1600 Stroker motor build....

Hi Pete

For reference, with 0.5mm of piston above the deck, and the head shaved to reduce the combustion chamber volume to 30cc, the static compression ration would be about 10.5:1, with all else unchanged.

With that setup, I believe that you would have piston to valve contact if the engine were timed incorrectly, but then a lot of engines are intentionally designed that way, so no worries as long as attention is paid to timing it correctly, and the timing belt is not run too long.
 
I'm sure you know what you are talking about, but hopefully someone else can verify or dispute whether or not having the recessed area milled off and .5mm piston above deck will create an interference engine situation.

'PeteX1/9
 
I wouldn't get too worried about whether or not it's interference or not. Most engines are interference and it's pretty much a non-issue. Also, if you have over-sized valves you might need to modify the pistons in order to achieve non-interference status and that will reduce the compression to some degree. I'm pretty sure it's possible to build a non-interference motor with the compression you are looking for but I don't think it's worth it if you have to do anything unusually to get it. Just make sure your running clearances are okay and change the timing belt periodically.
 
Chris.O
This write-up regarding the pistons you sell is off your store front.
Do you know or could you find out where in the bore these pistons used with the 67.4mm crankshaft in 1500 block and stock rods will place the piston?

NEW - SPECIFICALLY TO USE WITH 67.4 MM STROKE CRANKSHAFT 7588670 IN 1500 BLOCK WITH STOCK 1500 RODS, 86.4 MM & 0.4 MM OVERSIZE PISTON ASSEMBLY SET, 33.64 MM COMPRESSION HEIGHT. INCLUDES 4 PISTONS, 4 TOP RINGS, 4 MIDDLE RINGS, 4 OIL RINGS, 4 PISTON PINS, & 8 PIN CIRCLIPS. ESTIMATED COMPRESSION WOULD BE 9.2:1

'PeteX1/9
 
The next obstacle will be the con-rods. I've been told that the stock forged con-rods will make contact with the block using a 67.4mm crankshaft.

I'd love to get other members views on various con-rods. I'm posting a link to con-rods I'm considering and hopefully there won't be any contact.


H-beam ($250.00/4)
http://www.ebay.com/itm/400555994833...84.m1423.l2661

Scat H-beam ($350.00/4)
http://www.ebay.com/itm/190869342463?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649


Anyone else used these con-rods and your thoughts either with a stroker build or not.

'PeteX1/9
 
Of course now that I'm looking for it I can't find it. Multiple members have told me that stock con-rods will make contact with the block using a 67.4mm crank so material needs to be grinded away close to the oil galleries. I have been told that after market con-rods won't have this issue but not sure exactly which aftermarket con-rods they were referring to.

'PeteX1/9
 
Ok,you are right,the 1.6 engines have this grind on the oil gallery. You can make it yourself,but the thickness is around 5-8 mm there.

Here is my I-beam rod compared to the stock rod. On the original rod,the bolt head could contact the gallery.

jtex.jpg
 
Great explananation

Yes, exactly.
So it probably doesn't matter which aftermarket rod you get.

Grinding the block for stock rods is very easy to do though...
 
Ulix if you are speaking from experience regarding grinding the block, did you happen to take any photos of where exactly the material needs to be ground from.

'PeteX1/9
 
Thanks for the picture but I can't tell the difference and tell exactly where the material was removed.

Sorry,
'PeteX1/9
 
You can see the half round casting just over the bores,it goes from one end of the engine to the other,it is the oil gallery. The shiny surface is the factory grinding.
 
Your guess is as good as mine, why ask me, ask the seller.

I, for one, cannot understand your compulsion to want to go with standard 86.4mm piston....

why???

your going to be removing the engine to replace the crankshaft, so what's your problem with reboring the block and having nice fresh round bores and a good cross hatch to bed rings with???

SteveC
 
Definitely

In this case, it is pretty much like this:
You can either have a non-interference OR a performance engine.
 
I have messaged the seller in Italy and they haven't responded yet. I asked you because I read in your write-up on "turbo124.com" about your SOHC 1600 build and how the 34.15CH pistons were used on 1301cc Fiat Uno/Ritmo/Regatta engines and this ad matched that description.

As for boring the engine out, that is still an option. At the very least I was going to have the machine shop skim the top of the block for flatness and I was going to hone the cylinders with my own cylinder honing tool for those hatch marks. Thanks for all the advice.

'PeteX1/9
 
Now I see it :geek: Having that grinded away recess in the oil gallery doesn't affect the operation of the engine or cause any issues?

I'll consider that option but for the minimal cost of new con-rods that may be the way to go as they will be balance within 1gram aswell.

'PeteX1/9
 
The recess in the gallery has absolutely no effect on engine operation,only the wall thickness is reduced by a few mm. If you can,go with the aftermarket rods,then there is no hassle with the engine,no cleaning after grinding.

However,if you want to buy new pistons,get an oversize and bore the block. It has some scratches for sure. Flex hone will do the crosshatch finish,but the bore is getting bigger,and is not round anymore for sure.
 
Who told you the stock rods wont fit?

have they actually done the job? or is it "what they have heard?"

I can tell you the stock rod will clear, in most cases as I'm sure there is maybe 1 in a 1000 that might just touch, but they come VERY VERY close to the oil gallery most times... a little touch with a die grinder would suffice at most... but as the SCAT rods are so cheap, it doesn't make sense to not use them. but make sure you go for the good hardware, and go for a reputable brand, lots of crap chinese knockoffs around these days.

don't waste your time honing and refitting stock sizes pistons, it just doesn't make sense.... unless you usea flex hone often, chances are you'll do a rubbish job anyway.

same with you fasination or interference and non interference!!! What a load of rubbish... it doesn't matter unless you slip or break a belt anyway, and if it's built right and maintained, that is NEVER going to happen.

SteveC
 
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