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 Posted: 07-09-2005 10:20 pm
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Joel
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Okay. I've had my car for about a week now. New tires on Mon or TUes - then I can start playing around with getting the oil changed and things dialed in a bit better. I have searched thru the forums and have a couple of questions that didn't get answered:

1) What weight oil does everyone run? I saw 20/50 somewhere. I was thinking that synthetic 20/50 might be the ticket - after I flush the motor w/ cheap stuff and some 'gunk'. I liked that idea from whomever posted it.

2) When I first start the car - until it warms up (10 minutes??) I hear a bit of what I would call a 'knock'. It seems to go away after the engine warms up. Oil pressure comes up fast and everything seems fine but this seems odd to me. I wonder if it is related to 3. . .

3) I think the carbs are way too rich. For several reasons. When you tromp on it - there is a little bit of a lag in the acceleration. This seems to go away after a little bit of driving at higher RPMS. I'm thinking too rich carbs are fouling the plugs and driving at the higher rpms is cleaning them off - ideas? The other thing is that there is a really really sweet smell of exhaust. Sitting in traffic you could possible aphixiate yourself. . .no holes in the exhaust that I can find. I think it's just burning too much gas . . .anyone agree?

4) Anyone here in San Diego want to help me screw around with the carbs?

The car is a 74. vin 18397 fitted with an 4 speed overdrive transmission and stombergs. I have an extra pair of dellortos (i think 40s) a five speed with rearend, and an extra head. When I get my garage built I'm considering getting a block and building another motor with the extra head, dellortos etc - but that's a ways off. Right now I just want to get this bad boy running right. Anyone know a good mechanic in San Diego that can help me with the stuff I might not either have the time to do myself or have problems with?

Thanks! The info on this site has been VERY VERY helpful already.

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 Posted: 07-10-2005 03:00 am
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Mark Rosenbaum
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Congratulations on buying a JH.  They're great cars.  If you have a 4-speed with overdrive, and it works, then my advice is, sell the 5-speed!

To comment on your questions:

1) Oil - 20W50 is correct whenever the average temp is above freezing, 10W40 below that.  One caution: the 'gunk' used when flushing an engine is a light solvent and is NOT the degreaser used on the outside of an engine!
     Synthetic oils are great on a fresh engine after it's been broken in, but some users report near-incurable leaks on well-used engines.  It's an expensive experiment if a quart of the stuff leaks out every 100 miles....

2) Knock at startup - could be piston slap, which is sort of normal, or it could be indicating a problem, but it's rather hard to tell without actually hearing the sounds.  If your oil pressure comes up within say 4 seconds after starting when the car's sat overnight since its last use, and if you have at least 5 psi pressure at idle even when fully warmed up, you're probably OK for the forseeable future.  A lot of funny noises go away after a few hundred miles and an oil change.

3) Carburetion - if the exhaust smells 'sweet' you probably are running too rich.  If you don't have a CO meter handy, the quickest way to determine this would be to take the car to your friendly local smog test station, have them do a 'pre-test', and see what your numbers are -- if the HC is within Calif. spec and the CO is fairly low, then look elsewhere.
     Strombergs do have an inherent slight (fractional-second) lag between stomp-throttle and car-go, but it's not much worse than with Del'lortos, and you learn to compensate for this.  Mostly by keeping the engine speed above 3500 rpm.

4) Not in San Diego so can't help you there.  However, there are lots of JH owners in southern Calif., and perhaps one of them knows of a good Brit-car mechanic.

Good luck with your car.

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 Posted: 07-10-2005 03:28 am
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Joel
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thanks for the comments mark.

i've heard the same thing about synthetics on an older engine - mebbe I should thing again about using it. . .

and i was using 'gunk' metaphorically :-)

the carb issue is more than just a bit of hesitation on hard acceleration under 3500-4000 rpms. it's more of a burble and stumble before it catches. again - makes me think it's too rich.

i need to look at the books on the carbs. . .

i was told that with more hp the overdrive tranny wouldn't handle it. but, i don't need to worry about that right now. i can burn that bridge when i come to it.

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 Posted: 07-10-2005 04:06 am
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Mark Rosenbaum
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Ah, metaphors... but I'd rather belabor the obvious than have someone ruin an engine due to a misunderstanding.

Strombergs are pretty easy to deal with.  There's a four-part article on rebuilding them, which I wrote, printed in the March to June issues of the JHPS magazine, and this may be of some benefit to you.  If you don't have access to these issues, there may still be a version of this article in the old JHPS archives, and there's a lot of useful stuff online, particularly in association with Volvos. 

Don't know for sure what the HP limit of the overdrive is, but I'd guess it's around 150 to 165 HP.  A lot depends on how you're going to use the car.  I do think the overdrive would be invaluable if you're planning on lots of freeway miles.  For really ambitious driving, though, something with available spares might be a more prudent choice.  As the Getrag 5-speed is said to shift rather slowly, and is also spares-limited, you might want to investigate the tranny conversions from New Zealand (see the JHPS boutique for details).

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 Posted: 07-10-2005 05:37 am
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Joel
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truth be known - the toyota conversion is my favorite option if I have the $$ when I do it.

i just joined jhps so i should be able to view the archives. are they searchable?

Last edited on 07-10-2005 05:38 am by Joel

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 Posted: 07-10-2005 02:56 pm
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Mark Rosenbaum
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The stuff in the 'Garage' is just sort of there and probably isn't searchable in any meaningful fashion.  A lot of the older magazines have been converted to PDF format but there's about a two-year backlog yet to be processed.  The old message board at
http://www.jensenhealey.com/msgboard.mv?parm_func=showmain 
is what I was referring to -- and yes, the word 'archive' does tend to be confusing in this case, so I should have been more exact in my terminology.

While the old message board does have a search function, it's sort of brain-dead and about the only way I've found to use it at all effectively is to use single keywords for items in the 'subject' line.  It won't search the text of posts at all.  That said, there's a wealth of useful information there, if you have the time to winnow it out.

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