Polo motor build for junkyard coupe 58367

[JTR70]

Dedicated build thread for the new hot rod Polopolus 911 4-cylinder engine for my motorless Carrera coupe restoration.

To keep entries of this particular aspect of the build from getting lost in the shuffle with the body details I thought it best to begin a separate thread post. Will share all information, build details, plans and current progress. This may take a little while; being a regular guy I have to do this a dime at a time...


My brand new Polopolus casted engine block the day I got it home. What a beautiful work of art with so much potential!


No longer a cut and re-welded factory 911 engine block but a brand spanking new casting. Dean says this was almost 20 years in its development to find the right foundry and the metallurgists to create these pieces.


As of this entry a Basic kit from Dean which includes this block, a New crankshaft, a pair of cams and a shortend pair of 911 cam towers is just under 20K. It is then up to the owner to procure the stock 911 components to complete the engine. A turnkey motor from Dean of course goes up from there and also depends on how radical you wish to build it.

This engine:
I am of the opinion that there is no replacement for displacement so I told Dean I wanted to push the CC's up as far as we could while keeping good reliability. I want a "stump-puller" motor that makes its move at the lower RPM ranges.(that's were I like to drive) I do not like high-winding engines that make their peak HP above 5K RPM. Although I know they can operate fine in that range I personally don't like hanging out there. So for my taste and enjoyment I need this engine to make lots of HP under 5K RPM.
Displacement:
The Pistons and cylinders I bought were an incomplete set of 5 (perfect for my application) 102mm Mahle factory racing 3.8 RSR units in good used condition.

Big recessed pockets for some heavy-duty valves.

In keeping with my large displacement desire, this motor is going to come out at just under 2.7 liters These 102MM units along with an 80mm stroke crankshaft.


Cylinders show no wear or scoring. Not the Teflon coated piston skirts. I just love race parts! More later.. Thanks for reading this! Justin

[JTR70]

Cylinder heads:
I've said it before; I'm a sucker for old race parts! Since most of the HP gains are made in the heads I wanted the biggest and best set of "lungs" I could get my hands on for this motor. I was able to locate a partial set of 5 Factory 3.8 RSR sprint heads which correlated to the piston and cylinders purchased earlier. 3 units were fine but the second pair would need work.

Totally trick units! twin plug of course. Giant 54MM titanium intakes with 43MM titanium exhuasts. Super hard beryllium/copper valve seats. 100% smooth and sculpted ports. Note the ceramic coated exhaust ports. Can't really come up with a better performance head for this motor which is what I was after.
Direct comparison with an early 2 liter 911 head


Though at opposite ends of chamber and valve size spectrum they surprisingly both fit perfectly together on an early cam tower. Same basic casting which just became larger with time.

Intake ports

exhaust ports


This first bad head had a dinged up chamber and seat.
The other damaged one had a crack along the intake wall.

Walt from CE said he could definitely help so off they went.

Here's a progress shot Walt had sent me. New custom made Beryllium/copper seats going in. Notice he is wearing rubber gloves. I would bet he was also wearing a respirator too. While it makes the seats harder, beryllium is extremely corrosive and toxic to the human body. It poses more of an inhailation hazard when working with it but bare skin contact should be at a minimum. From what I gather it makes lead and mercury look like an essential mineral to the body.

I had purchased these heads complete with Titanium valves, springs, keepers and retainers. I was having Walt not only doing the repairs on the damaged heads but also a complete valve job on the rest so I'd have "bolt-on" ready heads once it was all over.

Walt soon informed me that every single valve I got with these heads was bent! Horrible news! What can I say; its old used racing equipment that has had a hard life. Buyer beware. I checked with several Porsche vendors about a new set. I was getting quotes in the 750.00-1,000.00 range. PER VALVE!!! Fortunately, I found a manufacturer that could duplicate them for me at a much more realistic price. Still not cheap but managable.

It was a company called Del West that saved the day. They are a manufacturing company that specialize in titanium racing engine components primarily in the Drag racing world. I just had to send them a sample valve and they handled the rest.

New Titanium exhaust valves the day they arrived. Stunning! They were like fine silverware sitting in that box! Only needed 4 of each but the job minimum was 8. Oh well, a spare set cant hurt. The intakes were soon to follow. I was going to be at around 2,300.00 for these new valves, not cheap but far more realistic than those Porsche vendors!

Several weeks later I had my new intakes. Just as beautiful as the exhaust only bigger.

Finally! A complete set of 4 intakes and 4 exhaust to send out to Walt. I would soon learn that this would not be my last hurdle. Thanks for reading this! Justin

[Craig Richter]

Justin,
Del West used to make me titanium 356 valves, 8mm stems, 42mm intakes, great stuff, almost indestructible, and really nice people to deal with. Luckily for me, their minimum was smaller back then...
Best, Craig

By the way, I am a big fan (and friend) of Dean and his motor. I used to kid him about who was going to buy this bitchin' motor he was spending so much time on. Luckily he had a lot more vision than me, and has sold them all over the world

[JTR70]

I could not agree with you more Craig. The guys at Del West were most courteous and helpful, not to mention the quality of the finished parts! I would most definitely do business with them again! Your right, Dean is a great guy and visionary! Justin

Once I sent the new valves off to CE I thought I was home free. A week later I get an email saying that the valve springs were now coil binding with the cam profile we chose and Walt stated that we needed to gain 2MM for proper clearance. He Could not mill the heads for this distance due to the radical porting; Not enough meat there.


Only option was custom made retainers with this 2M offset over stock. Comparison shot above. Stock on the right and new one on the left.

It was Del West to the rescue again with these new Titanium retainers with corrected 2mm offset over stock. They came out just a beautiful as the valves.

Again the job minimum was more than I needed so I have some spares. (above) This was the final glitch and Walt was finally able to assemble and finish this very lengthy job.

[JTR70]

After almost 2 years of expense, heartache, and replanning I finally had a set of four bolt-on ready heads for my Polo engine as of May 2012. Walt Watson at CE of course did not disappoint!! I wanted to thank him again for all of his patients and hard work that went into finally making this set happen. So thanks again Walt, you're the best!

Had just unpacked the last little box. It was Christmas in May.

All the custom ordered parts from Del West To complete these heads: A full set of new Titanium valves and retainers. The bill with them was 3,165.17 alone for those items.


These babies are gonna flow, even Walt made a comment on how well this engine should perform with these which helped relieve some of the sting. Note that wide open shot the Fuel/air will have at the back of that intake valve! (bottom right) Again final displacement of this motor is going to be just shy of 2.7 liters. Great stand-in powerplant for that old long lost 4-cam unit.

After coming so far I could not cheapen-out on the machine services. I had Walt resurface all the heads to matched height as well. We did the complete service.


Well, at long last there they are, 4 bolt-on ready units, it was painful though. Including core head purchase, custom titanium parts and machine service I'm into these heads $8,111.82 as pictured!!! No choice, I had to see them through. By the time I was made aware of all the problems it was too late to pull the plug and go another direction. New in the box versions of these heads go for about 15-20K for a set of six so I did not get completely upside down. I also had the luxury of spreading costs out over 2 years which made it possible on my budget. Anyway, the heads are Done!!

Here's a quick mock up photo I took just to help keep the motivation up. Thanks for reading this! Justin

[JTR70]

Cooling fan Accessories:
Will of course be running a stock 911 cooling and have acquired a few of the parts:

The yellow shroud is a mock-up loaner from Dean. I will have one made of clear fiberglass for an RSR look.

I had the fan housing powder coated a while back and the alternator rebuilt. I ordered that lightened mount strap for a racier look.

The coolest conversion piece for this build would be to retro-fit a 4-cam blower housing onto this motor. However to do this would require machining and modification to the top of the engine block. A lot of extra work and quite the added expense. I can't justify cost at this point and this would considerably add to the delay of this motors completion date.

This is Bill Sargents beautifully done replica 4-cam blower that is going on his push-rod 356 motor. This unit as pictured will set you back 10,000.00!!! A tremendous added expense for a cosmetic effect.

It would be cool looking though, maybe I'll do it as an after project once the dust settles. Another shortfall too is that I would be back to a generator versus an alternator. Its so easy to spend yourself into oblivion... Thanks for reading this! Justin

[Bill Sargent]

Hi Justin,

Ibrahim sold all of the first 50 units of his 4 cam cooling set up - about 30 went on real 4 cams, 14 on 356 pushrod motors and 6 on special Polo motor castings that Michael Doyle had made to accept the 4 cam cooling set up. Ibrahim is currently making another run and the cost, including the fan from Bob Garretson, is about $11,500. Not cheap, but it is the real deal. Ibrahim disassembled a factory shroud to make the tooling to reproduce it. Even the spot welds are in the same places. In addition to the unit in your photos, I did a deal thru Ibrahim and traded a reproduction shroud for a real shroud that had the correct duct and inner vanes to feed an Eberspacher B3 gas heater. Basically purchased a second unit and traded the shrouds. Thus my faux cam will have heat!

Drove the car from Seattle to Santa Fe and back for the west coast holiday. 3300 miles and a LOT of fun. Photo below was taken near Shiprock, NM on the way back. My friend, Ralfy, from Alaska flew down to the holiday and did the drive back with me. The tall 4th gear in the Skirmants built Trans was great - 3700 rpm at 80mph.


Regards,

Bill

[JTR70]

Hey Bill,

Thanks for the heads-up on that! WOW, I should have bought when they were cheaper. That is a great photo of your car and looks like it should be on the cover of a catalog! It sounds like you had an amazing trip; Any more photos?? Thanks for your reply! Justin

[JTR70]

11/27/13
Just dropped the case halves off at my buddy Bill's machine shop for a little milling to free up some extra Horsepower.

By foiling the edges on the back of these main bearing bosses for windage(the air being pushed back into the crankcase by the back of the piston on the down stroke) the Porsche factory claimed an increase of up to 10 additional Horsepower. Dean is not a big proponent of doing this but I figure if it helps with efficiency and creates just 5 extra HP, why the hell not.

Here is a photo my buddy Dave Liddle sent me of a case which has had its mains opened up and shaped for windage. Just a little my aero dynamic with the rounded corners versus the flat-blunt bosses on my case.

Here's Bill going over his plan of attack with me. It should be done in couple weeks once the new smaller diameter cutter he's ordered arrives. Thanks for looking! Justin

[Rad-Ride]

Hey Justin,
We clearance our VW motors like that also. My friend that builds our motors and transmissions raced VW's and shows us all the tricks he has learned over the years. They had a Dyno where he worked and confirmed to get some gains with this modification.

[JTR70]

Thanks for the confirmation Frank! Sounds like your motor will have all these tricks as well. Every little bit helps! The other trick Dave Liddle told me about was called "windowing" the bases of the cylinders to also allow for better internal air flow. The photo below shows an example of "windowing".

Stock on the left and a "windowed" unit on the right. The cylinder is designated to a specific position on the case. A marker is used to trace the cylinder overhang inside case and the section is trimmed away provided its not cut deeper than bottom piston ring at its max lowest stroke. I need to double check but I believe this is done to the lateral sections of the walls. Again every little bit helps and it all eventually adds up so I'll be having Bill help me with this as well.
Thanks for stopping by! Justin

[Tony G]

Justin,
I am REALLLLLY enjoying this post! I can't wait to see the parts in person.

[JTR70]

Thanks Tony, anytime! Your expertise is of course always welcomed.

1/25/14

Case halves cut for windage.

Bill finally knocked these out for me and I picked them up this afternoon. Note the numbers in magic marker; Bill asked what the displacement on this engine was going to be so I gave him the bore and stroke and he came up with the engine's size: 2,680CC or 165.35 Cubic inches.

Bill thought it best to stay conservative with the cuts as to not sacrifice integrity.

oil squirters were of course a limiting factor as to how far across he could mill.

these could of course been opened up a bit more in areas but they will at least flow better now. I may hand polish and round-off the sharp corners.

Bill has been a machinist for over 35 years and has seen it all; each time I met with him he was extremely complimentary to Dean and the quality of his engine cases. Both times he said that these were among the best cast pieces he has ever seen and were just beautiful! A true testament to the quality of Dean's offerings! Just about ready to send this motor off to Dean and finally get this thing built! Getting very excited about that prospect! Thanks for stopping by! Justin

[JTR70]

1/26/14
Spent a good hour hand shaping the edges of the first main boss.

Main goal was soften all the sharp corners and make the boss just a bit more slippery.

it began taking on a nice swoopy shape which I was liking.

You can see here a bit of overhanging material was left at the base of some of the bosses.

Filed away that excess then rounded and polished the area as well.

That's one, only 7 more to go. I figure I can do one per session to keep from getting burned out so maybe by this time next week. Thanks for stopping by! Justin

[JTR70]

1/29/14
One down one to go.

Finished up the last boss this afternoon.

Went the extra step and polished them.

The air should flow a little freer...

Begin the other side tomorrow. Thanks for looking! Justin