Double pumper carbs and bore wash?

[ian_uk1975]

Guys,

I'm looking to buy an AC Cobra replica with a Ford 351w. The engine spec includes Edelbrock Performer RPM intake and GT40 iron heads. Originally, the engine was supplied with a 600cfm vac secondary carb, but the current owner changed it for a 650cfm double pumper and this has me worried. Some guys on a Cobra replica forum have scared me with stories of premature bore wear with double pumper carbs due to overfuelling and bore wash. I must admit, when I went out in the car, the fumes from the sidepipes were quite heady and the car banged and popped on the overrun. The engine has covered a total of 11k miles, but I'm not sure how many of those were on the DP set-up (guesstimate around 7k-9k miles). There was no blue smoke from the exhaust and the owner claims it doesnt use a drop of oil. Also, the engine did feel very strong when he gunned it.

What do you think?

Cheers,
Ian.

[ian.stewart]

Hi, the bore wash thing is a set up on DPs is all about how the carb was set up in the first place, same as any carb, I would not put a set of webbers straight out the box and expect the carbs to be spot on, neither would the Holley to be spot on straight out of the box, generally they are reasonable how they come but will allways work better with a tune up, However dont expect the carb to be economical when you are giving it large, they are thirsty buggers
I think if you look at the carb thing from another point, Holley would not have produced Zillions of these carbs if they destroyed an engine every time they were sold,
Ian

[Lewis]

Give the oil a sniff, that'll tell you!

Sounds like a good purchase though, you could always revert to a 600 or get a rolling road to fine tune it (one that knows how to work with carbs) to prevent any overfuelling

[ian_uk1975]

If the car was running so rich as to be causing major bore wash, wouldn't it be evident in the way the engine runs? This engine seemed to run pretty sweetly and had no problem starting from cold or cruising at part throttle. I'll definitely take a sniff of the oil though.

Cheers,
Ian.

[kev_the_mole]

Hi (another) Ian,

I've got a double pumper on my Chev 350 and while I can't comment on bore wash it certainly doesn't help on tickover or when the engine is cold

Cheers,

Ian (another)