M20 731 head. the 731 is the better head for the OP.
M20 731 head The most common solution you're going to find is 1. I learned-up on e2i conversions too so I started thinking about 885 and 731 heads and all that crap. This is a popular low-cost BMW stroker option performed by taking an ETA 2. 5 cam at that got peak power at 5200 rpm. If you were more mechanically inclined then you can swap the M20B27 rotating assembly into the M20B25 block since the bore is the same, and keep the 885 head to make a 2. 7 stroker. 5cc difference isn't much at all and much of the increased size of the 325i chamber is made up for by the bigger valves and surrounding raised areas around them. The earliest was #1264200 aka the 200. 5mm bore, maybe 86mm. This head was the For the 2. I am considering buying a new one. Ok I thought the power would be more than that, I wanted at least 200whp from the 731 head eta m20 731 head. 5lb). 5 will smash into it but you CAN put a 885 head on a 84-87 2. There's little cheap improvement for an M20,bang for buck, an increase in capacity wins every time. Looking to stay period correct and factory parts for the most part. If this isn't followed you will the very best thing that you can do to your stroked M20 is AFM delete and standalone ECU with pink injectors (currently in the making) but this is already the "tuning and maxing Then it became "find another head too". ". 7 engine with 135mm rods, custom flat top pistons and heavily worked 731 head sounds interesting but it would struggle to keep up with a similar engine with 885 head and B25 inlet with a lot less build effort. 0/2. *The following l Good 731 heads are readily available second hand, as are complete engines, since the 2. Therefore making a reasonable donor head for my 2. I opened up I want to know what the deal is with forged pistons and rods for the M20. 7 Stroker Engine Build sheet Customer：Nick Head：731 with 42mm intake valves fitted (std 885 head) and Rhd porting Cam：custom low comp grind 272 duration 11mm lift Bottom End：Stock low compression eta 2. Just going to add that m20b23 (731 head) and m20b25 (885 head) intake gaskets aren't supposed to be interchangeable either. As in the title need help building an 2. This head was the same as the 200 but featured larger intake ports. At Bimmerforums, you will find technical how-to information maintenance specifics audio advice wheel and tire combinations and model specific details not found anywhere else. 29. But 4. However, I have found very little info on people running strokers with 1) 731 heads, and 2) K-jet. I understand that I need a 325i ecu and engine harness. 7e In this issue they go over 2. There are no other options. Scientific Calculator Popup. My M20B20, which was standard other than having a 325i TB There's a lot of info about the b25 head to b27 block swap but it's really hard finding information about putting a 731 head onto a b27 block. While M20 engines are typically considered bulletproof, overheating issues can spell serious issues for the M20’s cylinder head. 7 block and run a megasquirt? Bimmerforums is the preferred online BMW Forum and community for BMW owners. All newer M20 engines from 1983 or so. 7i stroker build any advice would be A 325 manifold will fit fine, and the ports on the 731 head are about the same size a a 325i head just a different shape. 1 had a better pull that made 188, but this is just the one he had handy to overlay The car is running a 731 head. By using a 2. Much better just to stuff the whole M20B25 into the engine bay if that's the way you're going. I want to learn how to diy and enjoy the task with my daughters. Second hand head is unlikely to be cracked (unlike the 855 head from the 2. Fit the manifold from that comes with cylinder head. JE, CP etc would be a reasonable choice. 7 chip and BBTB. 7L with 731 head on my racecar My motor has 10. Upgrade: 731 head In the later M20's (2. Or you can buy a new head from BMW, they seem to be still available. 5 block, just cause ive been offered a 2. 0 litre engine isn't greatly loved in E30 circles. This performance chip is made specifically for the 731 or 885 head on the B27 2. ANSI/ASME B18. 8:1. " http If you want to do a 2. Maybe its due to my location, or popularity with the 2. Early M20 cooling systems were notoriously bad due to weak radiator fan Anyone have any cheap mods to extract power from an M20 B20, a 731 head fit with a 2. I don't want huge power or forced induction. Cheers. M20 2. Basicly I want to know the main differences between the two heads. 5:1 pistons. 3) that came with better flowing 731 head had L jetronic instead of mechanical K jetronic and different intake manifold (and exhaust too I think). ↳ M20 Engines; ↳ M30 Engines; ↳ M40 / M42 Engines; ↳ M50 / M52 Engines; ↳ M54 Engines; ↳ S50 Engines; ↳ M60/M62 Engines; head 731 with 42mm intake valves fitted (std 885 head) and Rhd porting. Metric Socket Head Cap Screws Size Table. Then I bought an 340k mile 88 528e "Super-Eta" parts car on Craigslist on a whim. This combination makes easy going power in the Personally i have mostly been looking at the 2. 325i valve sizes are 42mm inlet and 36mm there was a thread about stroker builds on e30tech with some dyno graphs for differeny head/piston combos and the 731 head with 2. This done 193bhp on the rolling road. Im running a 2. Is there an easy way to determine if I have The debate between a built M20 and M50 goes on forever, but I do not want a 90's engine in my pristine 80's car. Welcome to the Zone! I gather the 324d uses the same bore (80mm) and stroke (81mm) as the M20B27 eta (325e) engine, so I suppose you could fit an eta head and pistons, or a 320i (731) head. Fit a 731 head from a 520i, E30 320 or /323i. I actually bought a partially refurbished M20 200 head on Craigslist. My old 3. The final version was #1705885 or "885" introduced in the 325i. Please specify if 731 or 885 head was used, as the combustion chamber designs differ. Cam custom low comp grind 272 duration 11mm lift. 3 motronic swap and i parts rather than a 731 head swap. 7 stroker conversion, but there is nothing around right now. Bottom end Stock low compression eta 2. 1L M20 (same dyno) with heavily ported 731 head with +2mm valves, 10. There was obvious corrosion where the steam holes are supposed to go. Hi everyone. Actually, let me know if you want to get rid of it, I would like one to play with on the flow bench. I have never tried it but I do remember a conversation with Ant Woodjets of A-Tech (here in sunny England who has built several 2. Intake RHD ITB's This is my first motor build and I'm happy it's an m20. Reply With Quote. This is especially prevalent in early-model, pre-1987, cars due to their underperforming cooling systems. 7i”, or “327i”. The semi-hemi pistons of a 2. It was introduced eight years after the larger BMW M30 straight-six engine, which remained in production alongside the M20. This video shows how I repaired an exhaust manifold face, replace the exhaust valve guides, and gas flow the cylinder head on a BMW M20. 8 so you would be 0. Would I be able to fit the 731 head without any problems ↳ M20 Engines; ↳ M30 Engines; ↳ M40 / M42 Engines; ↳ M50 / M52 Engines; ↳ M54 Engines; ↳ S50 Engines; ↳ M60/M62 Engines; M20 "I" head Vs "E" head 09-03-2010, 04:38 PM. even that is still only part of the story there is a B23 cam found in a 200 head (E21 323i) and the B20 cam found in a 731 (E30 320i) so we all should be more specific. Thread Tools. 3 upgrade. WTB 731 M20 Cylinder Head Hey all, I just picked up an '89 325I coupe with a blown motor but good head, and have a good spare '87 325E M20 laying around. Bimmerforums is the preferred online BMW Forum and community for BMW owners. People run the 731 head as opposed to the 885 to maintain a higher compression ratio due to the piston shape and combustion chamber. 5mm less than an i block. However I have access to a 731 head and was wondering how it would run with a completely stock eta motronic/injector setup while I source parts for a M1. Stock 2. Who here has purchased a new M20 head, 885 or 731, in recent years? What is the quality of them like? A 731 head on an m20b25 would be like stuffing a sock in the intake: you'd just be choking the engine. The head is from a euro 323i Just going to add that m20b23 (731 head) and m20b25 (885 head) intake gaskets aren't supposed to be interchangeable either. Subscri Today's Posts; Member List; Calendar; Forum; E30 Technical Forums; Engine & Drivetrain; M20; If this is your first visit, be sure to check out the FAQ by clicking the link above. Horsepower is a measure of work done over time, or the rate at which work is done. I want to fit a 731 head and 325i manifold and throttle body. 3 motronic swap with i parts. Possibly on an early eta block? I will say no more. 7 build with lots of attention where it counts but it only has 731 head with 42mm valves etc. A flat top 2. Engineering ANSI Hardware Design Data M20 × 2. My old car had a 2. 3 conversion. Top. It all depends on whether the head has been skimmed. 5cc and the 731 and 200 heads have a chamber volume of @38cc. Eta block has ~200k on it. Hi all I'm planning a project car. Thecatmilton. To start viewing messages, select the forum that you want to visit from the I do not know if this is the proper place to post this. The initial M20 model had a displacement of 2. ;) The recipe for a budget-friendly 731 head is to use 885 valves ground/faced down 1mm, seats/throats opened to match. K/Engines Your customer might be interested in this roller cam conversion, I currently have the head off mine and the first prototype is going in over the next He considers the m20 a "shitty" and weak engine (for the head that is prone to crack, and probably timing belt. e pistons with 885 head drops the CR a bit but the combustion chamber is the right diameter at least. I do take a shine when it comes to that m20 731 head. if you balance things like cranck conrods ald rework the heads in and outlet ports and put in a mild I have a healthy m20 too with the best of 200rwkw (265Hp) on a fairly straight forward 2. He told me that all m20's are actually a bit lower than they are rated and that there shop had calculated the compression ratio for an eta to be 8. 1. 2:1 euro pistons, full b25 intake, ported head, b23 cam, extractors and made 160whp@5500rpm while For anyone wanting to know what the cross section of the ports looks like, here is a silicone casting of the ports and combustion chamber. Today's Posts; Member List; Calendar; Forum; E30 Classified Forums; For Sale & Wanted; Parts For Sale; If this is your first visit, be sure to check out the FAQ by clicking the link above. Thread: WTB 731 M20 Cylinder Head. 5 or 2. 7 m20, I will be keeping the k jet system and using a 731 head. 7i M20's), where I am sure he said using a 731 head on an 11:1 CR engine is sucide for said engine. I think the e30 323i also had a head on it that was the 200 series if you read the casting numbers on the 731 head came on e30 323i later, J Last edited by jjgbmw323; 08-16-2005 at 12:22 AM. the 731 is the better head for the OP. I have an M20B23, an unusual spec, but it seems JE Pistons do them for this model. 3. 7, 135mm rods, 8. I used the 731 head from a EU 323i to keep compression up, and the cam they used on that model is fairly aggressive. 7 with 87 eta block/731 head. 5:1 due to a different combustion chamber design and the pistons not matching the head. Look for a head off 2. In that way the choice of head dictates the choice of pistons and the other way around. 325 pistons with an 885 head or Eta pistons with a 200 or 731 head. Hey everyone. For those doing a head gasket job, or a 'stroker' m20 job, you can spend a lot of money having the machine shop take apart your head for cleaning/resufacing. 05-02-2011, 05:16 AM #12. The 325i head has a chamber volume of @ 42. 30. Is the lack of the mounting point and a side distributor(non motronic) IIRC the m20 eta block has a slightly shorter deck height, approx 0. - "200" cylinder head - "731" cylinder head - 528 intake manifold - 535i ECU - Cams, np-bmw-m20) - 731 Head - 731 Intake Manifold - M30 Throttle Body - Upsized Injectors (INJ-260) I am also getting rid of MAP/MAF, ICV and cold start stuff since the "smarter" ECU can deal with all that on its own. Our professionals are here to help make sure you find the answers you need to your questions and Calling M20 Engine Specialists - 731 Head Blemishes I have a quadrajet-carburated m20b20 engine on my e21. The head is from a euro 323i btw, and it was recently fully rebuilt. In small block 400 heads they added these steam holes, and if blocked off caused pretty bad air pockets that would create heat marks in the First of all the 525i uses the M30 engine. The recommended method is by profiling the squish band of the head where the pistons protrude. 7 bottom end and M20B25 pistons to match BMW M20 Cracked Cylinder Head. Lucky the 731 head is meant to be used with flat top so no fancy domes required. The head you use is up to you. Since the 885 head doesn't match the eta pistons and drops compression a fair amount I've been thinking about trimming down a 731 head to more easily reach compression around 11 to 1. 7) - Bore out b20 block to b25 and make m20b27 using b27 crank, b25 pistons and b25 (885) head (Building a 2. e21Keith E21 Fanatic As a base you need the 122hp 27 6e a type eta block . s da replied to s da's topic in Electrical system I recently bought a 325es, but it has at least a head, intake, DME, and five speed swap from a 1989 325i. diameter inlet/outlet inlet eta head the 885 flows a fair bit more but ports are quite a bit larger so not suited for small cc M20 731 came in e30 323i and late e30 I refreshed a complete 1985 Hardy and Beck 327"s" euro engine with built 731 head and euro bottom end with balanced 2,7L crank+rods and 10. 8 m20, sure. ross2009 E30 Zone Addict Posts: 2762 Joined: Mon Nov 19, 2007 11:00 pm E30 head will physically work, intake ports are larger, so it may run badly. The next version was #1277731 aka the 731. 20. otherwise you are buggering up the design of the combustion chamber. This information is very useful for anyone looking to build there m20. Hence my conundrum ☺️ If im reading u guys right - swap out to 2. And also disproves a lot of theories that were around then. Alpina only got 210 with the 885 head using all the low-hanging-fruit gains available. 7) a little bit of porting basics on the 885 head, I'll do some more minor porting videos with basics that work and how to improve your M20 at home with minimum Another way you can do it is with the 731 head, (F/L 320i, or 323i head). s da posted a topic in Want to buy. 731 is a bit less prone to cracking to. 3 M20B23 like in the E30) you can find the next version: was 11 12 1 277 731 aka the "731". I'm having trouble finding a good 731 head for my M20 rebuild. 7i builds, 2. There's a lot of info about the b25 head to b27 block swap but it's really hard finding information about putting a 731 head onto a b27 block. ?), (731) head (Daimlerman 2. I'm trying to do as little work and money spending as possible so I'd rather not go get some I pistons. ETA head and the 885 both have the extra steam holes, as does the ETA block. 731 head left 885 head right. That being said, I've dialed in the 731 head swap pretty well, but have little experience with e30's with any sort of a different cam. 7 Eta block fully rebuilt, 320i head (731) with 325i valves and 3 angle grind with a 272/272 dbilas camshaft, 325i manifolds, zone 2. I was wondering if anyone here in NZ has done this conversion or know if it is possible, or could lead me in the right direction, regards phil. Frickin awesome platform to learn on. 7 block. 7 stroker worth doing going by the dyno graphs posted would be an 885 head with 2. Since the 731 head came off an m20 that used that same cooling system as the rest of the m20's, then you would suspect that the passages would line up. Today's Posts; Member List; Calendar; Forum; E30 Technical Forums; Engine & Drivetrain; M20; If this is your first visit, be sure to check out the FAQ by clicking the link above. Membership Services. The 731 head is a boat anchor and should be sent to me immediately for proper disposal lol. plug and play with the 731 head . The E28 and E30 earlier eta cars has cyl head casting very similar to the one used on the E21. Not as high flowing as the 885 head, AFM etc. the 325i uses an M20 engine. 5 engine), but could possibly do with replacement exhaust valve guides and seats recut. The bottom end has excellent compression and I have a completely rebuilt 200 eta head in storage that I It's not really the head that dictates rev-limit - unless you're querying at what point the valves will start to bounce. 1M. [1]The first cars to use the M20 were the E12 5 Series and the E21 3 Series. need to be careful on the context of that discussion. 7 STROKER ENGINE UPGRADE - Racehead Engineering | Racing Hardware Developments. Related Resources: hardware. hey, I'm after good 731 head, not cracked or warped to go straight on motor, manifolds not essential January 22, 2010; 2 replies manual coversion 525e block & box into 320i. They are in fact notorious for their low rpm red-line (imposed by the cams, valves, runners ets). 5lb injectors (standard m20 are 14. 89 E30 The 885 head on my 2. BTW I WROTE that article on M20 cylinder heads years ago when I was still studying -doing my Automotive MSc. With a 731 head the combustion chamber maintains the CR but is smaller (80 diameter). E21 323i came with the same 200 head casting as 2. . 1/1. 7L 325e block, preferably with Motronic 1. Start with a the eta bottom end. The BMW M20 is a SOHC straight-six petrol engine which was produced from 1977 to 1993. 7 ETA but had as many cam journals as 731 or 885 head and higher lift cam (~260 degrees). On the other hand, 731 heads are somewhat plentiful, from 323i/320i euro e21's or m20 e34's for example. 0 M20, there cars are more common than 323i's. redc6t Posts: 7 Joined: Jan Three different head castings were used over the engine's production run. M20; If this is your first visit, be sure to check out the FAQ by clicking the link above. 200 = 325e 731 = 323i 885 = 325i. Aid aim to have a My old car had a 2. 7 block, will the 731 head compliment it and give the optimum output the engine is capable off? It's also on Ljet management which I read is a bit restrictive. 8l stroked version of the m20, i know the 731 head is already desinged to use the flat piston but in doing so i would have to perform a lot more head work and the CR would be Getting my 731 head to breathe! im in australia where e30 parts are expensive etc an 885 head is about a 1000 bucks second hand and custom piston about 800-1000 any advice on what i can do to get my 731 head to breath so far i have a 325i inlet manifold and throttle body and exhaust manifold this is for my 2. So Daimlerman's 2. 7), by modifying the engine. I was using 17. 7 bottom always seems to make less HP than a standard 325i, makes a little more torque tho. mid range torque is instantaneous. Show Printable Version; Today, 10:30 AM #1. 885 head off 325i will not work, you will end up with extremely low compression ratio and wrong intake ports. 3 with a 200 series head. 5:1 pistons Intake：RHD ITB's Exhaust：Generic production h American National Standard Socket Head Cap Screws & Metric Series per. View this was the best I could find. 0. FAQ [] very true, in general a 731/320 head MUST have FLAT pistons and an 885/325 head MUST have BOWLED pistons. This gets you larger valves without having to change the seats. 731 and 885 have nothing to do with the cams, they're different M20 head castings. Just got a hold of an ETA engine from an e30 and a 731 head and I'm thinking of putting these on the e21 (then in the future, install an ITB and performance chips). I understand that it will bolt up fine and will offer improved performance with the i motronics, intake, etc, but would drive-ability suffer with the 731 worse than running the 200 head if I keep I am not positve that a 731 head works on an 11:1 CR engine. The bowl shaped b25 pistons and Super ETA pistons need the 885 head. 19. The head is a 4 bearing 200. That being said, considering the flow potential of M10's and M20's are pretty close in terms of head design, I found this fellas 885 heads are therefore completely incompatible with B20 or B23 blocks, and the 200 head can only be used with the 325e pistons. Would anyone know if you can fit a 731 (320i) head onto a m20/b25 (325i) block? An article came up on the Malayan BMW web site that this increases the torque quite significantly with no adverse affects. 7 uses an 731 head with 2. 0 M20B20 and 2. WTB 731 M20 Cylinder Head M20 Low Compression 2. FranzE21. Our professionals are here to help make sure you find the answers you need to your questions and Find many great new & used options and get the best deals for BMW M20 731 Cylinder Head European at the best online prices at eBay! Free shipping for many products! The only thing that might work is if you could get M20B23 pistons, they are 80mm and flat top for the 731 head but the crank is supposed to be 76. You also might want new exhaust manifold A 731 head fitted with 42/36 valves and commensurate porting should comfortably flow 180ish cfm up from 140 which is plenty of flow for those power goals. Please bare with me as these are not general stroker questions, I understand the concept and the advantages, Im wondering about the numbers of this specific setup. The swap is more about a 1. 7 eta project. 5 . Rebuilding the cylinder head on my 1979 barn find BMW E12 520 because the engine suffered oil starvation and the camshaft seized in the head. Typically this is referred to as: a “Frankenstein” engine, M20B257, M20B25+27, “stroker” motor, “2. 5 has cracked and i have a 731 head hanging around but it's from a 2. So my thinking is that maybe i can swap the 200 etas head for the 323i 731, a Conforti chip to raise the 86' eta's redline, and leave everything else Both the '731' and '885' ports are very accomplished and compare favourably even with a modern LS1 cylinder head. Those can be found in the B27 ETA, B27 Super ETA, the B25 non Cat and B25 Cat. ECS/Turner have them all. My understanding is that the valves will be smaller but everything else will remain the same. With the 885 head, the compression was dropped to around 9. You may have to register before you can post: click the register link above to proceed. 67 . So far as I am aware (and there's no saying that I am right) the M20 (regardless of head fitted) runs out of puff long before any sign of mechanical failure. I'm planning a 2. 7i build. the 885 head has too large ports for the OP's goals and with port work by a capable person the 731 will flow just as good with a smaller more optimal sized port with less chamber cc and can a flat top and generate squish. 5 block and wondering if i could change it for the 2, in my 320i? Top. If anyone is interested in copies of the pages let me know I can copy them, put it in a PDF and email it over. Although the "731 cyl head has much better flow performance than the "200 cyl head it has the same chamber volume, and valve sizes. 7 bottom end, 885 head, 284/280 cam, HD rocker arms, HD springs, New exhaust studs, eccentrics, water pump timing kit, ARP head studs, MLS head gasket, oil return bung. M20 experts- I was dropping off my 731 head at the machine shop when I realized that the 731 head has no steam holes. It also outlines the inferiority in this company of the '200' early 3 series port, and should hopefully bring home the folley in people who continue to pedal these cylinder heads for high performance/high capacity M20 conversions. 7L bottom end and fitting a 323i 731 option What i want to know is if the 520i m20 731 head is the same as the 323i m20 731 head. This head was the same as the 200 but featured larger intake ports. Secondly there serval routes for a 2. 53 . The m20 is a 2. You also might want new exhaust manifold studs and nuts as well as gaskets and hardware for the downpipe-to-exhaust-manifold connections (and possibly penetrating oil and/or a blowtorch and/or an impact driver and/or a lot of curse words). E30 cars (2. These were used in all E21 320/6 and 323i and E12 520/6 engines, and later in the E28 and E30 eta engines (eta = "Power With Economy"). That's it. 8l builds and using the 2 liter 731 head. I have a quadrajet-carburated m20b20 engine on my e21. have you seen the latest on the m20 thread? there may be help for you eta piston knuckle draggers yet. The choice of head dictates the choice of pistons, see My 86 528e has begun to show signs that the valve seals are failing. Only M20 b25 engine has the 135mm rods and domed pistons and a 75mm stroke crankshaft ( 885 head ) M20 b27 engine has the 130mm rods and the flat pistons and a 81mm stroke crankshaft (200 head and although rare later the 731 head) This is what I need to make sure: The M20 b25 engine block is the same as the M20 b27 engine block - 86mm bore. The cylinder head on the M30 will not fit an M20. 9mm down on your existing B20 giving it little compression but If using a 731 head you will need to modify the headgasket to allow oil into the spray bar. Notice the mid range torque difference on the 3. Is there a difference between the M20 2000cc cylinder head and the M20 2500cc cylinder head? Or is it just purely all bottom end displacement? BMW M20 engine Manufacturer BMW Production 1976–1994 Predecessor None Successor BMW M50 Class Straight-6 Engine 2. However, a 731 head from the 320i or 323i can be used on a 325i (and is essential if building a 2. 0 L (122 cu in), with later versions A Key point is you must use the pistons that match the head. 5 comp, 284/280 cam, stock intake mani, BBTB, Dbilas airbox, IE Long Tube headers vs Andrews 3L on standalone (no ITBS). only 2. ETA + 731 Head= Good Time Join Date Jun 2006 Location Bremerton, Washington Posts 786 My Cars 1986 325e, 1989 525i. I have a 7 bearing 731 head that would work great on a 2. 3. Only problem is, I noticed some blemishes on the head (see pictures). View Profile View Forum Posts Member Join Date Apr 2014 Location DFW TX USA Posts 1,457 My Cars 1983 320I, 1986 325E. 7 you'll need 84mm pistons. They should be able to do a 4032 alloy. (and 731) head than an 885 head. What would be next in my recipe is a 731 head (so i can run flat top pistons) Then it would be a dummy assembly to work out the pistons, say 85. Just a quick query guys. 00 . 0 L (1990 cc/121 in³) "731". I know strokers have been covered in length in the various e21/e30 forums. Plan is to get an e30 325e and rebuild/refresh anything that may need it in the bottom end. To start viewing messages, select the forum that you want to visit from the selection below. jsi sdycw mshtjts ghj mjkp eelsjg womlwii jyvyj letue vqqher fceoeg neisk waozqz fhxvs omni