Assistance with spark plug replacement

[Donewright]

Greetings,

I just acquired my first VW! It's a 1969 Beetle frame with a Sand Shark Dune Buggy body. I'm wanting to replace the spark plugs as part of my initial tune up.

What I know:

The number on the case is H 5692424 which I believe should be a 1500cc Single Port.

The previous owner indicated that the engine had an L88 kit installed. I am unable to find anything VW related to an L88 kit.

The engine currently has a 34PIC T-3 carb and is Dual Port.

When I looked up what plugs a 1969 beetle used, it indicates that they are Bosch WR8AC.

I removed a plug from #4 cylinder and it is a Champion RA6HC

The WR8AC does not look like the RA6HC

So I assume that heads have been replaced and a different spark plug is required.

Cross referencing to the RA6HC seems to show the following:

NGK DCPR8E, DCPR8EIX, DPR8EA-9

Bosch 7409, 7416, 7700, 7701, X4C, X5DC, XR2CS, XR4CS, XR5DC, Y6DC

DENSO X24EPRU9, X24EPRZU9, X24EPU9, X24EPZU9, X24ESRU, X24ESU, X24ESZU, X24EU


It would awesome if I can get an experienced opinion from you all on what you would use? (I'll just be driving on streets around town)

Thank you in advance for any insight!

[67rustavenger]

Some of your cross references are not quite matching. Some are for 12mm threads and others are for 14mm thread diameters.

What is the thread diameter for the Champion plugs you currently have in the engine?
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[Dale M.]

Lot to know about your RA6HC...

https://www.drivparts.com/part-details.html?brand_...me=%7B2%7D
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[Donewright]

Thanks for the replies,

The link Dale provided for the RA6HC shows: Thread Diameter (MM) 12.000

I suppose I could simply replace with Champion, but I've not seen a lot of good reviews. Mostly see folks praising the Bosch, NGK and Denso.

[DesertSasquatchXploration]

PO did new style heads that's great you have a better chamber and it uses stronger plugs,

You want,
NGK D6EA Peanut Plugs (3/4" Reach 12mm Hole)

If you do in-fact have the 12MM thread plugs you must have Big valve heads not sure why the PO did those with a stock carb that's weird.
_________________
Key is to have downward travel Preload keep both wheels on the ground at all times once you lift a tire your DONE. Guys worry about clearance instead think of the opposite you want the suspension to drop that tire in the hole and keep you going. A spider for example they keep their body low but their legs can reach pretty far so they don't (bottom out)

[Donewright]

Thank you for the recommendation!!

Im not familiar with all that has been done to the engine. I’ve only had it for a couple days. ive ordered the suggested manuals and will have a great time learning.

[DesertSasquatchXploration]

Here your L88 Kit. I would do a compression test. Hopefully its at the 135 150Psi range if so you have a nice little engine. Congrats

https://aapistons.com/products/88x69mm-1700cc-machine-in-85-5-case-90-5-head
_________________
Key is to have downward travel Preload keep both wheels on the ground at all times once you lift a tire your DONE. Guys worry about clearance instead think of the opposite you want the suspension to drop that tire in the hole and keep you going. A spider for example they keep their body low but their legs can reach pretty far so they don't (bottom out)

[rayjay]

When you take off the valve covers to adjust the valves you should find some identifying markings under the rocker arms. You also have a smaller diameter 'power pulley' that reduces the cooling of the engine which may or may not matter much on a lightweight buggy.

[Donewright]

thank you for the additional information. i did purchase a compression tester yesterday. ill be sure to check the compression.

ill also look for any numbers when i remove the valve covers.

[Dusty1]

L88 is a Chevy engine package. It's a 427 V8 originally an option in '67 to '69 Corvette.

.
.

[johnnyvw164]

Why would you have big valves if the plugs are 12mm? I have two sets of heads with standard size valves that have 12mm plugs....

[RWK]

Think L88 A is a Champion spark plug for VWs I remember getting them last century!
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[DesertSasquatchXploration]

The heads could be real VW heads with a 12mm sure but they look shinny like the new china units.

I'm not aware of any complete new stock size dual port china heads that use a 12mm thread. 14mm 3/4 reach yes but not 12mm. AA makes a bare head with 12MM plugs but i doubt the PO would do all that work. Put a stock carb on and sell it when stock valve heads with 14mm plugs are available to bolt on.

Possibly Donewright could take a closer pic of the heads they could be used rebuilt. Like Rayjay said need to pop off the valve covers and see
_________________
Key is to have downward travel Preload keep both wheels on the ground at all times once you lift a tire your DONE. Guys worry about clearance instead think of the opposite you want the suspension to drop that tire in the hole and keep you going. A spider for example they keep their body low but their legs can reach pretty far so they don't (bottom out)

[Donewright]

Update:

I replaced the Champion plugs with the recommended NGK D6EA plugs.

The engine started right up! The engine sounds good and seems to be really really smooth when I give it gas. Idle is a little rough, i mean it sounds ok, but the engine "bounces clockwise and counterclockwise". I'm not sure that is a good term, but it describes what I see. It does not die at idle and picks up and smooths out as soon as I hit the throttle.

I was able to check the compression and it looks like it is about 120 on each cylinder.

I sure appreciate the plug recommendation and will continue to learn

[rayjay]

You should raise the buggy up on jack stands and look at the transmission mounts. Stock ones are bonded rubber on steel and come apart eventually allowing the motor to move around more. And don't use the engine or transmission as a jacking point !! This will definitely cause premature failure of the transmission mounts.

[Donewright]

Thanks, i sure will check the mounts !

[Schepp]

We're not sure of your mechanical abilities, some back ground would help.
Do you own a caliper for taking measurements? If not, buy yourself a cheap digital one. It'll help answer a lot of your questions in regards to the size of things, like the spark plug size. The threads of a 12mm plug will be close to 12mm in diameter.
Metric bolt sizing is also easy with calipers. Example: M8 bolts are about 8mm thread diameter, etc.
It does take some practice to use them. Watch a video on how to use them.
Digital calipers have a button to switch from metric to inches so you don't have to do the math.
Just don't use it as a hammer, center-punch or c-clamp.
Back scratching is ok.

Post pics, detailed ones. Of everything in question, along with any part numbers you can find on said part in question.
Some of these Samba members have been in the VW scene for longer than I've been alive!

Dune buggies are super cool! Congrats on the new ride!

[Donewright]

Greetings Schepp.

Thanks for the tip. I do have calipers, I just didn't realize that there could be two different diameters of plug threads. I do know that now thanks to this group. I have also recently acquired the Bentley Manual and the book by John Muir.

This post has gone a bit off topic and I can create a new post if you prefer.

I found a chart from JMR which gives you Engine Displacement. I measured the Stroke of the #4 piston from TDC to BDC. Using my calipers, it measured 76.01mm. So if the engine builder did use 88mm pistons then according to the chart, that would be 1849cc

i do need to perform a better compression test, my initial results on 1 and 2 showed about 120. But I was running back and forth to the ignition key to turn the engine over.

I did examine the valves this morning and the #2 and #4 exhaust was over .024 !! Some were .009 so I adjust all 8 valves down to as close as I could to .006

I have replaced the plugs, plug wires, Engine Oil, Transfer Case Oil. The old plugs were dry black (not oil covered). The distributer looks like an 009 that has already had the points replaced with an electronic module. The car drove, but there was a stumble when starting to accelerate into the next gear. It was overcome by giving it more throttle.

I also covered the Heat Risers with blanks to block them off.

It's still early here in my neighborhood, so I can't start it up yet. I'm just hoping I have done no harm

You all have been quite generous with your information and it is greatly appreciated.

[DesertSasquatchXploration]

Good work and without issues

The flat spot is the most common issue. Get ready to get bombarded with opinions and much controversy. Once you sort thru the facts and crap the issue is very easy to understand and fix. Lots are hindered greatly by their own stubbornness and not looking at the Whole picture. Instead just blaming one thing like the carb or distributor when its a collection of issues.
_________________
Key is to have downward travel Preload keep both wheels on the ground at all times once you lift a tire your DONE. Guys worry about clearance instead think of the opposite you want the suspension to drop that tire in the hole and keep you going. A spider for example they keep their body low but their legs can reach pretty far so they don't (bottom out)