bypass vs no bypass

[abe]

Hey all,

I tried searching all over for a simple answer to a stupid question. First of all as you can see in my profile, i'm a 26 year old novice trying to rebuild a bugeye.

I saw that moss sells a stock probably rebuilt water pump that has a bypass hose inlet. I also saw that spritemania has a no bypass pump. My engine currently has a stock cylinder head with a bypass outlet to the water pump. the outlet is deteriorated and will need to be fixed. the questions are, do i need a bypass? what is better, bypass or no bypass? If no bypass, is there a way to plug the outlet from the cylinder head? If yes bypass, is there a way to repair the damaged outlet?

I would really appreciate some simple direction.

Thanks

Abe, Pomona,CA

 

[Glen_B]

The bypass is certainly helpful if your thermostat sticks. The fitting in the cylinder head was threaded in, and subsequently corroded into place for all time. It can be replaced by a good machine shop. They cut away the jagged remains, use a correct sized drill bit to remove most of the corroded threads and re-tap the threads in the head before replacing the fitting. Finding a relacement fitting can be fun.

Glen Byrns

 

[dklawson]

Hap Waldrop answered a thread during the past month or so about how to remove the bypass nipple from a cylinder head. See:
https://www.britishcarforum.com/bcforum/u...6768#Post396768

I've always thought you should keep what was on the car as built (if possible and not a safety issue). Were it me, I'd buy the pump with the bypass connection and I'd repair the cylinder head to use it.

I think Spritemania is another web entrance to the MiniMania site. If you are ordering the pump from them you may want to consider the high-flow pump. Some modification is required for small bore blocks. Regardless of whether you use the standard or high-flow pump... if you retain the bypass, don't use the accordion repair hose between the pump and head. Use a piece of 1/2" quality heater hose as it will last much longer.

 

[abe]

okay thanks guys. I think i'm going to try to get it out. If i lose the patience then i'll take it to a machine shop to have it removed and replaced. It seems the racer guys remove it but since my car isn't a racer with a small engine, i think i'll stick with it.

any other suggestions will be helpful.
thanks again
abe

 

[aeronca65t]

Yes...just backing up your decision here:

Race cars don't normally use a thermostat (they use a blanking plate that is sort of a flow resistor...just a simple disk with a hole in it).
No risk of having thermostat stick with a blanking plate.
Since street cars have thermostat, the bypass is important (if the thermostat sticks).

 

[abe]

okay. so I need to find a machine shop to do the work for me because i don't think i'm going to get the nipple on the cylinder head off. What type of materials do you guys suggest for the new nipple? What will last longer? DKL mentioned 1/2" heater hose instead of the accordian rubber hose and brass for the nipple. Any other suggestions?

thanks again!
abe

 

[GB1]

Abe:

I definately would go with heater hose vs. the accordian.

The only time that I would use the accordian is when I forget to put the hose on before bolting everything up (doh), but even then I think that I have managed to squeeze one in there.

Pat

 

[dklawson]

Abe and others, it always surprises me when unique questions show up at multiple places at the same time.

Please see:
https://www.minimania.com/web/threadid/89923/InfoID/1/SiteMessages/5/msgthread.cfm
for a discussion related to this.

 

[abe]

Thanks DKL for the personal message and link. I read through the minimania thread and saw the brass mentioned. It sounds like the best way to retap as it will not rust. There was another link provided to minimania's longer bypass. Do you know if that replacement is brass? I was also weighing the thought of cancelling the whole thing and risk running the car too cold. I'm really exploring all the options for this small thing but I'm not really there yet. I'm dismantling certain components of the engine to have it stripped and painted. At every step of the way, if i run into something that may be a problem, I do research to get an idea of whats to come.

See the progress of the engine through a few photos in my photobucket.

https://s263.photobucket.com/albums/ii155/abetellez/1958%20Austin%20Healey%20Sprite%20Bugeye/

I also don't know what water pump to get and what will fit my 948cc. In extent I also have the alternator conversion in mind while the engine is out. So the question is now should i cancel the bypass with a sleeve or not?

abe

 

[dklawson]

Hi Abe,

On the "other" board, Kevin (the guy who mentioned brass bypass nipples) makes his own. Kevin has a small lathe at home copied an old nipple to make his own. I'm not sure what is available new from Mini Mania or other sources.

If you decide not to use the bypass, go back to the other thread I provided the link to in my first post. In that thread Hap Waldrop talks about what they do on race engines when they don't use the bypass.

According to the product description, the high-flow water pump will fit the small bore block with some modification. However, the standard pump will probably be just fine. I defer to the Bugeye owners. My preference is to use pumps with cast impellers instead of formed sheet metal ones.

That's an interesting looking oil feed line you have there and I've never seen a spin-on filter mounted that way on an older A-series. Is that the sandwich plate spin on converter?

 

[abe]

Just got back from a trip to nor cal where i had no internet access. I went to see, Mr.Byrns and his turbocharged BE in Davis while i was up there. The filter system is a spin on conversion kit that moss sells. Its basically a adapter plate. the return hose was actually a bit of a pain to put on because its just the right size.

Thanks for the info. I now have a spare cylinder head that i need to get checked for cracks. If all is good on this head, i can rebuild it with the brass component and new rockers, lifters and the whole thing. we'll see what the magnaflux test says... /bcforum/images/%%GRAEMLIN_URL%%/grin.gif

abe