First of the Texas Twins, First Build Options

[Puebloswatcop]

MIght consider asking around for another fan. That one appears to be missing a fin.

Thanks for pointing that out Aaron. I looked back at my pics and realized I posted the wrong fan in the pre-loaded stage...I did discard that fan for another and it does have all of the fins.

Meanwhile I wanted to get the cooling fan installed so it didn't get damaged sitting around the garage.

The first photo shows how bad it looked prior to disassembling it, blasting it, having the belt ring powder coated. Etc. Before disassembly I indexed the fan in orientation to the ring, with an index dot where the balance weight was installed in the belt ring. Since these came balanced from the factory, I believed this was the only way I could come back with as close to being balanced in the end.

[Puebloswatcop]

Hmm, have you read all the pros and cons on venting the heads? After buying mine from Len Hoffman, he explained his position firmly: no vents.

So Bob, I guess my question is if you don't vent the heads, how do you vent bypass gasses so they don't build up in the engine case? Did, Len give you any insight? I can always plug the hole(s) since they are threaded. My concern is the pressure building in the engine case would lead to oil leakage...etc.

Any 914 with L-Jet didn't have vents in the heads. The crankcase was vented to the intake hose, and that was on the downstream side of the air flow meter. Any blowby was pulled into the intake and burned.

IIRC... the late 2.0 engines didn't have head vents either.

Clay, thanks for the input. So if I am not using LJet and the engine is carbureted, what is the best way to proceed?

[bkrantz]

Hmm, have you read all the pros and cons on venting the heads? After buying mine from Len Hoffman, he explained his position firmly: no vents.

So Bob, I guess my question is if you don't vent the heads, how do you vent bypass gasses so they don't build up in the engine case? Did, Len give you any insight? I can always plug the hole(s) since they are threaded. My concern is the pressure building in the engine case would lead to oil leakage...etc.

Here is the page about venting Type 4 motors on Len's website. As I understand, forcing any excess air pressure inside the valve covers to exit into the case via the push rod tubes helps to flush oil back into the case. And the case will vent through the top breather, with or without a PCV. BTW, I omitted the PCV but then routed the vent hose to a catch can.

https://newsite.hamheads.com/2016/12/10/typ...tests-analysis/

[ClayPerrine]

Hmm, have you read all the pros and cons on venting the heads? After buying mine from Len Hoffman, he explained his position firmly: no vents.

So Bob, I guess my question is if you don't vent the heads, how do you vent bypass gasses so they don't build up in the engine case? Did, Len give you any insight? I can always plug the hole(s) since they are threaded. My concern is the pressure building in the engine case would lead to oil leakage...etc.

Any 914 with L-Jet didn't have vents in the heads. The crankcase was vented to the intake hose, and that was on the downstream side of the air flow meter. Any blowby was pulled into the intake and burned.

IIRC... the late 2.0 engines didn't have head vents either.

Clay, thanks for the input. So if I am not using LJet and the engine is carbureted, what is the best way to proceed?

I would route both head vents and the pcv valve to a puke box. Something like https://www.cbperformance.com/product-p/1754.htm

Also, If you want to replace the fan with the broken fin, I have a few laying around.

[Puebloswatcop]

Hmm, have you read all the pros and cons on venting the heads? After buying mine from Len Hoffman, he explained his position firmly: no vents.

So Bob, I guess my question is if you don't vent the heads, how do you vent bypass gasses so they don't build up in the engine case? Did, Len give you any insight? I can always plug the hole(s) since they are threaded. My concern is the pressure building in the engine case would lead to oil leakage...etc.

Any 914 with L-Jet didn't have vents in the heads. The crankcase was vented to the intake hose, and that was on the downstream side of the air flow meter. Any blowby was pulled into the intake and burned.

IIRC... the late 2.0 engines didn't have head vents either.

Clay, thanks for the input. So if I am not using LJet and the engine is carbureted, what is the best way to proceed?

I would route both head vents and the pcv valve to a puke box. Something like https://www.cbperformance.com/product-p/1754.htm

Also, If you want to replace the fan with the broken fin, I have a few laying around.

Thanks Clay, that was my plan was to run the lines to a oil can and to the PCV. This is what I do with my regular engines, so I assumed it would work on an air-cooled engine as well.

As for the fan I will be needing a replacement, so let me know how much you would want and we can either arrange shipping or I can pick it up next time I am up your way.. thanks.

[ClayPerrine]

As for the fan I will be needing a replacement, so let me know how much you would want and we can either arrange shipping or I can pick it up next time I am up your way.. thanks.

I have plenty of spare fans, so come get some of the mass out of my garage. (IMG:style_emoticons/default/biggrin.gif)

[Puebloswatcop]

Hmm, have you read all the pros and cons on venting the heads? After buying mine from Len Hoffman, he explained his position firmly: no vents.

So Bob, I guess my question is if you don't vent the heads, how do you vent bypass gasses so they don't build up in the engine case? Did, Len give you any insight? I can always plug the hole(s) since they are threaded. My concern is the pressure building in the engine case would lead to oil leakage...etc.

Here is the page about venting Type 4 motors on Len's website. As I understand, forcing any excess air pressure inside the valve covers to exit into the case via the push rod tubes helps to flush oil back into the case. And the case will vent through the top breather, with or without a PCV. BTW, I omitted the PCV but then routed the vent hose to a catch can.

https://newsite.hamheads.com/2016/12/10/typ...tests-analysis/

Thanks Bob. Very interesting reading. I think I may just plug the vent hole I just did and try it without the venting...If I decide I want to vent the heads, I can always remove the plugs and install the nipples, and reroute any hoses......

[bkrantz]

Hmm, have you read all the pros and cons on venting the heads? After buying mine from Len Hoffman, he explained his position firmly: no vents.

So Bob, I guess my question is if you don't vent the heads, how do you vent bypass gasses so they don't build up in the engine case? Did, Len give you any insight? I can always plug the hole(s) since they are threaded. My concern is the pressure building in the engine case would lead to oil leakage...etc.

Here is the page about venting Type 4 motors on Len's website. As I understand, forcing any excess air pressure inside the valve covers to exit into the case via the push rod tubes helps to flush oil back into the case. And the case will vent through the top breather, with or without a PCV. BTW, I omitted the PCV but then routed the vent hose to a catch can.

https://newsite.hamheads.com/2016/12/10/typ...tests-analysis/

Thanks Bob. Very interesting reading. I think I may just plug the vent hole I just did and try it without the venting...If I decide I want to vent the heads, I can always remove the plugs and install the nipples, and reroute any hoses......

Len's heads have threaded holes, and shipped with both hose fittings and plugs. Initially I planned to use vent hoses but then Len convinced me to try them plugged. So far, with running on the street and during my session on the dyno I have not noticed any problems.

[Puebloswatcop]

Hmm, have you read all the pros and cons on venting the heads? After buying mine from Len Hoffman, he explained his position firmly: no vents.

So Bob, I guess my question is if you don't vent the heads, how do you vent bypass gasses so they don't build up in the engine case? Did, Len give you any insight? I can always plug the hole(s) since they are threaded. My concern is the pressure building in the engine case would lead to oil leakage...etc.

Here is the page about venting Type 4 motors on Len's website. As I understand, forcing any excess air pressure inside the valve covers to exit into the case via the push rod tubes helps to flush oil back into the case. And the case will vent through the top breather, with or without a PCV. BTW, I omitted the PCV but then routed the vent hose to a catch can.

https://newsite.hamheads.com/2016/12/10/typ...tests-analysis/

Thanks Bob. Very interesting reading. I think I may just plug the vent hole I just did and try it without the venting...If I decide I want to vent the heads, I can always remove the plugs and install the nipples, and reroute any hoses......

Len's heads have threaded holes, and shipped with both hose fittings and plugs. Initially I planned to use vent hoses but then Len convinced me to try them plugged. So far, with running on the street and during my session on the dyno I have not noticed any problems.

Thanks Bob. I think I will tap the vent into the other head at this point, but plug them and try running them without the hoses....I can always change it to breather hoses later if there is a need.

[Puebloswatcop]

So after drilling and tapping the heads for threaded fittings to vent the heads, I got allot of feedback. Pros and Cons of venting. Thanks to all who provided input. Thanks Bob for sending the link to Len Hoffmans printed research article. After researching this I have decided to plug the heads and go un-vented for now. The good thing is, if I discover this to be a problem area, I can always uncrew the plugs, screw in the fittings and change things in about 5 minutes....

[Puebloswatcop]

Finally had some time to work on the engine this weekend. Got all of the new parts needed to install the flywheel. Since the crankshaft had been reworked, the spacer had been removed. Not sure if I did it or the machine shop did, but it was missing, so I grabbed one from one of my spare crankshafts. In the second pic you can see that the spacer is missing.

[Puebloswatcop]

Spacer installed and then the rear main seal...

[Puebloswatcop]

Then I needed to install the o-ring and pilot bearing into the flywheel. After installing the O ring, I lubed it with assembly lube. I believe it will hold up better than oil while the engine waits to be run in.

Since I didn't have a press available I improvised with a bolt, nut and two washers. The bearing came un-lubricated, so first I packed it with very high temp grease. Then ligned it up and using the bolt pulled it into place.

[ClayPerrine]

Did you check the crankshaft end play? The shims between the flywheel and the case determine the end play.

[Puebloswatcop]

After lubricating the rear main seal (using assebly lube) it was time to mate the flywheel to the crankshaft. After alligning the flywheel I used the bolts and the old ring to pull it into place. After removing the old mounting ring, I put in the oil soaked wool seal in place and installed the new mounting ring and torqued the flywheel in place.

[Puebloswatcop]

After the flywheel was in place I checked the valve adjustment one more time and then installed the engine tin. I decided to go with stainless low profile socket cap screws to attach the tin. While its not original, I believe that it will be easier to remove should the need arise, and I think it looks a bit more modern too.

[Puebloswatcop]

After installing the engine tin, I went to re-install the distributor. It would not go back in because it interfered with the tin. I realized I had the distributor installed 180 degrees out. So after re-installing the distributor drive and re-orienting the distributor, it all ligned up perfectly.

[ClayPerrine]

After installing the engine tin, I went to re-install the distributor. It would not go back in because it interfered with the tin. I realized I had the distributor installed 180 degrees out. So after re-installing the distributor drive and re-orienting the distributor, it all ligned up perfectly.

That's not a stock distributor. What is it?

[Puebloswatcop]

After installing the engine tin, I went to re-install the distributor. It would not go back in because it interfered with the tin. I realized I had the distributor installed 180 degrees out. So after re-installing the distributor drive and re-orienting the distributor, it all ligned up perfectly.

That's not a stock distributor. What is it?

It's just a mock up distributor. The plan is to install a 123 distributor so I can tune it via blue tooth

[ClayPerrine]

Did you check the flywheel end play?