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| Unleaded inserts for 1275 https://www.ausmini.com/forums/viewtopic.php?f=2&t=1101 |
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| Author: | drmini in aust [ Fri Jul 09, 2004 8:04 pm ] |
| Post subject: | Unleaded inserts for 1275 |
Just got some nice new TAM2069 unleaded inserts in from MiniSpares UK for my latest head purchase (a 12H1316). These inserts are only 5.41GBP each there (plus freight, but they weigh bugger all). 998 ones (TAM2068) are even cheaper. Now I've got to twist someone's arm to bore the head to suit, or go buy a $300 boring head for my boss's Bridgeport clone... or, make a simple one up.. 
I'll let you know how I go- 
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| Author: | a_man_a_dog_and_a_mini [ Fri Jul 09, 2004 8:08 pm ] |
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I haven't looked up part number yet, but I assume you're refering to valve seat inserts? Now correct me if I'm wrong... be gentle... you also need new valve guides to convert to unleaded head.. yes? If unleaded fuel allows minute deposits on valve flanges, how do modern motors prevent it from happening? I'd like to convert motor to unleaded without having to worry about additives or having to use premium... |
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| Author: | drmini in aust [ Fri Jul 09, 2004 8:16 pm ] |
| Post subject: | |
Yep that's the valve seat inserts. For unleaded without additives, you have several valve & guide choices: 1. Ordinary standard iron guides and chromed stem valves (Rover Metro etc) I put these in my A+ motor already. 2. Bronze guides and tufftrided stainless valves. I'll put these into this head. 
If you run an iron Mini head (no inserts) on straight unleaded, the hot valves will micro-weld to the iron `seats' and pull lumps of metal out. One of my 1098 heads did this in 6 months after a valve job. 
<edit> Modern motors run very hard headed valves (often 2 piece, friction-welded) and austenitic (high nickel stainless) seats. I'm not aware of deposits- my EA Ford was clean as a whistle after 220,000km. Major problem is with plain iron heads, prior to 1988 or so. |
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| Author: | a_man_a_dog_and_a_mini [ Fri Jul 09, 2004 8:21 pm ] |
| Post subject: | |
thanks Doc. Which do you prefer? I've heard chromed valve stems suffer a lot of wear, whereas stainless last longer. Is this correct? Which is the best way to go? |
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| Author: | drmini in aust [ Fri Jul 09, 2004 8:26 pm ] |
| Post subject: | |
No it's the unchromed valves that wear, especially in iron guides. Chrome was added to make valves compatible. Unleaded has bugger-all lubricating properties- it's 1/2 paint thinners these days. I like stainless valves. They are one piece so their heads don't come off at 8000 rpm... The ones in my 1310 (running Flashlube, no unleaded seats) have done 40,000 miles now, still good. I have bronze guides in it. |
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| Author: | a_man_a_dog_and_a_mini [ Fri Jul 09, 2004 8:30 pm ] |
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I suppose it's how you drive. I'm a truck driver and tend to shift early. Don't think I've ever revved a car over 5k. That's why I'm planning for a high torque engine. Not just to pull the tall diff
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| Author: | PhildoD [ Fri Jul 09, 2004 10:05 pm ] |
| Post subject: | |
From experience I have nearluy always heard of Stainless valves being used with hardened valve seats. I agree with doc on the point of Stainless being one piece, and if ya can get sodium filled exhaust valves all the better.
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| Author: | drmini in aust [ Fri Jul 09, 2004 10:14 pm ] |
| Post subject: | |
The sodium filled turbo ones have given a few people trouble in UK (Jimster etc). Also Jukka. Heads came off...They reckon S/S ones are better. For a road car, Metro ones are OK, they are designed for these seats. Or MiniSpares stellite tipped ones. Cheaper than S/S too. 
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| Author: | PhildoD [ Fri Jul 09, 2004 10:25 pm ] |
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Hmmmmmm, never had a drama on my ol thumper 253. And I was running pretty damn high compression in the poor thing. |
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| Author: | kazjim [ Fri Jul 09, 2004 10:52 pm ] |
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Think of the difference in thickness of a 253 valve and a mini one.......... I ran Sodium valves in my Brock "B" castings on my Twin-turbo 253 for about 2 years..... never a hassle, but 253's generally dont turn 7500RPM plus ! Agree, Stainless valves.... J |
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| Author: | PhildoD [ Fri Jul 09, 2004 11:29 pm ] |
| Post subject: | |
They do when ya have em destroked to 244  Used to wind to 10 grand on the trusty ole MonsterTach
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| Author: | 9YaTaH [ Sat Jul 10, 2004 12:21 am ] |
| Post subject: | Flashlube |
drmini in aust wrote: Yep that's the valve seat inserts.
If you run an iron Mini head (no inserts) on straight unleaded, the hot valves will micro-weld to the iron `seats' and pull lumps of metal out. One of my 1098 heads did this in 6 months after a valve job. Major problem is with plain iron heads, prior to 1988 or so. So Doctor, do you now run an additive in engines without tougher exhaust seats?? A lot of people also believe that the likelihood of damage even without an additive is proportional to the amount of revs you pull consistently.....so our short shifting truck driver may not necessarily have trouble with an unmodified head and unleaded...?????
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| Author: | drmini in aust [ Sat Jul 10, 2004 7:07 am ] |
| Post subject: | |
I'm putting these inserts in the 1316, not because I want to run straight unleaded but because the seats are worn and I want to save the head. I'll probably still use Flashlube in it. I'm sold on its benefits: 1. It's an upper cylinder lube (stops valves sticking) 2. It stops microwelding of exhaust valves to seats. Last time I took the valves out of the 1310 (no inserts) to fit new stem seals, the valves & seats were so good that I wire brushed them and gave the exhausts a quick lap with fine paste. They were perfect after 30,000 miles. I have never had such results back in the days of leaded fuel. 3. Unlike Valvemaster additive, it doesn't fill the ports, plugs and chambers with brown shite.. which can cause plugs to break down.. I have seen the damage that neat unleaded can do to a normal Mini head... after 6 months in a stock 1098 too.. 
I don't believe that short shifting will solve this problem- metal actually got pulled out of the `seats' in the head. |
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| Author: | a_man_a_dog_and_a_mini [ Sat Jul 10, 2004 9:52 am ] |
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Well, I'll investigate both of Docs previous suggestions. Thanks matey. A lot of people focus on high horsepower engines. I was thinking of aiming at torque. Someone famous, can't think who - Enzo Ferrari rings a bell, said "High horsepower sells cars, high torque wins races". Now, considering I'm thinking of running a 2.9 or 2.7 diff because I do a lot of highway running I figure I'll need a fairly torquey engine to do this, especially from a standing start with a reasonable amount of acceleration. What points would you suggest I look at to aim for a strong torque curve? |
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| Author: | 9YaTaH [ Sat Jul 10, 2004 11:19 am ] |
| Post subject: | Cubes |
a_man_a_dog_and_a_mini wrote: Well, I'll investigate both of Docs previous suggestions. Thanks matey.
A lot of people focus on high horsepower engines. I was thinking of aiming at torque. Someone famous, can't think who - Enzo Ferrari rings a bell, said "High horsepower sells cars, high torque wins races". Now, considering I'm thinking of running a 2.9 or 2.7 diff because I do a lot of highway running I figure I'll need a fairly torquey engine to do this, especially from a standing start with a reasonable amount of acceleration. What points would you suggest I look at to aim for a strong torque curve? No substitute for cubic inches - go 1275+ to pull those high diffs...and be careful of the wheel/tyre combo you use as that could also slighty effect the final ratio |
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