At last. Stroker pistons......
06-27-2007, 02:27 AM
#16
We are such nerds waiting in anticipation and baited breath for more info on the weight of some chunks of aluminum and steel. 
Cool!
Cool!
06-27-2007, 03:29 AM
#17
Hi Adam, this isn't going to be the engine with the throttle body setup is it? If it is I'm worried, that block thickness with 100 hp per litre going on is not going to last in my opinion. If it isn't cool and I don't want to worry you, only trying to save you heartache on money.
Best
Greg
Best
Greg
06-27-2007, 04:45 AM
#18
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Thread Starter
B.C. wrote:
Agreed. 
Well since we've steered my thread OT temporarily, I should mention that I did see a fully working megasquirt system on a 32vS engine this last weekend. VERY COOL.
Yes it is Greg. I'll be honest with you, I'm kind of beyond worrying about it all. I'd have to check back over my notes, by I seem to recall that by nikasiling my bores, it brings me back inside the recognized safety zone of cylinder wall thickness for strokers, which I believe is in the .220"+ range. Reynolds minimum spec is .250".
We are such nerds waiting in anticipation and baited breath for more info on the weight of some chunks of aluminum and steel.
Well since we've steered my thread OT temporarily, I should mention that I did see a fully working megasquirt system on a 32vS engine this last weekend. VERY COOL.
Hi Adam, this isn't going to be the engine with the throttle body setup is it? If it is I'm worried, that block thickness with 100 hp per litre going on is not going to last in my opinion. If it isn't cool and I don't want to worry you, only trying to save you heartache on money.
06-29-2007, 03:04 AM
#19
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Thread Starter
Well at least I planned ahead.
The 968 pistons stuck out of the cylinders slightly. Nothing major, about 5 thousandths. So I order the ROSS's, and on the order form indcate that they are to raise the pin bosses 10 thousanths to get the pistons back down in the holes.
Looks like they went the wrong way. Yup, nice attention to detail. I looked on the build sheet, and there is no spec referencing the location of the wrist pin hole, so I don't know how they determined where they put it.
When I filled out the build sheet, I spec'd it for a 1.5mm head gasket, so if ROSS went too big with the dish or too high with the pin height, I could use a 1mm, or if they went the other way, I could use a 2mm. Looks like I'm going with a 2mm (cometic).
The 968 pistons stuck out of the cylinders slightly. Nothing major, about 5 thousandths. So I order the ROSS's, and on the order form indcate that they are to raise the pin bosses 10 thousanths to get the pistons back down in the holes.
Looks like they went the wrong way. Yup, nice attention to detail. I looked on the build sheet, and there is no spec referencing the location of the wrist pin hole, so I don't know how they determined where they put it.
When I filled out the build sheet, I spec'd it for a 1.5mm head gasket, so if ROSS went too big with the dish or too high with the pin height, I could use a 1mm, or if they went the other way, I could use a 2mm. Looks like I'm going with a 2mm (cometic).
06-29-2007, 08:48 AM
#20
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Originally Posted by atb
The 968 pistons stuck out of the cylinders slightly. Nothing major, about 5 thousandths. So I order the ROSS's, and on the order form indcate that they are to raise the pin bosses 10 thousanths to get the pistons back down in the holes.
Looks like they went the wrong way.
Looks like they went the wrong way.
I'm sorry to hear it.
06-29-2007, 08:59 AM
#21
By Swaybar
I'd have to agree with Swaybar, a thick gasket is not what you want, infact as thin as you can get it is best. Porsche have 2 gasket thicknesses, 1.1 and 1.6? 2 mm is a thick gasket. I would have the pistons decked to corect the issue. I would get them to pay for it too.
Greg
Aw man, that is some serious suck-age!
Greg
06-29-2007, 10:54 AM
#23
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Originally Posted by Stan.Shaw@Excell.Net
Hmm, my block was decked too, so perhaps I should do a trial fit before I get everything balanced...
06-29-2007, 01:31 PM
#25
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Just put crank in with few bearings and add block lower half and bolt it into place with few nuts. Then install one rod piston combination into each cylinder one by one and every time carefully rotate crank around. While doing this monitor how close parts move. This will tell a lot whats going on and what needs to be done. Doing this only after balancing could mean totally wasted job.
Do measure how much space there is between counterweight and piston at BTC. This can obviously be done more easily without crank being inside block. I'm especially interested about the numbers since I think you have 5.85" rods and 968 pistons.
Do measure how much space there is between counterweight and piston at BTC. This can obviously be done more easily without crank being inside block. I'm especially interested about the numbers since I think you have 5.85" rods and 968 pistons.
06-29-2007, 01:52 PM
#26
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Originally Posted by Vilhuer
Do measure how much space there is between counterweight and piston at BTC. This can obviously be done more easily without crank being inside block. I'm especially interested about the numbers since I think you have 5.85" rods and 968 pistons.
Do you have the 6cwt Scat crank too? Otherwise my measurements won't help you, right? Yes, I do have 968 pistons and 5.85" rods.
07-03-2007, 12:14 PM
#28
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Thread Starter
Got some time to go back over my figures with my nice tall pistons. Looks like I'll still be okay with a 2mm gasket. I spec's the pistons for a target C/R of 11.3:1 with a 1.5mm gasket. With the 2mm gasket, I'll be at 11.04:1. Not too bad. Not what I was shooting for, but not a deal breaker.
07-11-2007, 10:00 PM
#29
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Thread Starter
Another fly in the ointment.
My machinest left me a message stating that 6 of my wrist pins are at 123.5 grams, one is at 129 grams, and one is at 129.5 grams. Says he can't go any further until I get a set of eight matching pins, 6 grams is too much to take out of the piston to balance.
I'll tell ya, ROSS is really making my day.
My machinest left me a message stating that 6 of my wrist pins are at 123.5 grams, one is at 129 grams, and one is at 129.5 grams. Says he can't go any further until I get a set of eight matching pins, 6 grams is too much to take out of the piston to balance.
I'll tell ya, ROSS is really making my day.
07-11-2007, 11:41 PM
#30
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Originally Posted by atb
My machinest left me a message stating that 6 of my wrist pins are at 123.5 grams, one is at 129 grams, and one is at 129.5 grams. Says he can't go any further until I get a set of eight matching pins, 6 grams is too much to take out of the piston to balance.