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Post by scottydugg on Jun 22, 2019 12:15:53 GMT
Thanks everyone for the info, I think it might be a minimal skim to 20 thou max at this rate. Keep my options open for FI in the future. I'll update with what the machine shop say also.
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Post by scottydugg on Jul 9, 2019 10:21:48 GMT
Anyone any experience with buying these gasket kits from Autolink ( HERE) I know I'll need a new inlet gasket that isn't included within this kit. Teardown is well underway in prep for the skim.
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Post by Zed. on Jul 9, 2019 10:54:01 GMT
I know I'll need a new inlet gasket that isn't included within this kit. I use silly-con as inlet gasket sealer trust it more than old cornflakes packet or the oem 'caf'* or 'metal' types Rich. *'CAF' = Compressed Asbestos Fibre, old type proper flange gasket. now banned under the geneva convention etc.
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Post by dadbif on Jul 9, 2019 16:40:54 GMT
I’ve got a roll of that in the garage, used to be used for steam joints on boilers, don’t intend crumbling it up and sniffing it or telling the damned Eu...
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Post by Vindi (Russell) on Jul 10, 2019 8:25:21 GMT
If you are intending to go for turbo or supercharger in the future the last thing you need is a higher compression engine.. Not actually true, it's easier to get a safe map with a low compression engine, but if you really want to push for the most power a higher compression engine is better Russell
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jon
Chats A Lot
Posts: 270
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Post by jon on Jul 10, 2019 8:53:09 GMT
Not actually true, it's easier to get a safe map with a low compression engine, but if you really want to push for the most power a higher compression engine is better Russell It's a balance of a load of different things ... Higher compression is more efficient, but means that you are more likely to run into pre-ignition and/or knock/detonation at a given boost and ignition timing level, which is what kills engines. To avoid this, you reduce boost (less power) or retard the ignition timing (less power and more heat). Or you increase the octane of the fuel, but in the UK there's limited options for that past SUL petrol. If you retard timing, you increase the heat, which is also one the contributors to det. As the exhaust gasses get hotter, you also can run into issues with burnt valves, red hot exhaust pipes, etc etc etc Easy way round this on an agricultural mazda engine from the 80s is to lower the compression, which makes things less efficient but means you can get the missing power back with more ignition timing and moar boost. If you look at a modern factory boosted engine they tend to run much higher compression ratios because they are designed to cope with the stresses and are more efficient because of it.
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Post by scottydugg on Jul 10, 2019 9:21:21 GMT
This thread has certainly taught me a few things, will I be ok with the Autolink gasket set? specifically the valves stem seals? I don't believe they are genuine Mazda parts.
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jon
Chats A Lot
Posts: 270
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Post by jon on Jul 10, 2019 9:29:17 GMT
For something that's not easily changed, if the price difference isn't too much I'd always go with OE. Something like a valve cover seal which you can change in half an hour, it doesn't matter so much if it lasts 12 months, but valve seals you'd be really really annoyed at...
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Post by wannabe on Jul 10, 2019 10:08:45 GMT
Not actually true, it's easier to get a safe map with a low compression engine, but if you really want to push for the most power a higher compression engine is better Russell It's a balance of a load of different things ... Higher compression is more efficient, but means that you are more likely to run into pre-ignition and/or knock/detonation at a given boost and ignition timing level, which is what kills engines. To avoid this, you reduce boost (less power) or retard the ignition timing (less power and more heat). Or you increase the octane of the fuel, but in the UK there's limited options for that past SUL petrol. If you retard timing, you increase the heat, which is also one the contributors to det. As the exhaust gasses get hotter, you also can run into issues with burnt valves, red hot exhaust pipes, etc etc etc Easy way round this on an agricultural mazda engine from the 80s is to lower the compression, which makes things less efficient but means you can get the missing power back with more ignition timing and moar boost. If you look at a modern factory boosted engine they tend to run much higher compression ratios because they are designed to cope with the stresses and are more efficient because of it. The whole timing / ignition timing / advance / retard thing makes my head hurt lol
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Post by wannabe on Jul 10, 2019 10:12:11 GMT
For something that's not easily changed, if the price difference isn't too much I'd always go with OE. Something like a valve cover seal which you can change in half an hour, it doesn't matter so much if it lasts 12 months, but valve seals you'd be really really annoyed at... I hear you... I had this dilemma myself recently, as getting a valve replaced meant I thought I might as well do everything. The main issue is that inlet and exhaust valve stem seals are £5.99 each for OEM kit: www.mx5parts.co.uk/valve-stem-seal-inlet-mk1-25-p-1869.htmlwww.mx5parts.co.uk/valve-stem-seal-exhaust-mk1-25-p-1868.htmlAnd with 8 of each needed, that makes it £96 for 16 small bits of plasticky stuff... Alternatively, Autolink do a complete set for £16 (at this moment in time): www.autolinkmx5.com/valve-stem-oil-seal-set-mazda-mx-5-1989-2005-3863-p.aspI guess that if the only thing you are doing is the head overhaul, finding the money for OEM seals would be a reasonable cost, but if you're doing a whole lot of other parts as well, OEM kit starts to get expensive! I went with the Autolink set in the end - I'll have to report back with any issues when (if...) it's up and running again.
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Post by scottydugg on Jul 10, 2019 12:22:48 GMT
For something that's not easily changed, if the price difference isn't too much I'd always go with OE. Something like a valve cover seal which you can change in half an hour, it doesn't matter so much if it lasts 12 months, but valve seals you'd be really really annoyed at... I hear you... I had this dilemma myself recently, as getting a valve replaced meant I thought I might as well do everything. The main issue is that inlet and exhaust valve stem seals are £5.99 each for OEM kit: www.mx5parts.co.uk/valve-stem-seal-inlet-mk1-25-p-1869.htmlwww.mx5parts.co.uk/valve-stem-seal-exhaust-mk1-25-p-1868.htmlAnd with 8 of each needed, that makes it £96 for 16 small bits of plasticky stuff... Alternatively, Autolink do a complete set for £16 (at this moment in time): www.autolinkmx5.com/valve-stem-oil-seal-set-mazda-mx-5-1989-2005-3863-p.aspI guess that if the only thing you are doing is the head overhaul, finding the money for OEM seals would be a reasonable cost, but if you're doing a whole lot of other parts as well, OEM kit starts to get expensive! I went with the Autolink set in the end - I'll have to report back with any issues when (if...) it's up and running again. That's along the lines of my thinking, if it does go wrong then at least I'll have the skill set/tools to take it out and change it again (or just buy another head). I did some reading about the Autolink kit, they seem to have sold quite a few and not had issue. I'll keep an eye out for how you're getting on.
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