The Tom Thatch Modification

[hanleyclifford]

This engineering idea has been rolling around in the brain for some time. Here is the change executed on my engine using a few items from the "possibles" bag. A more complete visual can be seen on my album.

[thatch]

"Wow"

Hanley,
I am flattered and humbled that you would tie this minor modification to me. I personally feel that the input from some seasoned pro's like you, N. Dutton, Dave Neptune, Latt 64 and many other contributors has done an imeasureable amount of good toward lengthening the life span of these unique engines. Shortly after buying an A4 powered sailboat a couple of years ago, and after doing some research, it became apparant that there was no suitable replacement engine (other than deisel) that would suit our needs nearly as well. I even went so far as to check things like "rod ratio" and "horsepower per cu.in." compared to other popular power plants, and soon realized why our little 30 H.P. gems were so prized. The patience and comradery displayed on this site is also a testament to the efforts by many toward the common goal of prolonging the legend of our "little beasties".
Thank's, Tom
P.S. Please forgive the ommision of mentioning the great photographic contributions by many and of course for the Moyer "family" for providing us with this gathering place.

[hanleyclifford]

For some of the original thinking on this idea go to the thread "another thought on coolant flow".

[lat 64]

Speaking of flattery

I'm just a hack. My base is in car stuff. The product of a mis-spent youth.
I'm really a new A-4 owner (10-2008). I have only one to show for my experience, but they have to run on the same physics—fire, air and Jurasic hi-test.
Also it's kinda cold and dark up here so I post a lot. You see, I'm just too much of a loose canon to have a Facebook page. Now that'd be bad for everybody

Keep thinkin' outside the box all,
Russ

[thatch]

"For what It's worth"

Russ,
I participate on one website, this one, because of the importance of the subject matter, (the A4) and because of the sincere, grass roots mentality of most of the participants. You're a perfect fit to the cause, so please don't underestimate your importance here.
Sincerely, Tom

[Baltimore Sailor]

I'm a bit confused. Could this mod be used on a raw water cooled engine as well? Or is it a design for FWC engines only?

[Dave Neptune]

?Dreamin'

Hanley, did you run and shoot with the I/R gun and notice any additional cooling at the "U" spot? Tom same inquiry to you also.
I have been wanting to turn mine around mostly because I check and clean out the manifold exit every year or two. It is just easier access at the front end.
I'd really like to know if anyone has played with a differant cam profile. I can't help but think (a personl weakness) that since so many of us are using the A-4's power at a much lower RPM range than it is rated for that a differant cam for the direct drives may have a bit of an advantage. Or perhaps has anyone tried to advance the existing cam a bit?

Dave Neptune

[hanleyclifford]

I'm a bit confused. Could this mod be used on a raw water cooled engine as well? Or is it a design for FWC engines only?

I think Dave is still running raw water, and he is considering the modification.

[hanleyclifford]

California Dreamin'

Dave - I love the way you west coast guys think. I guess you could advance the cam one tooth and see what happens. Or we could get Iskendarien to cook up (a re-grind?) something for us. I still dream about rollers on the mains and rods but I may be getting senile! Regards, Hanley

[Dave Neptune]

Teeth?

Baltimore, yes my A-4 is raw water cooled and going on it's 41st year.

Tom, I don't know how many teeth are on the A-4s cam drive assembly, actually can't remember. Going a whole tooth would be a bunch. Is either gear mounted ar are they all fixed? Perhaps Isky could regrind a stock cam to a lesser duration and have it open about 2~3 degrees sooner.

Over the years Isky has made a few custom cams for me and they worked great. There is a lot of knowledge in their shop to draw on. I still like the idea of a roller cam on a flathead. I know a few who have redone their 32 roadsters and pulled the SSB Chevy's out and put back in the flatheads with roller cams. Yes they did sacrafice a bit of power compared with the SSB Chevy but they lost a lot of weight in the total drive line~~ie smaller trans and rear ends. They look awesome with the Strombergs and polished Copper heads.

Dave Neptune

[ILikeRust]

For those of us just tuning in and having not a clue what the hell you guys are on about - could you expand a bit as to what the mod is and why it's a good thing?

And while you're at it, type slowly and use small words for us slow types.

[Baltimore Sailor]

Let me see if I can explain it right, so that I'll know if I have a grip on the concept.

Rather than take the outlet from the thermostat to the forward (next to the thermostat) inlet on the manifold, you run the line down to the aft fitting, then run an outlet from the forward fitting to the injection point. The thinking behind this mod is that the vast majority of A4s tilt toward the aft, so that cooling water introduced at the forward inlet just runs "downhill" to the aft inlet. By introducing the coolant at the rear of the manifold it's forced to fill "uphill" before it can exit to the muffler.

Is that right?

[hanleyclifford]

Exactly right.

[hanleyclifford]

I made an hour long test run today with the TTM in place and discovered something unexpected. Even though I have been FWC for many years and recently did a thorough cleaning of the manifold including removal of both freeze/expansion plugs, I noticed a significant amount of crud in the strainer as soon as I started up. The strainer had been almost clear. FWIW.

[sastanley]

Tom , there was a Kaminsky modification a while back that I think is now standard practice on the reversing gears from Moyer...why not have a modification to the cooling system called the "Thatch cooling modification" if it proves effective!?!?!

I just pulled some of my cooling lines today (still RWC for the moment) and the aft manifold area was nasty and clogged...even if you stay RWC, having this 'flushing' forward and not resting and settling in the aft end of the manifold seems an improvement to me.

It is backyard innovators bucking the standards that keep these motors running.

(psst. Lat64, I am only at Lat 38 and I don't have a Facebook either..it is a social engineering scam!!!!)