m20b27 block skim super/turbo charger advice

[mongomushroom]

Thanks again guys for all your help. Expecting a call back from the machine shop today with regards to the condition of the crankshaft. Plus then it'll be a few days until I get bearings, rings etc. so will keep you guys posted once I've made some progress. Project is still in very early stages and I've got quite a bit of shopping to do. turbo will probably be the next thing once I have the engine build underway. I reckon a shinny new turbo will be pretty motivating. Think I'll sell the old supercharger aswell, could be ideal for somebody with an M42 or maybe somebody with m20b25 would take for a small increase in power and huge increase in torque(with all brackets etc).

Anyway Guys i'll keep you posted once some progress has been made

[Gunni]

That's your subjective opinion Gunni and you're entitled to it. You're pissing in the face of common sense, and not to mention on quite a few well respected engineers. I don't think that this is the sort of thing that Geoff Goddard would have taught you at Brookes.

There are a few opinions going around.

Small injectors at 80% supplying the fuel or larger ones giving out the same amount of fuel in less time. The oppinions go both ways.

One says he gets better BSFC with larger injector running less duty cycle. But the norm is to use injectors that will reach 80% duty cycle.

I´m not saying anybody should use 2000cc injectors as norm as they are ridicoulusly expensive, but if lambda can be easily maintained then I don´t see a problem really.

We are not talking OEM emissions drivability here either.

[mongomushroom]

i'm going to shoot somebody!!!!!!!!!!!!!

I got myself a very nice m20b25 crankshaft from ezagood on here therefore decided to just keep the original setup. I gave my block to local engine shop and instructed them to hone it and price up some new rings. I just got back from offshore on Thursday and yesterday went in to pick up the block and give the new crankshaft for measuring polishing and supplying new bearings. they told the block was ready, honed and a 1MM SKIM OFF THE BLOCK. it seems that the people working there are complete f*cking idiots. I had asked them before for a rough estimate for skimming 1 or 2mm off the block if i was to go down that route. I told definitely not to skim anything off the block but they did it anyway. Naturally I lost my temper. I was shouting and swearing and blowing superheated steam out my ears. their suggestion was to skim 1mm off the pistons. That sounds like a bad idea to me since theres a big turbo going to be fitted and not to mention valve clearances. was thinking about maybe a spacer plate and a headgasket on either side of it. maybe a new block would a better idea. any thoughts would be greatly appreciated. Its a dam shame since that block was a belter and this has set me back a good while as well.

[GeoffBob]

Oh my that's not good! And I thought I was the only one who had to work with complete idiots (RE my gearbox issues) - looks like they're all over the place (must be breeding).

Iain, I wish I had an easy answer for you but I am afraid I don’t. Skimming 1mm off your pistons is not a viable solution unless it’s a ”a3D skim”a (if you see what I mean) since the M20B25 piston has a significant dome (is not flat topped). Basically, you would need to lower your whole dome, dish and valve pockets down by 1mm to get the same CR as before. Simply taking 1mm off the very top of the crown would do nothing to stop the piston from smacking the underside of the head.

Your only option I’m afraid is a 1mm thicker MLS** (multi-layer steel) gasket. Not my favourite solution but workable.

I know how awkward these situations can get. If you can, get them to buy you a replacement block since you never gave them a formal instruction to do any work. Normal procedure would be to get your signature on the bottom of a quote and/or job-card before doing anything otherwise they’d have a hard time recovering money from cash strapped customers. Without that you at least have a leg to stand on. If, however, they refuse to replace your block, I doubt there is much you can do short of taking legal action.

**An MLS gasket comprises a flat steel plate available in a variety of thicknesses (typically up to around 3mm if memory serves). Two thin pressed steel plates are affixed either side of the middle plate to make up a ”asteel sandwich”a. The thinner outside plates are profiled/contoured to provide the necessary seal between the head and the middle plate and the deck and the middle plate when the head is torqued down.

[mongomushroom]

thanks for your speedy reply geoffbob. its a crap situation to say the least. it was all verbal so not sure how to go about this. they're denying everything of course. i told them they would have to get a new block but they laughed. That was the point when i really lost my temper. Shortly after they refused to talk to me until I calmed down. Thats when they said they'd skim the pistons. they asked what type they were. I told them they had them. Turned out they lost the pistons as well. they found the pistons after half an hour of denying they had them. These people are f*cking useless. Anybody reading this in the glasgow area they're called Pistons and Components also known as Cylinder Head Express.

What do you think of spacer plate between 2 head gaskets. I've got 12.9 grade m10's for the head aswell. I'm not crazy about it but if its a viable fix I might just have to go for it, it would need to be spot on for the timing. might just need to get myself another block. i'm just about to start crying here

[GeoffBob]

[mongomushroom]

cant see them supplying an MLS gasket. I'm familiar with them. Was just thinking they could sort out a spacer plate themselves. Might just have to sell this block to somebody doing a m20b27 and get myself another 1.

cheers for the advice geoffbob, your a star

[Gunni]

1mm thicker then stock MLS will solve this back to where you should have been.

Don´t go machining the pistons

[CHR1S1990]

If it was me, id be getting an m20b20 block off the zone (people are giving these away after doing m5x conversions etc), then instruct your 'machinist' to bore it out and hone it, free of charge for their cock up. Worst comes to worst, a b20 block would cost you no more than £50, and ive just been quoted £100+ VAT for 6 bores bored out with a finishing hone. So all in all, will cost considerably less than an MLS gasket (consider postage from states, import tax etc..don't know of any UK stockists?) and probably quicker.

[Gunni]

I can get them pretty quick.

www.motorworx.net

[mongomushroom]

Hmm, theres a thought. I've actually got an m20b20 engine sitting here in my garden.If I was to do that would I be able to just fit the m20b25 rods, head, pistons and crank without any issues then? My other 325 overheated whilst I was in the machine shop getting the bad news and i've got a nasty suspicion that the head gasket cooked although i havent checked it out yet. thats another (although not my favourite) option. Anybody bored out an m20b20 before that can offer any advice?

[CHR1S1990]

quite a few have done this before as the blocks are identical (minus the steam holes on the b25, which aren't really that necessary)

[CHR1S1990]

how quick is quick gunni? I'll be looking at one myself, along with some ARP head studs

[mongomushroom]

chris1990 you've made my day . I'll look it up on here and hopefully get time to strip it tomorrow. hopefully i'll have made some decent progress soon and start a write up for anybody who's interested. Just had word that a borgwarner k27 will be coming my way soon. just need to get my shell sorted and i'll be well under way

[mongomushroom]

m20b20 block stripped and dropped off at the 'specialists' for rebore and finishing hone for standard b25 pistons. Very specific list of instructions written and left with them. Hope they won't f@ck this 1 up. The responsible machinist turned around and left when he saw me!!

[CHR1S1990]

glad I can be of some help, 'least this way youl have a nice straight block for sure

[mongomushroom]

ye its probably better this way although the other block was pretty good. Almost chucked the m20b20 to the scrappys. I was told it was a 2.5 when i took a mountain of spares of a guy that sold me a car. Pays to be a hoarder.

[mongomushroom]

For anybody who's interested I never got the issuie resolved with pistons and components/cylinder head express. I thought they'd be keen to sort this out but they kept on messing me about for almost 2 weeks afterwards. I told them just to scrap that block they ruined because I was getting really tired of their bullshit. Anyway i took my b20 block to a company just outside glasgow in coatbridge called t m smith for rebore and polish crank. Spoke to the guy for a while and had a look around and I'm very confident that he's going to do a proper job. Wish I had gone to him in the first place. very knowlegeable and experienced. He recomended a very light skim off the top of the block aswell after rebore since theres so much being taken off. he said it would only be a couple of thou and shouldn't affect the compression ratio. havent made up my mind yet but reckon a couple of thou should be fine.

He identified a mistake in the haynes manual aswell. The conversion of metirc to imperial with regards to cylinder bore on m20b25 is wrong. Could be an expensive one for somebody!

[CHR1S1990]

glad you're now on the right path! how much for the re-bore and clean-up skim if you don't mind me asking?

[mongomushroom]

between 160 and 180 for the rebore and another 50 on top for skim. Thats the cheapest I found in the glasgow area. it's a lot to be bored out so i'm happy with that price and confident that i'm getting quality work done. Was quoted more than 600 by another firm