1973.5 2.4 cis top end rebuild !

[gibran911]

Ordered rings from pelican two weeks ago as they were listed on the site.
Just found out from them that Porsche changed the part list #'s and now only sell them seperatly (each ring in a set of 3 per cylinder - individully)- so the price went from $230 to $540 for all 6 cylinders.
DEVES / PAECO Industries says that the can make a complete set (6 cylinders ) for about $160, but I need to send them a piston.

[gibran911]

Good news!
Picked up parts from machine works today and all is well.
Was able to locate rings through Total Seal in Phoenix and should receive them Monday.
Keeping my fingers crossed.
Anyone have a 1973.5 CIS system they are wanting to get rid of?
Need it for spare parts - "just in case"
Also interested in a CIS gas tank. - Need it while I repair mine.

[E Sully]

I hope the tank comes out well. Just another of those expensive and hard to get 6 month only items. So far it sounds like its coming together nicely. Could you either post the part # for the rings or pm it to me. I could only find rings for the non cis cars on the website.

[gibran911]

Do not have the part #.
Just call them and tell them what you need. The were able to locate the ring sizes from a 4CYL set that had the correct ring sizes (the odd 1.75) and split a second set to get the six I need.
They even went so far as to confirm the piston ring depth ad circumference (I had to measure) to be sure.
I should know by tuesday if they are correct and will post what I find out.

Thanks for your encouragement. I am looking into replacing the swirl pot lid. The tank is fine otherwise. Will take someone with the ability to open the tank and fab a new lid (have the old one in about 9 pieces to replicate). Maybe out of aluminum as the old one was plastic. Looks a lot like tupperware.
Know anyone?
I posted a while back regarding the tank as well as fuel distributor rebuilding.
Till then, I would like to buy a tank for temporary use.

[E Sully]

You might be able to use the later cis tank. They have the swirl pot. They will only hold the space saver spare. Maybe buy a leaking later tank to take the swirl pot out for yours. I don't know if aluminium would work. Their might be a reaction between the different metals. You could post a question about the fit on the Technical Forum.
Hope the engine is moving along smoothly.

[gibran911]

Received new rings from Total Seal.
Will be taking them to the machine shop to check on how they fit and will post there findings.
The cost was $167 shipped.

[E Sully]

How's it coming along? Any luck with the fuel tank.

[Desertpagoda]

Gibran,
I have a '73.5 T w/cis also. It runs sweet! Stop by the shop and check it out!
Keith Brooks

[tom1394racing]

I can provide a '73.5 CIS system and CIS tank should you need them

PM me if interested

Good news!

Picked up parts from machine works today and all is well.

Was able to locate rings through Total Seal in Phoenix and should receive them Monday.

Keeping my fingers crossed.

Anyone have a 1973.5 CIS system they are wanting to get rid of?

Need it for spare parts - "just in case"

Also interested in a CIS gas tank. - Need it while I repair mine.

[gibran911]

OK - So I took the rings I received from Total Seal to Machineworks and the situation is this....
the top ring is about 2 thousandths thinner then the one it will be replacing and so, is just out of spec. The Porsche guide the shop has states that there should be no more than 3 thousandth and with the new ring we come up with 3.3 thousands. I am referring to gap between the upper and lower surface of the ring landing with the ring mounted.

The compression ring comes out within spec - good news.
And lastly,the oil ring is also just out of spec. Again, gap just beyond spec.


I spoke with the sales rep at Total Seal and he stated that the have dyno'd engines with 10 thousands of gap with no noticeable effects and said that it would be fine to run what they sent me.

Just looking to hear what the experts think of this.

[911 tweaks]

not an expert by any means, BUT, out of spec = out of spec...!! Yeah it will work, but I would be willing to bet it will work for a significantly shorter life than a correctly spec'd ring...just my 2 cents here...me no use...
Lets see what the experts say...
Good luck...!! Bob

[E Sully]

I'm curious if the problem is with the rings or the ring grooves in the pistons. Were the ring grooves measured and within specifications, or is this just a problem with the new ring thickness?

[914/6]

I have a set of 6 NOS 73.5 CIS pistons , The cylinders were used for another project.
If anyone is interested LMK jeff

[E Sully]

Gibran911, how are you making out? I hope you are having some luck with the rebuild.

[gibran911]

Hi, remodeling the guest bathroom has kept me from my project of choice.

OK - So the rings from total seal did not fit correctly, they were somewhat thinner than the stock ones which came out of the car. the only ones that fit within spec were the middle compression rings (1.75) that are unique to the 73.5 cis car. I have kept these and will be ordering the remaining rings from porsche.
I beleave the rings I ned are the 911 t k and the part numbers for each ring thrue my local Porsche dealer are: top 911 103 348 00, Middle 911 103 358 00, bottom 911 103 355 02 and are $33-$37 each.
Can anyone verify the part numbers?

As an aside, the tech I spoke with said he could only locate 5 of the middle compression rings in the states, somewhere on the east coast in a warehouse.
visions of the ending to Indiana Jones fill my head.

Happy Holidays!

[gibran911]

Took a giant leap today and ordered the last 5 sets available of 1.75 middle rings 911 103 358 00, as well as the 5 upper 911 103 348 00 and 5 the lower 911 103 355 02 rings to go with the one OEM set of 911 103 94100 I was able to obtain on E-Bay.
Looks like I will be building in about 4 weeks.

[E Sully]

Good Luck. Let us know how it turns out.

[gibran911]

Finally received all the rings needed to rebuild the top end.
Will get going on this as time permits.
I am sure to need help from the gang here on pelican!

Gib

[E Sully]

Good to see you found them. The rest of the rebuild should go well now.

[gibran911]

Hi,
Anyone know the specs on 2.7s cam upgrade on the 2.4 cis engine?
Also, what are the benefits of this "upgrade" , effect on HP, compression, etc.
When rebuilding with these cams I assume that the specs for cam timing are the 2.7 cam specs, any adjustment?

Thanks,
Gib