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yorkshire_spam

4cyl engine and Maxspeeding rods

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Has anyone hereabouts successfully used maxpeeding/maxspeeding rods in a 4 cylinder engine? I've got part way through building mine to find that because the rods are straight bolted rather than angled no. 3 is fouling the oil pump! Or am I doing something epically stupid?

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I've got a blown 1500 with those rods that I ran successfully (for some definitions of success) for 10 years or so.  I don't remember this ever being an issue and I'm pretty sure I replaced the pump body at one point, so don't think I modified anything but next time I'm in the garage (next weekend probably now, I can double check and take some photos).

I was trying to use them for a 1300 (small crank) block, but for now their use is on hold as the offsets on the ones supplied were wrong so using standard, lightened rods for the time being.

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There are definitely some shape variations on the oil pump bodies. How much would have to be removed to clear?

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16 minutes ago, Nick Jones said:

There are definitely some shape variations on the oil pump bodies. How much would have to be removed to clear?

Not sure Nick, but it looks like "too much" to me. I'm going to get one of my spares and the die grinder out and see what's what.

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26 minutes ago, yorkshire_spam said:

looks like "too much" to me.

Yeah..... does in the pic too.  The earlier cast iron housings are definitely different (also shorter and lower capacity) and I think there are at least two variations of the aluminium body, but not sure whether they follow the variation of the cover/pick-up or are interchangeable.  Might have an old iron body one but pretty sure not any aluminium ones.  Mostly I have 6 cylinder parts scattered around.

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No help to you, Y-S, but I found that MaxSpeeding rods made building a 2.5 for a Vitesse (or GT6) easier, as they clear the shallower 2L sump floor!

John

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Quite annoyed by this, I was enjoying myself bolting this together. Mind you plenty of other jobs to do, Spitfire to tune, garage to tidy, roll cab to assemble and then tools to re-distribute. It shouldn't be many more weeks before the head is ready for collection too!

 

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The TE link you posted earlier suggested 1/16th" was enough - that's 1.6mm.  Depends how far you think you can go without striking oil!

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1/16" = 65 thou!     will the big end deviate that much??

From memory you should leave 30thou between the piston and the head, to cater for rod stretch.   A crank's circumferential velocity will be the same as the max piston speed, but a journal is not as long as a conrod and a lot thicker.   Would 30 thou do?

John

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Based on nothing better than gut feeling I think something around 30 thou minimum is probably enough. But if I can get more than that without:

17 hours ago, Nick Jones said:

striking oil!

I'll be happy.

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I checked and I hadn't replaced the pump in mine, just the pickup.  The body had been ground away to accommodate this, although not very much..  Sadly that's the conrod that went out the side of the block, so I can't check the exact clearance but from looking at it I'd guess less than 1mm removed (so 30 thou would be in the right ballpark).

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1 hour ago, richy_rich said:

I checked and I hadn't replaced the pump in mine, just the pickup.  The body had been ground away to accommodate this, although not very much..  Sadly that's the conrod that went out the side of the block, so I can't check the exact clearance but from looking at it I'd guess less than 1mm removed (so 30 thou would be in the right ballpark).

Brilliant, thanks for taking the time to check Richy!

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13 hours ago, azoth said:

Thanks Azoth, as much as anything it's a big re-assurance for me to know:

  1. I'm not doing something totally dumb like fitting the pump body or the conrod wrongly
  2. Other people have solved the problem the same way I have without destroying the pump/engine/conrod.

Cheers, Sam

 

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Hello All

              I may be talking complete rubbish(again) but why not knock the steel blanking plug out and get the hole welded up and reshape to what you want as long as you can keep the inside flow the same

Roger

ps I do not have an old aluminium pump to check the theory! and I am not taking the sump off the spare engine just to look!

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22 hours ago, rogerguzzi said:

Hello All

              I may be talking complete rubbish(again) but why not knock the steel blanking plug out and get the hole welded up and reshape to what you want as long as you can keep the inside flow the same

Roger

ps I do not have an old aluminium pump to check the theory! and I am not taking the sump off the spare engine just to look!

Hi Roger, I think the internal port that runs down the "slanted" section lo the left side of the pump (as pictured above) is a bigger concern than the horizontal port at the back of the plug.

Anway, I've  ground it to the point where I'm happy with the minimum clearance. And then filed it a bit to smoother than the die grinder left it.

Cheers, Sam

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