ISS Piston/Cylinders?????

356 Porsche-related discussions and questions.
Message
Author
User avatar
Ben Sherman
356 Fan
Posts: 118
Joined: Sun Mar 30, 2008 5:17 pm

ISS Piston/Cylinders?????

#1 Post by Ben Sherman »

I just recently installed a set of Biral Cylinder ISS Piston/Cylinders. New. Now I am experiencing some over heating issues. For you younger guys, ISS was a pre cursor to NPR when they came out in the 1980's. NPR offered a cast iron cylinder where as ISS did not in the 1720cc kits. Anyway, I took these off the deep shelf and used them. My question is has anybody had any heating issues with these? Would it be recommended to switch to double flapper heating boxes ?
Thanks
Ben Sherman

User avatar
David Jones
Classifieds Moderator
Posts: 7323
Joined: Tue Mar 25, 2008 6:32 pm
Tag: I wish I knew as much as I think I know.
Location: Kentucky

Re: ISS Piston/Cylinders?????

#2 Post by David Jones »

Not enough info Ben. What car, single/double grill? late or early fan shroud? 16 or 18 blade fan? Carbs? CR?, timing? camshaft? heads? Oil overheating or cylinder heads? How did you check the temp? what kind of driving and for how long?
If I had known I would live this long I would have pushed the envelope a little harder.
Cymru am byth
David Jones #9715

User avatar
Ben Sherman
356 Fan
Posts: 118
Joined: Sun Mar 30, 2008 5:17 pm

Re: ISS Piston/Cylinders?????

#3 Post by Ben Sherman »

David
Sorry about that: basically ‘59 A engine, New overhaul using ISS PC’s, john Jenks rebuilt BR18 distributer with 32*total advance, SC fan impeller, New Aluminium oil cooler, single flap heater boxes, rebuilt ZN carbs running jets to make it rich. On assembly, crank was rotated while case bolt torqued . Free as a bird. Same on 912 rods. Engine has 200 miles with excellent oil pressure of 55psi at start up. Unfortunately, engine runs hot- 250* with rpms Never exceeding 3500 rpm. Last thing I did to help rectify problem was to install the aluminium oil cooler which oddly seem to make it worse!
In my estimation it either has to do with the ISS biral- steel sleeved PC’s or the Aluminium oil cooler. Just looking for advice on the ISS (they haven’t been made for a long time), or maybe even the Al oil cooler ( this is the first one I’ve installed
Sorry for the long winded fill in
Benj

User avatar
David Jones
Classifieds Moderator
Posts: 7323
Joined: Tue Mar 25, 2008 6:32 pm
Tag: I wish I knew as much as I think I know.
Location: Kentucky

Re: ISS Piston/Cylinders?????

#4 Post by David Jones »

Ben, just my opinion but 250*F with an ambient of say 85*F would not be too hot. Hot yes but not too hot. Before doing any mechanical work I would first try advancing the timing to 35 *BTDC. Typically retarded timing will give a slight increase in running temps and too far will really make it run hot. After putting about 1K miles on the engine and if it is still in your estimation running hot you could try switching to a synthetic oil, maybe a 10/30 which will flow a little better through the system while giving you a much better coefficient of heat transfer. Whenever I have switched an air-cooled engine to synthetic I have seen at least a 10 *F drop in oil temp.
I see no reason why your biral cylinders would make it run hotter and likewise the al cooler though I confess I have no experience with biral cylinders. Theoretically the al cooler should help for sure.
You could also leave the engine lid cracked open on a run and see if that helps and also check for air leaks or recirculating air from around the muffler back into the engine bay as well as making sure the flaps on the heater boxes are fully open.
Hope you can find the solution soon so you can enjoy the car through the summer.
In passing I should comment that I have a big bore kit on 2 of my engines but not the 59 cabrio which is a stock normal and none of them run hot and they are all running 87 octane gas. I have seen 250*F but only on days over 85*F and as soon as I back off the throttle and go back to cruising even at 3500 the temps drop back.
If I had known I would live this long I would have pushed the envelope a little harder.
Cymru am byth
David Jones #9715

User avatar
Ben Sherman
356 Fan
Posts: 118
Joined: Sun Mar 30, 2008 5:17 pm

Re: ISS Piston/Cylinders?????

#5 Post by Ben Sherman »

Thanks Dave, you have always provided cogent replies to technical questions.. I have tried changing oil grades, cracking the engine hood, and even removing the rear eng tray on cool days (70*). Even today of barely 80*, and light driving, below 3500 rpm, the temp got up to 280*! No, there is no rag or obstruction covering the air inlet to the engine. Suddenly, after changing to ISS pistons& an Aluminium oil filter, things went from bad to worse!! It’t Got to be something with the new PC’s or the new Oil cooler?
I have OH some 20 engines, with few problems ( I am still learning &will never stop learning), so I am open for new approaches from so many of you who are better than I . I am just baffled with this one and certainly appreciate sage advice???

User avatar
David Jones
Classifieds Moderator
Posts: 7323
Joined: Tue Mar 25, 2008 6:32 pm
Tag: I wish I knew as much as I think I know.
Location: Kentucky

Re: ISS Piston/Cylinders?????

#6 Post by David Jones »

Ben, you did not mention ignition timing change. Have you tried running at 35 * advance at 3000 rpm? I believe from personal experience that 32 is just not enough advance.
Oil grades may not do it but as I said one of the advantages of synthetic oil is it's better coefficient of heat transfer both in picking up heat and discarding it. $25 worth of synthetic is cheaper and easier than switching oil coolers.
I guess the easiest thing to try other than that and timing is to switch out oil coolers but that is not easy other than comparing it to changing cylinders. Logically the same amount of heat is generated no matter what P&C's you use so oil cooler seems the obvious culprit.
If I had known I would live this long I would have pushed the envelope a little harder.
Cymru am byth
David Jones #9715

User avatar
David Baugh
356 Fan
Posts: 673
Joined: Thu Mar 05, 2009 9:29 pm
Location: Daytona Beach, FL

Re: ISS Piston/Cylinders?????

#7 Post by David Baugh »

Hi, Ben.

I've been running an AA biral 1720 kit and aluminum oil cooler in my '58 normal with a Neutek SC cam and 912 rods for nearly 10 yrs with no overheating issues. I do see readings in the 250* range on the hottest Florida summer days, but oil pressure never drops below 50 psi at 3000 rpm and 15 - 20 psi at idle. The larger displacement will cause your engine to run hotter. I'm using Mobil 1 oil, 15w50. Oil pressure cold is 55 and 40psi at 3000 rpm and idle.

Dave
When in doubt .... Gas it! 
'58 356A Coupe

Dick Weiss
356 Fan
Posts: 4181
Joined: Sun Apr 20, 2008 12:54 am

Re: ISS Piston/Cylinders?????

#8 Post by Dick Weiss »

Ben,

Changing to hi-compression P/Cs on an engine w/the small oil pump will tend to 'heat up'. Was the oil pump assembly rebuilt to specs?
Was the oil pressure checked w/a wet gauge replacing the pressure switch? Which carbs exist and tuned/jetted properly?
You may back off the timing a few degrees if that helps, but having an aluminum oil cooler won't make a lotta difference unless the fan shroud has the volute ring air entry.

Dick

User avatar
David Baugh
356 Fan
Posts: 673
Joined: Thu Mar 05, 2009 9:29 pm
Location: Daytona Beach, FL

Re: ISS Piston/Cylinders?????

#9 Post by David Baugh »

I should also mention that I installed a later third piece with the large oil pump and new gears. At the same time, I equipped it with a Premat remote full flow oil filter adapter.

Dave
When in doubt .... Gas it! 
'58 356A Coupe

User avatar
Neil Bardsley
356 Fan
Posts: 1099
Joined: Tue Mar 20, 2012 10:21 am
Location: London

Re: ISS Piston/Cylinders?????

#10 Post by Neil Bardsley »

May I ask how you are measuring the temp of the oil? I'm not sure how much I trust the 6v sender/temp gauges in our cars. If the temp high after sustained running of the engine. Does it drop after running at lower revs for a well.

User avatar
Ben Sherman
356 Fan
Posts: 118
Joined: Sun Mar 30, 2008 5:17 pm

Re: ISS Piston/Cylinders?????

#11 Post by Ben Sherman »

Dick
That may be what I am experiencing. Since it is an A engine, it does not have the Volute fan configuration. My problem was that after I installed the Aluminium unit, the proble seemed to get worse. It acts like there is a partial obstruction as it more readily gets up to 280* after only 15-20 of causual driving. How do you check the cooler for a partial obstruction? I see where Stoddard actually offers a seal kit for use on only A engine’s and for their own Aluminium cooler(although it looks a lot like the Sierra Madre unit which is $200 cheaper! I ordered my cooler off eBay from a “original equipment manufacturer”. But, by appearance alone, it looks shabby in comparison to either
Stoddard’s or SMC’s
All temperature measurements are taken with a Fluke infra red unit aimed at the temperature sender cluster.
Ben

User avatar
David Baugh
356 Fan
Posts: 673
Joined: Thu Mar 05, 2009 9:29 pm
Location: Daytona Beach, FL

Re: ISS Piston/Cylinders?????

#12 Post by David Baugh »

Ben, which oil bypass booster line does your engine have? Is it internal or external? If that system is not working properly, the oil may be bypassing the oil cooler.

My oil cooler is from Stoddard. Oil temp is read from my dipstick thermometer after a spirited drive, and the dash gauge never exceeds the midpoint.

Dave
When in doubt .... Gas it! 
'58 356A Coupe

User avatar
Ben Sherman
356 Fan
Posts: 118
Joined: Sun Mar 30, 2008 5:17 pm

Re: ISS Piston/Cylinders?????

#13 Post by Ben Sherman »

The Final Results are in,
I could not increase my distributer advance beyond 32* because when I had it rebuilt, the builder advised me to max it at 32* considering todays gas. So couldn't try that one. I bought an oil cooler off of ebay thinking that there was only one manufacturer. The ebay add read "From an original equipment Manufacturer" So I bought it and installed it. (see picture comparison). I couldn't believe it when I experienced very little change and at one point it was actually much worse when I tried to climb the crest of the mountain at 7000', but had to shut it down half way up on that try because the temp had already gotten to 285*. Tim Berarrdeli informed me that the heater I had bought was the old fashion design of years ago and Stoddard, SMC, and Jaques LeFriant sell much better ones now. Old design had many flaws. I have to admit to an amateur overbite here which leaves me red faced but didactic for others. When I tried my last trick of installing a heater box of double flappers, and after I had dropped the engine to switch out the single flappers for double flappers, I found a piece of paper towel covering the wire fan grate in the back of the fan housing! !At one point, after I had installed the Aluminum oil cooler, I had removed the Zenith carbs to change to richer jets, and I had used a paper towel to catch the gas when I disconnected the fuel line. Well,removing that helped explain the sudden temp spike
What helped the most was adding double flap heater boxes. I didn't notice any difference driving around town- 180*, but going up the 6 mile hill to 7000' the temp only got to 240 - not 285*!
What I learned:
Small oil pump engines are going to run hotter at hight altitudes mainly because the lesser oil volume doesn't move oil through the oil cooler as fast as the 36mm pump.
Large pump engines run cooler because the higher volumes can take advantage of Volute fan housing allowing increased ambient air volume, and consequently they also need double flapper to evacuate increased air.
additionally they can take advantage of the properties of newer Aluminum oil coolers: surface area and temperature conductivity
ISS Biral 1720 cylinders DO NOT significantly impact thermal output and thus higher operating temps

Many thanks to people that helped me figure this high altitude running problem and Tim Berarrdeli Racing and Steve Proctor for actually calling me. You guys are what makes 356's a great,
indurring, and endearing organization
Many thanks
Ben Sherman
'59 Cabriolet

Dick Weiss
356 Fan
Posts: 4181
Joined: Sun Apr 20, 2008 12:54 am

Re: ISS Piston/Cylinders?????

#14 Post by Dick Weiss »

Hi Ben,

There are several different versions of steel and aluminum oil coolers existing; I have a cooler w/a double stack of
8-vertical tubes for total of 16. Then the later steel coolers have the common 6-vertical tubes, but here come the aluminum coolers having 5-vertical tubes (never got an answer which tubes are inlets or outlets), and just received a 4-vertical tube cooler!

Only the later steel and aluminum coolers have the hi-mesh between the tubes for more surface area, BUT they'll get clogged easier if any oil leaks or mist (including dirt/dust) from the fan's airflow.

And finally, never run the engine w/o the rear cover (over the muffler) having the single-flapper boxes; The hot exhaust air tends to bounce off the muffler and the fan will catch some of it--that's why the shield plate is added between the flapper boxes (to protect the oil pump) and not really required if double flapper boxes exist which 'downdrafts' the hot
air--the Euro system doesn't use or need it.

Dick

User avatar
Ben Sherman
356 Fan
Posts: 118
Joined: Sun Mar 30, 2008 5:17 pm

Re: ISS Piston/Cylinders?????

#15 Post by Ben Sherman »

Dick
Here is a picture of my very early oil cooler that was made by an "original equip manufacturer" You can see it only has 5 columns and the over all length of the cooling fins is noticeably less than a Factory steel unit. Quid Pro Quo
Image-1.jpg
As far as the rear tray issue, I didn't know that it had a direct impact on engine operating temps in a single flap heater box. My experience has always been with double flap systems and thus weren't part of my consideration. Very Cogent point though. The rear tray was in place on my final run, so maybe that was the reason for the 40* difference?????
A engines in their entirety are certainly a different sort of animal and you and your long experience would certainly know this.
By the way, I first met you at the PCA event in Aspen, Colorado. Fortunately for all of us at the event we had somebody like you who spent most of your time helping some poor guy from Michigan who's trans failed to work at the event. You selflessly donated your expertise in fixing his serous problem. Kudo's to you.
Ben

Post Reply