H50 big block

[copyman]

Hi, I had a few questions about this H50 big block I picked up (see pics). The person told me block was designed for go cart racing. It's from the 1990's TEC motor sports division.
Also told me many old H50 parts that I have will fit which is why I bought it. Already put old H50 crank, valves, etc etc and they all fit fine. Bore is same at 2.625 Only differences I see are 4 bolt holes on one side, not sure what their for??? and posts on FW side for solid state ignition. And most obvious is block isn't aluminium like old H50's.

Here are my questions:

Can I use a conventional carb instead of diaphragm type shown on parts diagram?

Can I use internal ignition with points & condenser or do I have to use those posts for external solid state??

Can I add governor to this block? (there is a hole on top and stud inside sump cover for gov parts but didn't come with gov because racing engines don't use)

That's all I can think of now may have some more questions later.

Any other info appreciated?

Thanks for the help

 

[mustangfrank]

Hi, I had a few questions about this H50 big block I picked up (see pics). The person told me block was designed for go cart racing. It's from the 1990's TEC motor sports division.
Also told me many old H50 parts that I have will fit which is why I bought it. Already put old H50 crank, valves, etc etc and they all fit fine. Bore is same at 2.625 Only differences I see are 4 bolt holes on one side, not sure what their for??? and posts on FW side for solid state ignition. And most obvious is block isn't aluminium like old H50's.

Here are my questions:

Can I use a conventional carb instead of diaphragm type shown on parts diagram?

Can I use internal ignition with points & condenser or do I have to use those posts for external solid state??

Can I add governor to this block? (there is a hole on top and stud inside sump cover for gov parts but didn't come with gov because racing engines don't use)

That's all I can think of now may have some more questions later.

Any other info appreciated?

Thanks for the help

The engine package was designed for racing...the block is standard late H50.

To answer your questions: Yes, Yes (but why?) and Yes

They had a billet rod, modded H60 (stroker) crank and used a Tillotson carb but what you have is essentially a service block, usable for points or solid state ignitions with appropriate crank. Search Motorsports H50, it's been discussed pretty thoroughly.

 

[copyman]

The engine package was designed for racing...the block is standard late H50.

To answer your questions: Yes, Yes (but why?) and Yes

They had a billet rod, modded H60 (stroker) crank and used a Tillotson carb but what you have is essentially a service block, usable for points or solid state ignitions with appropriate crank. Search Motorsports H50, it's been discussed pretty thoroughly.

Thanks for the reply and will search the forum about the Motorsports engine.

You asked why? As I mentioned in my orig post I have a lot of New H50 extra parts that were left over from several old H50 rebuilds (see rebuilt H50 in one pic) Have parts like the carb, cyl head, crank with tapered end, valves, tappets, breather parts, magneto, points & condenser, etc etc. So just to be clear ALL these old H50 parts can be installed?

By the way any idea what those 4 threaded holes are for on side near oil fill hole? Holes not on old H50.

Thanks again

 

[mustangfrank]

Thanks for the reply and will search the forum about the Motorsports engine.

You asked why? As I mentioned in my orig post I have a lot of New H50 extra parts that were left over from several old H50 rebuilds (see rebuilt H50 in one pic) Have parts like the carb, cyl head, crank with tapered end, valves, tappets, breather parts, magneto, points & condenser, etc etc. So just to be clear ALL these old H50 parts can be installed?

By the way any idea what those 4 threaded holes are for on side near oil fill hole? Holes not on old H50.

Thanks again

That would be one use for a replacement block, yes. Just a waste in my opinion, going back to the dark ages of points versus 90s dependability and electronics, especially if you're using used parts in a new block.
Side cover is a "K" part number, ball bearing with accessory mount holes, again mid 70s and up engines all have these for TAV, cover, etc. mounting.

 

[copyman]

That would be one use for a replacement block, yes. Just a waste in my opinion, going back to the dark ages of points versus 90s dependability and electronics, especially if you're using used parts in a new block.
Side cover is a "K" part number, ball bearing with accessory mount holes, again mid 70s and up engines all have these for TAV, cover, etc. mounting.

Advice well taken. Will most likely use at least solid state ignition.

Are you saying it would be a waste for this block? You think it should be built as a racing motor as intended? Is it much more expensive to build a racing motor over regular motor?

Most of the parts I have are new old stock. Ended up with a lot of stuff, rods, pistons, rings, etc because when bought on ebay may have been a lot of 2 or 3 so ended up with a bunch of new parts for the old H50's. Also have new OEM float type carb, flange & gaskets so would like to use them. Will a setup like this work? I know have to get the blower housing with throttle setup etc., have the gov linkage.

Thanks again

 

[mustangfrank]

Advice well taken. Will most likely use at least solid state ignition.

Are you saying it would be a waste for this block? You think it should be built as a racing motor as intended? Is it much more expensive to build a racing motor over regular motor?

Most of the parts I have are new old stock. Ended up with a lot of stuff, rods, pistons, rings, etc because when bought on ebay may have been a lot of 2 or 3 so ended up with a bunch of new parts for the old H50's. Also have new OEM float type carb, flange & gaskets so would like to use them. Will a setup like this work? I know have to get the blower housing with throttle setup etc., have the gov linkage.

Thanks again

If you already have a NOS points crank/flywheel setup that makes sense, you can't mix and match. If you were starting from scratch it's definitely cheaper and easier to find the newer guts.

I went back and forth and ended up not buying any of the Motorsports H50s, for me it made more sense to rebuild the couple old H50s I had for originality and run HS50s on everything else. For the same money on the big bikes I went with new HM100s with billet rods and full alternator/lighting setups, they fit and weigh just about the same as the old H50s.

 

[markus]

Nothing there is Motorsports specific. Its just late model/last version H50/60 parts, The 4 holes on the block on the front are for a starter, the earlier blocks didn't always have them.

The motorsports sidecover, at least the last blue shroud versions, were not drilled, the earlier red ones may have been as some came with modified standard version carbs, and may have needed the pivot point to operate, but the later blue shrouds always came with tilly's so they had no type of throttle controls on the block so they left the sidecover unfinished, you better off with what you have there if you just going to build a stock type engine with what you have or you would be drilling a hole of the pivot arm. This one of the blue shroud H50's I had note arrow pointing to where the hole would be on a stock side cover.

 

[ole4]

Mine was drilled Markus, not sure of what vintage it was but it has the tilly HL-365B gas carb and stainless valves with alloy retainers and billet rod, hot coil ignition. This is not a great pic but you can see the holes in the pto side. Also it had a 1" rod journal .

 

[markus]

Mine was drilled Markus, not sure of what vintage it was but it has the tilly HL-365B gas carb and stainless valves with alloy retainers and billet rod, hot coil ignition. This is not a great pic but you can see the holes in the pto side. Also it had a 1" rod journal View attachment 279443 View attachment 279446 View attachment 279445 .

Did your fill it?.......cause the hole isn't there on yours in the bin:

 

[copyman]

Mine is drilled (see pic). So this means I can add a governor like my old H50 from the 1970's if i use older float type carb?

There is also a stud on inside of sump cover which assuming is for gov parts?

Another question, with that tapered crank I put in block, can I use a flywheel with external magnet for solid state ign?

Thanks again for all the great info

 

[ole4]

Markus, I was talking about the 4 holes to mount a clutch guard or TQ not the governor hole. That is what I thought you were referring to.

 

[mustangfrank]

Mine is drilled (see pic). So this means I can add a governor like my old H50 from the 1970's if i use older float type carb?

There is also a stud on inside of sump cover which assuming is for gov parts?

Another question, with that tapered crank I put in block, can I use a flywheel with external magnet for solid state ign?

Thanks again for all the great info

Yes, add away, it already had a governor or at least the pivot mounted at some point.

What is that crank, points or solid state? HS and HM cranks and flywheels cannot be intermixed as far as points or solid state, the diameter/taper is larger on the later cranks. I can only assume H cranks made the change too, I didn't have a later H external magnet flywheel in the shop to check. I've seen Tecumseh flywheel adapter sleeves floating around but never looked into applications...personally I wouldn't run one even if it is for this type of upgrade.

 

[copyman]

Yes, add away, it already had a governor or at least the pivot mounted at some point.

What is that crank, points or solid state? HS and HM cranks and flywheels cannot be intermixed as far as points or solid state, the diameter/taper is larger on the later cranks. I can only assume H cranks made the change too, I didn't have a later H external magnet flywheel in the shop to check. I've seen Tecumseh flywheel adapter sleeves floating around but never looked into applications...personally I wouldn't run one even if it is for this type of upgrade.

The crank I have is from an 1970 H50 with points / lightning coil from a Hilltopper so what are my options, points only? Was starting to like the idea of no timing headaches with using the solid state setup. The engine parts diagram show a bushing that goes on before FW, not sure if that is adapter you are talking about? The parts list provided by seller is for Motorsports SBH-9993 engine

Thanks again for help.

 

[mustangfrank]

The crank I have is from an 1970 H50 with points / lightning coil from a Hilltopper so what are my options, points only? Was starting to like the idea of no timing headaches with using the solid state setup. The engine parts diagram show a bushing that goes on before FW, not sure if that is adapter you are talking about? The parts list provided by seller is for Motorsports SBH-9993 engine

Thanks again for help.

I can't say 100%, I don't have a reference or later H flywheel to measure but I'm pretty sure they don't intermix like all the others. The flywheel/crankshaft adapter I mentioned is not listed on your engine parts list, I never researched them further after seeing them popup in my flywheel searches on eBay. I didn't like the looks of the stamped steel/keyway interface so I filed it away in a mental folder, search them out, might be an option if you're locked in to the conversion/update...or just find a newer crank.