the one and only e30 s52 engine swap
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Mistakes were made this past weekend
Pulled the car out of winter storage on Saturday. After taking it out for a little shake down I went for a ride over to a little local car meet going on. Well one thing led to another and here I am on the highway doing a few pulls against a couple quick cars. Downshifted down to 2nd... 3rd, went for 4th and instead grabbed 2nd again and dropped the clutch. Car banged the rev limiter once or twice before I got the clutch depressed again. As I'm rolling in neutral I checked my gauges, still got oil pressure and the engine is still running and sounds somewhat fine so I continued to drive along another half mile tell I found an exit to pull off. Came to a stop and I find myself driving to what seems to have about the power of a 3 cylinder. Luckily my buddies house was only about a mile up the road so I slowly limped the car, which still had good oil pressure, over to his place and shut it off. Got a ride home and the following day I came back with the truck and trailer and hauled it back over to my grandpa's shop who was less then excited to see it back so soon.
Right off the bat I whipped out the old trusty compression tester and started cranking.
After seeing my low compression numbers on 4 and 6 I drained the oil and pulled the filter to check for metal pieces or shavings.
Oil looked clean and normal as well as the filter so that was at least somewhat encouraging.
checked out each cylinder with an inspection camera and found that none of the piston heads appeared to have any markings from a valve hitting them.
The quality of the images aren't the greatest so I can't be 100% on anything but it was nice to see the possibility of no valve damage.
As of right now i'm thinking one or more of the following things happened:
Bent connecting rod
bent valve (but seeming less likely after what I found)
blown headgasket (it was just an oem one)
or recked piston rings
Things to consider: When I pulled the car into my buddies I shut it off and restarted it in which it fired right up again but was of course misfiring and had a slight knocking noise from the bottom end. I can also spin the engine by hand no problem and it doesn't feel like there is any binding.
Gonna try to start disassembly and removal of the head tonight.
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Yup, six bent exhaust valves.
More concerning is the nicks in the pistons that I think are beyond salvageable.
I'm afraid this rotating assembly is toast.
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These are not the updates I like here -
Bummer. On the plus side it sounds like an opportunity to make more power....
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Pain.
What actually causes the valves to contact the piston? When it over rev's, it exceeds the limits on the springs and the valve extends further than it should contacting the piston?
Ya I imagine the valves stretched a bit at the higher rpm and the cam spun faster than the valves could reciprocate, causing the valve stem to separate from the cam during the close cycle.
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Ya I imagine the valves stretched a bit at the higher rpm and the cam spun faster than the valves could reciprocate, causing the valve stem to separate from the cam during the close cycle.
Is that kind of the same principal why they offer HD springs for higher horsepower and higher revving builds?
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Is that kind of the same principal why they offer HD springs for higher horsepower and higher revving builds?
Correct
You want the lowest amount of spring force required to match the speed of the cam, as anything above is just added friction and wear.
When you over rev the spring force is not great enough to accelerate the valve fast enough to follow the cam and you get valve float, which can in turn cause the valve to contact the piston if the discrepancy is high enough.I did supertech springs in my S52 head and the spring force change becomes VERY noticeable when you try to get the cams back in...
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Correct
You want the lowest amount of spring force required to match the speed of the cam, as anything above is just added friction and wear.
When you over rev the spring force is not great enough to accelerate the valve fast enough to follow the cam and you get valve float, which can in turn cause the valve to contact the piston if the discrepancy is high enough.I did supertech springs in my S52 head and the spring force change becomes VERY noticeable when you try to get the cams back in...
Correct. Only thing that I would add is that the actual contact between valve and piston occurs due the valve bouncing off the seat. The cam profile is designed to decelerate the valve so that it gets placed "gently" onto the seat. When the valves "float", by the time the valve comes into contact with the seat, the cam has already rotated past the gentle decel part of the profile, and the valve slams hard into the seat and bounces back off, potentially multiple times, before the piston comes up and hits it.
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And as always, bad with keeping up with the updates on here.
Well not to long after I determined the motor was gonna need a full rebuild I got to ripping it out and getting things disassembled and ready for rebuild.
Other then the bent valves and scored tops of pistons/cylinder walls, the rest of the rotating assembly looked pretty good. Everything was torn down and boxed up for storage. As for cylinder walls and other bare metal surfaces I sprayed a layer of wd-40 over everything for surface rust prevention.
Originally I had intentions of diving into this and begin ordering parts/getting stuff machined to maybe have it up and going this year still but for financial reasons and being that I have a few other more important priorities right now I decided I'm gonna hold off for now.
In the mean time, I had some new door seals for the car that had come in a while back and decided to swap the old ones out. I didn't get any pics of them but the original ones were in rough shape and had holes all along the bottom portion. Water would leak in from time to time when I washed the car or it rained. It was also pretty easy to hear the outside wind and cars passing when on the highway which was getting pretty annoying so this was well overdue.
After finishing that up I gave er a good wash and topped off the gas tank. Also added another bottle of ethanol stabil treatment, seems to be doing a good job at keeping the e85 in somewhat good shape so far. Afterwards the car was parked back in storage.
I had a shelf on the other side of the shop where I was storing all the boxes with the motor parts. As for the crankshaft I had it wrapped up with plastic wrap and stood upright on the shelf cornered in by three other boxes. It was done that way in case it became unbalanced and fell it would only fall onto the cardboard. Unfortunately I hadn't made my grandpa aware of this right away and the following day he started moving the boxes of parts around that I had placed around the crank. This also caused the crank to become unbalanced and fall over and drop five feet to the concrete where it snapped in two. I am thankful that it fell on the ground and not him but I am now on the hunt for another crank.
And up tell about two weeks ago that's all that had been going on with this car.
For a period of time I had the idea of finding an m52 for cheap and throwing it in the car to still enjoy it for the summer. Unfortunately prices seemed to have go up quite a bit for those now so I kind of tossed the idea out.
Well a friend of mine messaged me saying he had an m52 he was gonna use for his car but ending up going with something else and said he would sell to me for cheap so I went and took a look at it.
I ended up bringing it home with me.
The motor was pulled apart because of a valve keeper popping out of place and dropping the valve in to the cylinder. At first I was hesitant about it since I figured the walls would be scored and would also need a rebuild which I was not looking to do with this. After looking it over I noticed no scoring on the walls of that cylinder (ran my finger nail around it) and the rest of the five cylinders looked fine. He also had it looked over by a few people who have built quite a few racing engines and said he would be fine running it.
Everything to turn this into a long block was included as well as some new gaskets. There was also a fresh cylinder head done for it that was hot tanked and decked, ready to be installed. On top of that he threw in the cylinder head that was originally from this motor which was missing the one valve and a few cam studs but the rest of the valves were in good shape and would be a good parts head for the s52.
Rotating assembly spins freely and smoothly by hand and just to be safe I pulled the piston out and inspect it. From what I can see it appears to be fine and I saw no major damage besides the scoring on the face.
So far this was my plan with this. Pop the piston back in and leave the bottom end as is. Check the block surface for any warpage and if there is any (I'm guessing there most likely will be), re deck the block using the wet honing stone method. Re seal the motor running a stock headgasket, and some arp head studs and see if I can't run high 300's on e85. This would only be a temporary motor to get the car back up and going tell I can start rebuilding the s52.
Sort of a budget build you could say.
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And the start of a new chapter begins...
After further consideration of my plans for putting back together the M52 I had picked up and throwing that in, I decided against it, rolled the car back into storage and let everything rest for the remainder of the year. Although the bottom end seemed alright to run as is, I felt foolish doing it and didn't want to go through all the time and effort of putting it back together just to possibly run into issues right away.
As things sat I slowly began acquiring parts needed for a full engine rebuild. I brought the old s52 block into a local machine shop to figure out what my options would be for piston size. After doing an inspection of the cylinder walls they said I would need to bore the cylinders 20 thousandths over which left me with going to an 87 mm piston. Initially I was good with this but after seeing possible issues with others having cylinder walls crack on them as well as not having any wiggle room with the cut rings on the HG and running into valve and piston head interference's I threw that block back up on the shelf and re-considered my options. Thankfully I had an M52 laying around now which gave me the option to run the piston size I wanted to so I landed on using that block for the rebuild.
Fast forward a few months and the block, pistons and rods were dropped off at the machine shop as well as an s52 crank that I purchased a few months prior. Unfortunately the crank main and rod journals were in rough shape and required a .010 grind and polish. I also had the machine shop do a re-balance of the entire rotating assembly. As for the block, it was bored out to 86.5 mm and honed with a torque plate installed afterwards. block was also decked with the timing cover attached and line honed for the upgraded arp main studs.
As for the cylinder head, I brought in the head that I got with the m52 and had the shop check the deck for straightness as well as vacuum testing it and pressure testing to see if it would need a valve job. Thankfully everything checked out good there. Had them run that through the hot tank to clean everything up.
Other machine work I had done included having the rod clearances checked and sized for the wrist pins and the cam shafts being polished up as they were a little scored up on the journals.
Everything when I got it back from the machine shop a few weeks later...
After spraying the entire block down with mineral spirits to remove all oils used for flash rush prevention it was time to paint the block
coat of primer first
Was pretty happy with how that turned out.
Assembly time rolled around and I ran into a small road barrier right away. First thing on the list was installing the oil squirters. I went through the six squirters I had from the blown s52 and used a small pick to test the spring pressure on each one. All of them had very weak or no spring pressure. So I dug up the six that came with the m52 and tested those. I found four of them that seemed to have fairly good pressure while the other two were very weak. Instead of just replacing the two bad ones I just ordered a whole new set of six.
With the squirters on the way I went ahead and got the main bearings installed so I could get the clearances checked.
When I went to set the crank in the motor I noticed it did not want to slide into place and was getting hung up on the thrust bearing washers. Pulled the crank out to see if I was missing something but after pulling the bearing out and attempting to place it on the journal I found there was no way it was going in and was larger then the width of the journal surfaces by a good amount.
Gave the machine shop a call and found that they had not ground down the thrust washer surfaces as they were unaware that the thrust bearing was a one piece design instead of the more common multi piece style. The oem .25 mm undersized bearings I ordered also make the thrust washer area undersized instead of keeping it oem size. After some extensive researching I was unable to find a thrust bearing on the market that came undersized but held the oem thrust washer thickness. So the crank needs to go back into the shop so they can grind that up correctly.
With me unable to do anything with the crank I switched gears and began the tedious process of gaping all my rings. Went with a slightly wider gap then oem spec for boost reasons.
I did have a hard time with my newly purchased ring gaping tool and on my first go around I messed up a top ring for cylinder #1 leaving me with too wide of a gap requiring me to order another set for that piston. Thankfully another ring set was fairly inexpensive. After that one I got a feel for how fast it took off material and the rest of the rings went pretty well.
Afterwards I switched gears and worked on getting the oil pump ready to go. Original plan was to reuse the oil pump from the blown s52 but after pulling the rotor out I found there to be quite a bit of scoring on both surfaces making the pump unusable.
Dug out the oil pump from the m52 block and found everything to be in much better shape and score free!
Purchased the Achilles upgraded oil pump shaft kit to go along with it. Went ahead and got the old shaft pressed out and the new shaft installed and set at the correct distance.
Also took the time to clean up the pump housing a bit and remove all the oil staining. Decided while I was in there I might as well do a full rebuild of the pump with an all new control valve, spring and rubber washer.
Once everything was lubed up and installed I got the pump primed and ready to go.
As for now that's all the progress I've managed to get done. Hoping to get the crank back to the machinist by Wednesday and maybe see it back by the end of the week or early next week so I can really get the ball rolling.
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Nice work! It'll be nice to see the car on the road again, all this work going into it is gonna make it so much better.
Every time I see your car, I get the forced induction bug for my S52! Lol
Thanks! I am very excited about this one. Going into this for the second time realizing all the mistakes I made on the first rebuild on top of all the knowledge I've accumulated on these engines over the years is hopefully gonna make for a much more solid power plant.
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Got the crankshaft back from the machine shop. They got .010 removed from the thrust services and the thrust bearings fit much better now! With that figured out I got to measuring all my main bearing clearances.
All seven mains came in at .002 clearance which was right within spec so I was good to get things lubed up and installed permanently.
So something that I did with the last rebuild which I decided to change up this time was involving the arp main studs. Straight from arp when you receive their set of main studs they end up being too short and the nut only engages about halfway. On the first rebuild I dropped small 1/4" ball bearings in the holes to raise the studs and be able to bottom them out. I wanted to look into this a little further then I had and see what arp actually recommends to solve this issue. Two options... Back the stud out tell you get full thread engagement or ditch the washers. After reading through what a lot of others have done it seemed the option used with the most success was just ditching the washers. So I did just that. Torqued them all down and followed the proper torque procedure and checked my crank end play with a dial indicator which came in right at .003, right within spec.
With that complete I moved on to assembling the connecting rods and pistons. For this setup I chose JE for my pistons and got them in a lowered 9:1 compression ratio. I plan to run this on a flex fuel setup so I wanted the extra room for pump gas. As for the connecting rods I chose a set of H beam rods from Molnar technologies. The fit and finish on these are very nice and will fit my power goals nicely.
Time to start dropping them in the block. In the past I've used an adjustable piston ring compressor for piston installs. There is a lot of headaches that come with using one of those and I wanted this to go nice and smoothly so I purchased a ring compressor specific to the bore spec. It was well worth the extra money spent as they made this part of the install a breeze! I also wiped all the cylinders, piston skirts and rings down with some marvel mystery oil prior to install as recommended from JE.
Checked my rod bearing clearances as I went a long and all six came in at .002 which was right in spec.
With that complete I moved on to installing the windage tray and oil pump. I got a new oil pump chain and crank sprocket which paired with the Achilles sprocket really tightened up the chain slack.
New guides and timing chain installed as well.
I got the timing cover installed as well as the rear main seal and all hardware for those torqued to spec.
On the previous motor I had my fair share of oil leaks, especially around the pan gasket area. Unfortunately when I had the baffle and turbo oil drain bung welded on it slightly warped the pan gasket service. I figured this will most likely continue if I used an oem gasket again. Instead I decided to ditch the gasket all together and run a small bead of the right stuff gasket maker. I have used this stuff in the past and it works really really well and should help fill in areas where the services may not sit completely flat.
Next on the list. Start getting the head prepped and ready to be installed!
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New crank sprocket and chain takes up a lot of the slack, did the same thing instead of installing a tensioner
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New crank sprocket and chain takes up a lot of the slack, did the same thing instead of installing a tensioner
I see a lot of people still running a tensioner even with new sprockets and a chain but I thought it was unnecessary when I felt how much chain slack there was.
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I see a lot of people still running a tensioner even with new sprockets and a chain but I thought it was unnecessary when I felt how much chain slack there was.
The tensioner I had was from SLG (think it was a PRD one they just resell) the shitty URO part wouldn’t have even worked with their included diagram/instructions for where to drill - @Rekpoint is my witness for that garbage
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The tensioner I had was from SLG (think it was a PRD one they just resell) the shitty URO part wouldn’t have even worked with their included diagram/instructions for where to drill - @Rekpoint is my witness for that garbage
Can confirm was a shitty URO part, Wasn't going to work unless modified either URO is never the answer anyways.
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