11 replies to this topic

[Dave6179]

G'day, I'm about to swap the YT head on the 202. The current head has the big plugs -  Bosch WR8DC+. They won't fit the new late 173 YT head which takes the small plugs. The only other one I can find to suit is the Champion OE050, equal to the Bosch HR5DC. I've checked the google but haven't been able to get a match, including perusing the Angelsumthinorother site.... 4 times. 

I also checked two of SCA's books on thier counter, asked a few questions, no luck.

The 202 has the Bosch HEI with Taylor leads, the new head will give me 10:1 comp as is but I'll probably have it skimmed just a lil bit more.

Anyone have ideas?

[dattoman]

BPR6EFS-13 NGK

[rexy]

Why don't you ring NGKs technical help number? I have always found them very helpful.

[Dave6179]

BPR6EFS-13 NGK

Hmm, I have a set of BPR5EFS-13's from the VN V6. They protrude into the combustion chamber 1/4 inch from the thread. Will they do the trick? I'm thinking of going to a colder plug for more oomph.

[Dr Terry]

If the plugs are too long then you don't have a 'late' 173. It sounds like a HQ-HZ 173 red head. The NGK plug for those is a BP5ES.

 

EH-HG use the 3/4"long spark plug with a washer. HQ-HZ use the 1/2" long (small) plug with the tapered seat & WB/VC onwards (blue/black) 6-cyls use the 3/4" long plugs with a tapered seat.

 

Dr Terry

[Dave6179]

This head has 'rectangular flat spots' above the zorst ports. The number comes back to a late 173, with fixed rocker gear. There are 'dimples' in the roof of the port just inside the manifold face. The VN plugs I threw in are 1/4 inch too long, are they 'std', or is there another one I should look at?

[Dr Terry]

Did you read my post ?

 

You have a HQ-HJ head, is its casting no. 2811930 ?

 

The VN plugs will be too long, they are the same length as the Blue/Black ones.

 

Use BP5ES, they are only 1/2"long, not 3/4".

 

Dr Terry

[Dave6179]

Yes I did read it. The number is 9937263 2940 7 H. Make any sense?

[Dr Terry]

Yep, no problems.

 

That head is an LX/UC/VB 173/2850 Red head (1976-1980).

 

It uses the same BP5ES spark plugs as the HQ/HJ red head.

 

Dr Terry

[Dave6179]

Sweet, thanks! I still have my HJ's original 173 engine (not really sure why?) and the head is definately not the same on the outside, just a nice radius.

Oh, BP5ES suitable for the HEI's large gap?

[Dr Terry]

Sweet, thanks! I still have my HJ's original 173 engine (not really sure why?) and the head is definately not the same on the outside, just a nice radius.

Oh, BP5ES suitable for the HEI's large gap?

Yes, NKG do a BP5ES-11 (1.1mm gap) & a BP5ES-13 (1.3mm gap).

 

Use the -13 ones. I always gap spark plugs to 1.3mm for Bosch HEI.

 

Dr Terry

[Dave6179]

Thanks! Always easier/quicker asking rather than spending days surfing and not finding what you want.