Flathead valve spring cover questions
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Flathead valve spring cover questions
I’m just starting to gather parts for a 80ci Flathead build, I’ve got cases, pistons, cylinders, heads and a set of cams.
I’m an experienced amateur Ford and Porsche motor builder but new to Harley motors.
Here’s a couple questions I have:
Are the threaded 45” tappet guides interchangeable into the larger 80ci Flathead motors ?
Which valve spring covers are most oil tight ?
Which cam gear covers will work on the UL big twin motor ? Are there any I should avoid ?
Any and all advice is greatly appreciated,
Gary
I’m an experienced amateur Ford and Porsche motor builder but new to Harley motors.
Here’s a couple questions I have:
Are the threaded 45” tappet guides interchangeable into the larger 80ci Flathead motors ?
Which valve spring covers are most oil tight ?
Which cam gear covers will work on the UL big twin motor ? Are there any I should avoid ?
Any and all advice is greatly appreciated,
Gary
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From: Canada
Not a bad idea to invest in Bruce Palmers Harley restoration books, that'll tell you all of the minute details of the engine such as the covers.
As for the valve cover tubes (without knowing much) the threaded ones to me look better and look like they would do a better job sealing, you'll need threaded tappet blocks to do it. My 41 UH has the spring loaded design, wish it didn't.
The big twin is a bit of an odd ball which I found out first hand when I redid the wheels and rods. Finding a crank pin that wasn't too long or had the correct taper to get it to seat deep enough was a challenge. Then rod bearing clearance and side clearance was still throwing up a hurdle. Not many people offer bottom end stuff thats right.
edit: I bought a set of Andrews cams, much better lobe / ramp design than stock. Mine is ready to put together, just need to find the time. Im also reluctant to change the cam bushings in the cover and case due to lack of tooling to get the alignment right. It seems there's a lot more challenges building one right vs a panhead.
As for the valve cover tubes (without knowing much) the threaded ones to me look better and look like they would do a better job sealing, you'll need threaded tappet blocks to do it. My 41 UH has the spring loaded design, wish it didn't.
The big twin is a bit of an odd ball which I found out first hand when I redid the wheels and rods. Finding a crank pin that wasn't too long or had the correct taper to get it to seat deep enough was a challenge. Then rod bearing clearance and side clearance was still throwing up a hurdle. Not many people offer bottom end stuff thats right.
edit: I bought a set of Andrews cams, much better lobe / ramp design than stock. Mine is ready to put together, just need to find the time. Im also reluctant to change the cam bushings in the cover and case due to lack of tooling to get the alignment right. It seems there's a lot more challenges building one right vs a panhead.
Last edited by hellonewman; Jul 15, 2022 at 05:29 PM.
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From: SW WA.
You might want to contact http://www.jeffsamericanclassics.com/
This guy has an amazing amount of parts for all models of antique H-D bikes,I've been to his shop.
Parts won't be cheap but he'll have them and know what's what.
This guy has an amazing amount of parts for all models of antique H-D bikes,I've been to his shop.
Parts won't be cheap but he'll have them and know what's what.
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From: California
Thanks for the reply fellow Canadian, I was born in Toronto.
I have UL cases from W&W cycles out of Germany on order and a set of Andrews cams.
Here’s the same questions worded differently,
Can I use either the spring loaded or threaded tappet blocks if I buy the correct covers ?
Are all of the Flathead roller lifters the same dimensions?
Are covers for the 45” the same length as the 80” ?
I have UL cases from W&W cycles out of Germany on order and a set of Andrews cams.
Here’s the same questions worded differently,
Can I use either the spring loaded or threaded tappet blocks if I buy the correct covers ?
Are all of the Flathead roller lifters the same dimensions?
Are covers for the 45” the same length as the 80” ?
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From: Canada
I'll thumb through my book tonight about the cover, if someone chimes in before that with info great. The lifter blocks are the same 45 and 80, I would be surprised if the lifters were different. The 80" lifters should have large holes drilled in them.
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From the overwhelming amount of information I just breezed through on the side valve engines and my lack of desire to scour through it on a Friday night, there are three different types of gear covers for the 45 alone depending on the cams and there are a variety of them for the U engine. Doesn't say they interchange between engine families but they might. My guess is no they don't but I dont know (yet). The 45 covers all have the same casting number but differ in how they are machined so you need to know what you're looking at.
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From: Canada
I read more. Casting number for big twin side valve engines is 131-40 and the 45 cover is casting 131-372.
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From: California
I appreciate the effort, don’t waste your Friday night on this.
I need to understand how the oiling works on these Flatheads and if improvements came be made, oil control is one of the most
important aspects of building a long lasting reliable motor.
I need to understand how the oiling works on these Flatheads and if improvements came be made, oil control is one of the most
important aspects of building a long lasting reliable motor.
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From: Canada
What year cases are the W&W a copy of? I assume not the blind hole early crank journal version. With cylinder baffles or just one cylinder baffled like 41?