S50B30 full rebuild, to forge or not? Need help!

[maxkarmonkey]

Hello guys!
I need your knowledge to know what I can do with the disaster of engine I purchased.
The engine have one heavy score cylinder, 4 valves are bent and want an opinion about the crankshaft that has STD bearings but doesn't look so good.

So first of all want to know if its imperative to bore the cylinder with a torque plate, because my machine doesn't have.

Wich pistona will you recommend? It's any good a forged alloy 2618 for a car that is going to be driven daily, and many times so small runs of 3miles and stop?

What about the valves and springs? Will you replace only the bad parts with stock parts or will you upgrade? Any brands to recommend?


In the crankshaft I will try to fit ACL bearings STDX that have higher tolerances but need to know waht my machine shops says.

Im sorry about my bad english, hope you guys can help me a little bit with the rebuild.
I post some pictures of the engine.




That scratch looks to me that its material from the bearing, could it be?

 

[M3Mo]

Torque plate would be better but not end of the world, I’ve had alloy blocks bored and honed without, that have worked fine. Generally it’s more important if the thread for the head bolts is lower in the block instead of under the deck face. You can get alloy torque plates made or find a machine shop that works on that engine that do have them already. If your going to use arp headstuds make sure the machine shop use them at the correct torque.

I prefer mahle motorsport pistons which are a 2618 material and come with a decent file to fit ring pack and good high quality pin as standard rather than something you need to pay extra for to upgrade. If your just using the car for road at standard power and not track you can just get normal mahle original pistons that would be cheaper, quieter and work fine.

Valves and spring should be checked , springs need to be checked on a flat surface and all the heights need to be exactly the same and also the installed heights if your having seats cut. Valves need to be checked for straight and refaced if required.
Standard setup would be fine for standard power road use.

From your second picture the piston looks like it has come into contact with the cylinder head so I would get your rod check for straight and also check the crankshaft is not bent. The marks on the crank may just be aluminium from the bearing which would clean up but it’s hard to see from the pictures, if you feel it with your finger nail does it feel like a hump or a valley? First check the crank is not bent then get the journals measured for size.
If your using acl extra clearance bearings be sure to measure the clearance you have otherwise oil pressure might end up being low.
Hope that helps, can give you more advice if I know what your using the car for like just road or a bit of track. Good luck with the build and remember to clean the oil gallery’s before assembly.

 

[maxkarmonkey]

Torque plate would be better but not end of the world, I’ve had alloy blocks bored and honed without, that have worked fine. Generally it’s more important if the thread for the head bolts is lower in the block instead of under the deck face. You can get alloy torque plates made or find a machine shop that works on that engine that do have them already. If your going to use arp headstuds make sure the machine shop use them at the correct torque.

I prefer mahle motorsport pistons which are a 2618 material and come with a decent file to fit ring pack and good high quality pin as standard rather than something you need to pay extra for to upgrade. If your just using the car for road at standard power and not track you can just get normal mahle original pistons that would be cheaper, quieter and work fine.

Valves and spring should be checked , springs need to be checked on a flat surface and all the heights need to be exactly the same and also the installed heights if your having seats cut. Valves need to be checked for straight and refaced if required.
Standard setup would be fine for standard power road use.

From your second picture the piston looks like it has come into contact with the cylinder head so I would get your rod check for straight and also check the crankshaft is not bent. The marks on the crank may just be aluminium from the bearing which would clean up but it’s hard to see from the pictures, if you feel it with your finger nail does it feel like a hump or a valley? First check the crank is not bent then get the journals measured for size.
If your using acl extra clearance bearings be sure to measure the clearance you have otherwise oil pressure might end up being low.
Hope that helps, can give you more advice if I know what your using the car for like just road or a bit of track. Good luck with the build and remember to clean the oil gallery’s before assembly.

M3Mo thank you so much for the long reply!!
I hvae measured the rod journals and they are on STD with tolerance for a polish maybe as its stated on the TIS manual, the lowest i get if I remember well its 49.981mm, I dont know if you use metric or imperial measurements.

About the piston and score cylinder, when i lifted the headcylinder i found a small metal stonechip, dont know where it belongs to, but I will check if the crank its bent at first. I will post a picture later so you will see the stone metal chip.

Have a great day all!!

 

[M3Mo]

No problem at all mate, sorry for the long post it did cover quite a bit. I’ll try keep this one short.

The measurements you have sound good as I believe standard size should be 50.00mm which makes your smallest journal 0.0019mm (0.0007”) undersize which will be fine to go again after a polish.
The polish process doesn’t take off any material it just changes the surface finish.
What did you use to measure the journals? A micrometer is perfect but a vernier is not accurate enough for precision measurements.
I wouldn’t use extra clearance bearings if your journals are lower tolerance just use std not stdx.

The metal stone chips you mentioned, are they on the topside of the piston (crown) or under? On all or just the one with the bent valves? It maybe from the piston coming into contact with the valves or the one picture you have above of the piston has come into contact with the head.
Do you know the mileage of this engine you have stripped?
I’ll have a look at your pictures when you post them.
I normally work in inches for engine measurements but can easily convert so whatever is easier for you bud.

 

[maxkarmonkey]

M3Mo good sunday morning!! i do love your longs post! Thank you.

Well, I i thought I did post all the engine pictures i had, but I did it in the build post of my e30, but I will post it here again.

I dont think the pistons have smashed the combustion chambers or valves, because all the rest of pistons a combustion chambers are perfect. The only piston that its bad its the one where I found the metal chip.


As you asked, the car will be for road use even if it had a rear roll cage, it will be on track days sporadically, but I do have an e36 to build for only track use and abus.

Yes Sir! Im using a micrometer as precise as 0.001mm, normally they are 0.01mm. its a Chinese brand but by now im doing consistent measurements. Brand it's shahe if anyone it's interested.

I'll post some pictures, but first I need to resize it.

 

[maxkarmonkey]

Number three beggining from the left, the combustion chamber as you see it's fully "pecked" don't know the right word in english.

I didn't mentioned, but the cylinder with problems didn't have any broken springs, as far as I remember now, but I do fully remember that broken springs were in two or three cylinlinders, maybe one in each cylinder.... I have mixed all valves now since the engine have been sitting for a while so i can't say exactly which cylinder have the bent valves, only I know now if they are admin or exhaust.



Thats the cylinder with the stone metal chip, you can see the damage. I do have a new headcylinder so Im not bothering repairing that one.




Cylinder number three starting from the top, in the lower section on the right you can see the metal chip, thats what I saw just after lifting the head.

I can't tell the material because I lost it... I'm an asshole!

 

[M3Mo]

Hi, just had a quick look at your build thread and saw the pictures, can you stick up a picture of the cylinder head so I can see the damage on there please. I’m thinking that the metal chips are from the damaged piston and I’m sure there will be damage to the combustion chamber on the head too from the aluminium bits flying around.
The only reason I think that one piston has hit the head is because of the two clean marks on the crown and the worn damaged bearings would have allowed for the extra travel to hit the head, you might have the same witness marks on the cylinder head.
What your using to measure is good enough and your machine shop can verify with their measurements too.
It would be nice if you can get a set of 4032 mahle motorsport pistons for the build but I think mahle original will work fine to get you back on the road.
Your build looks cool and the colour is perfect.

 

[maxkarmonkey]

As you see I'm taking seriously the building process, I'm not and expert so I need to do my best. I did design some 3d printed crankshaft supports so it's easier to take the measurements.







And thats the car for those that haven't been in my build post, fully stripped down, rust repaired, expoxy primer, etc, etc...
It was going to be a 10k-14k euros in my head, and I stopped counting on 22k, all do it by myself and without counting the tools that have been needing to build it.

 

[M3Mo]

You have a great setup my friend it looks perfect and I love the Renault 5 does it have the turbo engine or is it a campus as the badge on the tailgate? I had a white gt turbo a fair few years ago and wish I had kept it.
The marks on the cylinder head look like the aluminium bits have been hammering together for a bit and the piston might not have hit the head. That head can be repaired and used again if you need it in future.
The broken valve springs might just be from age or an over rev like wrong gear selection.
Have you measured the bores yet? You can get your machine shop to measure for wear and see if they have started to go oval before you purchase the new pistons so you know what size to get.
It’s always best to never add up the true cost of a build otherwise you will realise that you could have bought a Porsche gt3 for the same cost but it’s fun and a good learning experience. Your doing great so far matey.

 

[maxkarmonkey]

Hi, just had a quick look at your build thread and saw the pictures, can you stick up a picture of the cylinder head so I can see the damage on there please. I’m thinking that the metal chips are from the damaged piston and I’m sure there will be damage to the combustion chamber on the head too from the aluminium bits flying around.
The only reason I think that one piston has hit the head is because of the two clean marks on the crown and the worn damaged bearings would have allowed for the extra travel to hit the head, you might have the same witness marks on the cylinder head.
What your using to measure is good enough and your machine shop can verify with their measurements too.
It would be nice if you can get a set of 4032 mahle motorsport pistons for the build but I think mahle original will work fine to get you back on the road.
Your build looks cool and the colour is perfect

Did you saw the pictures of the cylinder head above your reply? Looks like we were replying at the same time and for me it takes quite effort to explain myself in a foreing language.


Those are all the measurements I took yesterday, in cross, two measument per journal. The measurement with the dot its the one near oil supply.
As you see it's all in tolerances but the crankshaft does have minors scratch so lets see how it's after the polish or regrind.

If I'm doing something wrong or do you have a tip I'm happy to listen everyone cause I'm a total noob.

 

[maxkarmonkey]

You have a great setup my friend it looks perfect and I love the Renault 5 does it have the turbo engine or is it a campus as the badge on the tailgate? I had a white gt turbo a fair few years ago and wish I had kept it.
The marks on the cylinder head look like the aluminium bits have been hammering together for a bit and the piston might not have hit the head. That head can be repaired and used again if you need it in future.
The broken valve springs might just be from age or an over rev like wrong gear selection.
Have you measured the bores yet? You can get your machine shop to measure for wear and see if they have started to go oval before you purchase the new pistons so you know what size to get.
It’s always best to never add up the true cost of a build otherwise you will realise that you could have bought a Porsche gt3 for the same cost but it’s fun and a good learning experience. Your doing great so far matey.

Yes it's a phase 1 gt turbo, in spain the pahse 1 didn't have a rear spoiler, but its a real one, from 1985, it's a devil.... It scared me every time i drive it.

I do have an alexometer to get the measuments of the cylinder bores, but one of the its really scored so i will need to rebore it.

The engine was 255k km, something like 160k miles... Engine was running before pull it out, the guy told me that it those have idle issues, i thought it will be an air leak or something but now i strongly believe it was from the broken springs.

The guy send me every vid I asked for, full throttle from low rpm in 4\5 gear to high rpm. Cold start, idling.....
I noticed it wasn't very fast but i couldn't imagine that kind of disaster.

I do really believe the engine have been abused a lot, the head gasket wasn't original, the head cylinlinders does have a resurface, from 95mm stock to 94.85mm, and i believe the oil pump its new cause its reallly clean and inmaculate... Also the bearings where like "new" no wear marks but with many scratches

 

[M3Mo]

Your English is perfect and a million times better than my Spanish!
Yes I saw the pictures and I think we posted at the same time, I also take a while to post a reply as I get distracted at home.

Your measuring is great for someone that’s just started, I would say that you should try to take measurements as far away from oil feed holes and also do three measurements in a row from the same spot until your readings are exactly the same so you know your measuring correctly.
I would also get your machine shop to verify your measurements to be safe.
Your rod journals seem fine but your mains journals seem too worn, I’m working from the number 1 journal which is the smallest out of all of them. If you use acl bearings they are all one size not like the BMW graded bearings that allow for different tolerances. You might end up having to use the BMW colour graded bearings to get the right oil clearance if the crank is not reground. You mentioned that it had new bearings fitted when you stripped the engine do you know what make they are?
Get some acl/ clevite plastigauge the green writing pack which measures from 0.025-0.076mm to confirm the measurements for oil clearance when you rebuild everything. It’s easy to use, fairly cheap and pretty accurate.

This engine sounds like it has had problems before and not rebuilt in the best way, the fact that the new bearings are scored shows that it was not cleaned correctly and probably had debris in the oil gallery’s of the engine block, crank or cylinder head which then got pumped around. That new oil pump may well be scrap due to that problem but worth taking apart to check for scores and also the oil pressure relief valve.
From the pictures of the crankshaft it looks like a bearing had spun and melted on it.
Can you post a picture up of the bearings please.
Can you also post a picture of some of the broken valve springs too. Is there any rust on them or black spots from rust or did they go coilbound?
Do you know why you have 4 bent valves as I can’t see marks on the pistons and the only two ways to bend a valve is from piston contact or hydro lock either by water or fuel which will also bend a rod.
Diagnosis of this engine is not going to be easy because of the previous rebuild and why it was taken apart the first time but we can see it wasn’t rebuilt right which is why your having to do the job again.
Best thing to do here is check everything that your using and go from there.
- Get your machine shop to check your crank for journal size and that it’s straight first.
- get the rods checked for size of the big end and small end and straight.
- I would probably get new valve springs and check installed heights to make sure you have enough seat pressure and they don’t go coilbound (that can break springs)
- get the valves refaced to make sure they are not bent a little.
- check the camshafts for wear and scores.
- get the block bored to see if the bores will clean up at first oversize then buy the new pistons and once you have the pistons get the bores honed to suit.
- get your spare cylinder head checked, valve guides, valve seat and a reface.
Then surgical clean everything and check clearances.

I’m fairly sure the metal chips are from the piston which might have been damaged before which may have been reused that then broke off and got hammered by the piston going up and down or a bit of metal got dropped in when they reassembled it or even something from the inlet manifold. It’s hard to say without having all the bits in front of me to check. Best to clean and inspect everything you bolt on to be sure and not bolt stuff together thinking that it will be ok.

My Renault 5 was a phase one 1986 but everything phase 2 was fitted, owned it for a long time bought as a standard car and ended up being fairly modified but most of the mods were engine and suspension. Absolutely loved it and still have a soft spot for them now. I can WhatsApp pictures over if you want to see it, I can’t post pictures on here as I don’t have an account to host pictures.
Speak to you soon.

 

[maxkarmonkey]

Your English is perfect and a million times better than my Spanish!
Yes I saw the pictures and I think we posted at the same time, I also take a while to post a reply as I get distracted at home.

Your measuring is great for someone that’s just started, I would say that you should try to take measurements as far away from oil feed holes and also do three measurements in a row from the same spot until your readings are exactly the same so you know your measuring correctly.
I would also get your machine shop to verify your measurements to be safe.
Your rod journals seem fine but your mains journals seem too worn, I’m working from the number 1 journal which is the smallest out of all of them. If you use acl bearings they are all one size not like the BMW graded bearings that allow for different tolerances. You might end up having to use the BMW colour graded bearings to get the right oil clearance if the crank is not reground. You mentioned that it had new bearings fitted when you stripped the engine do you know what make they are?
Get some acl/ clevite plastigauge the green writing pack which measures from 0.025-0.076mm to confirm the measurements for oil clearance when you rebuild everything. It’s easy to use, fairly cheap and pretty accurate.

This engine sounds like it has had problems before and not rebuilt in the best way, the fact that the new bearings are scored shows that it was not cleaned correctly and probably had debris in the oil gallery’s of the engine block, crank or cylinder head which then got pumped around. That new oil pump may well be scrap due to that problem but worth taking apart to check for scores and also the oil pressure relief valve.
From the pictures of the crankshaft it looks like a bearing had spun and melted on it.
Can you post a picture up of the bearings please.
Can you also post a picture of some of the broken valve springs too. Is there any rust on them or black spots from rust or did they go coilbound?
Do you know why you have 4 bent valves as I can’t see marks on the pistons and the only two ways to bend a valve is from piston contact or hydro lock either by water or fuel which will also bend a rod.
Diagnosis of this engine is not going to be easy because of the previous rebuild and why it was taken apart the first time but we can see it wasn’t rebuilt right which is why your having to do the job again.
Best thing to do here is check everything that your using and go from there.
- Get your machine shop to check your crank for journal size and that it’s straight first.
- get the rods checked for size of the big end and small end and straight.
- I would probably get new valve springs and check installed heights to make sure you have enough seat pressure and they don’t go coilbound (that can break springs)
- get the valves refaced to make sure they are not bent a little.
- check the camshafts for wear and scores.
- get the block bored to see if the bores will clean up at first oversize then buy the new pistons and once you have the pistons get the bores honed to suit.
- get your spare cylinder head checked, valve guides, valve seat and a reface.
Then surgical clean everything and check clearances.

I’m fairly sure the metal chips are from the piston which might have been damaged before which may have been reused that then broke off and got hammered by the piston going up and down or a bit of metal got dropped in when they reassembled it or even something from the inlet manifold. It’s hard to say without having all the bits in front of me to check. Best to clean and inspect everything you bolt on to be sure and not bolt stuff together thinking that it will be ok.

My Renault 5 was a phase one 1986 but everything phase 2 was fitted, owned it for a long time bought as a standard car and ended up being fairly modified but most of the mods were engine and suspension. Absolutely loved it and still have a soft spot for them now. I can WhatsApp pictures over if you want to see it, I can’t post pictures on here as I don’t have an account to host pictures.
Speak to you soon.

Thank you very much for the effort and time you are taking for reply!
Really enjoyed to read you and learn from you.
The problem is that here in mallorca there aren't so many reputable machine shops, so I'm the one that have to take care that everything it's in the right tolerances, i mean i need to check everything after the machine shop does his work.

Camshafts are not worn out but there is corrosion, looks like the car were without running for a long time and all the oil went to the sump and the humity did the rest!! Thats what i suppose.

Valves are not too much bent, i checked one and i assumed all the valves with broken springs are bent.

 

[maxkarmonkey]

I just mixed up all photos while ataching it,... They aren't all very scratched......

 

[M3Mo]

Hi, no problems happy to help.
The mains have definitely been put together dirty and the spots you can see on the bearing face is dirt pressed into them when the were assembled same with the rod bearings. I also think that they didn’t try to build up oil pressure before starting or use engine build lube when assembling.
It’s good practice to use engine build lube and build up oil pressure using the starter motor without the spark plugs fitted and fuel pump disabled first before starting the engine, I also disconnect the crank sensor to stop it sparking.
The rod bearings look in much better shape but you can still see dirt spots and one has one score on it, I would have expected those to be in worse condition than that after seeing the mains bearings.

I can understand living on a small island it would be hard to find a good machine shop but you still need to double check measurements and clearances afterwards even at a good machine shop.
Is there any tuning shops around that you can ask for a machine shop recommendation or even a boat engine repair shop that might be able to point you in the right direction?
Is it hard or expensive for you to get to the mainland so you have more choices perhaps?
The camshafts just clean up with wet and dry to clean off surface corrosion.
If you can see the valves are bent by eye then that’s a fair bit, can you see any marks on the edge of the head of the valves?

 

[Iain]

If your in there I would look to source an evo head, the ports are better and the valve stems are waisted. You can adjust the 3.0 headto match but the cost will be higher than the price of an evo head.
Using the evo buckets saves a lot of valve train weight 240g and allows you to use the thinner shim saving more weight and making it safer to run a higher rpm.
I would be very careful with the crank as the bottom end is generally the weakest link on the s50, personally I would be a bit surprised if the mains were worn, they are generally mint even at high miles, but get some lastigaugeas has been said and check them again

 

[maxkarmonkey]

Hi, no problems happy to help.
The mains have definitely been put together dirty and the spots you can see on the bearing face is dirt pressed into them when the were assembled same with the rod bearings. I also think that they didn’t try to build up oil pressure before starting or use engine build lube when assembling.
It’s good practice to use engine build lube and build up oil pressure using the starter motor without the spark plugs fitted and fuel pump disabled first before starting the engine, I also disconnect the crank sensor to stop it sparking.
The rod bearings look in much better shape but you can still see dirt spots and one has one score on it, I would have expected those to be in worse condition than that after seeing the mains bearings.

I can understand living on a small island it would be hard to find a good machine shop but you still need to double check measurements and clearances afterwards even at a good machine shop.
Is there any tuning shops around that you can ask for a machine shop recommendation or even a boat engine repair shop that might be able to point you in the right direction?
Is it hard or expensive for you to get to the mainland so you have more choices perhaps?
The camshafts just clean up with wet and dry to clean off surface corrosion.
If you can see the valves are bent by eye then that’s a fair bit, can you see any marks on the edge of the head of the valves?

there is no evidence of marks in the head or valves!! but i will check it again.
I do love your replyes, very helpfull and with lot of knowledge.

Sorry for the late reply but put the engine aside and im keeping with the build of the car, wiring, roll cage........

 

[maxkarmonkey]

If your in there I would look to source an evo head, the ports are better and the valve stems are waisted. You can adjust the 3.0 headto match but the cost will be higher than the price of an evo head.
Using the evo buckets saves a lot of valve train weight 240g and allows you to use the thinner shim saving more weight and making it safer to run a higher rpm.
I would be very careful with the crank as the bottom end is generally the weakest link on the s50, personally I would be a bit surprised if the mains were worn, they are generally mint even at high miles, but get some lastigaugeas has been said and check them again

I did have some news about the b32 head cylinder but i allready bought a s50b30 head for a fair price so im using that one..... I think I will have enought power in the e30 and...... well I changed my mind and im loooking to buy a donor car in uk; e46 m3, and i will take the rebuild of the engine more slowly.
thanks to all!! I´ll post you a picture later

 

[M3Mo]

Hi, no problem with late reply mate. I know too well a build like this will take some time as your not working on it everyday.

I think even though you can’t see sighs of damage on the pistons or head, if the valves are bent something has happened to do that and you don’t know the full history of that engine apart from it’s been opened up before and someone has done something. I would just start afresh and check everything.
So are you thinking of using an s54 engine now in the E30 body? That would make it a proper animal!!!
Is it not cheaper to get one from Europe instead of the uk?
I did have a look through my mahle motorsport catalogue and they didn’t list a piston for the s50 so it would end up being a custom order which would be expensive and normally takes the 3-4 months if they are not busy but my catalogue is a few years old. I did find that JE pistons make a shelf set that cost approximately over £1000 so I think a Mahle original would be the cheaper option and probably easier for you to get hold of.

With reference to Iain thoughts on crank being worn to me it looks more oil contamination with dirt/ metal then just wear but definitely agree that the crank will need to be checked along with everything else.

Good luck max sounds like your doing a great job.

 

[maxkarmonkey]

Hi Mo!!
Always so happy to read your replys!!
Yes!! I just changed my mind and the easiest and fast option its to get M3 convertible from UK, seems that the prices have dropped a little bit, my limit it's 11k£ and I see lot of options in UK at that price range.
Also with the s54 I can leave it stock, enought power for me with my buttery hands XD!!





I'm so desperate to see that card finished!!

I will rebuild the s50b30 slowly, learning and trying to do my best.

I'm not really interested in forge pistons, the car is going to be used a lot as a daily driver, 3 miles and stop, meetings and hopefully track days in winter time when I'm on holidays. So I will love to use cast mahle pistons, because they don't expand so much and are more suited for my purposes, do I'm right?

Also I saw JE pistons recommends to use a micrometer with blade tips so you can measure in the exact point and not on the treatment they add to the pistons.
I don't know if that matters but as my 2° engine build I need to be really meticulous.


Thats the first engine I fully rebuild, good learning, it's like a kinder egg.
I didn't measure anything, fully trusted the machine shop.
It lasted 800km, but cylinders and piston were from crappy china, don't know what happened, one cylinder and piston were very scratched.
I rebuilt it again with three of the crappy china cyl and pistons and one of old ones and the engine it's going strong, so I don't understand nothing hehe.
Just rebuilt it like this cause I don't know what was the failure.

Anyway, hope it makes sense what I have wrote, because my english is getting worse every year. I'm learning to rebuild engines and english in M3cutters forum!!
Enjoy all.