer, but I don't think the engine on the pallet will be reliable or run very long in its current condition.

Your picture of the #4 cylinder wall does not appear to be corrosion to me. Those splotches look to be where molten aluminum have been deposited on and smeared by the piston and rings. If you look at the piston to wall clearance at the lower part of the picture, it seems there is a very large gap at that point. The piston is where the suspect aluminum came from. Also, the top of the piston appears to be very rough without the sharp delineation of the machined piston dish. If you were to tear down the engine I believe you'll find the #4 rings to be solidly welded to the piston from smearing the molten aluminum on the cylinder walls.

There is a good chance the water passages around cylinder #4 are completely blocked causing that cylinder to overheat and leading to this issue. A quick check would be to pull one of the rearmost freeze plugs and check the interior condition of the block. If the water jacket isn't blocked, then cylinder #4 was running very lean compared to the other cylinders.


https://forum.sunbeamalpine.org/index.php?threads/engine-block-clean-out.30301/

Just a thought,
 
Acollin

Acollin

Donation Time
I do not have experience or expertise in this area, but would there not be easier ways to find out if water were flowing in the water jacket than pulling a freeze plug? A garden hose in the thermostat housing and seeing what comes out the bottom radiator hose?

I might also squirt some oil into the cylinders, turn the motor by hand a give a listen. If those rings are fused in place, it would make a sound — I would think—and you would be no worse off and have a better sense of what is going on in number4.
 
watisit

watisit

Diamond Level Sponsor
Hey John, I cant speak for the engine in its current condition or how its been treated since my ownership...... All I can say (as you know from a PM to you from another thread post) I purchased the car in June 2017 with that engine in. I ran the car until December 2017 with that same set up as you have on the stand. The engine ran fine with no issues what so ever. The only reason that engine was pulled was that I decided to go a different route with a different drive train (Miata). The engine was left at my friends shop and you know the rest......Just wanted to let you know how it was when I had it. Cheers Jason
 
londoner

londoner

Gold Level Sponsor
Thanks Jason. Thanks for that! The engine seems in great nick to me so l will fire it up! It sat for a few years so could just be some corrosion from sitting
 
londoner

londoner

Gold Level Sponsor
husky drvr said:
John,

I'm not wanting to be a naysayer, but I don't think the engine on the pallet will be reliable or run very long in its current condition.

Your picture of the #4 cylinder wall does not appear to be corrosion to me. Those splotches look to be where molten aluminum have been deposited on and smeared by the piston and rings. If you look at the piston to wall clearance at the lower part of the picture, it seems there is a very large gap at that point. The piston is where the suspect aluminum came from. Also, the top of the piston appears to be very rough without the sharp delineation of the machined piston dish. If you were to tear down the engine I believe you'll find the #4 rings to be solidly welded to the piston from smearing the molten aluminum on the cylinder walls.

There is a good chance the water passages around cylinder #4 are completely blocked causing that cylinder to overheat and leading to this issue. A quick check would be to pull one of the rearmost freeze plugs and check the interior condition of the block. If the water jacket isn't blocked, then cylinder #4 was running very lean compared to the other cylinders.


https://forum.sunbeamalpine.org/index.php?threads/engine-block-clean-out.30301/

Just a thought,
Click to expand...
I guess I will give it a run first and see! My intention was always to restore the original race engine. I would like to get the car running in the mean time (getting impatient after 15 years of pushing it from place to place)
Thanks for your input
John
 
husky drvr

husky drvr

Platinum Level Sponsor
Pictures to go along with my above post, #8.

This piston is from a 1725 - #4 cylinder. In this case I'm almost certain the problem was a lean condition.
100_1270.JPG 100_1271.JPG 100_1276.JPG 100_1278.JPG
 
RootesRooter

RootesRooter

Donation Time
Just to be sure: did you actually fire it up (briefly?) on a stand outside of the car? If so, did you have an oil pressure gauge hooked up?

I think you will need to tear it down for a partial rebuild. You might be able to hone #4 cylinder and get away with throwing another used piston into it, but if the cylinders are all worn, the rod bearings probably are too. And you won't know what the head is like until you pull it. If you manage to cob together a runnable, temporary engine, I wouldn't plan on taking it up to freeway rpms.
 
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londoner

londoner

Gold Level Sponsor
RootesRooter said:
Just to be sure: did you actually fire it up (briefly?) on a stand outside of the car? If so, did you have an oil pressure gauge hooked up?

I think you will need to tear it down for a partial rebuild. You might be able to hone #4 cylinder and get away with throwing another used piston into it, but if the cylinders are all worn, the rod bearings probably are too. And you won't know what the head is like until you pull it. If you manage to cob together a runnable, temporary engine, I wouldn't plan on taking it up to freeway rpms.
Click to expand...

I turned it over to do a compression test. I live between cape cod and NH. I will fire it up next week. Fingers crossed! Thanks for your input.
 
T

Tom H

Platinum Level Sponsor
Your piston does not look at all as bad as Don's , But I suspect some pinging damage , mostly on the head and valve seat in #4. I don't see any value whatsoever in firing it up in this condition. It's not that difficult to pull the head and see what you see. You might be lucky enough to find that a head repair is all you need. AND you'll get a good look at the cylinder walls and the piston.

I have experience with my engine. #4 cylinder had a damaged valve seat, due to overheating and pinging, Unfortunately the top ring also broke off and damaged the piston and cylinder, as well as damage to the head, caused by a broken piece of ring rattling around in the chamber before it embedded itself in the alloy head. You may be lucky enough to just have head damage.

Tom
 
londoner

londoner

Gold Level Sponsor
Tom H said:
Your piston does not look at all as bad as Don's , But I suspect some pinging damage , mostly on the head and valve seat in #4. I don't see any value whatsoever in firing it up in this condition. It's not that difficult to pull the head and see what you see. You might be lucky enough to find that a head repair is all you need. AND you'll get a good look at the cylinder walls and the piston.

I have experience with my engine. #4 cylinder had a damaged valve seat, due to overheating and pinging, Unfortunately the top ring also broke off and damaged the piston and cylinder, as well as damage to the head, caused by a broken piece of ring rattling around in the chamber before it embedded itself in the alloy head. You may be lucky enough to just have head damage.

Tom
Click to expand...
Thanks Tom. Good advice!
 
Knightowl61

Knightowl61

Gold Level Sponsor
husky drvr said:
John,

I'm not wanting to be a naysayer, but I don't think the engine on the pallet will be reliable or run very long in its current condition.

Your picture of the #4 cylinder wall does not appear to be corrosion to me. Those splotches look to be where molten aluminum have been deposited on and smeared by the piston and rings. If you look at the piston to wall clearance at the lower part of the picture, it seems there is a very large gap at that point. The piston is where the suspect aluminum came from. Also, the top of the piston appears to be very rough without the sharp delineation of the machined piston dish. If you were to tear down the engine I believe you'll find the #4 rings to be solidly welded to the piston from smearing the molten aluminum on the cylinder walls.

There is a good chance the water passages around cylinder #4 are completely blocked causing that cylinder to overheat and leading to this issue. A quick check would be to pull one of the rearmost freeze plugs and check the interior condition of the block. If the water jacket isn't blocked, then cylinder #4 was running very lean compared to the other cylinders.


https://forum.sunbeamalpine.org/index.php?threads/engine-block-clean-out.30301/

Just a thought,
Click to expand...
I saw the video and decided to take out the large side and rear freeze plugs since the engine is being rebuilt. #4 was caked up like the video but the other cylinders were clean. Had to really dig out the crud and pressure hosed the water passages.
I pulled out a 1/2" plug from the large side freeze plug, Any idea where it came from? DSC09867.JPG DSC09868.JPG
 
husky drvr

husky drvr

Platinum Level Sponsor
Knightowl61 said:
Had to really dig out the crud and pressure hosed the water passages.
I pulled out a 1/2" plug from the large side freeze plug, Any idea where it came from?
Click to expand...

Knightowl61,

Is it possibly the water direction insert from the large water port in the head surface?

Just a guess,

EDIT > Sunbeam specialties catalog > page 4 > Misc. engine parts > part 17
 
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