Piston to bore clearance - 1600 build
- Thread starter rjplenter
- Start date
petex19
True Classic
Tell me more about your stroker build....Is your BVhead a fabricated BVhead as PBS was doing or a factory Fiat Tipo 14 bolt BVhead ?
I'm assuming your using a 67.4mm crankshaft from the Fiat family of crankshafts. Is your engine going to be carb'd or Injected ?
What are your plans for camshaft ?
'PeteX1/9
I'm assuming your using a 67.4mm crankshaft from the Fiat family of crankshafts. Is your engine going to be carb'd or Injected ?
What are your plans for camshaft ?
'PeteX1/9
rjplenter
True Classic
Following the Fiat family group of parts
Hi Pete,
In the past there were two schools of thought when it came to upgrading the output of an X. Go the way of Uno Turbo transplants or shoe-horn in a twin cam engine and transaxle.
Today the two schools are go for the K20 transplant, or stick with N/A Fiat SOHC technology and wring as much as possible out of it. The current availability of longer stroke crankshafts has made this latter option more viable than in the past. This is obviously the option I've gone for, for several reasons. In my book all the above options are legitimate and subject to personal taste.
You are correct, we have a 67.4mm stroke crank. This will be matched with 87.0mm pistons resulting in a final capacity of 1603cc and we are aiming for CR in the 10.5:1 range. We have Scat rods to connect the pistons with crank, Vandervell crank bearings and Clevite 77 rod bearings and ARP main bearing cap bolts. This will all be going into the very low mileage 1500 block I found (and discussed in a separate thread) and should make for a strong bottom end.
The head is where the power will be made. I have a Yugo head that will have 39.5mm inlet and 33.5mm exhaust valves installed with appropriate deshrouding. Porting will be performed to match the valves for good air flow while hopefully maintaining good gas speeds. While I don't have access to a flow bench (envious that SteveC has one!!!) I have modified many heads this way and believe I have a good feel for how the ports should be shaped. Also the valve guides are slightly shorter than standard which will reduce obstruction to flow. I will be using lash caps on the valve stems to reduce the thickness of shims needed which will negate the need for stiffer valve springs thereby reducing potential parasitic losses.
The camshaft is an Alquati item with 110 degree lobe centres, 42/76 Intake - 68/36 Exhaust (seat-to-seat) timing and 10.25mm maximum lift.
Twin Dellorto 40mm DLRA carbs on an Alquati manifold will provide air/fuel mixture. And the exhaust system I recently made will be installed.
That's the plan, practically all the parts are sitting on my work bench, so we will see how we go!
Cheers,
Rob
Hi Pete,
In the past there were two schools of thought when it came to upgrading the output of an X. Go the way of Uno Turbo transplants or shoe-horn in a twin cam engine and transaxle.
Today the two schools are go for the K20 transplant, or stick with N/A Fiat SOHC technology and wring as much as possible out of it. The current availability of longer stroke crankshafts has made this latter option more viable than in the past. This is obviously the option I've gone for, for several reasons. In my book all the above options are legitimate and subject to personal taste.
You are correct, we have a 67.4mm stroke crank. This will be matched with 87.0mm pistons resulting in a final capacity of 1603cc and we are aiming for CR in the 10.5:1 range. We have Scat rods to connect the pistons with crank, Vandervell crank bearings and Clevite 77 rod bearings and ARP main bearing cap bolts. This will all be going into the very low mileage 1500 block I found (and discussed in a separate thread) and should make for a strong bottom end.
The head is where the power will be made. I have a Yugo head that will have 39.5mm inlet and 33.5mm exhaust valves installed with appropriate deshrouding. Porting will be performed to match the valves for good air flow while hopefully maintaining good gas speeds. While I don't have access to a flow bench (envious that SteveC has one!!!) I have modified many heads this way and believe I have a good feel for how the ports should be shaped. Also the valve guides are slightly shorter than standard which will reduce obstruction to flow. I will be using lash caps on the valve stems to reduce the thickness of shims needed which will negate the need for stiffer valve springs thereby reducing potential parasitic losses.
The camshaft is an Alquati item with 110 degree lobe centres, 42/76 Intake - 68/36 Exhaust (seat-to-seat) timing and 10.25mm maximum lift.
Twin Dellorto 40mm DLRA carbs on an Alquati manifold will provide air/fuel mixture. And the exhaust system I recently made will be installed.
That's the plan, practically all the parts are sitting on my work bench, so we will see how we go!
Cheers,
Rob
fiatfactory
Steve Cecchele
Make that four of us... I have a 1599 build underway as well...
(86.8 x 67.4) 14 bolt block, new (chinese) 14 bolt Tipo head, 39.6/33.4 valves, 36.5/28.5 seat throat (160cfm inlet/120cfm exh), 0872 Mahle (Kolben Schmidt) pistons with inlet flycuts enlarged, aiming for 11:1 Static CR, TRW valves (intakes lightened), TRW valve springs, Scat rods, ARP fastners, alloy toothed alt/w/pump drive, Kent vernier cam gear, under bucket lash adjustment, Tipo (10 tooth) oil pump, marelli Plex ignition. Pittatore steel 42/82 12.2mm cam, Alquati DCNF intake, twin 44dcnf, custom extractors, lightened and polished crank, windage tray, allloy flywheel... for the track car I'm building....
but first it's going to get the 1500 that's almost done...10 bolt X19 block 1982, 86.8 mondial 8551 pistons (35.3CH 1.6 dome) 1500 X19 euro head fitted with 39.6 valves, (36/28.25 seat throats) scat rods, arp fastners, stock crank, tipo oil pump, kent vernier cam gear, alloy toothed w/pump/alt drive,, single 40dcnf on modified stock 1500 euro manifold, stock 4/2 exhaust manifold, lightened steel flywheel ... basically the best engine I can build with all factory X19 parts including the manifolds.... apart from maybe the cam... which I could use a 24/68 9.9 but that might limit the output...so it might end up a Pittatore steel 42/82 10.75 cam.
SteveC
(86.8 x 67.4) 14 bolt block, new (chinese) 14 bolt Tipo head, 39.6/33.4 valves, 36.5/28.5 seat throat (160cfm inlet/120cfm exh), 0872 Mahle (Kolben Schmidt) pistons with inlet flycuts enlarged, aiming for 11:1 Static CR, TRW valves (intakes lightened), TRW valve springs, Scat rods, ARP fastners, alloy toothed alt/w/pump drive, Kent vernier cam gear, under bucket lash adjustment, Tipo (10 tooth) oil pump, marelli Plex ignition. Pittatore steel 42/82 12.2mm cam, Alquati DCNF intake, twin 44dcnf, custom extractors, lightened and polished crank, windage tray, allloy flywheel... for the track car I'm building....
but first it's going to get the 1500 that's almost done...10 bolt X19 block 1982, 86.8 mondial 8551 pistons (35.3CH 1.6 dome) 1500 X19 euro head fitted with 39.6 valves, (36/28.25 seat throats) scat rods, arp fastners, stock crank, tipo oil pump, kent vernier cam gear, alloy toothed w/pump/alt drive,, single 40dcnf on modified stock 1500 euro manifold, stock 4/2 exhaust manifold, lightened steel flywheel ... basically the best engine I can build with all factory X19 parts including the manifolds.... apart from maybe the cam... which I could use a 24/68 9.9 but that might limit the output...so it might end up a Pittatore steel 42/82 10.75 cam.
SteveC
petex19
True Classic
The Jedi master is building aswell :jedi: I learned so much from you and can't wait to see photos of your build. I'm not familiar with "alloy toothed alt/w/pump drive" or the "Tipo (10 tooth) oil pump" but I'm sure their the best at what they do or you wouldn't be using them.
Keep us posted so we can continue to learn.
'PeteX1/9
Keep us posted so we can continue to learn.
'PeteX1/9
rjplenter
True Classic
We also have a windage tray
I'm tempted to check out these pins:
http://www.summitracing.com/parts/ros-866-01-27/overview/
They represent a significant weight reduction, but I'm unsure of their ability to last. I'm not a metallurgist so have no idea if heat treated aircraft quality chromoly (5115) steel is any good. Of course, who knows what our original pins are made of...
Steve, where do you find your Tipo oil pumps? I've had no luck finding them.
Cheers,
Rob
I'm tempted to check out these pins:
http://www.summitracing.com/parts/ros-866-01-27/overview/
They represent a significant weight reduction, but I'm unsure of their ability to last. I'm not a metallurgist so have no idea if heat treated aircraft quality chromoly (5115) steel is any good. Of course, who knows what our original pins are made of...
Steve, where do you find your Tipo oil pumps? I've had no luck finding them.
Cheers,
Rob
fiatfactory
Steve Cecchele
if they are made by Ross pistons then I would say they will be up to the job, I wouldn't mind a set myself...will PM you re getting some parts and shipping them over for me if you don't mind...some sellers have really cheap parts (like summit and rock auto) but shipping to Australia is ridiculous!
Tipo oil pump, I found some original Fiat pumps in italy, recognised the OE part number and bought all three the guy had... there is even a late style oil pump drive gear that has close to double the spline engagement of the regular sohc drive gear too...good insurance.
The toothed belt drives are old Alquati items, NOS found on ebay... basically uses a toothed belt which is the same tooth width and pitch as the cam belt to drive the alt/w/pump instead of a V belt, no slippage and much lighter weight crank pulley... looks like the cam drive pulley but in alloy, will post some pics for you.
and I have stainless studs, bolts, nuts, capscrews, domenuts etc for all non critical engine hardware, just to dress them up a bit...
SteveC
Tipo oil pump, I found some original Fiat pumps in italy, recognised the OE part number and bought all three the guy had... there is even a late style oil pump drive gear that has close to double the spline engagement of the regular sohc drive gear too...good insurance.
The toothed belt drives are old Alquati items, NOS found on ebay... basically uses a toothed belt which is the same tooth width and pitch as the cam belt to drive the alt/w/pump instead of a V belt, no slippage and much lighter weight crank pulley... looks like the cam drive pulley but in alloy, will post some pics for you.
and I have stainless studs, bolts, nuts, capscrews, domenuts etc for all non critical engine hardware, just to dress them up a bit...
SteveC
rjplenter
True Classic
No worries, let me know and we'll work something out.
Would that part number be 46772183?
Thanks, would love to see more pics. I've been looking for one of these since I first saw your post on turbo124. I think 128fza sells a set, but they're just too pricey to justify for this build. I like Husseins research into a serpentine belt alternative.
I've been collecting stuff like that too :grin:
Cheers,
Rob
fiatfactory
Steve Cecchele
Between all the Mahle, KS, Borgo, Mondial and Mahle-Mondial pistons I have I have various pin weights from 135grams down to 120grams ... so at least one set of 100gram pins is now on my shopping list...as you said that is cheaper than what you can get the stock ones lightened for! and another 80 grams overall is a worthwhile saving.
Bare weight of the Mahle (KS pistons in a Mahle box) 0872's after the flycut has been done is 415grams bare. (that would be about 180grams total lighter than the mondials as standard in 86.8 size)
There are slight variations in ring weights, and it's important as they move independently... and have their own inertia... so lighter is better here too.
the 16v 86.4 bore variants use a much thinner ring set (available moly faced too) that is considerably lighter than the stock x19 type, I'll take some pics once I get my really accurate scales back as I bought a set to look at (lent my scales to a friend for his engine build) ... if you were getting pistons custom made they would definitely be a step in the right direction.
10 tooth tipo/unoT style pump (needs pickup swapped from an X19 pump) is 5962426 ... but there are probably a few different numbers as there are serveral designs of pickup, this has a rectangular pickup and uses the stock 128/x19 pump body, still has 128A000 4194643 cast into it... and there are types with a longer spline on the pump shaft too... this one is normal length.
SteveC
Bare weight of the Mahle (KS pistons in a Mahle box) 0872's after the flycut has been done is 415grams bare. (that would be about 180grams total lighter than the mondials as standard in 86.8 size)
There are slight variations in ring weights, and it's important as they move independently... and have their own inertia... so lighter is better here too.
the 16v 86.4 bore variants use a much thinner ring set (available moly faced too) that is considerably lighter than the stock x19 type, I'll take some pics once I get my really accurate scales back as I bought a set to look at (lent my scales to a friend for his engine build) ... if you were getting pistons custom made they would definitely be a step in the right direction.
10 tooth tipo/unoT style pump (needs pickup swapped from an X19 pump) is 5962426 ... but there are probably a few different numbers as there are serveral designs of pickup, this has a rectangular pickup and uses the stock 128/x19 pump body, still has 128A000 4194643 cast into it... and there are types with a longer spline on the pump shaft too... this one is normal length.
SteveC
rjplenter
True Classic
Piston speed and weight
I think I am a little nervous about using a 3mm wall-thickness pin in a "heavy" piston with a longer stroke. If the Ross pins are made of better material than the standard Fiat part, then that nervousness will dissipate. I have no idea what material is used for the standard pins.
My pistons are 438 grams now, but will lose some grams with enlarging of the valve reliefs and probably skimming off the top to adjust the pop-up height. Increasing the stroke will put more stresses on the "new" components. Some more weight could be lost if I am game enough to take some material off the skirt under the pin axis.
Approaching TDC on the exhaust stroke puts the greatest loads on the gudgeon (wrist) pins as the piston decelerates with little gas back pressure. A longer stroke increases those loads as does component weight.
Reducing rotating mass increases reliability and reduces parasitic losses. Areas we don't normally consider in our builds because we can get focused on "bigger is better" as our primary goal.
It's pretty cool that these 67.4mm stroke cranks are lighter than the older units we have AND they are also better balanced. Both factors are pluses in the build.
I think I am a little nervous about using a 3mm wall-thickness pin in a "heavy" piston with a longer stroke. If the Ross pins are made of better material than the standard Fiat part, then that nervousness will dissipate. I have no idea what material is used for the standard pins.
My pistons are 438 grams now, but will lose some grams with enlarging of the valve reliefs and probably skimming off the top to adjust the pop-up height. Increasing the stroke will put more stresses on the "new" components. Some more weight could be lost if I am game enough to take some material off the skirt under the pin axis.
Approaching TDC on the exhaust stroke puts the greatest loads on the gudgeon (wrist) pins as the piston decelerates with little gas back pressure. A longer stroke increases those loads as does component weight.
Reducing rotating mass increases reliability and reduces parasitic losses. Areas we don't normally consider in our builds because we can get focused on "bigger is better" as our primary goal.
It's pretty cool that these 67.4mm stroke cranks are lighter than the older units we have AND they are also better balanced. Both factors are pluses in the build.
rjplenter
True Classic
Progress today
Apart from a collection of parts that got washed and some of them painted, the block is machined, painted and ready to go...
My first pass at modifying the combustion chambers to de-shroud the inlet valves. Valves closed...
Valves opened...
And the guide plate I made to ensure all chambers are the same shape...
This side is for cylinders 2 & 4, the other for 1 & 3.
Apologies for the fuzzy pics, I think my camera is sick. :dead:
Back to it!!!
Cheers,
Rob
Apart from a collection of parts that got washed and some of them painted, the block is machined, painted and ready to go...
My first pass at modifying the combustion chambers to de-shroud the inlet valves. Valves closed...
Valves opened...
And the guide plate I made to ensure all chambers are the same shape...
This side is for cylinders 2 & 4, the other for 1 & 3.
Apologies for the fuzzy pics, I think my camera is sick. :dead:
Back to it!!!
Cheers,
Rob
rjplenter
True Classic
Lightweight gudgeon pins arrived today
Standard pin
Ross Racing pin
Using these pins will save 124 grams, that's over 1/4 pound in the old money. Well worth the price and cheaper than having the standard pins taper bored.
Inlet valves.
The polished valve on the right will flow better and not accumulate carbon as easily. The rough surface has been removed and the little lip formed by the seat surface has also been removed. Once the new seats are in and the seat surface on the valve head has been established they will be getting a three angle cut. Along with three angle cuts on the seats this will significantly increase flow.
These 39.5mm valves are 2 grams heavier than the standard valves. Utilising lash caps will reverse that and save 10 grams per valve assembly.
The head work continues...
Cheers,
Rob
Standard pin
Ross Racing pin
Using these pins will save 124 grams, that's over 1/4 pound in the old money. Well worth the price and cheaper than having the standard pins taper bored.
Inlet valves.
The polished valve on the right will flow better and not accumulate carbon as easily. The rough surface has been removed and the little lip formed by the seat surface has also been removed. Once the new seats are in and the seat surface on the valve head has been established they will be getting a three angle cut. Along with three angle cuts on the seats this will significantly increase flow.
These 39.5mm valves are 2 grams heavier than the standard valves. Utilising lash caps will reverse that and save 10 grams per valve assembly.
The head work continues...
Cheers,
Rob
johosjokers
Daily Driver
what are lash caps
And where can i get some?
And where can i get some?
rjplenter
True Classic
Lash caps
Two sources:
http://www.vickauto.com/newstore/index.php?main_page=product_info&products_id=2268
http://www.summitracing.com/parts/AFR-6609
Here's our piston/rings (87.0mm), rod, bearings, circlip and pin combined weight of 1124 grams:
I believe a stock 1500 rod with 86.4mm piston etc. weighs approximately 1180 grams.
Two sources:
http://www.vickauto.com/newstore/index.php?main_page=product_info&products_id=2268
http://www.summitracing.com/parts/AFR-6609
Here's our piston/rings (87.0mm), rod, bearings, circlip and pin combined weight of 1124 grams:
I believe a stock 1500 rod with 86.4mm piston etc. weighs approximately 1180 grams.
rjplenter
True Classic
CC'd combustion chambers
It was finally "warm" enough in the garage late this afternoon to get out do some more head work.
I CC'd the combustion chambers (post inlet valve deshrouding) and found they are 25.0cc (+/- 0.5cc) which would result in a compression ratio of approximately 12.3:1. That's too high!
I'll wait until our pistons have been flycut to suit bigger valves, measure their volume, then take more metal out of the head.
It was finally "warm" enough in the garage late this afternoon to get out do some more head work.
I CC'd the combustion chambers (post inlet valve deshrouding) and found they are 25.0cc (+/- 0.5cc) which would result in a compression ratio of approximately 12.3:1. That's too high!
I'll wait until our pistons have been flycut to suit bigger valves, measure their volume, then take more metal out of the head.
