Tom
Chats A Bit
Posts: 218
|
Post by Tom on Dec 8, 2016 23:13:53 GMT
Good day/evening,
As can be seen by my perpetual spamming of the forum with questions I am looking at building my turbo car into an NA car. With that comes some proper engine mods, cams etc. So I'm looking at taking ~50thou off my head depending on what I find when I whip it off! This will be followed by some fairly aggressive cam reprofiling (I have a question about this; coming right up) as well as upping my rev limit somewhat.
So my questions, which are mainly based on sketchy internet findings through google are as follows.
1. The mk2 heads moved away from HLAs- this is good for upping the rev limit as I have read the mk.1 HLAs give up the ghost at ~7500rpm. Is it worth swapping a head in? Can I get the HLAs separately and retrofit to my current head? And am i going to get some mega cam tappetty slappety noises with the solid lifters and a reprofiled cam?
2. Cams- how agressive have people gone sensibly? Where do people go? I know piper do it, but who else is good?
3. With solid lifters what rpm are people running on stock internals? I know the oil pump is the next thing to look at, can i run to 8 just eliminating the HLAs? At what point does valve float become an issue on the OE springs?
And finally,
Is anyone running larger inlet valves, if so which ones? I know FM do them but with the state of the pound to the dollar at the moment not to mention the import i had to pay on my clutch I would be glad to source some a little closer to home!
I have no doubt missed many glaringly obvious things, please do tell me!
|
|
|
Post by tropical on Dec 9, 2016 12:49:51 GMT
Hi Tom
I have been doing a bit of research into pretty much exactly this subject although my engine is a 1.8. I'm currently running Piper 270h regrinds on the standard HLAs and as you may have seen from a post on here when regularly running up to my new 7400rpm rev limit they get noisy as fook and I start to noticeably lose power.
1. The HLAs and solid lifters are interchangeable providing that you use the corresponding cams. The solid lifters would need reshimming if you don't use the entire untouched head/cam/lifter package from a mk2. To use the Mazda solid lifters with a reground cam would require very thick shims on top of the buckets, these would be even more susceptible to bring "spat out" at high revs, providing you could even get shims that thick!
2. I have spoken to Kent cams about regrinding a set of mk2 cams with a 33mm base circle and I think I can get a fairly aggressive set out of them, possibly 268/264 at 9 and a bit mm. I won't know for certain until I send them in. The reason for going for a 33mm BCD is that is what the Maruha shim under bucket lifters are designed for. If you're going to use regrinds with solid lifters I really can't see another option than to use SUBs. They are $208 plus import duty, VAT and shipping. You've then got to measure the lash and order the appropriate shims for each valve from Japan at $8+tax etc each and hope to hell you measured correctly!
3. Search miata turbo and .net, there are some threads on there regarding rev limits etc.
HTH
|
|
|
Post by tropical on Dec 9, 2016 13:39:09 GMT
Just to add, plenty of Americans claim that the HLAs are good for 7800rpm. I fitted a 16row oil cooler last weekend but haven't had the chance to give the car a good spanking yet, it may cure the lifter tick? I'll report back next week.
|
|
Tom
Chats A Bit
Posts: 218
|
Post by Tom on Dec 9, 2016 15:12:06 GMT
Thank you! Very informative response, but alas it is as I feared! I would be interested in the findings from the oil cooler! While 8k is something I would quite like to achieve, at that price its perhaps something that I can live without for the time being.
I did see your post re. the maruha lifters, and it sounds like quite the pain the backside! None the less I am not above it. Such a shame there is nowhere in the UK to source the bits! Please do keep us/me informed though, also very keen to hear about the kent regrind.
|
|
|
Post by Horney on Dec 9, 2016 17:17:28 GMT
My long term plan is a 9k rev limit. I can see this getting expensive!
|
|
|
Post by martiny on Dec 9, 2016 17:48:39 GMT
If the plan involves revving to 9k more than once then yes, I think you're right.
|
|
|
Post by Horney on Dec 9, 2016 18:12:56 GMT
Yes multiple occasions would be good. Lol.
|
|
Tom
Chats A Bit
Posts: 218
|
Post by Tom on Dec 9, 2016 18:24:27 GMT
9K would be epic, though I think the lack of low down torque would be a bit of a pain on the roads! Along with the expense you mention.
Solid lifters (depending on engine) Shims of some sort Rods (at 8+ the internet seems to suggest they are a good idea) Billet oil pump and/or harmonic damper; again seems to be suggested in general, but a must over 8k Valve springs
...I am sure there is more!
|
|
|
Post by Horney on Dec 9, 2016 18:39:20 GMT
It's not going to be much of a road car. Sprints, Hills and Trackways mostly.
|
|
|
Post by tropical on Dec 12, 2016 18:52:46 GMT
Well I didn't get the chance to give my now oil cooled HLAs a good seeing to this weekend due to excessive alcohol, sorry. âšī¸ I did however manage to purchase a set of 276deg 10.2mm lift camshafts. đ Now I just need to order the rest of the bits and fit the bloody things.
|
|
Tom
Chats A Bit
Posts: 218
|
Post by Tom on Dec 13, 2016 11:58:52 GMT
Well I didn't get the chance to give my now oil cooled HLAs a good seeing to this weekend due to excessive alcohol, sorry. âšī¸ I did however manage to purchase a set of 276deg 10.2mm lift camshafts. đ Now I just need to order the rest of the bits and fit the bloody things. Haha! Thats a valid excuse for me don't worry. Very nice! Where are the cams from? I think upping the rev limit over 7500 is something for me to attack later! So HLAs with lumpy cams, and now an oil cooler aswell are to come first!
|
|
|
Post by howardb66 on Dec 14, 2016 15:50:17 GMT
A main consideration for me for a high revving engine would be a good or new oil pump.
|
|
|
Post by josho on Dec 14, 2016 16:45:32 GMT
Ive got some 272deg 10mm lift cams waiting to go into a mk2 head, with shim under bucket lifters from the same manufacturer.
Going SUB for lightness and less likelihood of shims popping out, which i have heard is an issue on the mk2s??
|
|
|
Post by tropical on Dec 16, 2016 13:02:13 GMT
Well I didn't get the chance to give my now oil cooled HLAs a good seeing to this weekend due to excessive alcohol, sorry. âšī¸ I did however manage to purchase a set of 276deg 10.2mm lift camshafts. đ Now I just need to order the rest of the bits and fit the bloody things. Haha! Thats a valid excuse for me don't worry. Very nice! Where are the cams from? I think upping the rev limit over 7500 is something for me to attack later! So HLAs with lumpy cams, and now an oil cooler aswell are to come first! The cams are actually regrinds of UK nb originals (bp5a). I thought they had enough "meat on the bone" to get something quite fruity out of them but I didn't think they'd get 276deg at over 10mm lift! They are actually Piper Cams "ultimate road" BP285 mechanical. The mechanical bit just means solid lifters. I have measured the base circle diameter and they are as near as dammit 33mm so they should be perfect with the Mazda speed/Maruha shim under bucket lifters. I bought them off of a nutz member but they shouldn't be too pricy from Piper, definitely a LOT cheaper than from Maruha! I know the duration and lift don't tell the whole story on the cam profile but we'll see what they are like once I've got them fitted.
|
|