....- last weekend I f****d up the cam tower threads by following the pictures in 'how to rebuild your nissan OHC' and torqued them to 33ft-lb
Sometimes gut-feeling is a good idea with bolts (awaits Skid's response
)
-
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My "L29" build.
- Thread starter jonbills
- Start date
Sometimes gut-feeling is a good idea with bolts (awaits Skid's response
)
Sometimes gut-feeling is a good idea with bolts (awaits Skid's response
My point being that if it's a small bolt into aluminium then you don't need a high torque so double check if the figure seems excessive. I don't mean tighten it to two slips of the Stilsons!
Obviously torgue is critical on some components e.g. stretch cylinder head bolts.
A small update -
I've decided 89mm gaskets don't go well with 88.5mm bore engines :-(
I had a significant amount of pinking, so I just took the head off and this is what I found:
Not sure if you can see it properly - the thing that looks like a thread there is a strip of the metal sealing ring. Looks like the pistons have been hitting it and the metal seals are worn through on at least 3 cylinders. I guess the dowels don't locate it well enough with only 0.25 mm of clearance.
No harm done I think, and I've got a nice new 1.5 mm thick Kameari gasket to go on, that has 1mm clearance all the way round.
Another junior engine builder error
I've decided 89mm gaskets don't go well with 88.5mm bore engines :-(
I had a significant amount of pinking, so I just took the head off and this is what I found:
Not sure if you can see it properly - the thing that looks like a thread there is a strip of the metal sealing ring. Looks like the pistons have been hitting it and the metal seals are worn through on at least 3 cylinders. I guess the dowels don't locate it well enough with only 0.25 mm of clearance.
No harm done I think, and I've got a nice new 1.5 mm thick Kameari gasket to go on, that has 1mm clearance all the way round.
Another junior engine builder error
Last edited by a moderator:
SeanDezart
Well-Known Forum User
Can't see the photo mate.
SeanDezart
Well-Known Forum User
Yep - I know my eyes are sh*t but no image is asking too much.
Yes - Sean often can't see things e.g. ebay items.
Or common sense
SeanDezart
Well-Known Forum User
Ok from last night - it suddenly appeared and I was looking via two different PCs with different software and internet access'.
SeanDezart
Well-Known Forum User
Or common sense
Had enough to rejoin and support the club here......
I haven't posted on my engine for a long time, so due an update:
- Pinnacle of last year for the new engine was a 13.59 at Santa Pod
- Over the last winter, I've been getting a new head together - it's a P90 with porting & modified combustion chamber and a big cam.
- I also rebuilt an FS5W71C gearbox with a quickshift that I fitted over the Winter.
A couple of random photos - first the ports. I had the waterways tapped on 5 & 6 so I can later improve the cooling flow from the back end of the head.
And I also added a Kameari crank damper, 'cos it's going to rev a LOT more with this head
I put it together a couple of weeks ago. I hadn't got too far with (the carb equivalent of) mapping it before the diff died - hence my classified for a new R200 diff.
Over this weekend, I prepared the new diff, got the propshaft balanced by Bailey Morris and fitted it all.
I went for a test drive on Saturday and the vibration and noises from the diff & prop are all gone. I ran it up to 8000 a couple of times too which went well
Just as I got home, the rad sprang a like and it was misfiring a bit. The electric fan had worn a hole in the rad - so I've soldered that up and gone back to the viscous fan for now.
I pulled the spark plugs and they were not looking their best:
Some of the tips have melted
so that's where the weekend fun stopped.
I hope there's no serious damage - I've ordered some colder plugs. I'll retard the ignition timing a few degrees next weekend and see how it is, and build back up the revs, checking the plugs regularly.
Next up? stop melting plugs, get the fuelling right, go to Le Mans Classic, get a new exhaust manifold from Sean, get the fuelling right again, go to Northampton Motorsport for some time on the rolling road to optimise and see what it produces (and maybe Santa Pod along the way too).
I should also thank pmac & skiddell for their help. If it works well, it's down to them (and Phil who built it). if it doesn't work well, it'll be down to me
- Pinnacle of last year for the new engine was a 13.59 at Santa Pod
- Over the last winter, I've been getting a new head together - it's a P90 with porting & modified combustion chamber and a big cam.
- I also rebuilt an FS5W71C gearbox with a quickshift that I fitted over the Winter.
A couple of random photos - first the ports. I had the waterways tapped on 5 & 6 so I can later improve the cooling flow from the back end of the head.
And I also added a Kameari crank damper, 'cos it's going to rev a LOT more with this head
I put it together a couple of weeks ago. I hadn't got too far with (the carb equivalent of) mapping it before the diff died - hence my classified for a new R200 diff.
Over this weekend, I prepared the new diff, got the propshaft balanced by Bailey Morris and fitted it all.
I went for a test drive on Saturday and the vibration and noises from the diff & prop are all gone. I ran it up to 8000 a couple of times too which went well
Just as I got home, the rad sprang a like and it was misfiring a bit. The electric fan had worn a hole in the rad - so I've soldered that up and gone back to the viscous fan for now.
I pulled the spark plugs and they were not looking their best:
Some of the tips have melted
so that's where the weekend fun stopped.I hope there's no serious damage - I've ordered some colder plugs. I'll retard the ignition timing a few degrees next weekend and see how it is, and build back up the revs, checking the plugs regularly.
Next up? stop melting plugs, get the fuelling right, go to Le Mans Classic, get a new exhaust manifold from Sean, get the fuelling right again, go to Northampton Motorsport for some time on the rolling road to optimise and see what it produces (and maybe Santa Pod along the way too).
I should also thank pmac & skiddell for their help. If it works well, it's down to them (and Phil who built it). if it doesn't work well, it'll be down to me
racer
Club Member
Strange the plugs have gone like that John? The colour looks about right.
I was running eights in mine at 34 degrees total adavance. Gone back to sixes now and all is well with the same timing, and much better cold starting. I might end up with 7's when these are worn.
What timing were you running??
Did you weld up the P90 to compensate for the larger chamber?
I was running eights in mine at 34 degrees total adavance. Gone back to sixes now and all is well with the same timing, and much better cold starting. I might end up with 7's when these are worn.
What timing were you running??
Did you weld up the P90 to compensate for the larger chamber?
You can't see the insulators in the pic, but they are bone white which is odd - the mixture was rich if anything, going by my AFR gauge.
It was set at 35 degrees total, I've gone to about 32 degrees now but I might well go lower until I get on the RR- I've been reading a bit about chamber shape and advance, and the optimal advance may well be less than 35 for this head. I guess I'll only really know when I get on the RR.
Plugs were B7ES - I've got some BCR8ES coming today I hope.
Yes, had a fair bit of welding on the chambers to reshape and reduce the size. It's down to 39cc (so far from radical, CR in low 11s).
It was set at 35 degrees total, I've gone to about 32 degrees now but I might well go lower until I get on the RR- I've been reading a bit about chamber shape and advance, and the optimal advance may well be less than 35 for this head. I guess I'll only really know when I get on the RR.
Plugs were B7ES - I've got some BCR8ES coming today I hope.
Yes, had a fair bit of welding on the chambers to reshape and reduce the size. It's down to 39cc (so far from radical, CR in low 11s).
yeah, I think my squish is excellent - a lot of squish area with the welding and just over 0.5mm clearance between head and piston.
Could be the AFR setup, it's strange since the plugs looked as you'd expect for 'slightly rich' until I started revving it past 7k.
Time will tell.
Could be the AFR setup, it's strange since the plugs looked as you'd expect for 'slightly rich' until I started revving it past 7k.
Time will tell.
SeanDezart
Well-Known Forum User
And time will tell on your engine too at +7k.